#include "CliRunner.h"

#include "../converter/pipeline/ImageData.h"
#include "../converter/rawloader/RawLoader.h"
#include "../converter/preprocess/Preprocessor.h"
#include "../converter/negative/NegativeDetector.h"
#include "../converter/invert/Inverter.h"
#include "../converter/color/ColorCorrector.h"
#include "../converter/crop/CropProcessor.h"
#include "../converter/output/OutputWriter.h"

#include <algorithm>
#include <format>
#include <iostream>

namespace photoconv {

// ─────────────────────────────────────────────────────────────────────────────
// parse_args
// ─────────────────────────────────────────────────────────────────────────────

std::expected<CliRunner::Config, Error> CliRunner::parse_args(int argc, char* argv[]) {
    Config config;
    bool reading_inputs = false;

    for (int i = 1; i < argc; ++i) {
        const std::string arg{argv[i]};

        if (arg == "--cli") {
            reading_inputs = false;
            continue;
        }

        if (arg == "--batch") {
            config.batch_mode = true;
            reading_inputs    = false;
            continue;
        }

        if (arg == "--config") {
            reading_inputs = false;
            if (i + 1 < argc) {
                config.config_file = argv[++i];
                config.batch_mode  = true; // --config implies batch mode
            } else {
                return std::unexpected(make_error(
                    ErrorCode::InvalidArgument, "--config requires a file path"));
            }
            continue;
        }

        if (arg == "-i" || arg == "--input") {
            reading_inputs = true;
            continue;
        }

        if (arg == "-o" || arg == "--output") {
            reading_inputs = false;
            if (i + 1 < argc) {
                config.output_dir = argv[++i];
            } else {
                return std::unexpected(make_error(
                    ErrorCode::InvalidArgument, "--output requires a directory path"));
            }
            continue;
        }

        if (arg == "--format") {
            reading_inputs = false;
            if (i + 1 < argc) {
                config.output_format = argv[++i];
            } else {
                return std::unexpected(make_error(
                    ErrorCode::InvalidArgument, "--format requires a value (png16|png8|tiff16|jpeg)"));
            }
            continue;
        }

        if (arg == "--quality") {
            reading_inputs = false;
            if (i + 1 < argc) {
                config.jpeg_quality = std::stoi(argv[++i]);
            } else {
                return std::unexpected(make_error(
                    ErrorCode::InvalidArgument, "--quality requires a numeric value"));
            }
            continue;
        }

        if (arg == "-v" || arg == "--verbose") {
            config.verbose = true;
            reading_inputs = false;
            continue;
        }

        if (arg == "-h" || arg == "--help") {
            std::cout <<
                "Usage: photo-converter --cli [options] -i <files...>\n"
                "       photo-converter --batch --config config.ini\n"
                "\n"
                "Options:\n"
                "  --cli                     CLI mode (no GUI)\n"
                "  --batch                   Batch mode (read config for input directory)\n"
                "  --config <file>           INI configuration file (implies --batch)\n"
                "  -i, --input <files...>    Input image files (RAW or standard)\n"
                "  -o, --output <dir>        Output directory (default: output/)\n"
                "  --format <fmt>            Output format: png16 png8 tiff16 jpeg\n"
                "  --quality <0-100>         JPEG quality (default: 95)\n"
                "  -v, --verbose             Verbose output\n"
                "  -h, --help                Show this help\n"
                << std::endl;
            return std::unexpected(make_error(ErrorCode::InvalidArgument, "Help requested"));
        }

        // If reading_inputs is active or the argument does not start with '-',
        // treat it as an input file path.
        if (reading_inputs || (!arg.empty() && arg.front() != '-')) {
            config.input_files.emplace_back(arg);
            reading_inputs = true;
        }
    }

    // Validation: we need either input files or a config file for batch mode.
    if (!config.batch_mode && config.input_files.empty()) {
        return std::unexpected(make_error(
            ErrorCode::InvalidArgument,
            "No input files specified. Use -i <files...> or --batch --config config.ini"));
    }

    return config;
}

// ─────────────────────────────────────────────────────────────────────────────
// run
// ─────────────────────────────────────────────────────────────────────────────

std::expected<int, Error> CliRunner::run(const Config& config) const {
    // ── Resolve AppConfig ────────────────────────────────────────────────────
    AppConfig app_cfg{};

    if (!config.config_file.empty()) {
        auto cfg_result = AppConfig::load(config.config_file);
        if (!cfg_result.has_value()) {
            return std::unexpected(cfg_result.error());
        }
        app_cfg = std::move(cfg_result.value());
        std::cout << std::format("[CLI] Loaded config: {}", config.config_file.string())
                  << std::endl;
    }

    // CLI flags override config file values where set explicitly.
    if (!config.output_dir.empty()) {
        app_cfg.batch.output_dir = config.output_dir;
    }
    if (!config.output_format.empty() && config.output_format != "png16") {
        // "png16" is the default; only override if the user explicitly changed it.
        app_cfg.conversion.output_format = config.output_format;
    }
    if (config.jpeg_quality != 95) {
        app_cfg.quality.jpeg_quality = config.jpeg_quality;
    }

    // ── Collect input files ──────────────────────────────────────────────────
    std::vector<std::filesystem::path> files = config.input_files;

    if (files.empty() && config.batch_mode) {
        const auto extensions = app_cfg.parsed_extensions();
        files = collect_files(app_cfg.batch.input_dir, extensions,
                              app_cfg.batch.recursive);

        if (files.empty()) {
            std::cerr << std::format(
                "[CLI] No matching files found in: {}",
                app_cfg.batch.input_dir.string()) << std::endl;
            return 0;
        }
    }

    // ── Build pipeline ───────────────────────────────────────────────────────
    RawLoader loader;
    Pipeline  pipeline = build_pipeline(app_cfg);

    // ── Process files ────────────────────────────────────────────────────────
    int success_count = 0;
    const auto total  = static_cast<int>(files.size());

    for (int idx = 0; idx < total; ++idx) {
        const auto& file = files[static_cast<std::size_t>(idx)];

        std::cerr << std::format("[{}/{}] Processing {}...",
                                  idx + 1, total, file.filename().string())
                  << std::endl;

        // Load image
        auto load_result = loader.load(file);
        if (!load_result.has_value()) {
            std::cerr << std::format("[CLI] Load failed: {}",
                                      load_result.error().format()) << std::endl;
            continue;
        }

        // Run pipeline
        auto result = pipeline.execute(std::move(load_result.value()));
        if (!result.has_value()) {
            std::cerr << std::format("[CLI] Pipeline failed: {}",
                                      result.error().format()) << std::endl;
            continue;
        }

        ++success_count;
    }

    std::cout << std::format("\n[CLI] Done: {}/{} file(s) converted successfully",
                              success_count, total) << std::endl;

    return success_count;
}

// ─────────────────────────────────────────────────────────────────────────────
// collect_files
// ─────────────────────────────────────────────────────────────────────────────

std::vector<std::filesystem::path> CliRunner::collect_files(
    const std::filesystem::path& dir,
    const std::vector<std::string>& extensions,
    const bool recursive)
{
    std::vector<std::filesystem::path> result;

    if (!std::filesystem::is_directory(dir)) {
        std::cerr << std::format("[CLI] Input directory not found: {}", dir.string())
                  << std::endl;
        return result;
    }

    auto collect_entry = [&](const std::filesystem::directory_entry& entry) {
        if (!entry.is_regular_file()) return;

        // Compare extension case-insensitively.
        std::string ext = entry.path().extension().string();
        std::ranges::transform(ext, ext.begin(),
            [](unsigned char c) { return static_cast<char>(std::tolower(c)); });

        const bool match = std::ranges::any_of(extensions,
            [&ext](const std::string& e) { return e == ext; });

        if (match) {
            result.push_back(entry.path());
        }
    };

    if (recursive) {
        for (const auto& entry : std::filesystem::recursive_directory_iterator{dir}) {
            collect_entry(entry);
        }
    } else {
        for (const auto& entry : std::filesystem::directory_iterator{dir}) {
            collect_entry(entry);
        }
    }

    std::ranges::sort(result);
    return result;
}

// ─────────────────────────────────────────────────────────────────────────────
// build_pipeline
// ─────────────────────────────────────────────────────────────────────────────

Pipeline CliRunner::build_pipeline(const AppConfig& app_cfg) {
    Pipeline pipeline;

    // Resolve forced film type from config.
    // "auto" → Unknown (auto-detection), "c41" → ColorNegative, "bw" → BWNegative.
    FilmType forced_film = FilmType::Unknown;
    if (app_cfg.conversion.film_type == "c41") {
        forced_film = FilmType::ColorNegative;
    } else if (app_cfg.conversion.film_type == "bw") {
        forced_film = FilmType::BWNegative;
    }

    pipeline.add_stage(std::make_unique<Preprocessor>());
    pipeline.add_stage(std::make_unique<NegativeDetector>(forced_film));

    if (app_cfg.conversion.invert) {
        pipeline.add_stage(std::make_unique<Inverter>());
    }

    pipeline.add_stage(std::make_unique<ColorCorrector>());

    pipeline.add_stage(std::make_unique<CropProcessor>());

    pipeline.add_stage(std::make_unique<OutputWriter>(OutputConfig{
        app_cfg.batch.output_dir,
        app_cfg.output_format(),
        app_cfg.quality.jpeg_quality
    }));

    return pipeline;
}

} // namespace photoconv