use std::error::Error;
use reqwest::{
  IntoUrl,
  Client,
};
use rss::Channel as RawChannel;

type Result<T> = std::result::Result<T, Box<dyn Error>>;

pub struct AdapterOptions {
  database_url: String,
}

impl AdapterOptions {
  pub fn new() -> Self {
    Self {
      database_url: "sqlite:test.db".to_string(),
    }
  }

  pub fn database_url(mut self, url: &str) -> Self {
    self.database_url = url.to_string();
    self
  }

  pub async fn create(self) -> Result<Adapter> {
    let db = sqlx::sqlite::SqlitePoolOptions::new()
      .connect(&self.database_url).await?;

    Ok(Adapter { db })
  }
}

pub struct Adapter {
  db: sqlx::SqlitePool,
}

impl Adapter {
  pub async fn get_all_users(&self) -> Result<Vec<User>> {
      let users_query = sqlx::query!("SELECT id, name FROM users")
        .fetch_all(&self.db).await?;

      let mut all_users: Vec<User> = Vec::with_capacity(users_query.len());

      for user in users_query {
        all_users.push(User {
          id: user.id,
          name: user.name,
        })
      }

      Ok(all_users)
  }

  fn get_pool(&self) -> &sqlx::SqlitePool { &self.db }
}

pub struct User {
  id: i64,
  name: String,
}

impl User {
  pub async fn get_by_id(adapter: &Adapter, id: i64) -> Result<Self> {
    let user = sqlx::query!("SELECT name FROM users WHERE id = ?", id)
      .fetch_one(adapter.get_pool()).await?;

    Ok(Self {
      id: id,
      name: user.name,
    })
  }

  pub async fn create(adapter: &Adapter, name: &str) -> Result<Self> {
    let result = sqlx::query!("INSERT INTO users (name) VALUES (?)", name)
      .execute(adapter.get_pool()).await?;

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

  pub async fn change_name(
      &mut self, adapter: &Adapter, new_name: &str) -> Result<()> {
    sqlx::query!(
      "UPDATE users SET name = ? WHERE id = ?",
      new_name, self.id
    ).execute(adapter.get_pool()).await?;

    self.name = new_name.to_string();

    Ok(())
  }

  pub fn name(&self) -> &str { &self.name }
  pub fn id(&self) -> i64 { self.id }
}

pub struct Channel {
  pub channel: rss::Channel,
}

pub async fn fetch_channel<T: IntoUrl>(
  client: &Client, url: T) -> Result<Channel> {
  let content = client.get(url)
    .send().await?
    .bytes().await?;

  let raw_channel = RawChannel::read_from(&content[..])?;
  println!("{}", raw_channel.title);
  Ok(Channel { channel: raw_channel })
}