use sqlx::SqlitePool;
use crate::{
  Result,
  Feed,
  feed::UnparsedFeed,
};

#[derive(Copy, Clone)]
pub struct UserId(i64);
impl From<UserId> for i64 { fn from(id: UserId) -> Self { id.0 } }

pub struct UnparsedUser {
  pub id: i64,
  pub name: String,
}
impl UnparsedUser {
  pub fn parse(self) -> Result<User> {
    Ok(User {
      id: UserId(self.id),
      name: self.name
    })
  }
}

pub struct User {
  id: UserId,
  name: String,
}

impl User {
  pub fn id(&self) -> UserId { self.id }
  pub fn name(&self) -> &str { &self.name }

  pub async fn get(pool: &SqlitePool, id: UserId) -> Result<Self> {
    let user = sqlx::query_as!(
      UnparsedUser,
      "SELECT id, name FROM users WHERE id = ?",
      id.0
    ).fetch_one(pool).await?.parse();

    user
  }
  pub async fn get_all(pool: &SqlitePool) -> Result<Vec<Self>> {
    let users: Result<Vec<Self>> = sqlx::query_as!(
      UnparsedUser,
      "SELECT id, name FROM users"
    ).fetch_all(pool).await?.into_iter().map(UnparsedUser::parse).collect();

    users
  }

  pub async fn create(pool: &SqlitePool, name: &str) -> Result<Self> {
    let result = sqlx::query!(
      "INSERT INTO users (name)
       VALUES (?)
       RETURNING id, name",
      name
    ).fetch_one(pool).await?;

    Ok(Self {
      id: UserId(result.id),
      name: result.name,
    })
  }

  pub async fn update_name(
      pool: &SqlitePool, id: UserId, new_name: &str
  ) -> Result<()> {
    sqlx::query!(
      "UPDATE users SET name = ? WHERE id = ?",
      new_name, id.0
    ).execute(pool).await?;

    Ok(())
  }

  pub async fn get_feeds(&self, pool: &SqlitePool) -> Result<Vec<Feed>> {
    let feeds: Result<Vec<Feed>> = sqlx::query_as!(
        UnparsedFeed,
        "SELECT id, title FROM feeds WHERE user_id = ?",
        self.id.0
      ).fetch_all(pool).await?.into_iter()
        .map(UnparsedFeed::parse).collect();

    feeds
  }
}

#[cfg(test)]
mod tests {
  use super::*;
  use sqlx::SqlitePool;

  async fn setup_test_db() -> SqlitePool {
    let pool = SqlitePool::connect("sqlite::memory:").await.unwrap();
    sqlx::migrate!().run(&pool).await.unwrap();
    pool
  }
  
  #[tokio::test]
  async fn get_user() {
    let pool = setup_test_db().await;

    let new_user = User::create(&pool, "Alice").await.unwrap();

    let fetched_user = User::get(&pool, new_user.id).await.unwrap();
    assert_eq!(fetched_user.name, "Alice");
    assert!(fetched_user.id.0 > 0);
  }

  #[tokio::test]
  async fn create_user() {
    let pool = setup_test_db().await;

    let user = User::create(&pool, "Alice").await.unwrap();

    assert_eq!(user.name, "Alice");
    assert!(user.id.0 > 0);
  }
  
  #[tokio::test]
  async fn create_duplicate_user() {
    let pool = setup_test_db().await;

    let _user = User::create(&pool, "Alice").await.unwrap();
    let duplicate_user = User::create(&pool, "Alice").await;

    assert!(duplicate_user.is_err());
  }
  
  #[tokio::test]
  async fn get_all_users() {
    let pool = setup_test_db().await;

    User::create(&pool, "Alice").await.unwrap();
    User::create(&pool, "Bob").await.unwrap();

    let users = User::get_all(&pool).await.unwrap();

    assert_eq!(users.len(), 2);
    assert!(users.iter().any(|u| u.name == "Alice"));
    assert!(users.iter().any(|u| u.name == "Bob"));
  }

  #[tokio::test]
  async fn update_name() {
    let pool = setup_test_db().await;

    let user = User::create(&pool, "Alice").await.unwrap();
    User::update_name(&pool, user.id, "Alicia").await.unwrap();

    let updated = User::get(&pool, user.id).await.unwrap();
    assert_eq!(updated.name, "Alicia");
  }
  
  #[tokio::test]
  async fn update_name_to_duplicate() {
    let pool = setup_test_db().await;

    let alice = User::create(&pool, "Alice").await.unwrap();
    let _sam = User::create(&pool, "Sam").await.unwrap();
    let status = User::update_name(&pool, alice.id, "Sam").await;

    assert!(status.is_err());
  }

  #[tokio::test]
  async fn get_feeds_empty() {
    let pool = setup_test_db().await;

    let user = User::create(&pool, "Alice").await.unwrap();
    let feeds = user.get_feeds(&pool).await.unwrap();

    assert_eq!(feeds.len(), 0);
  }
}