use std::ops::{Deref, DerefMut};

use argon2::{password_hash::SaltString, Argon2, PasswordHasher};
use chrono::{Datelike, Local, NaiveDate};
use log::info;
use rocket::{
    async_trait,
    http::{Cookie, Status},
    request,
    request::{FromRequest, Outcome},
    time::{Duration, OffsetDateTime},
    Request,
};
use serde::{Deserialize, Serialize};
use sqlx::{FromRow, Sqlite, SqlitePool, Transaction};

use super::{log::Log, role::Role, tripdetails::TripDetails, Day};
use crate::{tera::admin::user::UserEditForm, AMOUNT_DAYS_TO_SHOW_TRIPS_AHEAD};

#[derive(FromRow, Serialize, Deserialize, Clone, Debug, Eq, Hash, PartialEq)]
pub struct User {
    pub id: i64,
    pub name: String,
    pub pw: Option<String>,
    pub deleted: bool,
    pub last_access: Option<chrono::NaiveDateTime>,
    pub user_token: String,
}

#[derive(Debug, Serialize, Deserialize)]
pub struct UserWithDetails {
    #[serde(flatten)]
    pub user: User,
    pub amount_unread_notifications: i64,
    pub allowed_to_steer: bool,
    pub roles: Vec<String>,
}

impl UserWithDetails {
    pub async fn from_user(user: User, db: &SqlitePool) -> Self {
        let allowed_to_steer = user.allowed_to_steer(db).await;

        Self {
            roles: user.roles(db).await,
            amount_unread_notifications: user.amount_unread_notifications(db).await,
            allowed_to_steer,
            user,
        }
    }
}

#[derive(Debug)]
pub enum LoginError {
    InvalidAuthenticationCombo,
    UserNotFound,
    UserDeleted,
    NotLoggedIn,
    NotAnAdmin,
    NotACox,
    NotATech,
    GuestNotAllowed,
    NoPasswordSet(Box<User>),
    DeserializationError,
}

impl User {
    pub async fn allowed_to_steer(&self, db: &SqlitePool) -> bool {
        self.has_role(db, "cox").await || self.has_role(db, "Bootsführer").await
    }

    pub async fn allowed_to_steer_tx(&self, db: &mut Transaction<'_, Sqlite>) -> bool {
        self.has_role_tx(db, "cox").await || self.has_role_tx(db, "Bootsführer").await
    }

    pub async fn amount_unread_notifications(&self, db: &SqlitePool) -> i64 {
        sqlx::query!(
            "SELECT COUNT(*) as count FROM notification WHERE user_id = ? AND read_at IS NULL",
            self.id
        )
        .fetch_one(db)
        .await
        .unwrap()
        .count
    }

    pub async fn has_role(&self, db: &SqlitePool, role: &str) -> bool {
        if sqlx::query!(
            "SELECT * FROM user_role WHERE user_id=? AND role_id = (SELECT id FROM role WHERE name = ?)",
            self.id,
            role
        )
        .fetch_optional(db)
        .await
        .unwrap()
        .is_some()
        {
            return true;
        }

        false
    }

    pub async fn allowed_to_update_always_show_trip(&self, db: &SqlitePool) -> bool {
        AllowedToUpdateTripToAlwaysBeShownUser::new(db, self.clone())
            .await
            .is_some()
    }

    pub async fn roles(&self, db: &SqlitePool) -> Vec<String> {
        sqlx::query!(
            "SELECT r.name FROM role r JOIN user_role ur ON r.id = ur.role_id JOIN user u ON u.id = ur.user_id WHERE ur.user_id = ? AND u.deleted = 0;",
            self.id
        )
            .fetch_all(db)
        .await
        .unwrap()
        .into_iter().map(|r| r.name).collect()
    }

    pub async fn real_roles(&self, db: &SqlitePool) -> Vec<Role> {
        sqlx::query_as!(
            Role,
            "SELECT r.id, r.name, r.cluster 
         FROM role r 
         JOIN user_role ur ON r.id = ur.role_id 
         JOIN user u ON u.id = ur.user_id 
         WHERE ur.user_id = ? AND u.deleted = 0;",
            self.id
        )
        .fetch_all(db)
        .await
        .unwrap()
    }

    pub async fn has_role_tx(&self, db: &mut Transaction<'_, Sqlite>, role: &str) -> bool {
        if sqlx::query!(
            "SELECT * FROM user_role WHERE user_id=? AND role_id = (SELECT id FROM role WHERE name = ?)",
            self.id,
            role
        )
        .fetch_optional(db.deref_mut())
        .await
        .unwrap()
        .is_some()
        {
            return true;
        }

        false
    }

    pub async fn find_by_id(db: &SqlitePool, id: i32) -> Option<Self> {
        sqlx::query_as!(
            Self,
            "
SELECT id, name, pw, deleted, last_access, user_token
FROM user 
WHERE id like ?
        ",
            id
        )
        .fetch_one(db)
        .await
        .ok()
    }

    pub async fn find_by_id_tx(db: &mut Transaction<'_, Sqlite>, id: i32) -> Option<Self> {
        sqlx::query_as!(
            Self,
            "
SELECT id, name, pw, deleted, last_access, user_token
FROM user 
WHERE id like ?
        ",
            id
        )
        .fetch_one(db.deref_mut())
        .await
        .ok()
    }

    pub async fn find_by_name(db: &SqlitePool, name: &str) -> Option<Self> {
        let name = name.trim().to_lowercase();

        sqlx::query_as!(
            Self,
            "
SELECT id, name, pw, deleted, last_access, user_token
FROM user 
WHERE lower(name)=?
        ",
            name
        )
        .fetch_one(db)
        .await
        .ok()
    }

    pub async fn all(db: &SqlitePool) -> Vec<Self> {
        Self::all_with_order(db, "last_access", false).await
    }

    pub async fn all_with_order(db: &SqlitePool, sort: &str, asc: bool) -> Vec<Self> {
        let mut query = format!(
            "
        SELECT id, name, pw, deleted, last_access, user_token
        FROM user
        WHERE deleted = 0
        ORDER BY {}
        ",
            sort
        );
        if !asc {
            query.push_str(" DESC");
        }

        sqlx::query_as::<_, User>(&query)
            .fetch_all(db)
            .await
            .unwrap()
    }

    pub async fn all_with_role(db: &SqlitePool, role: &Role) -> Vec<Self> {
        let mut tx = db.begin().await.unwrap();
        let ret = Self::all_with_role_tx(&mut tx, role).await;
        tx.commit().await.unwrap();
        ret
    }

    pub async fn all_with_role_tx(db: &mut Transaction<'_, Sqlite>, role: &Role) -> Vec<Self> {
        sqlx::query_as!(
            Self,
            "
SELECT id, name, pw, deleted, last_access, user_token
FROM user u
JOIN user_role ur ON u.id = ur.user_id
WHERE ur.role_id = ? AND deleted = 0
ORDER BY name;
        ",
            role.id
        )
        .fetch_all(db.deref_mut())
        .await
        .unwrap()
    }

    pub async fn cox(db: &SqlitePool) -> Vec<Self> {
        sqlx::query_as!(
            Self,
            "
SELECT id, name, pw, deleted, last_access, user_token
FROM user
WHERE deleted = 0 AND (SELECT COUNT(*) FROM user_role WHERE user_id=user.id AND role_id = (SELECT id FROM role WHERE name = 'cox')) > 0
ORDER BY last_access DESC
        "
        )
        .fetch_all(db)
        .await
        .unwrap()
    }

    pub async fn create(db: &SqlitePool, name: &str) {
        let name = name.trim();
        if sqlx::query!("INSERT INTO USER(name) VALUES (?)", name)
            .execute(db)
            .await
            .is_ok()
        {
            return;
        }

        sqlx::query!("UPDATE user SET deleted = false where name = ?", name)
            .execute(db)
            .await
            .unwrap();
    }

    pub async fn update(&self, db: &SqlitePool, data: UserEditForm) -> Result<(), String> {
        let mut db = db.begin().await.map_err(|e| e.to_string())?;

        sqlx::query!("UPDATE user SET name = ? where id = ?", data.name, self.id)
            .execute(db.deref_mut())
            .await
            .unwrap(); //Okay, because we can only create a User of a valid id

        // handle roles
        sqlx::query!("DELETE FROM user_role WHERE user_id = ?", self.id)
            .execute(db.deref_mut())
            .await
            .unwrap();

        for role_id in data.roles.into_keys() {
            let role = Role::find_by_id_tx(&mut db, role_id.parse::<i32>().unwrap())
                .await
                .unwrap();
            self.add_role_tx(&mut db, &role).await?;
        }

        db.commit().await.map_err(|e| e.to_string())?;

        Ok(())
    }

    pub async fn add_role(&self, db: &SqlitePool, role: &Role) -> Result<(), String> {
        sqlx::query!(
            "INSERT INTO user_role(user_id, role_id) VALUES (?, ?)",
            self.id,
            role.id
        )
        .execute(db)
        .await
        .map_err(|_| {
            format!(
                "User already has a role in the cluster '{}'",
                role.cluster
                    .clone()
                    .expect("db trigger can't activate on empty string")
            )
        })?;

        Ok(())
    }

    pub async fn add_role_tx(
        &self,
        db: &mut Transaction<'_, Sqlite>,
        role: &Role,
    ) -> Result<(), String> {
        sqlx::query!(
            "INSERT INTO user_role(user_id, role_id) VALUES (?, ?)",
            self.id,
            role.id
        )
        .execute(db.deref_mut())
        .await
        .map_err(|_| {
            format!(
                "User already has a role in the cluster '{}'",
                role.cluster
                    .clone()
                    .expect("db trigger can't activate on empty string")
            )
        })?;

        Ok(())
    }

    pub async fn remove_role(&self, db: &SqlitePool, role: &Role) {
        sqlx::query!(
            "DELETE FROM user_role WHERE user_id = ? and role_id = ?",
            self.id,
            role.id
        )
        .execute(db)
        .await
        .unwrap();
    }

    pub async fn login(db: &SqlitePool, name: &str, pw: &str) -> Result<Self, LoginError> {
        let name = name.trim().to_lowercase(); // just to make sure...
        let Some(user) = User::find_by_name(db, &name).await else {
            Log::create(db, format!("Username ({name}) not found (tried to login)")).await;
            return Err(LoginError::InvalidAuthenticationCombo); // Username not found
        };

        if user.deleted {
            Log::create(
                db,
                format!("User ({name}) already deleted (tried to login)."),
            )
            .await;
            return Err(LoginError::InvalidAuthenticationCombo); //User existed sometime ago; has
                                                                //been deleted
        }

        if let Some(user_pw) = user.pw.as_ref() {
            let password_hash = &Self::get_hashed_pw(pw);
            if password_hash == user_pw {
                return Ok(user);
            }
            Log::create(db, format!("User {name} supplied the wrong PW")).await;
            Err(LoginError::InvalidAuthenticationCombo)
        } else {
            info!("User {name} has no PW set");
            Err(LoginError::NoPasswordSet(Box::new(user)))
        }
    }

    pub async fn reset_pw(&self, db: &SqlitePool) {
        sqlx::query!("UPDATE user SET pw = null where id = ?", self.id)
            .execute(db)
            .await
            .unwrap(); //Okay, because we can only create a User of a valid id
    }

    pub async fn update_pw(&self, db: &SqlitePool, pw: &str) {
        let pw = Self::get_hashed_pw(pw);
        sqlx::query!("UPDATE user SET pw = ? where id = ?", pw, self.id)
            .execute(db)
            .await
            .unwrap(); //Okay, because we can only create a User of a valid id
    }

    fn get_hashed_pw(pw: &str) -> String {
        let salt = SaltString::from_b64("dS/X5/sPEKTj4Rzs/CuvzQ").unwrap();
        let argon2 = Argon2::default();
        argon2
            .hash_password(pw.as_bytes(), &salt)
            .unwrap()
            .to_string()
    }

    pub async fn logged_in(&self, db: &SqlitePool) {
        sqlx::query!(
            "UPDATE user SET last_access = CURRENT_TIMESTAMP where id = ?",
            self.id
        )
        .execute(db)
        .await
        .unwrap(); //Okay, because we can only create a User of a valid id
    }

    pub async fn delete(&self, db: &SqlitePool) {
        sqlx::query!("UPDATE user SET deleted=1 WHERE id=?", self.id)
            .execute(db)
            .await
            .unwrap(); //Okay, because we can only create a User of a valid id
    }

    pub async fn get_days(&self, db: &SqlitePool) -> Vec<Day> {
        let mut days = Vec::new();
        for i in 0..self.amount_days_to_show(db).await {
            let date = (Local::now() + chrono::Duration::days(i)).date_naive();

            if self.has_role(db, "scheckbuch").await {
                days.push(Day::new_guest(db, date, false).await);
            } else {
                days.push(Day::new(db, date, false).await);
            }
        }

        for date in TripDetails::pinned_days(db, self.amount_days_to_show(db).await - 1).await {
            if self.has_role(db, "scheckbuch").await {
                let day = Day::new_guest(db, date, true).await;
                if !day.events.is_empty() {
                    days.push(day);
                }
            } else {
                days.push(Day::new(db, date, true).await);
            }
        }
        days
    }

    pub(crate) async fn amount_days_to_show(&self, db: &SqlitePool) -> i64 {
        if self.allowed_to_steer(db).await {
            let end_of_year = NaiveDate::from_ymd_opt(Local::now().year(), 12, 31).unwrap(); //Ok,
                                                                                             //december
                                                                                             //has 31
                                                                                             //days
            let days_left_in_year = end_of_year
                .signed_duration_since(Local::now().date_naive())
                .num_days()
                + 1;

            if days_left_in_year <= 31 {
                let end_of_next_year =
                    NaiveDate::from_ymd_opt(Local::now().year() + 1, 12, 31).unwrap(); //Ok,
                                                                                       //december
                                                                                       //has 31
                                                                                       //days
                end_of_next_year
                    .signed_duration_since(Local::now().date_naive())
                    .num_days()
                    + 1
            } else {
                days_left_in_year
            }
        } else {
            AMOUNT_DAYS_TO_SHOW_TRIPS_AHEAD
        }
    }
}

#[async_trait]
impl<'r> FromRequest<'r> for User {
    type Error = LoginError;

    async fn from_request(req: &'r Request<'_>) -> request::Outcome<Self, Self::Error> {
        match req.cookies().get_private("loggedin_user") {
            Some(user_id) => match user_id.value().parse::<i32>() {
                Ok(user_id) => {
                    let db = req.rocket().state::<SqlitePool>().unwrap();
                    let Some(user) = User::find_by_id(db, user_id).await else {
                        return Outcome::Error((Status::Forbidden, LoginError::UserNotFound));
                    };
                    if user.deleted {
                        return Outcome::Error((Status::Forbidden, LoginError::UserDeleted));
                    }
                    user.logged_in(db).await;

                    let mut cookie = Cookie::new("loggedin_user", format!("{}", user.id));
                    cookie.set_expires(OffsetDateTime::now_utc() + Duration::weeks(2));
                    req.cookies().add_private(cookie);

                    Outcome::Success(user)
                }
                Err(_) => Outcome::Error((Status::Unauthorized, LoginError::DeserializationError)),
            },
            None => Outcome::Error((Status::Unauthorized, LoginError::NotLoggedIn)),
        }
    }
}

/// Creates a struct named $name. Allows to be created from a user, if one of the specified $roles are active for the user.
macro_rules! special_user {
    ($name:ident, $($role:tt)*) => {
        #[derive(Debug)]
        pub struct $name {
            pub(crate) user: User,
        }

        impl Deref for $name {
            type Target = User;
            fn deref(&self) -> &Self::Target {
                &self.user
            }
        }

        impl $name {
            pub fn into_inner(self) -> User {
                self.user
            }
        }

        #[async_trait]
        impl<'r> FromRequest<'r> for $name {
            type Error = LoginError;
            async fn from_request(req: &'r Request<'_>) -> request::Outcome<Self, Self::Error> {
                let db = req.rocket().state::<SqlitePool>().unwrap();
                match User::from_request(req).await {
                    Outcome::Success(user) => {
                        if special_user!(@check_roles user, db, $($role)*) {
                            Outcome::Success($name { user })
                        } else {
                            Outcome::Forward(Status::Forbidden)
                        }
                    }
                    Outcome::Error(f) => Outcome::Error(f),
                    Outcome::Forward(f) => Outcome::Forward(f),
                }
            }
        }

        impl $name {
            pub async fn new(db: &SqlitePool, user: User) -> Option<Self> {
                if special_user!(@check_roles user, db, $($role)*) {
                    Some($name { user })
                } else {
                    None
                }
            }
        }
    };
    (@check_roles $user:ident, $db:ident, $(+$role:expr),* $(,-$neg_role:expr)*) => {
        {
            let mut has_positive_role = false;
            $(
                if $user.has_role($db, $role).await {
                    has_positive_role = true;
                }
            )*
            has_positive_role
            $(
                && !$user.has_role($db, $neg_role).await
            )*
        }
    };
}

special_user!(SteeringUser, +"cox");
special_user!(AdminUser, +"admin");
special_user!(EventUser, +"manage_events");
special_user!(ManageUserUser, +"admin");
special_user!(AllowedToUpdateTripToAlwaysBeShownUser, +"admin");

#[cfg(test)]
mod test {
    use std::collections::HashMap;

    use crate::{tera::admin::user::UserEditForm, testdb};

    use super::User;
    use sqlx::SqlitePool;

    #[sqlx::test]
    fn test_find_correct_id() {
        let pool = testdb!();
        let user = User::find_by_id(&pool, 1).await.unwrap();
        assert_eq!(user.id, 1);
    }

    #[sqlx::test]
    fn test_find_wrong_id() {
        let pool = testdb!();
        let user = User::find_by_id(&pool, 1337).await;
        assert!(user.is_none());
    }

    #[sqlx::test]
    fn test_find_correct_name() {
        let pool = testdb!();
        let user = User::find_by_name(&pool, "admin".into()).await.unwrap();
        assert_eq!(user.id, 1);
    }

    #[sqlx::test]
    fn test_find_wrong_name() {
        let pool = testdb!();
        let user = User::find_by_name(&pool, "name-does-not-exist".into()).await;
        assert!(user.is_none());
    }

    #[sqlx::test]
    fn test_all() {
        let pool = testdb!();
        let res = User::all(&pool).await;
        assert!(res.len() > 3);
    }

    #[sqlx::test]
    fn test_cox() {
        let pool = testdb!();
        let res = User::cox(&pool).await;
        assert_eq!(res.len(), 4);
    }

    #[sqlx::test]
    fn test_succ_create() {
        let pool = testdb!();

        User::create(&pool, "new-user-name".into()).await;
    }

    #[sqlx::test]
    fn test_duplicate_name_create() {
        let pool = testdb!();

        User::create(&pool, "admin".into()).await;
    }

    #[sqlx::test]
    fn test_update() {
        let pool = testdb!();

        let user = User::find_by_id(&pool, 1).await.unwrap();
        user.update(
            &pool,
            UserEditForm {
                id: 1,
                name: "adminn".to_string(),
                roles: HashMap::new(),
            },
        )
        .await
        .unwrap();

        let user = User::find_by_id(&pool, 1).await.unwrap();

        assert_eq!(user.name, "adminn".to_string());
    }

    #[sqlx::test]
    fn succ_login_with_test_db() {
        let pool = testdb!();
        User::login(&pool, "admin".into(), "admin".into())
            .await
            .unwrap();
    }

    #[sqlx::test]
    fn wrong_pw() {
        let pool = testdb!();
        assert!(User::login(&pool, "admin".into(), "admi".into())
            .await
            .is_err());
    }

    #[sqlx::test]
    fn wrong_username() {
        let pool = testdb!();
        assert!(User::login(&pool, "admi".into(), "admin".into())
            .await
            .is_err());
    }

    #[sqlx::test]
    fn reset() {
        let pool = testdb!();
        let user = User::find_by_id(&pool, 1).await.unwrap();

        user.reset_pw(&pool).await;

        let user = User::find_by_id(&pool, 1).await.unwrap();
        assert_eq!(user.pw, None);
    }

    #[sqlx::test]
    fn update_pw() {
        let pool = testdb!();
        let user = User::find_by_id(&pool, 1).await.unwrap();

        assert!(User::login(&pool, "admin".into(), "abc".into())
            .await
            .is_err());

        user.update_pw(&pool, "abc".into()).await;

        User::login(&pool, "admin".into(), "abc".into())
            .await
            .unwrap();
    }
}