/* mcopy
 *
 * Rename music by specifying a format
 * Licensed under the GNU General Public License version 3.
 * See included LICENSE file for copyright and license details.
 */

#include <tag.h>
#include <fileref.h>
#include <filesystem>
#include <unordered_map>
#include <fstream>
#include <core.hpp>

std::pair<mcopy::FileStatus, mcopy::FileData> mcopy::get_metadata_from_file(const std::string& file) {
    TagLib::FileRef _file = TagLib::FileRef(TagLib::FileName(file.c_str()));

    if (_file.isNull() || !_file.audioProperties()) {
        return {mcopy::FileStatus::Failure, {}};
    }

    TagLib::Tag* tag = _file.tag();

    const auto get_title = [&tag]() -> std::string { return tag->title().to8Bit(true); };
    const auto get_album = [&tag]() -> std::string { return tag->album().to8Bit(true); };
    const auto get_artist = [&tag]() -> std::string { return tag->artist().to8Bit(true); };
    const auto get_track = [&tag]() -> std::string { return std::to_string(tag->track()); };
    const auto get_year = [&tag]() -> std::string { return std::to_string(tag->year()); };
    const auto get_genre = [&tag]() -> std::string { return tag->genre().to8Bit(true); };
    const auto get_comment = [&tag]() -> std::string { return tag->comment().to8Bit(true); };
    const auto get_extension = [&file]() -> std::string { return file.find_last_of(".") + 1 != file.npos ? file.substr(file.find_last_of(".") + 1) : ""; };

    mcopy::FileData data{
        get_title(),
        get_album(),
        get_artist(),
        get_track(),
        get_year(),
        get_genre(),
        get_comment(),
        get_extension(),
    };

    return {mcopy::FileStatus::Success, data};
}

void mcopy::write_to_file(const mcopy::Settings& settings, const std::string& format, const std::string& file) {
    if (!std::filesystem::is_regular_file(file)) {
        std::cerr << "mcopy: invalid file '" << file << "' is skipped.\n";
        if (settings.strict) {
            std::exit(EXIT_FAILURE);
        }

        return;
    }

    std::pair<mcopy::FileStatus, mcopy::FileData> pair = mcopy::get_metadata_from_file(file);
    if (pair.first == mcopy::FileStatus::Failure) {
        std::cerr << "mcopy: invalid file '" << file << "' is skipped.\n";
        if (settings.strict) {
            std::exit(EXIT_FAILURE);
        }

        return;
    }

    mcopy::FileData& data = pair.second;
#ifdef _WIN32
    std::vector<char> the_forbidden_characters{'<', '>', ':', '"', '/', '\\', '|', '?', '*'};
#else
    std::vector<char> the_forbidden_characters{'/'};
#endif

    const std::vector<std::string*> data_members = {&data.title, &data.album, &data.artist, &data.track, &data.year, &data.genre, &data.comment, &data.extension};
    for (const auto& it : data_members) {
        for (const auto& c : the_forbidden_characters) {
            it->erase(std::remove_if(it->begin(), it->end(), [&c](char _c) { return c == _c; }), it->end());
        }
    }

    std::unordered_map<std::string, std::string> delim_map{
        {"@t", data.title},
        {"@a", data.album},
        {"@A", data.artist},
        {"@n", data.track},
        {"@y", data.year},
        {"@g", data.genre},
        {"@c", data.comment},
        {"@e", data.extension},
    };

    std::string output_filename = format;
    for (auto& it : delim_map) {
        while (output_filename.find(it.first) != std::string::npos) {
            if (it.second.empty()) {
                it.second = "Unknown";

                if (settings.ask) {
                    std::cerr << "mcopy: failed to retrieve data to represent " << it.first << ", enter an appropriate replacement: ";
                    std::getline(std::cin, it.second);
                }
            }

            output_filename.replace(output_filename.find(it.first), it.first.length(), it.second);
        }
    }

    std::ifstream ef(output_filename);
    if (ef.good() && settings.skip_existing) {
        std::cerr << "mcopy: file << '" << file << "' already exists, skipping\n";
        return;
    }

    const std::string dir{std::filesystem::path{output_filename}.remove_filename()};
    if (dir.empty()) {
        std::cerr << "mcopy: failed to retrieve directory: " << output_filename << "\n";
        if (settings.strict) {
            std::exit(EXIT_FAILURE);
        }

        return;
    }

    if (!std::filesystem::exists(dir) && !std::filesystem::create_directories(dir)) {
        std::cerr << "mcopy: failed to create directory '" << dir << "'\n";
        if (settings.strict) {
            std::exit(EXIT_FAILURE);
        }

        return;
    }

    if (!std::filesystem::copy_file(file, output_filename, std::filesystem::copy_options::overwrite_existing)) {
        std::cerr << "mcopy: failed to copy input file '" << file << "' to '" << output_filename << "'\n";
        if (settings.strict) std::exit(EXIT_FAILURE);
    } else if (!settings.quiet) {
        std::cout << "mcopy: copied input file '" << file << "' to '" << output_filename << "'\n";
    }
}