// Copyright 2016 Matthew Collins
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::collections::HashMap;
use std::marker::PhantomData;
use std::io;
use std::fmt;
use crate::protocol;
use crate::protocol::Serializable;
use crate::format;
use crate::item;
use crate::shared::Position;
use crate::nbt;

pub struct MetadataKey<T: MetaValue> {
    index: i32,
    ty: PhantomData<T>,
}

impl <T: MetaValue> MetadataKey<T> {
    #[allow(dead_code)]
    fn new(index: i32) -> MetadataKey<T> {
        MetadataKey {
            index,
            ty: PhantomData,
        }
    }
}

pub struct Metadata {
    map: HashMap<i32, Value>,
}

impl Metadata {
    pub fn new() -> Metadata {
        Metadata { map: HashMap::new() }
    }

    pub fn get<T: MetaValue>(&self, key: &MetadataKey<T>) -> Option<&T> {
        self.map.get(&key.index).map(T::unwrap)
    }

    pub fn put<T: MetaValue>(&mut self, key: &MetadataKey<T>, val: T) {
        self.map.insert(key.index, val.wrap());
    }

    fn put_raw<T: MetaValue>(&mut self, index: i32, val: T) {
        self.map.insert(index, val.wrap());
    }
}

impl Serializable for Metadata {

    fn read_from<R: io::Read>(buf: &mut R) -> Result<Self, protocol::Error> {
        let mut m = Metadata::new();
        loop {
            let index = u8::read_from(buf)? as i32;
            if index == 0xFF {
                break;
            }
            let ty = protocol::VarInt::read_from(buf)?.0;
            match ty {
                0 => m.put_raw(index, i8::read_from(buf)?),
                1 => m.put_raw(index, protocol::VarInt::read_from(buf)?.0),
                2 => m.put_raw(index, f32::read_from(buf)?),
                3 => m.put_raw(index, String::read_from(buf)?),
                4 => m.put_raw(index, format::Component::read_from(buf)?),
                5 => m.put_raw(index, Option::<item::Stack>::read_from(buf)?),
                6 => m.put_raw(index, bool::read_from(buf)?),
                7 => m.put_raw(index,
                               [f32::read_from(buf)?,
                                f32::read_from(buf)?,
                                f32::read_from(buf)?]),
                8 => m.put_raw(index, Position::read_from(buf)?),
                9 => {
                    if bool::read_from(buf)? {
                        m.put_raw(index, Option::<Position>::read_from(buf)?);
                    } else {
                        m.put_raw::<Option<Position>>(index, None);
                    }
                }
                10 => m.put_raw(index, protocol::VarInt::read_from(buf)?),
                11 => {
                    if bool::read_from(buf)? {
                        m.put_raw(index, Option::<protocol::UUID>::read_from(buf)?);
                    } else {
                        m.put_raw::<Option<protocol::UUID>>(index, None);
                    }
                }
                12 => m.put_raw(index, protocol::VarInt::read_from(buf)?.0 as u16),
                13 => {
                    let ty = u8::read_from(buf)?;
                    if ty != 0 {
                        let name = nbt::read_string(buf)?;
                        let tag = nbt::Tag::read_from(buf)?;

                        m.put_raw(index, nbt::NamedTag(name, tag));
                    }
                }
                _ => return Err(protocol::Error::Err("unknown metadata type".to_owned())),
            }
        }
        Ok(m)
    }

    fn write_to<W: io::Write>(&self, buf: &mut W) -> Result<(), protocol::Error> {
        for (k, v) in &self.map {
            (*k as u8).write_to(buf)?;
            match *v {
                Value::Byte(ref val) => {
                    u8::write_to(&0, buf)?;
                    val.write_to(buf)?;
                }
                Value::Int(ref val) => {
                    u8::write_to(&1, buf)?;
                    protocol::VarInt(*val).write_to(buf)?;
                }
                Value::Float(ref val) => {
                    u8::write_to(&2, buf)?;
                    val.write_to(buf)?;
                }
                Value::String(ref val) => {
                    u8::write_to(&3, buf)?;
                    val.write_to(buf)?;
                }
                Value::FormatComponent(ref val) => {
                    u8::write_to(&4, buf)?;
                    val.write_to(buf)?;
                }
                Value::OptionalItemStack(ref val) => {
                    u8::write_to(&5, buf)?;
                    val.write_to(buf)?;
                }
                Value::Bool(ref val) => {
                    u8::write_to(&6, buf)?;
                    val.write_to(buf)?;
                }
                Value::Vector(ref val) => {
                    u8::write_to(&7, buf)?;
                    val[0].write_to(buf)?;
                    val[1].write_to(buf)?;
                    val[2].write_to(buf)?;
                }
                Value::Position(ref val) => {
                    u8::write_to(&8, buf)?;
                    val.write_to(buf)?;
                }
                Value::OptionalPosition(ref val) => {
                    u8::write_to(&9, buf)?;
                    val.is_some().write_to(buf)?;
                    val.write_to(buf)?;
                }
                Value::Direction(ref val) => {
                    u8::write_to(&10, buf)?;
                    val.write_to(buf)?;
                }
                Value::OptionalUUID(ref val) => {
                    u8::write_to(&11, buf)?;
                    val.is_some().write_to(buf)?;
                    val.write_to(buf)?;
                }
                Value::Block(ref val) => {
                    u8::write_to(&11, buf)?;
                    protocol::VarInt(*val as i32).write_to(buf)?;
                }
                Value::NBTTag(ref _val) => {
                    u8::write_to(&13, buf)?;
                    // TODO: write NBT tags metadata
                    //nbt::Tag(*val).write_to(buf)?;
                }
            }
        }
        u8::write_to(&0xFF, buf)?;
        Ok(())
    }
}

impl fmt::Debug for Metadata {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "Metadata[ ")?;
        for (k, v) in &self.map {
            write!(f, "{:?}={:?}, ", k, v)?;
        }
        write!(f, "]")
    }
}

impl Default for Metadata {
    fn default() -> Metadata {
        Metadata::new()
    }
}

#[derive(Debug)]
pub enum Value {
    Byte(i8),
    Int(i32),
    Float(f32),
    String(String),
    FormatComponent(format::Component),
    OptionalItemStack(Option<item::Stack>),
    Bool(bool),
    Vector([f32; 3]),
    Position(Position),
    OptionalPosition(Option<Position>),
    Direction(protocol::VarInt), // TODO: Proper type
    OptionalUUID(Option<protocol::UUID>),
    Block(u16), // TODO: Proper type
    NBTTag(nbt::NamedTag),
}

pub trait MetaValue {
    fn unwrap(_: &Value) -> &Self;
    fn wrap(self) -> Value;
}

impl MetaValue for i8 {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::Byte(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::Byte(self)
    }
}

impl MetaValue for i32 {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::Int(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::Int(self)
    }
}

impl MetaValue for f32 {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::Float(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::Float(self)
    }
}

impl MetaValue for String {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::String(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::String(self)
    }
}

impl MetaValue for format::Component {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::FormatComponent(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::FormatComponent(self)
    }
}

impl MetaValue for Option<item::Stack> {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::OptionalItemStack(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::OptionalItemStack(self)
    }
}

impl MetaValue for bool {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::Bool(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::Bool(self)
    }
}

impl MetaValue for [f32; 3] {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::Vector(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::Vector(self)
    }
}

impl MetaValue for Position {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::Position(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::Position(self)
    }
}

impl MetaValue for Option<Position> {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::OptionalPosition(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::OptionalPosition(self)
    }
}

impl MetaValue for protocol::VarInt {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::Direction(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::Direction(self)
    }
}

impl MetaValue for Option<protocol::UUID> {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::OptionalUUID(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::OptionalUUID(self)
    }
}

impl MetaValue for u16 {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::Block(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::Block(self)
    }
}

impl MetaValue for nbt::NamedTag {
    fn unwrap(value: &Value) -> &Self {
        match *value {
            Value::NBTTag(ref val) => val,
            _ => panic!("incorrect key"),
        }
    }
    fn wrap(self) -> Value {
        Value::NBTTag(self)
    }
}

#[cfg(test)]
mod test {
    use super::*;
    use std::marker::PhantomData;

    const TEST: MetadataKey<String> =
        MetadataKey {
        index: 0,
        ty: PhantomData,
    };

    #[test]
    fn basic() {
        let mut m = Metadata::new();

        m.put(&TEST, "Hello world".to_owned());

        match m.get(&TEST) {
            Some(val) => {
                assert!(val == "Hello world");
            }
            None => panic!("failed"),
        }
    }
}