use std::collections::HashSet;
use std::convert::TryFrom;

use rusqlite::params;

use crate::database::Db;
use crate::id::Id;
use crate::result::RudeResult;
use crate::try_log;
use crate::world::Zone;

impl Db {
	/// Save a zone to the database.
	pub fn save_zone(&self, zone: &Zone) -> RudeResult<()> {
		let mut statement = try_log!(
			self.0.prepare(
				"insert into zones (id, parent, name, users_visible) values (?, ?, ?, ?) on conflict(id) do update set id=?, parent=?, name=?, users_visible=?;"
			),
			"Unable to prepare sql statement"
		);

		let _ = try_log!(
			statement.execute(params![
				zone.id,
				zone.parent,
				zone.name,
				zone.users_visible,
				zone.id,
				zone.parent,
				zone.name,
				zone.users_visible,
			]),
			"Unable to perform query"
		);

		Ok(())
	}

	/// Load a zone from the database.
	pub fn load_zone(&self, id: Id) -> RudeResult<Option<Zone>> {
		let mut statement = try_log!(
			self.0
				.prepare("select id, parent, name, users_visible from zones where id = ?"),
			"Unable to prepare sql statement"
		);

		let mut rows = try_log!(statement.query(params![id]), "Unable to perform query");

		let mut zone = if let Some(row) = try_log!(rows.next(), "Unable to retrieve row") {
			try_log!(Zone::try_from(row), "Unable to get Zone from Row")
		} else {
			return Ok(None);
		};

		zone.areas = {
			let mut a = HashSet::new();

			let mut statement = try_log!(
				self.0.prepare("select id from zones where parent = ?;"),
				"Unable to prepare sql statement"
			);

			let mut rows = try_log!(statement.query(params![id]), "Unable to perform query");

			while let Some(row) = try_log!(rows.next(), "Unable to retrieve row") {
				let new_id = try_log!(row.get(0), "Unable to retrieve field");
				if new_id != id {
					a.insert(new_id);
				}
			}

			let mut statement = try_log!(
				self.0.prepare("select id from rooms where zone = ?;"),
				"Unable to prepare sql statement"
			);

			let mut rows = try_log!(statement.query(params![id]), "Unable to perform query");

			while let Some(row) = try_log!(rows.next(), "Unable to retrieve row") {
				a.insert(try_log!(row.get(0), "Unable to retrieve field"));
			}

			a
		};

		Ok(Some(zone))
	}
}