use std::panic::catch_unwind;

use mlua::{Error, Function, Result, Thread, ThreadStatus};

include!("_lua.rs");

#[test]
fn test_thread() -> Result<()> {
    let lua = make_lua();

    let thread = lua.create_thread(
        lua.load(
            r#"
                function (s)
                    local sum = s
                    for i = 1,4 do
                        sum = sum + coroutine.yield(sum)
                    end
                    return sum
                end
            "#,
        )
        .eval()?,
    )?;

    assert_eq!(thread.status(), ThreadStatus::Resumable);
    assert_eq!(thread.resume::<_, i64>(0)?, 0);
    assert_eq!(thread.status(), ThreadStatus::Resumable);
    assert_eq!(thread.resume::<_, i64>(1)?, 1);
    assert_eq!(thread.status(), ThreadStatus::Resumable);
    assert_eq!(thread.resume::<_, i64>(2)?, 3);
    assert_eq!(thread.status(), ThreadStatus::Resumable);
    assert_eq!(thread.resume::<_, i64>(3)?, 6);
    assert_eq!(thread.status(), ThreadStatus::Resumable);
    assert_eq!(thread.resume::<_, i64>(4)?, 10);
    assert_eq!(thread.status(), ThreadStatus::Unresumable);

    let accumulate = lua.create_thread(
        lua.load(
            r#"
                function (sum)
                    while true do
                        sum = sum + coroutine.yield(sum)
                    end
                end
            "#,
        )
        .eval::<Function>()?,
    )?;

    for i in 0..4 {
        accumulate.resume::<_, ()>(i)?;
    }
    assert_eq!(accumulate.resume::<_, i64>(4)?, 10);
    assert_eq!(accumulate.status(), ThreadStatus::Resumable);
    assert!(accumulate.resume::<_, ()>("error").is_err());
    assert_eq!(accumulate.status(), ThreadStatus::Error);

    let thread = lua
        .load(
            r#"
            coroutine.create(function ()
                while true do
                    coroutine.yield(42)
                end
            end)
        "#,
        )
        .eval::<Thread>()?;
    assert_eq!(thread.status(), ThreadStatus::Resumable);
    assert_eq!(thread.resume::<_, i64>(())?, 42);

    let thread: Thread = lua
        .load(
            r#"
            coroutine.create(function(arg)
                assert(arg == 42)
                local yieldarg = coroutine.yield(123)
                assert(yieldarg == 43)
                return 987
            end)
        "#,
        )
        .eval()?;

    assert_eq!(thread.resume::<_, u32>(42)?, 123);
    assert_eq!(thread.resume::<_, u32>(43)?, 987);

    match thread.resume::<_, u32>(()) {
        Err(Error::CoroutineInactive) => {}
        Err(_) => panic!("resuming dead coroutine error is not CoroutineInactive kind"),
        _ => panic!("resuming dead coroutine did not return error"),
    }

    Ok(())
}

#[test]
fn coroutine_from_closure() -> Result<()> {
    let lua = make_lua();

    let thrd_main = lua.create_function(|_, ()| Ok(()))?;
    lua.globals().set("main", thrd_main)?;
    let thrd: Thread = lua.load("coroutine.create(main)").eval()?;
    thrd.resume::<_, ()>(())?;

    Ok(())
}

#[test]
fn coroutine_panic() {
    match catch_unwind(|| -> Result<()> {
        // check that coroutines propagate panics correctly
        let lua = make_lua();
        let thrd_main = lua.create_function(|_, ()| -> Result<()> {
            panic!("test_panic");
        })?;
        lua.globals().set("main", thrd_main.clone())?;
        let thrd: Thread = lua.create_thread(thrd_main)?;
        thrd.resume(())
    }) {
        Ok(r) => panic!("coroutine panic not propagated, instead returned {:?}", r),
        Err(p) => assert!(*p.downcast::<&str>().unwrap() == "test_panic"),
    }
}