use serde_derive::{Deserialize, Serialize};
use std::borrow::Borrow;
use std::ops::DerefMut;

use sqlx::pool::PoolConnection;
use sqlx::Sqlite;

use crate::db::errors::DatabaseError;
use crate::db::model_utils::Period;
use crate::db::tag::Tag;
use crate::types::EmgauwaUid;

#[derive(Debug, Serialize, Clone)]
pub struct Schedule {
	#[serde(skip)]
	pub id: i64,
	#[serde(rename(serialize = "id"))]
	pub uid: EmgauwaUid,
	pub name: String,
	pub periods: Periods,
}

#[derive(Debug, Serialize, Deserialize, PartialEq, Clone)]
pub struct Periods(pub Vec<Period>);

impl Schedule {
	pub async fn get_all(
		conn: &mut PoolConnection<Sqlite>,
	) -> Result<Vec<Schedule>, DatabaseError> {
		Ok(sqlx::query_as!(Schedule, "SELECT * FROM schedules")
			.fetch_all(conn.deref_mut())
			.await?)
	}

	pub async fn get_by_uid(
		conn: &mut PoolConnection<Sqlite>,
		filter_uid: &EmgauwaUid,
	) -> Result<Schedule, DatabaseError> {
		sqlx::query_as!(
			Schedule,
			"SELECT * FROM schedules WHERE uid = ?",
			filter_uid
		)
		.fetch_optional(conn.deref_mut())
		.await
		.map(|s| s.ok_or(DatabaseError::NotFound))?
	}

	pub async fn get_by_tag(
		conn: &mut PoolConnection<Sqlite>,
		tag: &Tag,
	) -> Result<Vec<Schedule>, DatabaseError> {
		Ok(sqlx::query_as!(Schedule, "SELECT schedule.* FROM schedules AS schedule INNER JOIN junction_tag ON junction_tag.schedule_id = schedule.id WHERE junction_tag.tag_id = ?", tag.id)
			.fetch_all(conn.deref_mut())
			.await?)
	}

	pub async fn delete_by_uid(
		conn: &mut PoolConnection<Sqlite>,
		filter_uid: EmgauwaUid,
	) -> Result<(), DatabaseError> {
		let filter_uid = match filter_uid {
			EmgauwaUid::Off => Err(DatabaseError::Protected),
			EmgauwaUid::On => Err(DatabaseError::Protected),
			EmgauwaUid::Any(_) => Ok(filter_uid),
		}?;

		sqlx::query!("DELETE FROM schedules WHERE uid = ?", filter_uid)
			.execute(conn.deref_mut())
			.await
			.map(|res| match res.rows_affected() {
				0 => Err(DatabaseError::DeleteError),
				_ => Ok(()),
			})?
	}

	pub async fn create(
		conn: &mut PoolConnection<Sqlite>,
		new_name: &str,
		new_periods: &Periods,
	) -> Result<Schedule, DatabaseError> {
		let uid = EmgauwaUid::default();
		sqlx::query_as!(
			Schedule,
			"INSERT INTO schedules (uid, name, periods) VALUES (?, ?, ?) RETURNING *",
			uid,
			new_name,
			new_periods,
		)
		.fetch_optional(conn.deref_mut())
		.await?
		.ok_or(DatabaseError::InsertGetError)
	}

	pub async fn update(
		&self,
		conn: &mut PoolConnection<Sqlite>,
		new_name: &str,
		new_periods: &Periods,
	) -> Result<Schedule, DatabaseError> {
		// overwrite periods on protected schedules
		let new_periods = match self.uid {
			EmgauwaUid::Off | EmgauwaUid::On => self.periods.borrow(),
			EmgauwaUid::Any(_) => new_periods,
		};

		sqlx::query!(
			"UPDATE schedules SET name = ?, periods = ? WHERE id = ?",
			new_name,
			new_periods,
			self.id,
		)
		.execute(conn.deref_mut())
		.await?;

		Schedule::get_by_uid(conn, &self.uid).await
	}

	pub async fn get_tags(
		&self,
		conn: &mut PoolConnection<Sqlite>,
	) -> Result<Vec<String>, DatabaseError> {
		Ok(sqlx::query_scalar!("SELECT tag FROM tags INNER JOIN junction_tag ON junction_tag.tag_id = tags.id WHERE junction_tag.schedule_id = ?", self.id)
			.fetch_all(conn.deref_mut())
			.await?)
	}

	pub async fn set_tags(
		&self,
		conn: &mut PoolConnection<Sqlite>,
		new_tags: &[String],
	) -> Result<(), DatabaseError> {
		sqlx::query!("DELETE FROM junction_tag WHERE schedule_id = ?", self.id)
			.execute(conn.deref_mut())
			.await?;

		for new_tag in new_tags {
			let tag: Option<Tag> =
				sqlx::query_as!(Tag, "SELECT * FROM tags WHERE tag = ?", new_tag)
					.fetch_optional(conn.deref_mut())
					.await?;

			let tag = match tag {
				Some(id) => id,
				None => Tag::create(conn, new_tag).await?,
			};

			tag.link_schedule(conn, self).await?;
		}
		Ok(())
	}
}