use argon2::{password_hash::SaltString, Argon2, PasswordHash, PasswordHasher, PasswordVerifier};
use axum::async_trait;
use como_core::users::UserService;
use como_domain::Context;
use rand_core::OsRng;

use crate::database::ConnectionPool;

pub struct DefaultUserService {
    pool: ConnectionPool,
}

impl DefaultUserService {
    pub fn new(pool: ConnectionPool) -> Self {
        Self { pool }
    }

    fn hash_password(&self, _context: &Context, password: String) -> anyhow::Result<String> {
        let salt = SaltString::generate(&mut OsRng);
        let argon2 = Argon2::default();

        let password_hash = argon2
            .hash_password(password.as_bytes(), &salt)
            .map_err(|e| anyhow::anyhow!(e))?
            .to_string();

        Ok(password_hash)
    }

    fn validate_password(
        &self,
        _context: &Context,
        password: String,
        hashed_password: String,
    ) -> anyhow::Result<bool> {
        let argon2 = Argon2::default();

        let parsed_hash = PasswordHash::new(&hashed_password).map_err(|e| anyhow::anyhow!(e))?;
        match argon2.verify_password(password.as_bytes(), &parsed_hash) {
            Ok(..) => Ok(true),
            Err(..) => Ok(false),
        }
    }
}

#[async_trait]
impl UserService for DefaultUserService {
    async fn add_user(
        &self,
        context: &Context,
        username: String,
        password: String,
    ) -> anyhow::Result<String> {
        let hashed_password = self.hash_password(context, password)?;

        let rec = sqlx::query!(
            r#"
            INSERT INTO users (username, password_hash) 
            VALUES ( $1, $2 ) 
            RETURNING id
            "#,
            username,
            hashed_password
        )
        .fetch_one(&self.pool)
        .await?;

        Ok(rec.id.to_string())
    }

    async fn validate_user(
        &self,
        context: &Context,
        username: String,
        password: String,
    ) -> anyhow::Result<Option<String>> {
        let rec = sqlx::query!(
            r#"
            SELECT * from users
            where username=$1
            "#,
            username,
        )
        .fetch_optional(&self.pool)
        .await?;

        match rec {
            Some(user) => match self.validate_password(context, password, user.password_hash)? {
                true => Ok(Some(user.id.to_string())),
                false => Ok(None),
            },
            None => Ok(None),
        }
    }
}