use crate::{
    convert::{IteratorJs, List},
    value::Constructor,
    Array, Ctx, Error, IntoAtom, IntoJs, Object, Result, StdResult, StdString, String, Value,
};
use std::{
    cell::{Cell, RefCell},
    collections::{BTreeMap, BTreeSet, HashMap, HashSet, LinkedList, VecDeque},
    sync::{Mutex, RwLock},
    time::SystemTime,
};

#[cfg(feature = "either")]
use either::{Either, Left, Right};

#[cfg(feature = "indexmap")]
use indexmap::{IndexMap, IndexSet};

impl<'js> IntoJs<'js> for Value<'js> {
    fn into_js(self, _: &Ctx<'js>) -> Result<Value<'js>> {
        Ok(self)
    }
}

impl<'js> IntoJs<'js> for &Value<'js> {
    fn into_js(self, _: &Ctx<'js>) -> Result<Value<'js>> {
        Ok(self.clone())
    }
}

impl<'js> IntoJs<'js> for StdString {
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        self.as_str().into_js(ctx)
    }
}

impl<'js> IntoJs<'js> for &StdString {
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        self.as_str().into_js(ctx)
    }
}

impl<'js> IntoJs<'js> for &str {
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        String::from_str(ctx.clone(), self).map(|String(value)| value)
    }
}

impl<'js, T> IntoJs<'js> for &[T]
where
    for<'a> &'a T: IntoJs<'js>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        self.iter()
            .collect_js(ctx)
            .map(|Array(value)| value.into_value())
    }
}

impl<'js> IntoJs<'js> for () {
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        Ok(Value::new_undefined(ctx.clone()))
    }
}

impl<'js> IntoJs<'js> for &() {
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        Ok(Value::new_undefined(ctx.clone()))
    }
}

impl<'js, T> IntoJs<'js> for Option<T>
where
    T: IntoJs<'js>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        Ok(match self {
            Some(value) => value.into_js(ctx)?,
            _ => Value::new_undefined(ctx.clone()),
        })
    }
}

impl<'js, T> IntoJs<'js> for &Option<T>
where
    for<'a> &'a T: IntoJs<'js>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        Ok(match self {
            Some(value) => value.into_js(ctx)?,
            _ => Value::new_undefined(ctx.clone()),
        })
    }
}

impl<'js, T, E> IntoJs<'js> for StdResult<T, E>
where
    T: IntoJs<'js>,
    Error: From<E>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        self.map_err(Error::from)
            .and_then(|value| value.into_js(ctx))
    }
}

impl<'js, T, E> IntoJs<'js> for &StdResult<T, E>
where
    for<'a> &'a T: IntoJs<'js>,
    for<'a> Error: From<&'a E>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        self.as_ref()
            .map_err(Error::from)
            .and_then(|value| value.into_js(ctx))
    }
}

/// Convert the either into JS
#[cfg(feature = "either")]
#[cfg_attr(feature = "doc-cfg", doc(cfg(feature = "either")))]
impl<'js, L, R> IntoJs<'js> for Either<L, R>
where
    L: IntoJs<'js>,
    R: IntoJs<'js>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        match self {
            Left(value) => value.into_js(ctx),
            Right(value) => value.into_js(ctx),
        }
    }
}

/// Convert the either into JS
#[cfg(feature = "either")]
#[cfg_attr(feature = "doc-cfg", doc(cfg(feature = "either")))]
impl<'js, L, R> IntoJs<'js> for &Either<L, R>
where
    for<'a> &'a L: IntoJs<'js>,
    for<'a> &'a R: IntoJs<'js>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        match self {
            Left(value) => value.into_js(ctx),
            Right(value) => value.into_js(ctx),
        }
    }
}

impl<'js, T> IntoJs<'js> for &Box<T>
where
    for<'r> &'r T: IntoJs<'js>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        self.as_ref().into_js(ctx)
    }
}

impl<'js, T> IntoJs<'js> for Box<T>
where
    T: IntoJs<'js>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        (*self).into_js(ctx)
    }
}

impl<'js, T> IntoJs<'js> for &Cell<T>
where
    T: IntoJs<'js> + Copy,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        self.get().into_js(ctx)
    }
}

impl<'js, T> IntoJs<'js> for &RefCell<T>
where
    for<'r> &'r T: IntoJs<'js>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        self.borrow().into_js(ctx)
    }
}

impl<'js, T> IntoJs<'js> for Mutex<T>
where
    T: IntoJs<'js>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        // TODO: determine we should panic her or just unpack the value.
        self.into_inner().expect("mutex was poisoned").into_js(ctx)
    }
}

impl<'js, T> IntoJs<'js> for &Mutex<T>
where
    for<'r> &'r T: IntoJs<'js>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        // TODO: determine we should panic her or just unpack the value.
        self.lock().expect("mutex was poisoned").into_js(ctx)
    }
}

impl<'js, T> IntoJs<'js> for RwLock<T>
where
    T: IntoJs<'js>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        // TODO: determine we should panic her or just unpack the value.
        self.into_inner().expect("lock was poisoned").into_js(ctx)
    }
}

impl<'js, T> IntoJs<'js> for &RwLock<T>
where
    for<'r> &'r T: IntoJs<'js>,
{
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        // TODO: determine we should panic her or just unpack the value.
        self.read().expect("lock was poisoned").into_js(ctx)
    }
}

macro_rules! into_js_impls {
    // for cells
    (cell: $($type:ident,)*) => {
        $(
            impl<'js, T> IntoJs<'js> for $type<T>
            where
                T: IntoJs<'js>,
            {
                fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
                    self.into_inner().into_js(ctx)
                }
            }
        )*
    };

    // for tuple types
    (tup: $($($type:ident)*,)*) => {
        $(
            impl<'js, $($type,)*> IntoJs<'js> for List<($($type,)*)>
            where
                $($type: IntoJs<'js>,)*
            {
                #[allow(non_snake_case)]
                fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
                    let ($($type,)*) = self.0;
                    let array = Array::new(ctx.clone())?;
                    $(array.set(into_js_impls!(@idx $type), $type)?;)*
                    Ok(array.into_value())
                }
            }
        )*
    };

    // for list-like Rust types
    (list: $($(#[$meta:meta])* $type:ident $({$param:ident})*,)*) => {
        $(
            $(#[$meta])*
            impl<'js, T $(,$param)*> IntoJs<'js> for $type<T $(,$param)*>
            where
                T: IntoJs<'js>,
            {
                fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
                    self.into_iter()
                        .collect_js(ctx)
                        .map(|Array(value)| value.into_value())
                }
            }

            $(#[$meta])*
            impl<'js, T $(,$param)*> IntoJs<'js> for &$type<T $(,$param)*>
            where
                for<'a> &'a T: IntoJs<'js>,
            {
                fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
                    self.into_iter()
                        .collect_js(ctx)
                        .map(|Array(value)| value.into_value())
                }
            }
        )*
    };

    // for map-like Rust types
    (map: $($(#[$meta:meta])* $type:ident $({$param:ident})*,)*) => {
        $(
            $(#[$meta])*
            impl<'js, K, V $(,$param)*> IntoJs<'js> for $type<K, V $(,$param)*>
            where
                K: IntoAtom<'js>,
                V: IntoJs<'js>,
            {
                fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
                    self.into_iter()
                        .collect_js(ctx)
                        .map(|Object(value)| value)
                }
            }

            $(#[$meta])*
            impl<'js, K, V $(,$param)*> IntoJs<'js> for &$type<K, V $(,$param)*>
            where
                for<'a> &'a K: IntoAtom<'js>,
                for<'a> &'a V: IntoJs<'js>,
            {
                fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
                    self.into_iter()
                        .collect_js(ctx)
                        .map(|Object(value)| value)
                }
            }
        )*
    };

    // for primitive types using `new` function
    (val: $($new:ident: $($type:ident)*,)*) => {
        $(
            $(
                impl<'js> IntoJs<'js> for $type {
                    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
                        Ok(Value::$new(ctx.clone(), self as _))
                    }
                }

                impl<'js> IntoJs<'js> for &$type {
                    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
                        (*self).into_js(ctx)
                    }
                }
            )*
        )*
    };

    // for primitive types with two alternatives
    // (ex. u32 may try convert as i32 or else as f64)
    (val: $($alt1:ident $alt2:ident => $($type:ty)*,)*) => {
        $(
            $(
                impl<'js> IntoJs<'js> for $type {
                    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
                        let val = self as $alt1;
                        if val as $type == self {
                            val.into_js(ctx)
                        } else {
                            (self as $alt2).into_js(ctx)
                        }
                    }
                }

                impl<'js> IntoJs<'js> for &$type {
                    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
                        (*self).into_js(ctx)
                    }
                }
            )*
        )*
    };

    (@idx A) => { 0 };
    (@idx B) => { 1 };
    (@idx C) => { 2 };
    (@idx D) => { 3 };
    (@idx E) => { 4 };
    (@idx F) => { 5 };
    (@idx G) => { 6 };
    (@idx H) => { 7 };
    (@idx I) => { 8 };
    (@idx J) => { 9 };
    (@idx K) => { 10 };
    (@idx L) => { 11 };
    (@idx M) => { 12 };
    (@idx N) => { 13 };
    (@idx O) => { 14 };
    (@idx P) => { 15 };
}

into_js_impls! {
    cell:
    Cell,
    RefCell,
}

into_js_impls! {
    tup:
    A,
    A B,
    A B C,
    A B C D,
    A B C D E,
    A B C D E F,
    A B C D E F G,
    A B C D E F G H,
    A B C D E F G H I,
    A B C D E F G H I J,
    A B C D E F G H I J K,
    A B C D E F G H I J K L,
    A B C D E F G H I J K L M,
    A B C D E F G H I J K L M N,
    A B C D E F G H I J K L M N O,
    A B C D E F G H I J K L M N O P,
}

into_js_impls! {
    list:
    /// Convert from Rust vector to JS array
    Vec,
    /// Convert from Rust vector deque to JS array
    VecDeque,
    /// Convert from Rust linked list to JS array
    LinkedList,
    /// Convert from Rust hash set to JS array
    HashSet {S},
    /// Convert from Rust btree set to JS array
    BTreeSet,
    /// Convert from Rust index set to JS array
    #[cfg(feature = "indexmap")]
    #[cfg_attr(feature = "doc-cfg", doc(cfg(feature = "indexmap")))]
    IndexSet {S},
}

into_js_impls! {
    map:
    /// Convert from Rust hash map to JS object
    HashMap {S},
    /// Convert from Rust btree map to JS object
    BTreeMap,
    /// Convert from Rust index map to JS object
    #[cfg(feature = "indexmap")]
    #[cfg_attr(feature = "doc-cfg", doc(cfg(feature = "indexmap")))]
    IndexMap {S},
}

into_js_impls! {
    val:
    new_bool: bool,
    new_int: i8 i16 i32 u8 u16,
    new_float: f32 f64,
}

into_js_impls! {
    val:
    i32 f64 => i64 u32 u64 usize isize,
}

fn millis_to_date<'js>(ctx: &Ctx<'js>, millis: i64) -> Result<Value<'js>> {
    let date_ctor: Constructor = ctx.globals().get("Date")?;

    date_ctor.construct((millis,))
}

impl<'js> IntoJs<'js> for SystemTime {
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        let millis = match self.duration_since(SystemTime::UNIX_EPOCH) {
            // since unix epoch
            Ok(duration) => {
                let millis = duration.as_millis();

                if millis > i64::MAX as _ {
                    return Err(Error::new_into_js_message(
                        "SystemTime",
                        "Date",
                        "Timestamp too big",
                    ));
                }

                millis as i64
            }
            // before unix epoch
            Err(error) => {
                let millis = error.duration().as_millis();

                if millis > -(i64::MIN as i128) as _ {
                    return Err(Error::new_into_js_message(
                        "SystemTime",
                        "Date",
                        "Timestamp too small",
                    ));
                }

                (-(millis as i128)) as i64
            }
        };

        millis_to_date(ctx, millis)
    }
}

#[cfg(feature = "chrono")]
impl<'js, Tz: chrono::TimeZone> IntoJs<'js> for chrono::DateTime<Tz> {
    fn into_js(self, ctx: &Ctx<'js>) -> Result<Value<'js>> {
        millis_to_date(ctx, self.timestamp_millis())
    }
}

#[cfg(test)]
mod test {
    #[test]
    fn system_time_to_js() {
        use crate::{Context, IntoJs, Runtime};
        use std::time::{Duration, SystemTime};

        let runtime = Runtime::new().unwrap();
        let ctx = Context::full(&runtime).unwrap();

        let ts = SystemTime::now();
        let millis = ts
            .duration_since(SystemTime::UNIX_EPOCH)
            .unwrap()
            .as_millis();

        ctx.with(|ctx| {
            let globs = ctx.globals();
            globs.set("ts", ts.into_js(&ctx).unwrap()).unwrap();
            let res: i64 = ctx.eval("ts.getTime()").unwrap();
            assert_eq!(millis, res as _);
        });

        let ts = SystemTime::UNIX_EPOCH - Duration::from_millis(123456);
        let millis = SystemTime::UNIX_EPOCH
            .duration_since(ts)
            .unwrap()
            .as_millis();

        ctx.with(|ctx| {
            let globs = ctx.globals();
            globs.set("ts", ts.into_js(&ctx).unwrap()).unwrap();
            let res: i64 = ctx.eval("ts.getTime()").unwrap();
            assert_eq!(-(millis as i64), res as _);
        });
    }

    #[cfg(feature = "chrono")]
    #[test]
    fn chrono_to_js() {
        use crate::{Context, IntoJs, Runtime};
        use chrono::Utc;

        let runtime = Runtime::new().unwrap();
        let ctx = Context::full(&runtime).unwrap();

        let ts = Utc::now();
        let millis = ts.timestamp_millis();

        ctx.with(|ctx| {
            let globs = ctx.globals();
            globs.set("ts", ts.into_js(&ctx).unwrap()).unwrap();
            let res: i64 = ctx.eval("ts.getTime()").unwrap();
            assert_eq!(millis, res);
        });
    }
}