use argon2::PasswordVerifier;
use argon2::PasswordHash;
use diesel_derive_enum::DbEnum;
use crate::diesel::QueryDsl;
use crate::diesel::BoolExpressionMethods;
use crate::diesel::ExpressionMethods;
use crate::diesel::Connection;
use rocket_sync_db_pools::database;
use serde::{Serialize, Deserialize};
use rocket::{Rocket, Build};
use diesel::RunQueryDsl;
use argon2::{
    password_hash::{
        rand_core::OsRng,
        PasswordHasher
    },
    Argon2
};
use argon2::password_hash::SaltString;

#[database("gamenight_database")]
pub struct DbConn(diesel::SqliteConnection);

table! {
    gamenight (id) {
        id -> Integer,
        game -> Text,
        datetime -> Text,
    }
}

table! {
    known_games (game) {
        id -> Integer,
        game -> Text,
    }
}

table! {
    use diesel::sql_types::Integer;
    use diesel::sql_types::Text;
    use super::RoleMapping;
    user(id) {
        id -> Integer,
        username -> Text,
        email -> Text,
        role -> RoleMapping,
    }
}

table! {
    pwd(id) {
        id -> Integer,
        password -> Text,
    }
}

allow_tables_to_appear_in_same_query!(
    gamenight,
    known_games,
);

pub enum DatabaseError {
    Hash(password_hash::Error),
    Query(String)
}

impl std::fmt::Display for DatabaseError {
    
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::result::Result<(), std::fmt::Error> {
        match self {
            DatabaseError::Hash(err) => write!(f, "{}", err),
            DatabaseError::Query(err) => write!(f, "{}", err)
        }  
    }
}

pub async fn get_all_gamenights(conn: DbConn) -> Vec::<GameNight> {
    conn.run(|c| {
        gamenight::table.load::<GameNight>(c).unwrap()
    }).await
}

pub async fn insert_gamenight(conn: DbConn, new_gamenight: GameNightNoId) -> () {
    conn.run(|c| {
        diesel::insert_into(gamenight::table)
            .values(new_gamenight)
            .execute(c)
            .unwrap()
    }).await;
}

pub async fn insert_user(conn: DbConn, new_user: Register) -> Result<(), DatabaseError> {
    let salt = SaltString::generate(&mut OsRng);

    let argon2 = Argon2::default();

    let password_hash = match argon2.hash_password(new_user.password.as_bytes(), &salt) {
         Ok(hash) => hash.to_string(),
         Err(error) => return Err(DatabaseError::Hash(error))
    };

    match conn.run(move |c| {
        c.transaction(|| {
            diesel::insert_into(user::table)
                .values((user::username.eq(&new_user.username), user::email.eq(&new_user.email), user::role.eq(Role::User)))
                .execute(c)?;
    
            let ids : Vec::<i32> = match user::table
                .filter(user::username.eq(&new_user.username).and(user::email.eq(&new_user.email)))
                .select(user::id)
                .get_results(c) {
                    Ok(id) => id,
                    Err(e) => return Err(e)
                };

            diesel::insert_into(pwd::table)
                .values((pwd::id.eq(ids[0]), pwd::password.eq(&password_hash)))
                .execute(c)
        })
    }).await {
        Err(e) => Err(DatabaseError::Query(e.to_string())),
        _ => Ok(()),
    }
}

pub async fn login(conn: DbConn, login: Login) -> Result<LoginResult, DatabaseError> {
    conn.run(move |c| -> Result<LoginResult, DatabaseError> {
        let id : i32 = match user::table
            .filter(user::username.eq(&login.username))
            .or_filter(user::email.eq(&login.username))
            .select(user::id)
            .get_results(c) {
                Ok(id) => id[0],
                Err(error) => return Err(DatabaseError::Query(error.to_string()))
            };
        
        let pwd : String = match pwd::table
            .filter(pwd::id.eq(id))
            .select(pwd::password)
            .get_results::<String>(c) {
                Ok(pwd) => pwd[0].clone(),
                Err(error) => return Err(DatabaseError::Query(error.to_string()))
            };

        let parsed_hash = match PasswordHash::new(&pwd) {
            Ok(hash) => hash,
            Err(error) => return Err(DatabaseError::Hash(error))
        };

        if Argon2::default().verify_password(&login.password.as_bytes(), &parsed_hash).is_ok() {
            
            let role : Role = match user::table
                .filter(user::id.eq(id))
                .select(user::role)
                .get_results::<Role>(c) {
                    Ok(role) => role[0].clone(),
                    Err(error) => return Err(DatabaseError::Query(error.to_string()))
                };

            Ok(LoginResult {
                result: true,
                id: Some(id),
                role: Some(role)
            })
        } 
        else {
            Ok(LoginResult {
                result: false,
                id: None,
                role: None,
            })
        }
    }).await
}

pub async fn get_user(conn: DbConn, id: i32) -> User {
    conn.run(move |c| {
        user::table
            .filter(user::id.eq(id))
            .first(c)
            .unwrap()
    }).await
}

pub async fn run_migrations(rocket: Rocket<Build>) -> Rocket<Build> {
    // This macro from `diesel_migrations` defines an `embedded_migrations`
    // module containing a function named `run`. This allows the example to be
    // run and tested without any outside setup of the database.
    embed_migrations!();

    let conn = DbConn::get_one(&rocket).await.expect("database connection");
    conn.run(|c| embedded_migrations::run(c)).await.expect("can run migrations");

    rocket
}

#[derive(Debug, Serialize, Deserialize, DbEnum, Clone)]
pub enum Role {
    Admin,
    User,
}

#[derive(Serialize, Deserialize, Debug, Insertable, Queryable)]
#[table_name="user"]
pub struct User {
    pub id: i32,
    pub username: String,
    pub email: String,
    pub role: Role
}

#[derive(Serialize, Deserialize, Debug, FromForm, Insertable)]
#[table_name="known_games"]
pub struct GameNoId {
    pub game : String,
}

#[derive(Serialize, Deserialize, Debug, FromForm, Queryable)]
pub struct Game {
    pub id: i32,
    pub game : String,
}

#[derive(Serialize, Deserialize, Debug, FromForm, Insertable)]
#[table_name="gamenight"]
pub struct GameNightNoId {
    pub game : String,
    pub datetime : String, 
}

#[derive(Serialize, Deserialize, Debug, FromForm, Queryable)]
pub struct GameNight {
    pub id: i32,
    pub game : String,
    pub datetime : String, 
}

#[derive(Serialize, Deserialize, Debug)]
pub struct Register {
    pub username: String,
    pub email: String,
    pub password: String,
    pub password_repeat: String,
}

#[derive(Serialize, Deserialize, Debug)]
pub struct Login {
    pub username: String,
    pub password: String
}

#[derive(Serialize, Deserialize, Debug)]
pub struct LoginResult {
    pub result: bool,
    pub id: Option<i32>,
    pub role: Option<Role>
}