#![cfg(not(feature = "no_function"))]
use rhai::{Dynamic, Engine, EvalAltResult, FnPtr, Func, FuncArgs, Scope, AST, INT};
use std::any::TypeId;

#[test]
fn test_call_fn() -> Result<(), Box<EvalAltResult>> {
    let engine = Engine::new();
    let mut scope = Scope::new();

    scope.push("foo", 42 as INT);

    let ast = engine.compile(
        "
            fn hello(x, y) {
                x + y
            }
            fn hello(x) {
                x *= foo;
                foo = 1;
                x
            }
            fn hello() {
                41 + foo
            }
            fn define_var(scale) {
                let bar = 21;
                bar * scale
            }
        ",
    )?;

    let r: INT = engine.call_fn(&mut scope, &ast, "hello", (42 as INT, 123 as INT))?;
    assert_eq!(r, 165);

    let r: INT = engine.call_fn(&mut scope, &ast, "hello", (123 as INT,))?;
    assert_eq!(r, 5166);

    let r: INT = engine.call_fn(&mut scope, &ast, "hello", ())?;
    assert_eq!(r, 42);

    assert_eq!(
        scope
            .get_value::<INT>("foo")
            .expect("variable foo should exist"),
        1
    );

    let r: INT = engine.call_fn(&mut scope, &ast, "define_var", (2 as INT,))?;
    assert_eq!(r, 42);

    assert!(!scope.contains("bar"));

    let args = [(2 as INT).into()];
    let r = engine
        .call_fn_raw(&mut scope, &ast, false, false, "define_var", None, args)?
        .as_int()
        .unwrap();
    assert_eq!(r, 42);

    assert_eq!(
        scope
            .get_value::<INT>("bar")
            .expect("variable bar should exist"),
        21
    );

    assert!(!scope.contains("scale"));

    Ok(())
}

#[test]
fn test_call_fn_scope() -> Result<(), Box<EvalAltResult>> {
    let engine = Engine::new();
    let mut scope = Scope::new();

    let ast = engine.compile(
        "
            fn foo(x) {
                let hello = 42;
                bar + hello + x
            }

            let bar = 123;
        ",
    )?;

    for _ in 0..50 {
        assert_eq!(
            engine
                .call_fn_raw(&mut scope, &ast, true, false, "foo", None, [Dynamic::THREE])?
                .as_int()?,
            168
        );
    }

    assert_eq!(scope.len(), 100);

    Ok(())
}

struct Options {
    pub foo: bool,
    pub bar: String,
    pub baz: INT,
}

impl FuncArgs for Options {
    fn parse<C: Extend<Dynamic>>(self, container: &mut C) {
        container.extend(Some(self.foo.into()));
        container.extend(Some(self.bar.into()));
        container.extend(Some(self.baz.into()));
    }
}

#[test]
fn test_call_fn_args() -> Result<(), Box<EvalAltResult>> {
    let options = Options {
        foo: false,
        bar: "world".to_string(),
        baz: 42,
    };

    let engine = Engine::new();
    let mut scope = Scope::new();

    let ast = engine.compile(
        "
            fn hello(x, y, z) {
                if x { `hello ${y}` } else { y + z }
            }
        ",
    )?;

    let result: String = engine.call_fn(&mut scope, &ast, "hello", options)?;

    assert_eq!(result, "world42");

    Ok(())
}

#[test]
fn test_call_fn_private() -> Result<(), Box<EvalAltResult>> {
    let engine = Engine::new();
    let mut scope = Scope::new();

    let ast = engine.compile("fn add(x, n) { x + n }")?;

    let r: INT = engine.call_fn(&mut scope, &ast, "add", (40 as INT, 2 as INT))?;
    assert_eq!(r, 42);

    let ast = engine.compile("private fn add(x, n, ) { x + n }")?;

    let r: INT = engine.call_fn(&mut scope, &ast, "add", (40 as INT, 2 as INT))?;
    assert_eq!(r, 42);

    Ok(())
}

#[test]
#[cfg(not(feature = "no_object"))]
fn test_fn_ptr_raw() -> Result<(), Box<EvalAltResult>> {
    let mut engine = Engine::new();

    engine
        .register_fn("mul", |x: &mut INT, y: INT| *x *= y)
        .register_raw_fn(
            "bar",
            &[
                TypeId::of::<INT>(),
                TypeId::of::<FnPtr>(),
                TypeId::of::<INT>(),
            ],
            move |context, args| {
                let fp = std::mem::take(args[1]).cast::<FnPtr>();
                let value = args[2].clone();
                let this_ptr = args.get_mut(0).unwrap();

                fp.call_raw(&context, Some(this_ptr), [value])
            },
        );

    assert_eq!(
        engine.eval::<INT>(
            r#"
                fn foo(x) { this += x; }

                let x = 41;
                x.bar(foo, 1);
                x
            "#
        )?,
        42
    );

    assert_eq!(
        engine.eval::<INT>(
            r#"
                fn foo(x, y) { this += x + y; }

                let x = 40;
                let v = 1;
                x.bar(Fn("foo").curry(v), 1);
                x
            "#
        )?,
        42
    );

    assert_eq!(
        engine.eval::<INT>(
            r#"
                private fn foo(x) { this += x; }

                let x = 41;
                x.bar(Fn("foo"), 1);
                x
            "#
        )?,
        42
    );

    assert_eq!(
        engine.eval::<INT>(
            r#"
                let x = 21;
                x.bar(Fn("mul"), 2);
                x
            "#
        )?,
        42
    );

    Ok(())
}

#[test]
fn test_anonymous_fn() -> Result<(), Box<EvalAltResult>> {
    let calc_func = Func::<(INT, INT, INT), INT>::create_from_script(
        Engine::new(),
        "fn calc(x, y, z,) { (x + y) * z }",
        "calc",
    )?;

    assert_eq!(calc_func(42, 123, 9)?, 1485);

    let calc_func = Func::<(INT, String, INT), INT>::create_from_script(
        Engine::new(),
        "fn calc(x, y, z) { (x + len(y)) * z }",
        "calc",
    )?;

    assert_eq!(calc_func(42, "hello".to_string(), 9)?, 423);

    let calc_func = Func::<(INT, String, INT), INT>::create_from_script(
        Engine::new(),
        "private fn calc(x, y, z) { (x + len(y)) * z }",
        "calc",
    )?;

    assert_eq!(calc_func(42, "hello".to_string(), 9)?, 423);

    let calc_func = Func::<(INT, &str, INT), INT>::create_from_script(
        Engine::new(),
        "fn calc(x, y, z) { (x + len(y)) * z }",
        "calc",
    )?;

    assert_eq!(calc_func(42, "hello", 9)?, 423);

    Ok(())
}

#[test]
fn test_call_fn_events() -> Result<(), Box<EvalAltResult>> {
    // Event handler
    struct Handler {
        // Scripting engine
        pub engine: Engine,
        // Use a custom 'Scope' to keep stored state
        pub scope: Scope<'static>,
        // Program script
        pub ast: AST,
    }

    const SCRIPT: &str = r#"
        fn start(data) { 42 + data }
        fn end(data) { 0 }
    "#;

    impl Handler {
        pub fn new() -> Self {
            let engine = Engine::new();

            // Create a custom 'Scope' to hold state
            let mut scope = Scope::new();

            // Add initialized state into the custom 'Scope'
            scope.push("state", false);

            // Compile the handler script.
            let ast = engine.compile(SCRIPT).unwrap();

            // Evaluate the script to initialize it and other state variables.
            // In a real application you'd again be handling errors...
            engine.run_ast_with_scope(&mut scope, &ast).unwrap();

            // The event handler is essentially these three items:
            Handler { engine, scope, ast }
        }

        // Say there are three events: 'start', 'end', 'update'.
        // In a real application you'd be handling errors...
        pub fn on_event(&mut self, event_name: &str, event_data: INT) -> Dynamic {
            let engine = &self.engine;
            let scope = &mut self.scope;
            let ast = &self.ast;

            match event_name {
                // The 'start' event maps to function 'start'.
                // In a real application you'd be handling errors...
                "start" => engine.call_fn(scope, ast, "start", (event_data,)).unwrap(),

                // The 'end' event maps to function 'end'.
                // In a real application you'd be handling errors...
                "end" => engine.call_fn(scope, ast, "end", (event_data,)).unwrap(),

                // The 'update' event maps to function 'update'.
                // This event provides a default implementation when the script-defined function is not found.
                "update" => engine
                    .call_fn(scope, ast, "update", (event_data,))
                    .or_else(|err| match *err {
                        EvalAltResult::ErrorFunctionNotFound(fn_name, ..)
                            if fn_name.starts_with("update") =>
                        {
                            // Default implementation of 'update' event handler
                            self.scope.set_value("state", true);
                            // Turn function-not-found into a success
                            Ok(Dynamic::UNIT)
                        }
                        _ => Err(err),
                    })
                    .unwrap(),
                // In a real application you'd be handling unknown events...
                _ => panic!("unknown event: {}", event_name),
            }
        }
    }

    let mut handler = Handler::new();
    assert!(!handler.scope.get_value::<bool>("state").unwrap());
    handler.on_event("update", 999);
    assert!(handler.scope.get_value::<bool>("state").unwrap());
    assert_eq!(handler.on_event("start", 999).as_int().unwrap(), 1041);

    Ok(())
}