#include "../include/VideoPlayer.hpp"
#include "../include/Storage.hpp"
#include "../include/Program.hpp"
#include "../include/Utils.hpp"
#include "../include/StringUtils.hpp"
#include "../include/Notification.hpp"
#include <string>
#include <json/reader.h>
#include <json/writer.h>
#include <memory>
#include <assert.h>

#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>

static ssize_t read_eintr(int fd, void *buffer, size_t size) {
    while(true) {
        ssize_t bytes_read = read(fd, buffer, size);
        if(bytes_read == -1) {
            if(errno != EINTR)
                return -1;
        } else {
            return bytes_read;
        }
    }
}

static ssize_t write_all_blocking(int fd, const void *buffer, size_t size) {
    ssize_t bytes_written = 0;
    while((size_t)bytes_written < size) {
        ssize_t written = write(fd, (char*)buffer + bytes_written, size - bytes_written);
        if(written == -1) {
            if(errno != EINTR && errno != EWOULDBLOCK)
                return -1;
        } else {
            bytes_written += written;
        }
    }
    return bytes_written;
}

namespace QuickMedia {
    static const double RETRY_TIME_SEC = 0.5;
    static const int MAX_RETRIES_CONNECT = 1000;
    static const double READ_TIMEOUT_SEC = 3.0;

    static std::string media_chapters_to_ffmetadata_chapters(const std::vector<MediaChapter> &chapters) {
        std::string result = ";FFMETADATA1\n\n";
        for(size_t i = 0; i < chapters.size(); ++i) {
            const MediaChapter &chapter = chapters[i];
            result += "[CHAPTER]\n";
            result += "TIMEBASE=1/1\n";
            result += "START=" + std::to_string(chapter.start_seconds) + "\n";
            result += "END=" + std::to_string(i + 1 == chapters.size() ? chapter.start_seconds : chapters[i + 1].start_seconds) + "\n";
            std::string title = chapter.title;
            string_replace_all(title, '\n', ' ');
            result += "title=" + std::move(title) + "\n\n";
        }
        return result;
    }

    // If |chapters| is empty then |tmp_chapters_filepath| is removed, otherwise the file is overwritten
    static bool create_tmp_file_with_chapters_data(char *tmp_chapters_filepath, const std::vector<MediaChapter> &chapters) {
        if(chapters.empty()) {
            if(tmp_chapters_filepath[0] != '\0') {
                remove(tmp_chapters_filepath);
                tmp_chapters_filepath[0] = '\0';
            }
            return true;
        }

        if(tmp_chapters_filepath[0] == '\0') {
            strcpy(tmp_chapters_filepath, "/tmp/qm-mpv-chapter-XXXXXX");
            mktemp(tmp_chapters_filepath);
            if(tmp_chapters_filepath[0] == '\0') {
                fprintf(stderr, "Failed to create temporay file\n");
                return false;
            }
        }

        if(file_overwrite(tmp_chapters_filepath, media_chapters_to_ffmetadata_chapters(chapters)) == 0) {
            return true;
        } else {
            remove(tmp_chapters_filepath);
            tmp_chapters_filepath[0] = '\0';
            return false;
        }
    }

    VideoPlayer::VideoPlayer(StartupArgs startup_args, EventCallbackFunc _event_callback, VideoPlayerWindowCreateCallback _window_create_callback) :
        exit_status(0),
        startup_args(std::move(startup_args)),
        video_process_id(-1),
        connect_tries(0),
        find_window_tries(0),
        event_callback(std::move(_event_callback)),
        window_create_callback(std::move(_window_create_callback)),
        window_handle(0),
        display(nullptr),
        request_id_counter(1),
        expected_request_id(0),
        request_response_data(Json::nullValue),
        response_data_status(ResponseDataStatus::NONE)
    {
        tmp_chapters_filepath[0] = '\0';
        display = XOpenDisplay(NULL);
        if (!display) {
            show_notification("QuickMedia", "Failed to open display to X11 server", Urgency::CRITICAL);
            abort();
        }
        fprintf(stderr, "Video max height: %d\n", startup_args.monitor_height);
    }

    VideoPlayer::~VideoPlayer() {
        if(video_process_id != -1) {
            kill(video_process_id, SIGTERM);
            wait_program(video_process_id);
        }
        
        if(ipc_socket != -1)
            close(ipc_socket);

        if(display)
            XCloseDisplay(display);

        if(tmp_chapters_filepath[0] != '\0')
            remove(tmp_chapters_filepath);
    }

    static Path get_config_dir_xdg() {
        Path path;
        const char *xdg_config_home_p = getenv("XDG_CONFIG_HOME");
        if(xdg_config_home_p)
            path = xdg_config_home_p;
        else
            path = get_home_dir().join(".config");
        return path;
    }

    VideoPlayer::Error VideoPlayer::launch_video_process() {
        int fd[2];
        if(socketpair(AF_UNIX, SOCK_STREAM, 0, fd) < 0) {
            perror("Failed to create socketpair for video player");
            return Error::FAIL_TO_CREATE_SOCKET;
        }
        ipc_socket = fd[0];

        int flags = fcntl(ipc_socket, F_GETFL, 0);
        if(flags != -1)
            fcntl(ipc_socket, F_SETFL, flags | O_NONBLOCK);

        const std::string ipc_fd = std::to_string(fd[1]);
        std::string cache_dir = "--cache-dir=" + std::move(get_cache_dir().join("media").data);

        std::string wid_arg = "--wid=";
        wid_arg += std::to_string(startup_args.parent_window);

        std::string video_player_filepath = startup_args.resource_root + "/video_player/sibs-build/linux_x86_64/"
#ifdef NDEBUG
        "release/"
#else
        "debug/"
#endif
        "quickmedia-video-player";

        if(get_file_type(video_player_filepath.c_str()) != FileType::REGULAR)
            video_player_filepath = "/usr/bin/quickmedia-video-player";

        std::string config_dir = "--config-dir=" + startup_args.resource_root + "mpv";

        std::vector<const char*> args;
        // TODO: Resume playback if the last video played matches the first video played next time QuickMedia is launched
        args.insert(args.end(), {
            video_player_filepath.c_str(),
            "--cursor-autohide=no",
            "--profile=pseudo-gui", // For gui when playing audio, requires a version of mpv that isn't ancient
            // TODO: Disable hr seek on low power devices?
            "--hr-seek=yes",
            "--force-seekable=yes",
            "--image-display-duration=5",
            "--cache-pause=yes",
            "--sub-font-size=50",
            "--sub-margin-y=60",
            "--sub-border-size=2.0",
            "--sub-bold=yes",
            "--input-default-bindings=yes",
            "--input-vo-keyboard=yes",
            wid_arg.c_str(),
            "--ipc-fd",
            ipc_fd.c_str()
        });

        if(startup_args.cache_on_disk) {
            args.insert(args.end(), {
                "--cache=yes",
                "--cache-on-disk=yes",
                "--cache-secs=86400", // 24 hours
                cache_dir.c_str()
            });
        }

        if(startup_args.resume) {
            args.push_back("--save-position-on-quit=yes");
            args.push_back("--resume-playback=yes");
        } else {
            args.push_back("--save-position-on-quit=no");
            args.push_back("--resume-playback=no");
        }
        
        if(is_running_wayland()) {
            args.push_back("--gpu-context=x11egl");
            fprintf(stderr, "Wayland detected. Launching mpv in x11egl mode\n");
        }

        if(startup_args.keep_open)
            args.push_back("--keep-open=yes");

        std::string ytdl_format;
        if(startup_args.no_video)
            ytdl_format = "--ytdl-format=bestaudio/best";
        else
            ytdl_format = "--ytdl-format=bestvideo[height<=?" + std::to_string(startup_args.monitor_height) + "]+bestaudio/best";

        if(!startup_args.use_youtube_dl)
            args.push_back("--ytdl=no");
        else
            args.push_back(ytdl_format.c_str());

        std::string mpris_arg;
        Path mpris_path = get_config_dir_xdg().join("mpv").join("scripts").join("mpris.so");
        if(get_file_type(mpris_path) == FileType::REGULAR)
            mpris_arg = "--scripts=" + mpris_path.data;

        if(startup_args.use_system_mpv_config) {
            args.push_back("--config=yes");
            args.push_back("--load-scripts=yes");
            args.push_back("--osc=yes");
        } else {
            args.insert(args.end(), {
                config_dir.c_str(),
                "--config=yes"
            });

            if(!mpris_arg.empty())
                args.push_back(mpris_arg.c_str());
        }

        std::string force_media_title_arg;
        if(!startup_args.title.empty()) {
            force_media_title_arg = "--force-media-title=" + startup_args.title;
            args.push_back(force_media_title_arg.c_str());
        }

        if(startup_args.no_video)
            args.push_back("--video=no");

        std::string chapters_file_arg;
        if(tmp_chapters_filepath[0] != '\0') {
            chapters_file_arg = std::string("--chapters-file=") + tmp_chapters_filepath;
            args.push_back(chapters_file_arg.c_str());
        }

        if(!startup_args.audio_path.empty()) {
            args.push_back("--audio-file");
            args.push_back(startup_args.audio_path.c_str());
        }

        std::string start_time_arg;
        if(!startup_args.start_time.empty()) {
            start_time_arg = "--start=" + startup_args.start_time;
            args.push_back(start_time_arg.c_str());
        }

        args.insert(args.end(), { "--", startup_args.path.c_str(), nullptr });

        if(exec_program_async(args.data(), &video_process_id) != 0) {
            close(fd[1]);
            close(ipc_socket);
            ipc_socket = -1;
            return Error::FAIL_TO_LAUNCH_PROCESS;
        }

        close(fd[1]);
        return Error::OK;
    }

    VideoPlayer::Error VideoPlayer::load_video() {
        // This check is to make sure we dont change window that the video belongs to. This is not a usecase we will have so
        // no need to support it for now at least.
        assert(!startup_args.path.empty());
        if(!create_tmp_file_with_chapters_data(tmp_chapters_filepath, startup_args.chapters))
            fprintf(stderr, "Warning: failed to create chapters file. Chapters will not be displayed\n");

        fprintf(stderr, "Playing video: %s, audio: %s\n", startup_args.path.c_str(), startup_args.audio_path.c_str());
        if(video_process_id == -1)
            return launch_video_process();

        fprintf(stderr, "TODO: Implement VideoPlayer::load_video without restarting the video player\n");
        abort();
        return VideoPlayer::Error::INIT_FAILED;
    }

    static std::vector<Window> get_child_window(Display *display, Window window) {
        std::vector<Window> result;
        Window root_window;
        Window parent_window;
        Window *child_window = nullptr;
        unsigned int num_children = 0;
        if(XQueryTree(display, window, &root_window, &parent_window, &child_window, &num_children) && child_window) {
            for(unsigned int i = 0; i < num_children; i++)
                result.push_back(child_window[i]);
            XFree(child_window);
        }
        return result;
    }

    VideoPlayer::Error VideoPlayer::update() {
        const int max_retries_find_window = 1000;

        if(video_process_id != -1) {
            if(wait_program_non_blocking(video_process_id, &exit_status)) {
                fprintf(stderr, "The video player exited!, status: %d\n", exit_status);
                close(ipc_socket);
                video_process_id = -1;
                ipc_socket = -1;
                window_handle = None;
                return Error::EXITED;
            }
        }

        if(ipc_socket == -1)
            return Error::INIT_FAILED;

        if(connect_tries == MAX_RETRIES_CONNECT)
            return Error::FAIL_TO_CONNECT_TIMEOUT;

        if(find_window_tries == max_retries_find_window)
            return Error::FAIL_TO_FIND_WINDOW;

        if(window_handle == 0 && retry_timer.get_elapsed_time_seconds() >= RETRY_TIME_SEC) {
            retry_timer.restart();
            std::vector<Window> child_windows = get_child_window(display, startup_args.parent_window);
            size_t num_children = child_windows.size();
            if(num_children == 0) {
                ++find_window_tries;
                if(find_window_tries == max_retries_find_window) {
                    fprintf(stderr, "Failed to find mpv window after %d seconds\n", (int)(RETRY_TIME_SEC * max_retries_find_window));
                    return Error::FAIL_TO_FIND_WINDOW_TIMEOUT;
                }
            } else if(num_children == 1) {
                window_handle = child_windows[0];
                if(window_create_callback)
                    window_create_callback(window_handle);
            } else {
                fprintf(stderr, "Expected window to have one child (the video player) but it has %zu\n", num_children);
                return Error::UNEXPECTED_WINDOW_ERROR;
            }
        }

        if(window_handle && event_callback) {
            Error err = read_ipc_func();
            if(err != Error::OK)
                return err;
        }

        return Error::OK;
    }

    static std::vector<std::string> json_array_to_string_list(const Json::Value &json) {
        std::vector<std::string> result;
        if(!json.isArray())
            return result;

        for(const Json::Value &item : json) {
            if(!item.isString())
                continue;

            result.push_back(item.asString());
        }

        return result;
    }

    VideoPlayer::Error VideoPlayer::read_ipc_func() {
        Json::Value json_root;
        Json::CharReaderBuilder json_builder;
        std::unique_ptr<Json::CharReader> json_reader(json_builder.newCharReader());
        std::string json_errors;

        char buffer[2048];
        ssize_t bytes_read = read_eintr(ipc_socket, buffer, sizeof(buffer));
        if(bytes_read == -1) {
            int err = errno;
            if(err != EAGAIN && err != EWOULDBLOCK) {
                fprintf(stderr, "Failed to read from ipc socket, error: %s\n", strerror(err));
                return Error::FAIL_TO_READ;
            }
        } else if(bytes_read > 0) {
            int start = 0;
            for(int i = 0; i < bytes_read; ++i) {
                if(buffer[i] != '\n')
                    continue;

                if(json_reader->parse(buffer + start, buffer + i, &json_root, &json_errors) && json_root.isObject()) {
                    const Json::Value &event = json_root["event"];
                    const Json::Value &args = json_root["args"];
                    if(event.isString()) {
                        if(event_callback)
                            event_callback(event.asCString(), json_array_to_string_list(args));
                    }

                    const Json::Value &request_id_json = json_root["request_id"];
                    if(expected_request_id != 0 && request_id_json.isNumeric() && request_id_json.asUInt() == expected_request_id) {
                        const Json::Value &status_json = json_root["status"];
                        if(!status_json.isString() || strcmp(status_json.asCString(), "error") == 0) {
                            response_data_status = ResponseDataStatus::ERROR;
                            const char *err_msg = "Unknown";
                            const Json::Value &message_json = json_root["message"];
                            if(message_json.isString())
                                err_msg = message_json.asCString();

                            fprintf(stderr, "VideoPlayer::send_command failed, error from video player: %s\n", err_msg);
                        } else {
                            response_data_status = ResponseDataStatus::OK;
                        }
                        request_response_data = json_root["data"];
                    }
                } else {
                    fprintf(stderr, "Failed to parse json for ipc: |%.*s|, reason: %s\n", (int)bytes_read, buffer, json_errors.c_str());
                }

                start = i + 1;
            }
        }
        return Error::OK;
    }

    VideoPlayer::Error VideoPlayer::get_time_in_file(double *result) {
        Json::Value json_root(Json::objectValue);
        json_root["command"] = "time-pos";

        Json::Value time_pos_json;
        Error err = send_command(json_root, &time_pos_json, Json::ValueType::realValue);
        if(err != Error::OK)
            return err;

        *result = time_pos_json.asDouble();
        return err;
    }

    VideoPlayer::Error VideoPlayer::get_duration_in_file(double *result) {
        Json::Value json_root(Json::objectValue);
        json_root["command"] = "duration";

        Json::Value duration_json;
        Error err = send_command(json_root, &duration_json, Json::ValueType::realValue);
        if(err != Error::OK)
            return err;

        *result = duration_json.asDouble();
        return err;
    }

    VideoPlayer::Error VideoPlayer::add_subtitle(const std::string &url, const std::string &title, const std::string &lang) {
        Json::Value data_json(Json::objectValue);
        data_json["file"] = url;
        if(!title.empty()) {
            data_json["title"] = title;
            if(!lang.empty())
                data_json["language"] = title;
        }

        Json::Value json_root(Json::objectValue);
        json_root["command"] = "sub-add";
        json_root["data"] = std::move(data_json);

        Json::Value result;
        return send_command(json_root, &result, Json::ValueType::nullValue);
    }

    VideoPlayer::Error VideoPlayer::cycle_fullscreen() {
        Json::Value json_root(Json::objectValue);
        json_root["command"] = "cycle-fullscreen";

        Json::Value result;
        return send_command(json_root, &result, Json::ValueType::nullValue);
    }

    uint32_t VideoPlayer::get_next_request_id() {
        unsigned int cmd_request_id = request_id_counter;
        ++request_id_counter;

        // Overflow check. 0 is defined as no request, 1 is the first valid one
        if(request_id_counter == 0)
            request_id_counter = 1;
        
        return cmd_request_id;
    }

    VideoPlayer::Error VideoPlayer::send_command(Json::Value &json_root, Json::Value *result, Json::ValueType result_type) {
        const uint32_t request_id = get_next_request_id();
        json_root["request_id"] = request_id;

        Json::StreamWriterBuilder builder;
        builder["commentStyle"] = "None";
        builder["indentation"] = "";
        const std::string cmd_str = Json::writeString(builder, json_root) + "\n";

        if(write_all_blocking(ipc_socket, cmd_str.data(), cmd_str.size()) == -1) {
            fprintf(stderr, "Failed to send to ipc socket, error: %s, command: %.*s\n", strerror(errno), (int)cmd_str.size(), cmd_str.c_str());
            return Error::FAIL_TO_SEND;
        }

        VideoPlayer::Error err;
        mgl::Clock read_timer;
        expected_request_id = request_id;
        do {
            err = read_ipc_func();
            if(err != Error::OK)
                goto cleanup;

            if(response_data_status != ResponseDataStatus::NONE)
                break;
        } while(read_timer.get_elapsed_time_seconds() < READ_TIMEOUT_SEC);

        if(response_data_status == ResponseDataStatus::OK) {
            if(request_response_data.type() == result_type)
                *result = request_response_data;
            else
                err = Error::READ_INCORRECT_TYPE;
        } else if(response_data_status == ResponseDataStatus::ERROR) {
            err = Error::READ_RESPONSE_ERROR;
            goto cleanup;
        } else {
            err = Error::READ_TIMEOUT;
            goto cleanup;
        }

        cleanup:
        expected_request_id = 0;
        response_data_status = ResponseDataStatus::NONE;
        request_response_data = Json::Value(Json::nullValue);
        return err;
    }
}