mod parse;
use parse::Parse;
use surrealdb::dbs::Session;
use surrealdb::err::Error;
use surrealdb::kvs::Datastore;
use surrealdb::sql::Value;

#[tokio::test]
async fn future_function_simple() -> Result<(), Error> {
	let sql = "
		UPDATE person:test SET can_drive = <future> { birthday && time::now() > birthday + 18y };
		UPDATE person:test SET birthday = <datetime> '2007-06-22';
		UPDATE person:test SET birthday = <datetime> '2001-06-22';
	";
	let dbs = Datastore::new("memory").await?;
	let ses = Session::for_kv().with_ns("test").with_db("test");
	let res = &mut dbs.execute(&sql, &ses, None, false).await?;
	assert_eq!(res.len(), 3);
	//
	let tmp = res.remove(0).result?;
	let val = Value::parse("[{ id: person:test, can_drive: NONE }]");
	assert_eq!(tmp, val);
	//
	let tmp = res.remove(0).result?;
	let val =
		Value::parse("[{ id: person:test, birthday: '2007-06-22T00:00:00Z', can_drive: false }]");
	assert_eq!(tmp, val);
	//
	let tmp = res.remove(0).result?;
	let val =
		Value::parse("[{ id: person:test, birthday: '2001-06-22T00:00:00Z', can_drive: true }]");
	assert_eq!(tmp, val);
	//
	Ok(())
}

#[tokio::test]
async fn future_function_arguments() -> Result<(), Error> {
	let sql = "
		UPDATE future:test SET
			a = 'test@surrealdb.com',
			b = <future> { 'test@surrealdb.com' },
			x = 'a-' + parse::email::user(a),
			y = 'b-' + parse::email::user(b)
		;
	";
	let dbs = Datastore::new("memory").await?;
	let ses = Session::for_kv().with_ns("test").with_db("test");
	let res = &mut dbs.execute(&sql, &ses, None, false).await?;
	assert_eq!(res.len(), 1);
	//
	let tmp = res.remove(0).result?;
	let val = Value::parse(
		"[
			{
				a: 'test@surrealdb.com',
				b: 'test@surrealdb.com',
				id: 'future:test',
				x: 'a-test',
				y: 'b-test',
			}
		]",
	);
	assert_eq!(tmp, val);
	//
	Ok(())
}

#[tokio::test]
async fn concurrency() -> Result<(), Error> {
	// cargo test --package surrealdb --test future --features kv-mem --release -- concurrency --nocapture

	const MILLIS: usize = 50;

	// If all futures complete in less than double `MILLIS`, then they must have executed
	// concurrently. Otherwise, some executed sequentially.
	const TIMEOUT: usize = MILLIS * 19 / 10;

	/// Returns a query that will execute `count` futures that each wait for `millis`
	fn query(count: usize, millis: usize) -> String {
		// TODO: Find a simpler way to trigger the concurrent future case.
		format!(
			"SELECT foo FROM [[{}]] TIMEOUT {TIMEOUT}ms;",
			(0..count)
				.map(|i| format!("<future>{{[sleep({millis}ms), {{foo: {i}}}]}}"))
				.collect::<Vec<_>>()
				.join(", ")
		)
	}

	/// Returns `true` iif `limit` futures are concurrently executed.
	async fn test_limit(limit: usize) -> Result<bool, Error> {
		let sql = query(limit, MILLIS);
		let dbs = Datastore::new("memory").await?;
		let ses = Session::for_kv().with_ns("test").with_db("test");
		let res = dbs.execute(&sql, &ses, None, false).await;

		if matches!(res, Err(Error::QueryTimedout)) {
			Ok(false)
		} else {
			let res = res?;
			assert_eq!(res.len(), 1);

			let res = res.into_iter().next().unwrap();

			let elapsed = res.time.as_millis() as usize;

			Ok(elapsed < TIMEOUT)
		}
	}

	// Diagnostics.
	/*
	for i in (1..=80).step_by(8) {
		println!("{i} futures => {}", test_limit(i).await?);
	}
	*/

	assert!(test_limit(3).await?);

	// Too slow to *parse* query in debug mode.
	#[cfg(not(debug_assertions))]
	assert!(!test_limit(64 /* surrealdb::cnf::MAX_CONCURRENT_TASKS */ + 1).await?);

	Ok(())
}