/*
    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 anyhow::Result;
use glam::{Quat, vec3a};
use gltf::{
    Animation,
    animation::{Property, util::ReadOutputs},
    buffer::Data,
};
use log::{debug, info};
use std::collections::BTreeMap;
use weareshared::{
    Affine3A,
    packets::Resource,
    resources::{AnimationChannel, AnimationPart},
    store::ResourceStore,
};

pub fn import_animation(
    a: Animation<'_>,
    store: &ResourceStore,
    transform: Affine3A,
    joint_index_to_ibm: &BTreeMap<usize, Affine3A>,
    joint_index_to_arm_index: &BTreeMap<usize, usize>,
    node_to_meshes: &BTreeMap<usize, Vec<usize>>,
    buffers: &[Data],
) -> Result<Resource<AnimationPart>> {
    let mut max_time = 0f32;
    let mut channels = Vec::new();
    for c in a.channels() {
        let node = c.target().node().index();
        let reader = c.reader(|i| Some(&buffers[i.index()].0));
        let inputs: Vec<f32> = reader.read_inputs().unwrap().collect::<Vec<f32>>();
        let outputs: Vec<f32> =
            if joint_index_to_ibm.contains_key(&node) || transform != Affine3A::IDENTITY {
                let t = transform
                    * joint_index_to_ibm
                        .get(&node)
                        .copied()
                        .unwrap_or_default()
                        .inverse();
                let (_, rot, _) = t.to_scale_rotation_translation();
                match reader.read_outputs().unwrap() {
                    ReadOutputs::Translations(iter) => iter
                        .flat_map(|[x, y, z]| (t.matrix3 * vec3a(x, y, z)).to_array())
                        .collect(),
                    ReadOutputs::Rotations(iter) => iter
                        .into_f32()
                        .map(Quat::from_array)
                        .map(|q| rot.mul_quat(q))
                        .flat_map(|q| q.to_array())
                        .collect(),
                    ReadOutputs::Scales(iter) => iter
                        .flat_map(|[x, y, z]| (t.matrix3 * vec3a(x, y, z)).to_array())
                        .collect(),
                    ReadOutputs::MorphTargetWeights(iter) => iter.into_f32().collect(),
                }
            } else {
                match reader.read_outputs().unwrap() {
                    ReadOutputs::Translations(iter) => iter.flatten().collect(),
                    ReadOutputs::Rotations(iter) => iter.into_f32().flatten().collect(),
                    ReadOutputs::Scales(iter) => iter.flatten().collect(),
                    ReadOutputs::MorphTargetWeights(iter) => iter.into_f32().collect(),
                }
            };
        for x in &inputs {
            max_time = max_time.max(*x)
        }
        let time = store.set(&inputs)?;
        let value = store.set(&outputs)?;

        if let Some(&m) = joint_index_to_arm_index.get(&node) {
            let a = 0; // TODO
            let mut ch = AnimationChannel::default();
            match c.target().property() {
                Property::Translation => ch.t_joint_translation = Some((a, m as u32)),
                Property::Rotation => ch.t_joint_rotation = Some((a, m as u32)),
                Property::Scale => ch.t_joint_scale = Some((a, m as u32)),
                Property::MorphTargetWeights => continue,
            }
            ch.time = Some(time.clone());
            ch.value = Some(value.clone());
            debug!(
                "animation channel {:?} of joint {m} of armature {a} with {} time and {} component values",
                c.target().property(),
                inputs.len(),
                outputs.len()
            );
            channels.push(ch);
        }
        if let Some(meshes) = node_to_meshes.get(&node) {
            for &m in meshes {
                let mut ch = AnimationChannel::default();
                match c.target().property() {
                    Property::Translation => ch.t_mesh_translation = Some(m as u32),
                    Property::Rotation => ch.t_mesh_rotation = Some(m as u32),
                    Property::Scale => ch.t_mesh_scale = Some(m as u32),
                    Property::MorphTargetWeights => continue,
                }
                ch.time = Some(time.clone());
                ch.value = Some(value.clone());
                debug!(
                    "animation channel {:?} of mesh {m} with {} time and {} component values",
                    c.target().property(),
                    inputs.len(),
                    outputs.len()
                );
                channels.push(ch);
            }
        }
    }
    info!("adding animation with {} channels", channels.len());
    store.set(&AnimationPart {
        name: a.name().map(|n| n.to_string()),
        channel: channels,
        duration: Some(max_time),
    })
}