#include "rigging.hpp"

#include "assets/Assets.hpp"
#include "coders/json.hpp"
#include "data/dynamic_util.hpp"
#include "graphics/core/Model.hpp"
#include "graphics/render/ModelBatch.hpp"

#define GLM_ENABLE_EXPERIMENTAL
#include <glm/ext/matrix_transform.hpp>
#include <glm/gtx/norm.hpp>

using namespace rigging;

void ModelReference::refresh(const Assets* assets) {
    if (updateFlag) {
        model = assets->get<model::Model>(name);
        updateFlag = false;
    }
}

Bone::Bone(
    size_t index,
    std::string name,
    std::string model,
    std::vector<std::unique_ptr<Bone>> bones,
    glm::vec3 offset
)
    : index(index),
      name(std::move(name)),
      bones(std::move(bones)),
      offset(offset),
      model({model, nullptr, true}) {
}

void Bone::setModel(const std::string& name) {
    if (model.name == name) {
        return;
    }
    model = {name, nullptr, true};
}

Skeleton::Skeleton(const SkeletonConfig* config)
    : config(config),
      pose(config->getBones().size()),
      calculated(config->getBones().size()),
      flags(config->getBones().size()),
      textures(),
      modelOverrides(config->getBones().size()),
      visible(true) {
    const auto& bones = config->getBones();
    for (size_t i = 0; i < bones.size(); i++) {
        flags[i].visible = true;
    }
}

static void get_all_nodes(std::vector<Bone*>& nodes, Bone* node) {
    nodes[node->getIndex()] = node;
    for (auto& subnode : node->getSubnodes()) {
        get_all_nodes(nodes, subnode.get());
    }
}

SkeletonConfig::SkeletonConfig(
    const std::string& name, std::unique_ptr<Bone> root, size_t nodesCount
)
    : name(name), root(std::move(root)), nodes(nodesCount) {
    get_all_nodes(nodes, this->root.get());
}

size_t SkeletonConfig::update(
    size_t index, Skeleton& skeleton, Bone* node, glm::mat4 matrix
) const {
    auto boneMatrix = skeleton.pose.matrices[index];
    auto boneOffset = node->getOffset();
    glm::mat4 baseMatrix(1.0f);
    if (glm::length2(boneOffset) > 0.0f) {
        baseMatrix = glm::translate(glm::mat4(1.0f), boneOffset);
    }
    skeleton.calculated.matrices[index] = matrix * baseMatrix * boneMatrix;
    size_t count = 1;
    for (auto& subnode : node->getSubnodes()) {
        count += update(
            index + count,
            skeleton,
            subnode.get(),
            skeleton.calculated.matrices[index]
        );
    }
    return count;
}

void SkeletonConfig::update(Skeleton& skeleton, glm::mat4 matrix) const {
    update(0, skeleton, root.get(), matrix);
}

void SkeletonConfig::render(
    Assets* assets,
    ModelBatch& batch,
    Skeleton& skeleton,
    const glm::mat4& matrix
) const {
    update(skeleton, matrix);

    if (!skeleton.visible) {
        return;
    }
    for (size_t i = 0; i < nodes.size(); i++) {
        auto* node = nodes[i];
        if (!skeleton.flags[i].visible) {
            continue;
        }
        node->model.refresh(assets);
        auto model = node->model.model;
        auto& modelOverride = skeleton.modelOverrides.at(i);
        if (modelOverride.updateFlag) {
            modelOverride.refresh(assets);
        }
        model = modelOverride.model ? modelOverride.model : model;
        if (model) {
            batch.draw(
                skeleton.calculated.matrices[i],
                skeleton.tint,
                model,
                &skeleton.textures
            );
        }
    }
}

Bone* SkeletonConfig::find(std::string_view str) const {
    for (size_t i = 0; i < nodes.size(); i++) {
        auto* node = nodes[i];
        if (node->getName() == str) {
            return node;
        }
    }
    return nullptr;
}

static std::tuple<size_t, std::unique_ptr<Bone>> read_node(
    const dynamic::Map_sptr& root, size_t index
) {
    std::string name;
    std::string model;
    root->str("name", name);
    root->str("model", model);

    glm::vec3 offset(0.0f);
    dynamic::get_vec(root, "offset", offset);

    std::vector<std::unique_ptr<Bone>> bones;
    size_t count = 1;
    if (auto nodesList = root->list("nodes")) {
        for (size_t i = 0; i < nodesList->size(); i++) {
            if (const auto& map = nodesList->map(i)) {
                auto [subcount, subNode] = read_node(map, index + count);
                count += subcount;
                bones.push_back(std::move(subNode));
            }
        }
    }
    return {
        count,
        std::make_unique<Bone>(index, name, model, std::move(bones), offset)};
}

std::unique_ptr<SkeletonConfig> SkeletonConfig::parse(
    std::string_view src, std::string_view file, std::string_view name
) {
    auto root = json::parse(file, src);
    auto rootNodeMap = root->map("root");
    if (rootNodeMap == nullptr) {
        throw std::runtime_error("missing 'root' element");
    }
    auto [count, rootNode] = read_node(rootNodeMap, 0);
    return std::make_unique<SkeletonConfig>(
        std::string(name), std::move(rootNode), count
    );
}