use crate::{
  AdapterPool,
  Result,
  db::{
    Channel,
    ChannelId,
    FeedId,
    Item,
    UserId,
    channel::UnparsedChannel,
    item::UnparsedItem,
  },
};

pub struct UnparsedFeed {
  pub id: i64,
  pub title: String,
}
impl UnparsedFeed {
  pub fn parse(self) -> Result<Feed> {
    Ok(Feed {
      id: FeedId(self.id),
      title: self.title,
    })
  }
}

pub struct Feed {
  id: FeedId,
  title: String,
}

impl Feed {
  pub fn id(&self) -> FeedId { self.id }
  pub fn title(&self) -> &str { &self.title }

  pub async fn get(
    pool: &AdapterPool, id: FeedId
  ) -> Result<Self> {
    let feed = sqlx::query_as!(
      UnparsedFeed,
      "SELECT id, title FROM feeds WHERE id = ?",
      id.0
    ).fetch_one(&pool.0).await?.parse();

    feed
  }

  pub async fn create(
    pool: &AdapterPool, user_id: UserId, title: &str
  ) -> Result<Self> {
    let int_id = i64::from(user_id);
    let new_feed = sqlx::query_as!(
      UnparsedFeed,
      "INSERT INTO feeds (user_id, title) 
       VALUES (?, ?)
       RETURNING id as `id!`, title",
      int_id, title
    ).fetch_one(&pool.0).await?.parse();

    new_feed
  }

  pub async fn update_title(
    pool: &AdapterPool, id: FeedId, new_title: &str
  ) -> Result<()> {
    sqlx::query!(
      "UPDATE feeds SET title = ? WHERE id = ?",
      new_title, id.0
    ).execute(&pool.0).await?;

    Ok(())
  }

  pub async fn add_channel(
    &self, pool: &AdapterPool, channel_id: ChannelId
  ) -> Result<()> {
    let int_channel_id = i64::from(channel_id);
    sqlx::query!(
      "INSERT INTO feed_channels (feed_id, channel_id)
       VALUES (?, ?)",
      self.id.0, int_channel_id
    ).execute(&pool.0).await?;

    Ok(())
  }

  pub async fn get_items(
    &self, pool: &AdapterPool, limit: u8, offset: u32
  ) -> Result<Vec<Item>> {
    let items: Result<Vec<Item>> = sqlx::query_as!(
      UnparsedItem,
      "SELECT i.id as `id!`, i.channel_id, i.guid, i.fetched_at, i.title,
         i.description, i.content
       FROM items i
       JOIN feed_items fi on i.id = fi.item_id
       WHERE feed_id = ? AND archived = FALSE
       ORDER BY score DESC
       LIMIT ? OFFSET ?",
      self.id.0, limit, offset
    ).fetch_all(&pool.0).await?.into_iter().map(UnparsedItem::parse).collect();

    items
  }

  pub async fn get_channels(
    &self, pool: &AdapterPool
  ) -> Result<Vec<Channel>> {
    let channels: Result<Vec<Channel>> = sqlx::query_as!(
      UnparsedChannel,
      "SELECT c.id as `id!`, c.title, c.link, c.description, c.last_fetched
       FROM channels c
       JOIN feed_channels fc on c.id = fc.channel_id
       WHERE fc.feed_id = ?",
      self.id.0
    ).fetch_all(&pool.0).await?.into_iter()
      .map(UnparsedChannel::parse).collect();

    channels
  }
}

#[cfg(test)]
mod tests {
  use super::*;
  use crate::{
    Adapter,
    AdapterBuilder,
    db::User,
  };

  async fn setup_adapter() -> Adapter {
    AdapterBuilder::new()
      .database_url("sqlite::memory:")
      .create().await.unwrap()
  }

  #[tokio::test]
  async fn create_feed() {
    let adapter = setup_adapter().await;
		let pool = adapter.get_pool();
    let user = User::create(pool, "Alice").await.unwrap();

    let feed = Feed::create(pool, user.id(), "Tech News").await.unwrap();

    assert_eq!(feed.title(), "Tech News");
    assert!(feed.id().0 > 0);
  }

  #[tokio::test]
  async fn test_update_title() {
    let adapter = setup_adapter().await;
		let pool = adapter.get_pool();
    let user = User::create(pool, "Alice").await.unwrap();
    let feed = Feed::create(pool, user.id(), "Tech News").await.unwrap();

    Feed::update_title(pool, feed.id(), "Technology").await.unwrap();

    let updated = Feed::get(pool, feed.id()).await.unwrap();
    assert_eq!(updated.title(), "Technology");
  }
}