#include "../include/AsyncImageLoader.hpp"
#include "../include/DownloadUtils.hpp"
#include "../include/Program.hpp"
#include "../include/ImageUtils.hpp"
#include "../include/Scale.hpp"
#include "../include/SfmlFixes.hpp"
#include "../external/hash-library/sha256.h"

#include <sys/stat.h>
#include <malloc.h>
#include <assert.h>

namespace QuickMedia {
    bool create_thumbnail(const Path &thumbnail_path, const Path &thumbnail_path_resized, sf::Vector2i resize_target_size, ContentType content_type) {
        Path input_path = thumbnail_path;

        // TODO: Remove this when imagemagick supports webp
        // Convert webp to png
        bool remove_tmp_input = false;
        if(content_type == ContentType::IMAGE_WEBP) {
            Path result_path_tmp = thumbnail_path_resized;
            result_path_tmp.append(".tmp.png");

            const char *args[] = { "ffmpeg", "-y", "-v", "quiet", "-i", input_path.data.c_str(), "--", result_path_tmp.data.c_str(), nullptr};
            int res = exec_program(args, nullptr, nullptr);
            if(res != 0)
                return false;

            input_path = std::move(result_path_tmp);
            remove_tmp_input = true;
        }

        // > is to only shrink image if smaller than the target size
        std::string new_size = std::to_string(resize_target_size.x) + "x" + std::to_string(resize_target_size.y) + ">";

        // We only want the first frame if its a gif
        Path thumbnail_path_first_frame = input_path;
        thumbnail_path_first_frame.append("[0]");

        Path result_path_tmp = thumbnail_path_resized;
        result_path_tmp.append(".tmp");

        const char *args[] = { "convert", thumbnail_path_first_frame.data.c_str(), "-thumbnail", new_size.c_str(), result_path_tmp.data.c_str(), nullptr};
        int convert_res = exec_program(args, nullptr, nullptr);
        if(remove_tmp_input)
            remove(input_path.data.c_str());
        if(convert_res == 0 && rename_atomic(result_path_tmp.data.c_str(), thumbnail_path_resized.data.c_str()) == 0)
            return true;
        else
            return false;
    }

    // Create thumbnail and load it. On failure load the original image
    static void create_thumbnail(const Path &thumbnail_path, const Path &thumbnail_path_resized, ThumbnailData *thumbnail_data, sf::Vector2i resize_target_size) {
        FileAnalyzer file_analyzer;
        if(!file_analyzer.load_file(thumbnail_path.data.c_str(), false)) {
            fprintf(stderr, "Failed to convert %s to a thumbnail, using the original image\n", thumbnail_path.data.c_str());
            thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
            return;
        }

        if(is_content_type_video(file_analyzer.get_content_type())) {
            if(video_get_first_frame(thumbnail_path.data.c_str(), thumbnail_path_resized.data.c_str(), resize_target_size.x, resize_target_size.y))
                load_image_from_file(*thumbnail_data->image, thumbnail_path_resized.data);
            thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
            return;
        }

        if(create_thumbnail(thumbnail_path, thumbnail_path_resized, resize_target_size, file_analyzer.get_content_type())) {
            load_image_from_file(*thumbnail_data->image, thumbnail_path_resized.data);
        } else {
            load_image_from_file(*thumbnail_data->image, thumbnail_path.data);
            fprintf(stderr, "Failed to convert %s to a thumbnail, using the original image\n", thumbnail_path.data.c_str());
        }
        thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
    }

    AsyncImageLoader& AsyncImageLoader::get_instance() {
        static AsyncImageLoader *instance = nullptr;
        if(!instance)
            instance = new AsyncImageLoader();
        return *instance;
    }

    AsyncImageLoader::AsyncImageLoader() {
        for(int i = 0; i < NUM_IMAGE_LOAD_THREADS; ++i) {
            loading_image[i] = false;
        }

        load_image_thread = std::thread([this]() mutable {
            std::optional<ThumbnailLoadData> thumbnail_load_data_opt;
            while(true) {
                thumbnail_load_data_opt = image_load_queue.pop_wait();
                if(!thumbnail_load_data_opt)
                    break;

                ThumbnailLoadData &thumbnail_load_data = thumbnail_load_data_opt.value();
                thumbnail_load_data.thumbnail_data->image = std::make_unique<sf::Image>();

                Path thumbnail_path_resized = thumbnail_load_data.thumbnail_path;
                if(thumbnail_load_data.resize_target_size.x != 0 && thumbnail_load_data.resize_target_size.y != 0)
                    thumbnail_path_resized.append("_" + std::to_string(thumbnail_load_data.resize_target_size.x) + "x" + std::to_string(thumbnail_load_data.resize_target_size.y));

                if(get_file_type(thumbnail_path_resized) == FileType::REGULAR) {
                    load_image_from_file(*thumbnail_load_data.thumbnail_data->image, thumbnail_path_resized.data);
                    thumbnail_load_data.thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
                    fprintf(stderr, "Loaded %s from thumbnail cache\n", thumbnail_path_resized.data.c_str());
                    continue;
                }

                Path thumbnail_original_path;
                if(thumbnail_load_data.local)
                    thumbnail_original_path = thumbnail_load_data.path;
                else
                    thumbnail_original_path = thumbnail_load_data.thumbnail_path;

                if(thumbnail_load_data.resize_target_size.x != 0 && thumbnail_load_data.resize_target_size.y != 0)
                    create_thumbnail(thumbnail_original_path, thumbnail_path_resized, thumbnail_load_data.thumbnail_data.get(), thumbnail_load_data.resize_target_size);
                else
                    load_image_from_file(*thumbnail_load_data.thumbnail_data->image, thumbnail_original_path.data);

                thumbnail_load_data.thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
            }
        });
    }

    AsyncImageLoader::~AsyncImageLoader() {
        image_load_queue.close();
        if(load_image_thread.joinable()) {
            program_kill_in_thread(load_image_thread.get_id());
            load_image_thread.join();
        }

        for(size_t i = 0; i < NUM_IMAGE_LOAD_THREADS; ++i) {
            if(download_image_thread[i].joinable()) {
                program_kill_in_thread(download_image_thread[i].get_id());
                download_image_thread[i].join();
            }
        }
    }

    void AsyncImageLoader::load_thumbnail(const std::string &url, bool local, sf::Vector2i resize_target_size, std::shared_ptr<ThumbnailData> thumbnail_data) {
        if(thumbnail_data->loading_state != LoadingState::NOT_LOADED)
            return;

        if(url.empty()) {
            thumbnail_data->image = std::make_unique<sf::Image>();
            thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
            return;
        }
        
        SHA256 sha256;
        sha256.add(url.data(), url.size());
        Path thumbnail_path = get_cache_dir().join("thumbnails").join(sha256.getHash());
        if(local) {
            struct stat file_stat;
            if(stat(url.c_str(), &file_stat) != 0 || !S_ISREG(file_stat.st_mode)) {
                thumbnail_data->image = std::make_unique<sf::Image>();
                thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
                return;
            }

            thumbnail_path.append("_" + std::to_string(file_stat.st_mtim.tv_sec));
            thumbnail_data->loading_state = LoadingState::LOADING;
            image_load_queue.push({ url, thumbnail_path, true, thumbnail_data, resize_target_size });
            return;
        }

        if(get_file_type(thumbnail_path) == FileType::REGULAR) {
            thumbnail_data->loading_state = LoadingState::LOADING;
            image_load_queue.push({ url, thumbnail_path, false, thumbnail_data, resize_target_size });
            return;
        }

        int free_index = get_free_load_index();
        if(free_index == -1)
            return;

        loading_image[free_index] = true;
        thumbnail_data->loading_state = LoadingState::LOADING;
        if(download_image_thread[free_index].joinable())
            download_image_thread[free_index].join();

        // TODO: Keep the thread running and use conditional variable instead to sleep until a new image should be loaded. Same in ImageViewer.
        download_image_thread[free_index] = std::thread([this, free_index, thumbnail_path, url, resize_target_size, thumbnail_data]() mutable {
            thumbnail_data->image = std::make_unique<sf::Image>();

            Path thumbnail_path_resized = thumbnail_path;
            if(resize_target_size.x != 0 && resize_target_size.y != 0)
                thumbnail_path_resized.append("_" + std::to_string(resize_target_size.x) + "x" + std::to_string(resize_target_size.y));

            if(get_file_type(thumbnail_path_resized) == FileType::REGULAR) {
                load_image_from_file(*thumbnail_data->image, thumbnail_path_resized.data);
                thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
                fprintf(stderr, "Loaded %s from thumbnail cache\n", thumbnail_path_resized.data.c_str());
                return;
            }

            if(get_file_type(thumbnail_path.data) == FileType::FILE_NOT_FOUND && download_to_file(url, thumbnail_path.data, {}, true) != DownloadResult::OK) {
                thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
                loading_image[free_index] = false;
                return;
            }

            if(resize_target_size.x != 0 && resize_target_size.y != 0)
                create_thumbnail(thumbnail_path, thumbnail_path_resized, thumbnail_data.get(), resize_target_size);
            else
                load_image_from_file(*thumbnail_data->image, thumbnail_path.data);

            thumbnail_data->loading_state = LoadingState::FINISHED_LOADING;
            loading_image[free_index] = false;
            return;
        });
    }

    std::shared_ptr<ThumbnailData> AsyncImageLoader::get_thumbnail(const std::string &url, bool local, sf::Vector2i resize_target_size) {
        // TODO: Instead of generating a new hash everytime to access thumbnail, cache the hash of the thumbnail url
        auto &thumbnail_data = thumbnails[url];
        if(!thumbnail_data)
            thumbnail_data = std::make_shared<ThumbnailData>();
        thumbnail_data->counter = counter;
        load_thumbnail(url, local, resize_target_size, thumbnail_data);
        return thumbnail_data;
    }

    void AsyncImageLoader::update() {
        bool loaded_textures_changed = false;
        for(auto it = thumbnails.begin(); it != thumbnails.end();) {
            if(it->second->counter != counter) {
                it = thumbnails.erase(it);
                loaded_textures_changed = true;
            } else {
                ++it;
            }
        }

        ++counter;
        if(loaded_textures_changed)
            malloc_trim(0);
    }

    int AsyncImageLoader::get_free_load_index() const {
        for(int i = 0; i < NUM_IMAGE_LOAD_THREADS; ++i) {
            if(!loading_image[i])
                return i;
        }
        return -1;
    }
}