/*
    wearechat - generic multiplayer game with voip
    Copyright (C) 2025 metamuffin

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published by
    the Free Software Foundation, version 3 of the License only.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/
use crate::{
    helper::ReadWrite,
    resources::{Prefab, PrefabIndex},
};
use anyhow::{Result, bail};
use glam::{Affine3A, Vec3A};
use std::{
    fmt::{Debug, Display},
    hash::Hash,
    io::{Read, Write},
    marker::PhantomData,
};

#[derive(Clone, Copy)]
pub struct Resource<T = ()>(pub [u8; 32], pub PhantomData<T>);

impl<T> PartialEq for Resource<T> {
    fn eq(&self, other: &Self) -> bool {
        self.0 == other.0
    }
}
impl<T> Eq for Resource<T> {}
impl<T> Hash for Resource<T> {
    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
        self.0.hash(state);
    }
}
impl<T> PartialOrd for Resource<T> {
    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
        Some(self.cmp(other))
    }
}
impl<T> Ord for Resource<T> {
    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
        self.0.cmp(&other.0)
    }
}
impl<T> Resource<T> {
    pub fn to_generic(&self) -> Resource {
        Resource(self.0, PhantomData)
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct Object(pub u128);

#[derive(Clone)]
pub struct Data(pub Vec<u8>);
#[derive(Debug, Clone)]
pub struct Message(pub String);

#[derive(Debug, Clone)]
pub enum Packet {
    Connect(u128),
    Disconnect,
    RequestResource(Resource),
    RespondResource(Resource, Data),
    Add(Object, Resource<Prefab>),
    Remove(Object),
    Position(Object, Vec3A, Vec3A),
    Pose(Object, Vec<(u16, Affine3A)>),
    Parent(Object, Object),
    Sound(Object, Data),
    PrefabIndex(Resource<PrefabIndex>),
    AnnouncePrefab(Resource<Prefab>),
    Chat(Object, Message),
}

impl Object {
    pub fn new() -> Self {
        Self(rand::random())
    }
}
impl Default for Object {
    fn default() -> Self {
        Self::new()
    }
}
impl Packet {
    fn serialize_inner(&self, w: &mut impl Write) -> Result<()> {
        match self {
            Packet::Connect(id) => {
                w.write_all(&[0x00])?;
                w.write_all(&id.to_le_bytes())?;
            }
            Packet::Disconnect => {
                w.write_all(&[0xff])?;
            }
            Packet::RequestResource(resource) => {
                w.write_all(&[0x01])?;
                w.write_all(&resource.0)?;
            }
            Packet::RespondResource(resource, data) => {
                w.write_all(&[0x02])?;
                resource.write(w)?;
                data.write(w)?;
            }
            Packet::Add(object, resource) => {
                w.write_all(&[0x03])?;
                w.write_all(&object.0.to_le_bytes())?;
                w.write_all(&resource.0)?;
            }
            Packet::Remove(object) => {
                w.write_all(&[0x04])?;
                object.write(w)?;
            }
            Packet::Position(object, pos, rot) => {
                w.write_all(&[0x05])?;
                w.write_all(&object.0.to_le_bytes())?;
                pos.write(w)?;
                rot.write(w)?;
            }
            Packet::Pose(object, vec) => {
                w.write_all(&[0x06])?;
                w.write_all(&object.0.to_le_bytes())?;
                w.write_all(&(vec.len() as u32).to_le_bytes())?;
                for (i, a) in vec {
                    i.write(w)?;
                    a.write(w)?;
                }
            }
            Packet::Parent(parent, child) => {
                w.write_all(&[0x07])?;
                w.write_all(&parent.0.to_le_bytes())?;
                w.write_all(&child.0.to_le_bytes())?;
            }
            Packet::Sound(object, data) => {
                w.write_all(&[0x08])?;
                w.write_all(&object.0.to_le_bytes())?;
                data.write(w)?;
            }
            Packet::PrefabIndex(resource) => {
                w.write_all(&[0x09])?;
                resource.write(w)?;
            }
            Packet::AnnouncePrefab(resource) => {
                w.write_all(&[0x0a])?;
                resource.write(w)?;
            }
            Packet::Chat(object, message) => {
                w.write_all(&[0x0b])?;
                object.write(w)?;
                message.write(w)?;
            }
        }
        Ok(())
    }
}
impl ReadWrite for Packet {
    fn write(&self, w: &mut dyn Write) -> Result<()> {
        let mut buf = Vec::new();
        self.serialize_inner(&mut buf)?;
        w.write_all(&(buf.len() as u32).to_le_bytes())?;
        w.write_all(&buf)?;
        Ok(())
    }
    fn read(r: &mut dyn Read) -> Result<Self> {
        let packet_len = u32::read(r)?;
        Ok(match u8::read(r)? {
            0x00 => Packet::Connect(read_u128(r)?),
            0x01 => Packet::RequestResource(Resource::read(r)?),
            0x02 => Packet::RespondResource(Resource::read(r)?, Data::read(r)?),
            0x03 => Packet::Add(Object::read(r)?, Resource::read(r)?),
            0x04 => Packet::Remove(Object::read(r)?),
            0x05 => Packet::Position(
                Object::read(r)?,
                Vec3A::new(f32::read(r)?, f32::read(r)?, f32::read(r)?),
                Vec3A::new(f32::read(r)?, f32::read(r)?, f32::read(r)?),
            ),
            0x06 => Packet::Pose(Object::read(r)?, read_params(r)?),
            0x07 => Packet::Parent(Object::read(r)?, Object::read(r)?),
            0x08 => Packet::Sound(Object::read(r)?, Data::read(r)?),
            0x09 => Packet::PrefabIndex(Resource::read(r)?),
            0x0a => Packet::AnnouncePrefab(Resource::read(r)?),
            0x0b => Packet::Chat(Object::read(r)?, Message::read(r)?),
            tag => {
                for _ in 0..packet_len.max(1) - 1 {
                    r.read_exact(&mut [0])?;
                }
                bail!("unknown packet tag {tag:x}");
            }
        })
    }
}

fn read_u128(r: &mut dyn Read) -> Result<u128> {
    let mut buf = [0; 16];
    r.read_exact(&mut buf)?;
    Ok(u128::from_le_bytes(buf))
}

fn read_params(r: &mut dyn Read) -> Result<Vec<(u16, Affine3A)>> {
    let mut size = [0; 4];
    r.read_exact(&mut size)?;
    let size = u32::from_le_bytes(size);
    let mut v = Vec::with_capacity(size as usize);
    for _ in 0..size {
        v.push((u16::read(r)?, Affine3A::read(r)?));
    }
    Ok(v)
}

impl<T> Display for Resource<T> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "Res{{{:016x}{:016x}{:016x}{:016x}}}",
            u64::from_le_bytes(self.0[0..8].try_into().unwrap()),
            u64::from_le_bytes(self.0[8..16].try_into().unwrap()),
            u64::from_le_bytes(self.0[16..24].try_into().unwrap()),
            u64::from_le_bytes(self.0[24..32].try_into().unwrap()),
        )
    }
}
impl<T> Debug for Resource<T> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self)
    }
}

impl Debug for Data {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_tuple("Data").finish_non_exhaustive()
    }
}
impl Display for Object {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_tuple("Object")
            .field_with(|f| write!(f, "{:016x}", self.0))
            .finish()
    }
}
impl Object {
    pub const ROOT: Object = Object(0);
}