use crate::auth::validate::{
    get_full_user_from_headers, get_user_record_from_bearer_token,
};
use crate::auth::{AuthProvider, AuthenticationError, get_user_from_headers};
use crate::database::models::DBUser;
use crate::database::models::flow_item::DBFlow;
use crate::database::models::notification_item::NotificationBuilder;
use crate::database::redis::RedisPool;
use crate::file_hosting::{FileHost, FileHostPublicity};
use crate::models::notifications::NotificationBody;
use crate::models::pats::Scopes;
use crate::models::users::{Badges, Role};
use crate::queue::email::EmailQueue;
use crate::queue::session::AuthQueue;
use crate::routes::ApiError;
use crate::routes::internal::session::issue_session;
use crate::util::captcha::check_hcaptcha;
use crate::util::env::parse_strings_from_var;
use crate::util::ext::get_image_ext;
use crate::util::img::upload_image_optimized;
use crate::util::validate::validation_errors_to_string;
use actix_web::web::{Data, Query, ServiceConfig, scope};
use actix_web::{HttpRequest, HttpResponse, delete, get, patch, post, web};
use argon2::password_hash::SaltString;
use argon2::{Argon2, PasswordHash, PasswordHasher, PasswordVerifier};
use ariadne::ids::base62_impl::{parse_base62, to_base62};
use ariadne::ids::random_base62_rng;
use base64::Engine;
use chrono::{Duration, Utc};
use lettre::message::Mailbox;
use rand_chacha::ChaCha20Rng;
use rand_chacha::rand_core::SeedableRng;
use reqwest::header::AUTHORIZATION;
use serde::{Deserialize, Serialize};
use sqlx::postgres::PgPool;
use std::collections::HashMap;
use std::str::FromStr;
use std::sync::Arc;
use validator::Validate;
use zxcvbn::Score;

pub fn config(cfg: &mut ServiceConfig) {
    cfg.service(
        scope("auth")
            .service(init)
            .service(auth_callback)
            .service(delete_auth_provider)
            .service(create_account_with_password)
            .service(login_password)
            .service(login_2fa)
            .service(begin_2fa_flow)
            .service(finish_2fa_flow)
            .service(remove_2fa)
            .service(reset_password_begin)
            .service(change_password)
            .service(resend_verify_email)
            .service(set_email)
            .service(verify_email)
            .service(subscribe_newsletter)
            .service(get_newsletter_subscription_status),
    );
}

#[derive(Debug)]
pub struct TempUser {
    pub id: String,
    pub username: String,
    pub email: Option<String>,

    pub avatar_url: Option<String>,
    pub bio: Option<String>,

    pub country: Option<String>,
}

impl TempUser {
    async fn create_account(
        self,
        provider: AuthProvider,
        transaction: &mut sqlx::Transaction<'_, sqlx::Postgres>,
        client: &PgPool,
        file_host: &Arc<dyn FileHost + Send + Sync>,
        redis: &RedisPool,
    ) -> Result<crate::database::models::DBUserId, AuthenticationError> {
        if let Some(email) = &self.email
            && crate::database::models::DBUser::get_by_email(email, client)
                .await?
                .is_some()
        {
            return Err(AuthenticationError::DuplicateUser);
        }

        let user_id =
            crate::database::models::generate_user_id(transaction).await?;

        let mut username_increment: i32 = 0;
        let mut username = None;

        while username.is_none() {
            let test_username = format!(
                "{}{}",
                self.username,
                if username_increment > 0 {
                    username_increment.to_string()
                } else {
                    "".to_string()
                }
            );

            let new_id = crate::database::models::DBUser::get(
                &test_username,
                client,
                redis,
            )
            .await?;

            if new_id.is_none() {
                username = Some(test_username);
            } else {
                username_increment += 1;
            }
        }

        let (avatar_url, raw_avatar_url) = if let Some(avatar_url) =
            self.avatar_url
        {
            let res = reqwest::get(&avatar_url).await?;
            let headers = res.headers().clone();

            let img_data = if let Some(content_type) = headers
                .get(reqwest::header::CONTENT_TYPE)
                .and_then(|ct| ct.to_str().ok())
            {
                get_image_ext(content_type)
            } else {
                avatar_url.rsplit('.').next()
            };

            if let Some(ext) = img_data {
                let bytes = res.bytes().await?;

                let upload_result = upload_image_optimized(
                    &format!("user/{}", ariadne::ids::UserId::from(user_id)),
                    FileHostPublicity::Public,
                    bytes,
                    ext,
                    Some(96),
                    Some(1.0),
                    &**file_host,
                )
                .await;

                if let Ok(upload_result) = upload_result {
                    (Some(upload_result.url), Some(upload_result.raw_url))
                } else {
                    (None, None)
                }
            } else {
                (None, None)
            }
        } else {
            (None, None)
        };

        if let Some(username) = username {
            crate::database::models::DBUser {
                id: user_id,
                github_id: if provider == AuthProvider::GitHub {
                    Some(
                        self.id.clone().parse().map_err(|_| {
                            AuthenticationError::InvalidCredentials
                        })?,
                    )
                } else {
                    None
                },
                discord_id: if provider == AuthProvider::Discord {
                    Some(
                        self.id.parse().map_err(|_| {
                            AuthenticationError::InvalidCredentials
                        })?,
                    )
                } else {
                    None
                },
                gitlab_id: if provider == AuthProvider::GitLab {
                    Some(
                        self.id.parse().map_err(|_| {
                            AuthenticationError::InvalidCredentials
                        })?,
                    )
                } else {
                    None
                },
                google_id: if provider == AuthProvider::Google {
                    Some(self.id.clone())
                } else {
                    None
                },
                steam_id: if provider == AuthProvider::Steam {
                    Some(
                        self.id.parse().map_err(|_| {
                            AuthenticationError::InvalidCredentials
                        })?,
                    )
                } else {
                    None
                },
                microsoft_id: if provider == AuthProvider::Microsoft {
                    Some(self.id.clone())
                } else {
                    None
                },
                password: None,
                paypal_id: if provider == AuthProvider::PayPal {
                    Some(self.id)
                } else {
                    None
                },
                paypal_country: self.country,
                paypal_email: if provider == AuthProvider::PayPal {
                    self.email.clone()
                } else {
                    None
                },
                venmo_handle: None,
                stripe_customer_id: None,
                totp_secret: None,
                username,
                email: self.email.clone(),
                email_verified: self.email.is_some(),
                avatar_url,
                raw_avatar_url,
                bio: self.bio,
                created: Utc::now(),
                role: Role::Developer.to_string(),
                badges: Badges::default(),
                allow_friend_requests: true,
                is_subscribed_to_newsletter: false,
            }
            .insert(transaction)
            .await?;

            Ok(user_id)
        } else {
            Err(AuthenticationError::InvalidCredentials)
        }
    }
}

impl AuthProvider {
    pub fn get_redirect_url(
        &self,
        state: String,
    ) -> Result<String, AuthenticationError> {
        let self_addr = dotenvy::var("SELF_ADDR")?;
        let raw_redirect_uri = format!("{self_addr}/v2/auth/callback");
        let redirect_uri = urlencoding::encode(&raw_redirect_uri);

        Ok(match self {
            AuthProvider::GitHub => {
                let client_id = dotenvy::var("GITHUB_CLIENT_ID")?;

                format!(
                    "https://github.com/login/oauth/authorize?client_id={client_id}&prompt=select_account&state={state}&scope=read%3Auser%20user%3Aemail&redirect_uri={redirect_uri}",
                )
            }
            AuthProvider::Discord => {
                let client_id = dotenvy::var("DISCORD_CLIENT_ID")?;

                format!(
                    "https://discord.com/api/oauth2/authorize?client_id={client_id}&state={state}&response_type=code&scope=identify%20email&redirect_uri={redirect_uri}"
                )
            }
            AuthProvider::Microsoft => {
                let client_id = dotenvy::var("MICROSOFT_CLIENT_ID")?;

                format!(
                    "https://login.live.com/oauth20_authorize.srf?client_id={client_id}&response_type=code&scope=user.read&state={state}&prompt=select_account&redirect_uri={redirect_uri}"
                )
            }
            AuthProvider::GitLab => {
                let client_id = dotenvy::var("GITLAB_CLIENT_ID")?;

                format!(
                    "https://gitlab.com/oauth/authorize?client_id={client_id}&state={state}&scope=read_user+profile+email&response_type=code&redirect_uri={redirect_uri}",
                )
            }
            AuthProvider::Google => {
                let client_id = dotenvy::var("GOOGLE_CLIENT_ID")?;

                format!(
                    "https://accounts.google.com/o/oauth2/v2/auth?client_id={}&state={}&scope={}&response_type=code&redirect_uri={}",
                    client_id,
                    state,
                    urlencoding::encode(
                        "https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/userinfo.profile"
                    ),
                    redirect_uri,
                )
            }
            AuthProvider::Steam => {
                format!(
                    "https://steamcommunity.com/openid/login?openid.ns={}&openid.mode={}&openid.return_to={}{}{}&openid.realm={}&openid.identity={}&openid.claimed_id={}",
                    urlencoding::encode("http://specs.openid.net/auth/2.0"),
                    "checkid_setup",
                    redirect_uri,
                    urlencoding::encode("?state="),
                    state,
                    self_addr,
                    "http://specs.openid.net/auth/2.0/identifier_select",
                    "http://specs.openid.net/auth/2.0/identifier_select",
                )
            }
            AuthProvider::PayPal => {
                let api_url = dotenvy::var("PAYPAL_API_URL")?;
                let client_id = dotenvy::var("PAYPAL_CLIENT_ID")?;

                let auth_url = if api_url.contains("sandbox") {
                    "sandbox.paypal.com"
                } else {
                    "paypal.com"
                };

                format!(
                    "https://{auth_url}/connect?flowEntry=static&client_id={client_id}&scope={}&response_type=code&redirect_uri={redirect_uri}&state={state}",
                    urlencoding::encode(
                        "openid email address https://uri.paypal.com/services/paypalattributes"
                    ),
                )
            }
        })
    }

    pub async fn get_token(
        &self,
        query: HashMap<String, String>,
    ) -> Result<String, AuthenticationError> {
        let redirect_uri =
            format!("{}/v2/auth/callback", dotenvy::var("SELF_ADDR")?);

        #[derive(Deserialize)]
        struct AccessToken {
            pub access_token: String,
        }

        let res = match self {
            AuthProvider::GitHub => {
                let code = query
                    .get("code")
                    .ok_or_else(|| AuthenticationError::InvalidCredentials)?;
                let client_id = dotenvy::var("GITHUB_CLIENT_ID")?;
                let client_secret = dotenvy::var("GITHUB_CLIENT_SECRET")?;

                let url = format!(
                    "https://github.com/login/oauth/access_token?client_id={client_id}&client_secret={client_secret}&code={code}&redirect_uri={redirect_uri}"
                );

                let token: AccessToken = reqwest::Client::new()
                    .post(&url)
                    .header(reqwest::header::ACCEPT, "application/json")
                    .send()
                    .await?
                    .json()
                    .await?;

                token.access_token
            }
            AuthProvider::Discord => {
                let code = query
                    .get("code")
                    .ok_or_else(|| AuthenticationError::InvalidCredentials)?;
                let client_id = dotenvy::var("DISCORD_CLIENT_ID")?;
                let client_secret = dotenvy::var("DISCORD_CLIENT_SECRET")?;

                let mut map = HashMap::new();
                map.insert("client_id", &*client_id);
                map.insert("client_secret", &*client_secret);
                map.insert("code", code);
                map.insert("grant_type", "authorization_code");
                map.insert("redirect_uri", &redirect_uri);

                let token: AccessToken = reqwest::Client::new()
                    .post("https://discord.com/api/v10/oauth2/token")
                    .header(reqwest::header::ACCEPT, "application/json")
                    .form(&map)
                    .send()
                    .await?
                    .json()
                    .await?;

                token.access_token
            }
            AuthProvider::Microsoft => {
                let code = query
                    .get("code")
                    .ok_or_else(|| AuthenticationError::InvalidCredentials)?;
                let client_id = dotenvy::var("MICROSOFT_CLIENT_ID")?;
                let client_secret = dotenvy::var("MICROSOFT_CLIENT_SECRET")?;

                let mut map = HashMap::new();
                map.insert("client_id", &*client_id);
                map.insert("client_secret", &*client_secret);
                map.insert("code", code);
                map.insert("grant_type", "authorization_code");
                map.insert("redirect_uri", &redirect_uri);

                let token: AccessToken = reqwest::Client::new()
                    .post("https://login.live.com/oauth20_token.srf")
                    .header(reqwest::header::ACCEPT, "application/json")
                    .form(&map)
                    .send()
                    .await?
                    .json()
                    .await?;

                token.access_token
            }
            AuthProvider::GitLab => {
                let code = query
                    .get("code")
                    .ok_or_else(|| AuthenticationError::InvalidCredentials)?;
                let client_id = dotenvy::var("GITLAB_CLIENT_ID")?;
                let client_secret = dotenvy::var("GITLAB_CLIENT_SECRET")?;

                let mut map = HashMap::new();
                map.insert("client_id", &*client_id);
                map.insert("client_secret", &*client_secret);
                map.insert("code", code);
                map.insert("grant_type", "authorization_code");
                map.insert("redirect_uri", &redirect_uri);

                let token: AccessToken = reqwest::Client::new()
                    .post("https://gitlab.com/oauth/token")
                    .header(reqwest::header::ACCEPT, "application/json")
                    .form(&map)
                    .send()
                    .await?
                    .json()
                    .await?;

                token.access_token
            }
            AuthProvider::Google => {
                let code = query
                    .get("code")
                    .ok_or_else(|| AuthenticationError::InvalidCredentials)?;
                let client_id = dotenvy::var("GOOGLE_CLIENT_ID")?;
                let client_secret = dotenvy::var("GOOGLE_CLIENT_SECRET")?;

                let mut map = HashMap::new();
                map.insert("client_id", &*client_id);
                map.insert("client_secret", &*client_secret);
                map.insert("code", code);
                map.insert("grant_type", "authorization_code");
                map.insert("redirect_uri", &redirect_uri);

                let token: AccessToken = reqwest::Client::new()
                    .post("https://oauth2.googleapis.com/token")
                    .header(reqwest::header::ACCEPT, "application/json")
                    .form(&map)
                    .send()
                    .await?
                    .json()
                    .await?;

                token.access_token
            }
            AuthProvider::Steam => {
                let mut form = HashMap::new();

                let signed = query
                    .get("openid.signed")
                    .ok_or_else(|| AuthenticationError::InvalidCredentials)?;
                form.insert(
                    "openid.assoc_handle".to_string(),
                    &**query.get("openid.assoc_handle").ok_or_else(|| {
                        AuthenticationError::InvalidCredentials
                    })?,
                );
                form.insert("openid.signed".to_string(), &**signed);
                form.insert(
                    "openid.sig".to_string(),
                    &**query.get("openid.sig").ok_or_else(|| {
                        AuthenticationError::InvalidCredentials
                    })?,
                );
                form.insert(
                    "openid.ns".to_string(),
                    "http://specs.openid.net/auth/2.0",
                );
                form.insert("openid.mode".to_string(), "check_authentication");

                for val in signed.split(',') {
                    if let Some(arr_val) = query.get(&format!("openid.{val}")) {
                        form.insert(format!("openid.{val}"), &**arr_val);
                    }
                }

                let res = reqwest::Client::new()
                    .post("https://steamcommunity.com/openid/login")
                    .header("Accept-language", "en")
                    .form(&form)
                    .send()
                    .await?
                    .text()
                    .await?;

                if res.contains("is_valid:true") {
                    let identity =
                        query.get("openid.identity").ok_or_else(|| {
                            AuthenticationError::InvalidCredentials
                        })?;

                    identity
                        .rsplit('/')
                        .next()
                        .ok_or_else(|| AuthenticationError::InvalidCredentials)?
                        .to_string()
                } else {
                    return Err(AuthenticationError::InvalidCredentials);
                }
            }
            AuthProvider::PayPal => {
                let code = query
                    .get("code")
                    .ok_or_else(|| AuthenticationError::InvalidCredentials)?;
                let api_url = dotenvy::var("PAYPAL_API_URL")?;
                let client_id = dotenvy::var("PAYPAL_CLIENT_ID")?;
                let client_secret = dotenvy::var("PAYPAL_CLIENT_SECRET")?;

                let mut map = HashMap::new();
                map.insert("code", code.as_str());
                map.insert("grant_type", "authorization_code");

                let token: AccessToken = reqwest::Client::new()
                    .post(format!("{api_url}oauth2/token"))
                    .header(reqwest::header::ACCEPT, "application/json")
                    .header(
                        AUTHORIZATION,
                        format!(
                            "Basic {}",
                            base64::engine::general_purpose::STANDARD
                                .encode(format!("{client_id}:{client_secret}"))
                        ),
                    )
                    .form(&map)
                    .send()
                    .await?
                    .json()
                    .await?;

                token.access_token
            }
        };

        Ok(res)
    }

    pub async fn get_user(
        &self,
        token: &str,
    ) -> Result<TempUser, AuthenticationError> {
        let res = match self {
            AuthProvider::GitHub => {
                let response = reqwest::Client::new()
                    .get("https://api.github.com/user")
                    .header(reqwest::header::USER_AGENT, "Modrinth")
                    .header(AUTHORIZATION, format!("token {token}"))
                    .send()
                    .await?;

                if token.starts_with("gho_") {
                    let client_id = response
                        .headers()
                        .get("x-oauth-client-id")
                        .and_then(|x| x.to_str().ok());

                    if client_id
                        != Some(&*dotenvy::var("GITHUB_CLIENT_ID").unwrap())
                    {
                        return Err(AuthenticationError::InvalidClientId);
                    }
                }

                #[derive(Serialize, Deserialize, Debug)]
                pub struct GitHubUser {
                    pub login: String,
                    pub id: u64,
                    pub avatar_url: String,
                    pub name: Option<String>,
                    pub email: Option<String>,
                    pub bio: Option<String>,
                }

                let github_user: GitHubUser = response.json().await?;

                TempUser {
                    id: github_user.id.to_string(),
                    username: github_user.login,
                    email: github_user.email,
                    avatar_url: Some(github_user.avatar_url),
                    bio: github_user.bio,
                    country: None,
                }
            }
            AuthProvider::Discord => {
                #[derive(Serialize, Deserialize, Debug)]
                pub struct DiscordUser {
                    pub username: String,
                    pub id: String,
                    pub avatar: Option<String>,
                    pub global_name: Option<String>,
                    pub email: Option<String>,
                }

                let discord_user: DiscordUser = reqwest::Client::new()
                    .get("https://discord.com/api/v10/users/@me")
                    .header(reqwest::header::USER_AGENT, "Modrinth")
                    .header(AUTHORIZATION, format!("Bearer {token}"))
                    .send()
                    .await?
                    .json()
                    .await?;

                let id = discord_user.id.clone();
                TempUser {
                    id: discord_user.id,
                    username: discord_user.username,
                    email: discord_user.email,
                    avatar_url: discord_user.avatar.map(|x| {
                        format!(
                            "https://cdn.discordapp.com/avatars/{id}/{x}.webp"
                        )
                    }),
                    bio: None,
                    country: None,
                }
            }
            AuthProvider::Microsoft => {
                #[derive(Deserialize, Debug)]
                #[serde(rename_all = "camelCase")]
                pub struct MicrosoftUser {
                    pub id: String,
                    pub mail: Option<String>,
                    pub user_principal_name: String,
                }

                let microsoft_user: MicrosoftUser = reqwest::Client::new()
                    .get("https://graph.microsoft.com/v1.0/me?$select=id,displayName,mail,userPrincipalName")
                    .header(reqwest::header::USER_AGENT, "Modrinth")
                    .header(AUTHORIZATION, format!("Bearer {token}"))
                    .send()
                    .await?.json().await?;

                TempUser {
                    id: microsoft_user.id,
                    username: microsoft_user
                        .user_principal_name
                        .split('@')
                        .next()
                        .unwrap_or_default()
                        .to_string(),
                    email: microsoft_user.mail,
                    avatar_url: None,
                    bio: None,
                    country: None,
                }
            }
            AuthProvider::GitLab => {
                #[derive(Serialize, Deserialize, Debug)]
                pub struct GitLabUser {
                    pub id: i32,
                    pub username: String,
                    pub email: Option<String>,
                    pub avatar_url: Option<String>,
                    pub name: Option<String>,
                    pub bio: Option<String>,
                }

                let gitlab_user: GitLabUser = reqwest::Client::new()
                    .get("https://gitlab.com/api/v4/user")
                    .header(reqwest::header::USER_AGENT, "Modrinth")
                    .header(AUTHORIZATION, format!("Bearer {token}"))
                    .send()
                    .await?
                    .json()
                    .await?;

                TempUser {
                    id: gitlab_user.id.to_string(),
                    username: gitlab_user.username,
                    email: gitlab_user.email,
                    avatar_url: gitlab_user.avatar_url,
                    bio: gitlab_user.bio,
                    country: None,
                }
            }
            AuthProvider::Google => {
                #[derive(Deserialize, Debug)]
                pub struct GoogleUser {
                    pub id: String,
                    pub email: String,
                    pub picture: Option<String>,
                }

                let google_user: GoogleUser = reqwest::Client::new()
                    .get("https://www.googleapis.com/userinfo/v2/me")
                    .header(reqwest::header::USER_AGENT, "Modrinth")
                    .header(AUTHORIZATION, format!("Bearer {token}"))
                    .send()
                    .await?
                    .json()
                    .await?;

                TempUser {
                    id: google_user.id,
                    username: google_user
                        .email
                        .split('@')
                        .next()
                        .unwrap_or_default()
                        .to_string(),
                    email: Some(google_user.email),
                    avatar_url: google_user.picture,
                    bio: None,
                    country: None,
                }
            }
            AuthProvider::Steam => {
                let api_key = dotenvy::var("STEAM_API_KEY")?;

                #[derive(Deserialize)]
                struct SteamResponse {
                    response: Players,
                }

                #[derive(Deserialize)]
                struct Players {
                    players: Vec<Player>,
                }

                #[derive(Deserialize)]
                struct Player {
                    steamid: String,
                    profileurl: String,
                    avatar: Option<String>,
                }

                let response: String = reqwest::get(
                    &format!(
                        "https://api.steampowered.com/ISteamUser/GetPlayerSummaries/v0002/?key={api_key}&steamids={token}"
                    )
                )
                    .await?
                    .text()
                    .await?;

                let mut response: SteamResponse =
                    serde_json::from_str(&response)?;

                if let Some(player) = response.response.players.pop() {
                    let username = player
                        .profileurl
                        .trim_matches('/')
                        .rsplit('/')
                        .next()
                        .unwrap_or(&player.steamid)
                        .to_string();
                    TempUser {
                        id: player.steamid,
                        username,
                        email: None,
                        avatar_url: player.avatar,
                        bio: None,
                        country: None,
                    }
                } else {
                    return Err(AuthenticationError::InvalidCredentials);
                }
            }
            AuthProvider::PayPal => {
                #[derive(Deserialize, Debug)]
                pub struct PayPalUser {
                    pub payer_id: String,
                    pub email: String,
                    pub picture: Option<String>,
                    pub address: PayPalAddress,
                }

                #[derive(Deserialize, Debug)]
                pub struct PayPalAddress {
                    pub country: String,
                }

                let api_url = dotenvy::var("PAYPAL_API_URL")?;

                let paypal_user: PayPalUser = reqwest::Client::new()
                    .get(format!(
                        "{api_url}identity/openidconnect/userinfo?schema=openid"
                    ))
                    .header(reqwest::header::USER_AGENT, "Modrinth")
                    .header(AUTHORIZATION, format!("Bearer {token}"))
                    .send()
                    .await?
                    .json()
                    .await?;

                TempUser {
                    id: paypal_user.payer_id,
                    username: paypal_user
                        .email
                        .split('@')
                        .next()
                        .unwrap_or_default()
                        .to_string(),
                    email: Some(paypal_user.email),
                    avatar_url: paypal_user.picture,
                    bio: None,
                    country: Some(paypal_user.address.country),
                }
            }
        };

        Ok(res)
    }

    pub async fn get_user_id<'a, 'b, E>(
        &self,
        id: &str,
        executor: E,
    ) -> Result<Option<crate::database::models::DBUserId>, AuthenticationError>
    where
        E: sqlx::Executor<'a, Database = sqlx::Postgres>,
    {
        Ok(match self {
            AuthProvider::GitHub => {
                let value = sqlx::query!(
                    "SELECT id FROM users WHERE github_id = $1",
                    id.parse::<i64>()
                        .map_err(|_| AuthenticationError::InvalidCredentials)?
                )
                .fetch_optional(executor)
                .await?;

                value.map(|x| crate::database::models::DBUserId(x.id))
            }
            AuthProvider::Discord => {
                let value = sqlx::query!(
                    "SELECT id FROM users WHERE discord_id = $1",
                    id.parse::<i64>()
                        .map_err(|_| AuthenticationError::InvalidCredentials)?
                )
                .fetch_optional(executor)
                .await?;

                value.map(|x| crate::database::models::DBUserId(x.id))
            }
            AuthProvider::Microsoft => {
                let value = sqlx::query!(
                    "SELECT id FROM users WHERE microsoft_id = $1",
                    id
                )
                .fetch_optional(executor)
                .await?;

                value.map(|x| crate::database::models::DBUserId(x.id))
            }
            AuthProvider::GitLab => {
                let value = sqlx::query!(
                    "SELECT id FROM users WHERE gitlab_id = $1",
                    id.parse::<i64>()
                        .map_err(|_| AuthenticationError::InvalidCredentials)?
                )
                .fetch_optional(executor)
                .await?;

                value.map(|x| crate::database::models::DBUserId(x.id))
            }
            AuthProvider::Google => {
                let value = sqlx::query!(
                    "SELECT id FROM users WHERE google_id = $1",
                    id
                )
                .fetch_optional(executor)
                .await?;

                value.map(|x| crate::database::models::DBUserId(x.id))
            }
            AuthProvider::Steam => {
                let value = sqlx::query!(
                    "SELECT id FROM users WHERE steam_id = $1",
                    id.parse::<i64>()
                        .map_err(|_| AuthenticationError::InvalidCredentials)?
                )
                .fetch_optional(executor)
                .await?;

                value.map(|x| crate::database::models::DBUserId(x.id))
            }
            AuthProvider::PayPal => {
                let value = sqlx::query!(
                    "SELECT id FROM users WHERE paypal_id = $1",
                    id
                )
                .fetch_optional(executor)
                .await?;

                value.map(|x| crate::database::models::DBUserId(x.id))
            }
        })
    }

    pub async fn update_user_id(
        &self,
        user_id: crate::database::models::DBUserId,
        id: Option<&str>,
        transaction: &mut sqlx::Transaction<'_, sqlx::Postgres>,
    ) -> Result<(), AuthenticationError> {
        match self {
            AuthProvider::GitHub => {
                sqlx::query!(
                    "
                    UPDATE users
                    SET github_id = $2
                    WHERE (id = $1)
                    ",
                    user_id as crate::database::models::DBUserId,
                    id.and_then(|x| x.parse::<i64>().ok())
                )
                .execute(&mut **transaction)
                .await?;
            }
            AuthProvider::Discord => {
                sqlx::query!(
                    "
                    UPDATE users
                    SET discord_id = $2
                    WHERE (id = $1)
                    ",
                    user_id as crate::database::models::DBUserId,
                    id.and_then(|x| x.parse::<i64>().ok())
                )
                .execute(&mut **transaction)
                .await?;
            }
            AuthProvider::Microsoft => {
                sqlx::query!(
                    "
                    UPDATE users
                    SET microsoft_id = $2
                    WHERE (id = $1)
                    ",
                    user_id as crate::database::models::DBUserId,
                    id,
                )
                .execute(&mut **transaction)
                .await?;
            }
            AuthProvider::GitLab => {
                sqlx::query!(
                    "
                    UPDATE users
                    SET gitlab_id = $2
                    WHERE (id = $1)
                    ",
                    user_id as crate::database::models::DBUserId,
                    id.and_then(|x| x.parse::<i64>().ok())
                )
                .execute(&mut **transaction)
                .await?;
            }
            AuthProvider::Google => {
                sqlx::query!(
                    "
                    UPDATE users
                    SET google_id = $2
                    WHERE (id = $1)
                    ",
                    user_id as crate::database::models::DBUserId,
                    id,
                )
                .execute(&mut **transaction)
                .await?;
            }
            AuthProvider::Steam => {
                sqlx::query!(
                    "
                    UPDATE users
                    SET steam_id = $2
                    WHERE (id = $1)
                    ",
                    user_id as crate::database::models::DBUserId,
                    id.and_then(|x| x.parse::<i64>().ok())
                )
                .execute(&mut **transaction)
                .await?;
            }
            AuthProvider::PayPal => {
                if id.is_none() {
                    sqlx::query!(
                        "
                        UPDATE users
                        SET paypal_country = NULL, paypal_email = NULL, paypal_id = NULL
                        WHERE (id = $1)
                        ",
                        user_id as crate::database::models::DBUserId,
                    )
                    .execute(&mut **transaction)
                    .await?;
                } else {
                    sqlx::query!(
                        "
                        UPDATE users
                        SET paypal_id = $2
                        WHERE (id = $1)
                        ",
                        user_id as crate::database::models::DBUserId,
                        id,
                    )
                    .execute(&mut **transaction)
                    .await?;
                }
            }
        }

        Ok(())
    }

    pub fn as_str(&self) -> &'static str {
        match self {
            AuthProvider::GitHub => "GitHub",
            AuthProvider::Discord => "Discord",
            AuthProvider::Microsoft => "Microsoft",
            AuthProvider::GitLab => "GitLab",
            AuthProvider::Google => "Google",
            AuthProvider::Steam => "Steam",
            AuthProvider::PayPal => "PayPal",
        }
    }
}

#[derive(Serialize, Deserialize)]
pub struct AuthorizationInit {
    pub url: String,
    #[serde(default)]
    pub provider: AuthProvider,
    pub token: Option<String>,
}
#[derive(Serialize, Deserialize)]
pub struct Authorization {
    pub code: String,
    pub state: String,
}

// Init link takes us to GitHub API and calls back to callback endpoint with a code and state
// http://localhost:8000/auth/init?url=https://modrinth.com
#[get("init")]
pub async fn init(
    req: HttpRequest,
    Query(info): Query<AuthorizationInit>, // callback url
    client: Data<PgPool>,
    redis: Data<RedisPool>,
    session_queue: Data<AuthQueue>,
) -> Result<HttpResponse, AuthenticationError> {
    let url =
        url::Url::parse(&info.url).map_err(|_| AuthenticationError::Url)?;

    let allowed_callback_urls =
        parse_strings_from_var("ALLOWED_CALLBACK_URLS").unwrap_or_default();
    let domain = url.host_str().ok_or(AuthenticationError::Url)?;
    if !allowed_callback_urls.iter().any(|x| domain.ends_with(x))
        && domain != "modrinth.com"
    {
        return Err(AuthenticationError::Url);
    }

    let user_id = if let Some(token) = info.token {
        let (_, user) = get_user_record_from_bearer_token(
            &req,
            Some(&token),
            &**client,
            &redis,
            &session_queue,
        )
        .await?
        .ok_or_else(|| AuthenticationError::InvalidCredentials)?;

        Some(user.id)
    } else {
        None
    };

    let state = DBFlow::OAuth {
        user_id,
        url: info.url,
        provider: info.provider,
    }
    .insert(Duration::minutes(30), &redis)
    .await?;

    let url = info.provider.get_redirect_url(state)?;
    Ok(HttpResponse::TemporaryRedirect()
        .append_header(("Location", &*url))
        .json(serde_json::json!({ "url": url })))
}

#[get("callback")]
pub async fn auth_callback(
    req: HttpRequest,
    Query(query): Query<HashMap<String, String>>,
    client: Data<PgPool>,
    file_host: Data<Arc<dyn FileHost + Send + Sync>>,
    redis: Data<RedisPool>,
) -> Result<HttpResponse, crate::auth::templates::ErrorPage> {
    let state_string = query
        .get("state")
        .ok_or_else(|| AuthenticationError::InvalidCredentials)?
        .clone();

    let state = state_string.clone();
    let res: Result<HttpResponse, AuthenticationError> = async move {
        let flow = DBFlow::get(&state, &redis).await?;

        // Extract cookie header from request
        if let Some(DBFlow::OAuth {
                        user_id,
                        provider,
                        url,
                    }) = flow
        {
            DBFlow::remove(&state, &redis).await?;

            let token = provider.get_token(query).await?;
            let oauth_user = provider.get_user(&token).await?;

            let user_id_opt = provider.get_user_id(&oauth_user.id, &**client).await?;

            let mut transaction = client.begin().await?;
            if let Some(id) = user_id {
                if user_id_opt.is_some() {
                    return Err(AuthenticationError::DuplicateUser);
                }

                provider
                    .update_user_id(id, Some(&oauth_user.id), &mut transaction)
                    .await?;

                let user = crate::database::models::DBUser::get_id(id, &**client, &redis).await?;

                if provider == AuthProvider::PayPal  {
                    sqlx::query!(
                        "
                        UPDATE users
                        SET paypal_country = $1, paypal_email = $2, paypal_id = $3
                        WHERE (id = $4)
                        ",
                        oauth_user.country,
                        oauth_user.email,
                        oauth_user.id,
                        id as crate::database::models::ids::DBUserId,
                    )
                        .execute(&mut *transaction)
                        .await?;
                } else if let Some(user) = user {
                    NotificationBuilder { body: NotificationBody::AuthProviderAdded { provider: provider.as_str().to_string() } }
                        .insert(user.id, &mut transaction, &redis)
                        .await?;
                }

                transaction.commit().await?;
                crate::database::models::DBUser::clear_caches(&[(id, None)], &redis).await?;

                Ok(HttpResponse::TemporaryRedirect()
                    .append_header(("Location", &*url))
                    .json(serde_json::json!({ "url": url })))
            } else {
                let user_id = if let Some(user_id) = user_id_opt {
                    let user = crate::database::models::DBUser::get_id(user_id, &**client, &redis)
                        .await?
                        .ok_or_else(|| AuthenticationError::InvalidCredentials)?;

                    if user.totp_secret.is_some() {
                        let flow = DBFlow::Login2FA { user_id: user.id }
                            .insert(Duration::minutes(30), &redis)
                            .await?;

                        let redirect_url = format!(
                            "{}{}error=2fa_required&flow={}",
                            url,
                            if url.contains('?') { "&" } else { "?" },
                            flow
                        );

                        return Ok(HttpResponse::TemporaryRedirect()
                            .append_header(("Location", &*redirect_url))
                            .json(serde_json::json!({ "url": redirect_url })));
                    }

                    user_id
                } else {
                    oauth_user.create_account(provider, &mut transaction, &client, &file_host, &redis).await?
                };

                let session = issue_session(req, user_id, &mut transaction, &redis).await?;
                transaction.commit().await?;

                let redirect_url = format!(
                    "{}{}code={}{}",
                    url,
                    if url.contains('?') { '&' } else { '?' },
                    session.session,
                    if user_id_opt.is_none() {
                        "&new_account=true"
                    } else {
                        ""
                    }
                );

                Ok(HttpResponse::TemporaryRedirect()
                    .append_header(("Location", &*redirect_url))
                    .json(serde_json::json!({ "url": redirect_url })))
            }
        } else {
            Err::<HttpResponse, AuthenticationError>(AuthenticationError::InvalidCredentials)
        }
    }.await;

    Ok(res?)
}

#[derive(Deserialize)]
pub struct DeleteAuthProvider {
    pub provider: AuthProvider,
}

#[delete("provider")]
pub async fn delete_auth_provider(
    req: HttpRequest,
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    delete_provider: web::Json<DeleteAuthProvider>,
    session_queue: Data<AuthQueue>,
) -> Result<HttpResponse, ApiError> {
    let user = get_user_from_headers(
        &req,
        &**pool,
        &redis,
        &session_queue,
        Scopes::USER_AUTH_WRITE,
    )
    .await?
    .1;

    if user.auth_providers.is_none_or(|x| x.len() <= 1)
        && !user.has_password.unwrap_or(false)
    {
        return Err(ApiError::InvalidInput(
            "You must have another authentication method added to this account!".to_string(),
        ));
    }

    let mut transaction = pool.begin().await?;

    delete_provider
        .provider
        .update_user_id(user.id.into(), None, &mut transaction)
        .await?;

    if delete_provider.provider != AuthProvider::PayPal {
        NotificationBuilder {
            body: NotificationBody::AuthProviderRemoved {
                provider: delete_provider.provider.as_str().to_string(),
            },
        }
        .insert(user.id.into(), &mut transaction, &redis)
        .await?;
    }

    transaction.commit().await?;
    crate::database::models::DBUser::clear_caches(
        &[(user.id.into(), None)],
        &redis,
    )
    .await?;

    Ok(HttpResponse::NoContent().finish())
}

pub async fn check_sendy_subscription(
    email: &str,
) -> Result<bool, AuthenticationError> {
    let url = dotenvy::var("SENDY_URL")?;
    let id = dotenvy::var("SENDY_LIST_ID")?;
    let api_key = dotenvy::var("SENDY_API_KEY")?;

    if url.is_empty() || url == "none" {
        tracing::info!(
            "Sendy URL not set, returning false for subscription check"
        );
        return Ok(false);
    }

    let mut form = HashMap::new();
    form.insert("api_key", &*api_key);
    form.insert("email", email);
    form.insert("list_id", &*id);

    let client = reqwest::Client::new();
    let response = client
        .post(format!("{url}/api/subscribers/subscription-status.php"))
        .form(&form)
        .send()
        .await?
        .text()
        .await?;

    Ok(response.trim() == "Subscribed")
}

#[derive(Deserialize, Validate)]
pub struct NewAccount {
    #[validate(length(min = 1, max = 39), regex(path = *crate::util::validate::RE_URL_SAFE))]
    pub username: String,
    #[validate(length(min = 8, max = 256))]
    pub password: String,
    #[validate(email)]
    pub email: String,
    pub challenge: String,
    pub sign_up_newsletter: Option<bool>,
}

#[post("create")]
pub async fn create_account_with_password(
    req: HttpRequest,
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    new_account: web::Json<NewAccount>,
    email: web::Data<EmailQueue>,
) -> Result<HttpResponse, ApiError> {
    new_account.0.validate().map_err(|err| {
        ApiError::InvalidInput(validation_errors_to_string(err, None))
    })?;

    if !check_hcaptcha(&req, &new_account.challenge).await? {
        return Err(ApiError::Turnstile);
    }

    if crate::database::models::DBUser::get(
        &new_account.username,
        &**pool,
        &redis,
    )
    .await?
    .is_some()
    {
        return Err(ApiError::InvalidInput("Username is taken!".to_string()));
    }

    let mut transaction = pool.begin().await?;
    let user_id =
        crate::database::models::generate_user_id(&mut transaction).await?;

    let new_account = new_account.0;

    let score = zxcvbn::zxcvbn(
        &new_account.password,
        &[&new_account.username, &new_account.email],
    );

    if score.score() < Score::Three {
        return Err(ApiError::InvalidInput(
            if let Some(feedback) = score.feedback().and_then(|x| x.warning()) {
                format!("Password too weak: {feedback}")
            } else {
                "Specified password is too weak! Please improve its strength."
                    .to_string()
            },
        ));
    }

    let hasher = Argon2::default();
    let salt = SaltString::generate(&mut ChaCha20Rng::from_entropy());
    let password_hash = hasher
        .hash_password(new_account.password.as_bytes(), &salt)?
        .to_string();

    if !crate::database::models::DBUser::get_by_case_insensitive_email(
        &new_account.email,
        &**pool,
    )
    .await?
    .is_empty()
    {
        return Err(ApiError::InvalidInput(
            "Email is already registered on Modrinth! Try 'Forgot password' to access your account.".to_string(),
        ));
    }

    crate::database::models::DBUser {
        id: user_id,
        github_id: None,
        discord_id: None,
        gitlab_id: None,
        google_id: None,
        steam_id: None,
        microsoft_id: None,
        password: Some(password_hash),
        paypal_id: None,
        paypal_country: None,
        paypal_email: None,
        venmo_handle: None,
        stripe_customer_id: None,
        totp_secret: None,
        username: new_account.username.clone(),
        email: Some(new_account.email.clone()),
        email_verified: false,
        avatar_url: None,
        raw_avatar_url: None,
        bio: None,
        created: Utc::now(),
        role: Role::Developer.to_string(),
        badges: Badges::default(),
        allow_friend_requests: true,
        is_subscribed_to_newsletter: new_account
            .sign_up_newsletter
            .unwrap_or(false),
    }
    .insert(&mut transaction)
    .await?;

    let session = issue_session(req, user_id, &mut transaction, &redis).await?;
    let res = crate::models::sessions::Session::from(session, true, None);

    let mailbox: Mailbox = new_account.email.parse().map_err(|_| {
        ApiError::InvalidInput("Invalid email address!".to_string())
    })?;

    let flow = DBFlow::ConfirmEmail {
        user_id,
        confirm_email: new_account.email.clone(),
    }
    .insert(Duration::hours(24), &redis)
    .await?;

    email
        .send_one(
            &mut transaction,
            NotificationBody::VerifyEmail { flow },
            user_id,
            mailbox,
        )
        .await?
        .as_user_error()?;

    transaction.commit().await?;

    Ok(HttpResponse::Ok().json(res))
}

#[derive(Deserialize, Validate)]
pub struct Login {
    #[serde(rename = "username")]
    pub username_or_email: String,
    pub password: String,
    pub challenge: String,
}

#[post("login")]
pub async fn login_password(
    req: HttpRequest,
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    login: web::Json<Login>,
) -> Result<HttpResponse, ApiError> {
    if !check_hcaptcha(&req, &login.challenge).await? {
        return Err(ApiError::Turnstile);
    }

    let user = if let Some(user) = crate::database::models::DBUser::get(
        &login.username_or_email,
        &**pool,
        &redis,
    )
    .await?
    {
        user
    } else {
        let user = crate::database::models::DBUser::get_by_email(
            &login.username_or_email,
            &**pool,
        )
        .await?
        .ok_or_else(|| AuthenticationError::InvalidCredentials)?;

        crate::database::models::DBUser::get_id(user, &**pool, &redis)
            .await?
            .ok_or_else(|| AuthenticationError::InvalidCredentials)?
    };

    let hasher = Argon2::default();
    hasher
        .verify_password(
            login.password.as_bytes(),
            &PasswordHash::new(
                &user
                    .password
                    .ok_or_else(|| AuthenticationError::InvalidCredentials)?,
            )?,
        )
        .map_err(|_| AuthenticationError::InvalidCredentials)?;

    if user.totp_secret.is_some() {
        let flow = DBFlow::Login2FA { user_id: user.id }
            .insert(Duration::minutes(30), &redis)
            .await?;

        Ok(HttpResponse::Ok().json(serde_json::json!({
            "error": "2fa_required",
            "description": "2FA is required to complete this operation.",
            "flow": flow,
        })))
    } else {
        let mut transaction = pool.begin().await?;
        let session =
            issue_session(req, user.id, &mut transaction, &redis).await?;
        let res = crate::models::sessions::Session::from(session, true, None);
        transaction.commit().await?;

        Ok(HttpResponse::Ok().json(res))
    }
}

#[derive(Deserialize, Validate)]
pub struct Login2FA {
    pub code: String,
    pub flow: String,
}

async fn validate_2fa_code(
    input: String,
    secret: String,
    allow_backup: bool,
    user_id: crate::database::models::DBUserId,
    redis: &RedisPool,
    pool: &PgPool,
    transaction: &mut sqlx::Transaction<'_, sqlx::Postgres>,
) -> Result<bool, AuthenticationError> {
    let totp = totp_rs::TOTP::new(
        totp_rs::Algorithm::SHA1,
        6,
        1,
        30,
        totp_rs::Secret::Encoded(secret)
            .to_bytes()
            .map_err(|_| AuthenticationError::InvalidCredentials)?,
    )
    .map_err(|_| AuthenticationError::InvalidCredentials)?;

    const TOTP_NAMESPACE: &str = "used_totp";
    let mut conn = redis.connect().await?;

    // Check if TOTP has already been used
    if conn
        .get(TOTP_NAMESPACE, &format!("{}-{}", input, user_id.0))
        .await?
        .is_some()
    {
        return Err(AuthenticationError::InvalidCredentials);
    }

    if totp
        .check_current(input.as_str())
        .map_err(|_| AuthenticationError::InvalidCredentials)?
    {
        conn.set(
            TOTP_NAMESPACE,
            &format!("{}-{}", input, user_id.0),
            "",
            Some(60),
        )
        .await?;

        Ok(true)
    } else if allow_backup {
        let backup_codes =
            crate::database::models::DBUser::get_backup_codes(user_id, pool)
                .await?;

        if !backup_codes.contains(&input) {
            Ok(false)
        } else {
            let code = parse_base62(&input).unwrap_or_default();

            sqlx::query!(
                "
                    DELETE FROM user_backup_codes
                    WHERE user_id = $1 AND code = $2
                    ",
                user_id as crate::database::models::ids::DBUserId,
                code as i64,
            )
            .execute(&mut **transaction)
            .await?;

            crate::database::models::DBUser::clear_caches(
                &[(user_id, None)],
                redis,
            )
            .await?;

            Ok(true)
        }
    } else {
        Err(AuthenticationError::InvalidCredentials)
    }
}

#[post("login/2fa")]
pub async fn login_2fa(
    req: HttpRequest,
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    login: web::Json<Login2FA>,
) -> Result<HttpResponse, ApiError> {
    let flow = DBFlow::get(&login.flow, &redis)
        .await?
        .ok_or_else(|| AuthenticationError::InvalidCredentials)?;

    if let DBFlow::Login2FA { user_id } = flow {
        let user =
            crate::database::models::DBUser::get_id(user_id, &**pool, &redis)
                .await?
                .ok_or_else(|| AuthenticationError::InvalidCredentials)?;

        let mut transaction = pool.begin().await?;
        if !validate_2fa_code(
            login.code.clone(),
            user.totp_secret
                .ok_or_else(|| AuthenticationError::InvalidCredentials)?,
            true,
            user.id,
            &redis,
            &pool,
            &mut transaction,
        )
        .await?
        {
            return Err(ApiError::Authentication(
                AuthenticationError::InvalidCredentials,
            ));
        }
        DBFlow::remove(&login.flow, &redis).await?;

        let session =
            issue_session(req, user_id, &mut transaction, &redis).await?;
        let res = crate::models::sessions::Session::from(session, true, None);
        transaction.commit().await?;

        Ok(HttpResponse::Ok().json(res))
    } else {
        Err(ApiError::Authentication(
            AuthenticationError::InvalidCredentials,
        ))
    }
}

#[post("2fa/get_secret")]
pub async fn begin_2fa_flow(
    req: HttpRequest,
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    session_queue: Data<AuthQueue>,
) -> Result<HttpResponse, ApiError> {
    let user = get_user_from_headers(
        &req,
        &**pool,
        &redis,
        &session_queue,
        Scopes::USER_AUTH_WRITE,
    )
    .await?
    .1;

    if !user.has_totp.unwrap_or(false) {
        let string = totp_rs::Secret::generate_secret();
        let encoded = string.to_encoded();

        let flow = DBFlow::Initialize2FA {
            user_id: user.id.into(),
            secret: encoded.to_string(),
        }
        .insert(Duration::minutes(30), &redis)
        .await?;

        Ok(HttpResponse::Ok().json(serde_json::json!({
            "secret": encoded.to_string(),
            "flow": flow,
        })))
    } else {
        Err(ApiError::InvalidInput(
            "User already has 2FA enabled on their account!".to_string(),
        ))
    }
}

#[post("2fa")]
pub async fn finish_2fa_flow(
    req: HttpRequest,
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    login: web::Json<Login2FA>,
    session_queue: Data<AuthQueue>,
) -> Result<HttpResponse, ApiError> {
    let flow = DBFlow::get(&login.flow, &redis)
        .await?
        .ok_or_else(|| AuthenticationError::InvalidCredentials)?;

    if let DBFlow::Initialize2FA { user_id, secret } = flow {
        let user = get_user_from_headers(
            &req,
            &**pool,
            &redis,
            &session_queue,
            Scopes::USER_AUTH_WRITE,
        )
        .await?
        .1;

        if user.id != user_id.into() {
            return Err(ApiError::Authentication(
                AuthenticationError::InvalidCredentials,
            ));
        }

        let mut transaction = pool.begin().await?;

        if !validate_2fa_code(
            login.code.clone(),
            secret.clone(),
            false,
            user.id.into(),
            &redis,
            &pool,
            &mut transaction,
        )
        .await?
        {
            return Err(ApiError::Authentication(
                AuthenticationError::InvalidCredentials,
            ));
        }

        DBFlow::remove(&login.flow, &redis).await?;

        sqlx::query!(
            "
            UPDATE users
            SET totp_secret = $1
            WHERE (id = $2)
            ",
            secret,
            user_id as crate::database::models::ids::DBUserId,
        )
        .execute(&mut *transaction)
        .await?;

        sqlx::query!(
            "
            DELETE FROM user_backup_codes
            WHERE user_id = $1
            ",
            user_id as crate::database::models::ids::DBUserId,
        )
        .execute(&mut *transaction)
        .await?;

        let mut codes = Vec::new();

        for _ in 0..6 {
            let mut rng = ChaCha20Rng::from_entropy();
            let val = random_base62_rng(&mut rng, 11);

            sqlx::query!(
                "
                INSERT INTO user_backup_codes (
                    user_id, code
                )
                VALUES (
                    $1, $2
                )
                ",
                user_id as crate::database::models::ids::DBUserId,
                val as i64,
            )
            .execute(&mut *transaction)
            .await?;

            codes.push(to_base62(val));
        }

        NotificationBuilder {
            body: NotificationBody::TwoFactorEnabled,
        }
        .insert(user.id.into(), &mut transaction, &redis)
        .await?;

        transaction.commit().await?;
        crate::database::models::DBUser::clear_caches(
            &[(user.id.into(), None)],
            &redis,
        )
        .await?;

        Ok(HttpResponse::Ok().json(serde_json::json!({
            "backup_codes": codes,
        })))
    } else {
        Err(ApiError::Authentication(
            AuthenticationError::InvalidCredentials,
        ))
    }
}

#[derive(Deserialize)]
pub struct Remove2FA {
    pub code: String,
}

#[delete("2fa")]
pub async fn remove_2fa(
    req: HttpRequest,
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    login: web::Json<Remove2FA>,
    session_queue: Data<AuthQueue>,
) -> Result<HttpResponse, ApiError> {
    let (scopes, user) = get_user_record_from_bearer_token(
        &req,
        None,
        &**pool,
        &redis,
        &session_queue,
    )
    .await?
    .ok_or_else(|| AuthenticationError::InvalidCredentials)?;

    if !scopes.contains(Scopes::USER_AUTH_WRITE) {
        return Err(ApiError::Authentication(
            AuthenticationError::InvalidCredentials,
        ));
    }

    let mut transaction = pool.begin().await?;

    if !validate_2fa_code(
        login.code.clone(),
        user.totp_secret.ok_or_else(|| {
            ApiError::InvalidInput(
                "User does not have 2FA enabled on the account!".to_string(),
            )
        })?,
        true,
        user.id,
        &redis,
        &pool,
        &mut transaction,
    )
    .await?
    {
        return Err(ApiError::Authentication(
            AuthenticationError::InvalidCredentials,
        ));
    }

    sqlx::query!(
        "
        UPDATE users
        SET totp_secret = NULL
        WHERE (id = $1)
        ",
        user.id as crate::database::models::ids::DBUserId,
    )
    .execute(&mut *transaction)
    .await?;

    sqlx::query!(
        "
        DELETE FROM user_backup_codes
        WHERE user_id = $1
        ",
        user.id as crate::database::models::ids::DBUserId,
    )
    .execute(&mut *transaction)
    .await?;

    NotificationBuilder {
        body: NotificationBody::TwoFactorRemoved,
    }
    .insert(user.id, &mut transaction, &redis)
    .await?;

    transaction.commit().await?;
    crate::database::models::DBUser::clear_caches(&[(user.id, None)], &redis)
        .await?;

    Ok(HttpResponse::NoContent().finish())
}

#[derive(Deserialize)]
pub struct ResetPassword {
    #[serde(rename = "username")]
    pub username_or_email: String,
    pub challenge: String,
}

#[post("password/reset")]
pub async fn reset_password_begin(
    req: HttpRequest,
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    reset_password: web::Json<ResetPassword>,
    email: web::Data<EmailQueue>,
) -> Result<HttpResponse, ApiError> {
    if !check_hcaptcha(&req, &reset_password.challenge).await? {
        return Err(ApiError::Turnstile);
    }

    let mut txn = pool.begin().await?;

    let user =
        match crate::database::models::DBUser::get_by_case_insensitive_email(
            &reset_password.username_or_email,
            &mut *txn,
        )
        .await?[..]
        {
            [] => {
                // Try finding by username or ID
                crate::database::models::DBUser::get(
                    &reset_password.username_or_email,
                    &mut *txn,
                    &redis,
                )
                .await?
            }
            [user_id] => {
                // If there is only one user with the given email, ignoring case,
                // we can assume it's the user we want to reset the password for
                crate::database::models::DBUser::get_id(
                    user_id, &mut *txn, &redis,
                )
                .await?
            }
            _ => {
                // When several users use variations of the same email with
                // different cases, we cannot reliably tell which user should
                // receive the password reset email, so fall back to case sensitive
                // search to avoid spamming multiple users
                if let Some(user_id) =
                    crate::database::models::DBUser::get_by_email(
                        &reset_password.username_or_email,
                        &mut *txn,
                    )
                    .await?
                {
                    crate::database::models::DBUser::get_id(
                        user_id, &mut *txn, &redis,
                    )
                    .await?
                } else {
                    None
                }
            }
        };

    if let Some(DBUser {
        id: user_id,
        email: user_email,
        ..
    }) = user
    {
        let flow = DBFlow::ForgotPassword { user_id }
            .insert(Duration::hours(24), &redis)
            .await?;

        if let Ok(mailbox) = user_email.unwrap_or_default().parse() {
            email
                .send_one(
                    &mut txn,
                    NotificationBody::ResetPassword { flow },
                    user_id,
                    mailbox,
                )
                .await?
                .as_user_error()?;
        }
    }

    txn.commit().await?;

    Ok(HttpResponse::Ok().finish())
}

#[derive(Deserialize, Validate)]
pub struct ChangePassword {
    pub flow: Option<String>,
    pub old_password: Option<String>,
    pub new_password: Option<String>,
}

#[patch("password")]
pub async fn change_password(
    req: HttpRequest,
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    change_password: web::Json<ChangePassword>,
    session_queue: Data<AuthQueue>,
) -> Result<HttpResponse, ApiError> {
    let user = if let Some(flow) = &change_password.flow {
        let flow = DBFlow::get(flow, &redis).await?;

        if let Some(DBFlow::ForgotPassword { user_id }) = flow {
            let user = crate::database::models::DBUser::get_id(
                user_id, &**pool, &redis,
            )
            .await?
            .ok_or_else(|| AuthenticationError::InvalidCredentials)?;

            Some(user)
        } else {
            return Err(ApiError::CustomAuthentication(
                "The password change flow code is invalid or has expired. Did you copy it promptly and correctly?".to_string(),
            ));
        }
    } else {
        None
    };

    let user = if let Some(user) = user {
        user
    } else {
        let (scopes, user) = get_user_record_from_bearer_token(
            &req,
            None,
            &**pool,
            &redis,
            &session_queue,
        )
        .await?
        .ok_or_else(|| AuthenticationError::InvalidCredentials)?;

        if !scopes.contains(Scopes::USER_AUTH_WRITE) {
            return Err(ApiError::Authentication(
                AuthenticationError::InvalidCredentials,
            ));
        }

        if let Some(pass) = user.password.as_ref() {
            let old_password = change_password.old_password.as_ref().ok_or_else(|| {
                ApiError::CustomAuthentication(
                    "You must specify the old password to change your password!".to_string(),
                )
            })?;

            let hasher = Argon2::default();
            hasher.verify_password(
                old_password.as_bytes(),
                &PasswordHash::new(pass)?,
            )?;
        }

        user
    };

    let mut transaction = pool.begin().await?;

    let update_password = if let Some(new_password) =
        &change_password.new_password
    {
        let score = zxcvbn::zxcvbn(
            new_password,
            &[&user.username, &user.email.clone().unwrap_or_default()],
        );

        if score.score() < Score::Three {
            return Err(ApiError::InvalidInput(
                if let Some(feedback) =
                    score.feedback().and_then(|x| x.warning())
                {
                    format!("Password too weak: {feedback}")
                } else {
                    "Specified password is too weak! Please improve its strength.".to_string()
                },
            ));
        }

        let hasher = Argon2::default();
        let salt = SaltString::generate(&mut ChaCha20Rng::from_entropy());
        let password_hash = hasher
            .hash_password(new_password.as_bytes(), &salt)?
            .to_string();

        Some(password_hash)
    } else {
        if !(user.github_id.is_some()
            || user.gitlab_id.is_some()
            || user.microsoft_id.is_some()
            || user.google_id.is_some()
            || user.steam_id.is_some()
            || user.discord_id.is_some())
        {
            return Err(ApiError::InvalidInput(
                "You must have another authentication method added to remove password authentication!".to_string(),
            ));
        }

        None
    };

    sqlx::query!(
        "
        UPDATE users
        SET password = $1
        WHERE (id = $2)
        ",
        update_password,
        user.id as crate::database::models::ids::DBUserId,
    )
    .execute(&mut *transaction)
    .await?;

    if let Some(flow) = &change_password.flow {
        DBFlow::remove(flow, &redis).await?;
    }

    if update_password.is_some() {
        NotificationBuilder {
            body: NotificationBody::PasswordChanged,
        }
        .insert(user.id, &mut transaction, &redis)
        .await?;
    } else {
        NotificationBuilder {
            body: NotificationBody::PasswordRemoved,
        }
        .insert(user.id, &mut transaction, &redis)
        .await?;
    }

    transaction.commit().await?;
    crate::database::models::DBUser::clear_caches(&[(user.id, None)], &redis)
        .await?;

    Ok(HttpResponse::Ok().finish())
}

#[derive(Deserialize, Validate)]
pub struct SetEmail {
    #[validate(email)]
    pub email: String,
}

#[patch("email")]
pub async fn set_email(
    req: HttpRequest,
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    email_address: web::Json<SetEmail>,
    email: web::Data<EmailQueue>,
    session_queue: Data<AuthQueue>,
    stripe_client: Data<stripe::Client>,
) -> Result<HttpResponse, ApiError> {
    email_address.0.validate().map_err(|err| {
        ApiError::InvalidInput(validation_errors_to_string(err, None))
    })?;

    let mailbox: Mailbox = email_address.email.parse().map_err(|_| {
        ApiError::InvalidInput("Invalid email address!".to_string())
    })?;

    let user = get_user_from_headers(
        &req,
        &**pool,
        &redis,
        &session_queue,
        Scopes::USER_AUTH_WRITE,
    )
    .await?
    .1;

    if !crate::database::models::DBUser::get_by_case_insensitive_email(
        &email_address.email,
        &**pool,
    )
    .await?
    .is_empty()
    {
        return Err(ApiError::InvalidInput(
            "Email is already registered on Modrinth! Try 'Forgot password' in incognito to access and delete your other account.".to_string(),
        ));
    }

    let mut transaction = pool.begin().await?;

    sqlx::query!(
        "
        UPDATE users
        SET email = $1, email_verified = FALSE
        WHERE (id = $2)
        ",
        email_address.email,
        user.id.0 as i64,
    )
    .execute(&mut *transaction)
    .await?;

    if let Some(user_email) = user.email.clone() {
        NotificationBuilder {
            body: NotificationBody::EmailChanged {
                new_email: email_address.email.clone(),
                to_email: user_email,
            },
        }
        .insert(user.id.into(), &mut transaction, &redis)
        .await?;
    }

    if let Some(customer_id) = user
        .stripe_customer_id
        .as_ref()
        .and_then(|x| stripe::CustomerId::from_str(x).ok())
    {
        stripe::Customer::update(
            &stripe_client,
            &customer_id,
            stripe::UpdateCustomer {
                email: Some(&email_address.email),
                ..Default::default()
            },
        )
        .await?;
    }

    let flow = DBFlow::ConfirmEmail {
        user_id: user.id.into(),
        confirm_email: email_address.email.clone(),
    }
    .insert(Duration::hours(24), &redis)
    .await?;

    email
        .send_one(
            &mut transaction,
            NotificationBody::VerifyEmail { flow },
            user.id.into(),
            mailbox,
        )
        .await?
        .as_user_error()?;

    transaction.commit().await?;

    crate::database::models::DBUser::clear_caches(
        &[(user.id.into(), None)],
        &redis,
    )
    .await?;

    Ok(HttpResponse::Ok().finish())
}

#[post("email/resend_verify")]
pub async fn resend_verify_email(
    req: HttpRequest,
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    session_queue: Data<AuthQueue>,
    email: web::Data<EmailQueue>,
) -> Result<HttpResponse, ApiError> {
    let user = get_user_from_headers(
        &req,
        &**pool,
        &redis,
        &session_queue,
        Scopes::USER_AUTH_WRITE,
    )
    .await?
    .1;

    if let Some(email_address) = user.email {
        if user.email_verified.unwrap_or(false) {
            return Err(ApiError::InvalidInput(
                "User email is already verified!".to_string(),
            ));
        }

        let flow = DBFlow::ConfirmEmail {
            user_id: user.id.into(),
            confirm_email: email_address.clone(),
        }
        .insert(Duration::hours(24), &redis)
        .await?;

        let mailbox: Mailbox = email_address.parse().map_err(|_| {
            ApiError::InvalidInput("Invalid email address!".to_string())
        })?;

        let mut transaction = pool.begin().await?;

        email
            .send_one(
                &mut transaction,
                NotificationBody::VerifyEmail { flow },
                user.id.into(),
                mailbox,
            )
            .await?
            .as_user_error()?;

        transaction.commit().await?;

        Ok(HttpResponse::NoContent().finish())
    } else {
        Err(ApiError::InvalidInput(
            "User does not have an email.".to_string(),
        ))
    }
}

#[derive(Deserialize)]
pub struct VerifyEmail {
    pub flow: String,
}

#[post("email/verify")]
pub async fn verify_email(
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    email: web::Json<VerifyEmail>,
) -> Result<HttpResponse, ApiError> {
    let flow = DBFlow::get(&email.flow, &redis).await?;

    if let Some(DBFlow::ConfirmEmail {
        user_id,
        confirm_email,
    }) = flow
    {
        let user =
            crate::database::models::DBUser::get_id(user_id, &**pool, &redis)
                .await?
                .ok_or_else(|| AuthenticationError::InvalidCredentials)?;

        if user.email != Some(confirm_email) {
            return Err(ApiError::InvalidInput(
                "E-mail does not match verify email. Try re-requesting the verification link."
                    .to_string(),
            ));
        }

        let mut transaction = pool.begin().await?;

        sqlx::query!(
            "
            UPDATE users
            SET email_verified = TRUE
            WHERE (id = $1)
            ",
            user.id as crate::database::models::ids::DBUserId,
        )
        .execute(&mut *transaction)
        .await?;

        DBFlow::remove(&email.flow, &redis).await?;
        transaction.commit().await?;
        crate::database::models::DBUser::clear_caches(
            &[(user.id, None)],
            &redis,
        )
        .await?;

        Ok(HttpResponse::NoContent().finish())
    } else {
        Err(ApiError::InvalidInput(
            "Flow does not exist. Try re-requesting the verification link."
                .to_string(),
        ))
    }
}

#[post("email/subscribe")]
pub async fn subscribe_newsletter(
    req: HttpRequest,
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    session_queue: Data<AuthQueue>,
) -> Result<HttpResponse, ApiError> {
    let user = get_user_from_headers(
        &req,
        &**pool,
        &redis,
        &session_queue,
        Scopes::USER_AUTH_WRITE,
    )
    .await?
    .1;

    sqlx::query!(
        "
        UPDATE users
        SET is_subscribed_to_newsletter = TRUE
        WHERE id = $1
        ",
        user.id.0 as i64,
    )
    .execute(&**pool)
    .await?;

    crate::database::models::DBUser::clear_caches(
        &[(user.id.into(), None)],
        &redis,
    )
    .await?;

    Ok(HttpResponse::NoContent().finish())
}

#[get("email/subscribe")]
pub async fn get_newsletter_subscription_status(
    req: HttpRequest,
    pool: Data<PgPool>,
    redis: Data<RedisPool>,
    session_queue: Data<AuthQueue>,
) -> Result<HttpResponse, ApiError> {
    let user = get_full_user_from_headers(
        &req,
        &**pool,
        &redis,
        &session_queue,
        Scopes::USER_READ,
    )
    .await?
    .1;

    let is_subscribed = user.is_subscribed_to_newsletter
        || if let Some(email) = user.email {
            check_sendy_subscription(&email).await?
        } else {
            false
        };

    Ok(HttpResponse::Ok().json(serde_json::json!({
        "subscribed": is_subscribed
    })))
}