#include "Inverter.h"

#include <opencv2/core.hpp>
#include <opencv2/imgproc.hpp>

#include <format>
#include <iostream>

namespace photoconv {

StageResult Inverter::process(ImageData data) const {
    if (data.rgb.empty()) {
        return std::unexpected(make_error(
            ErrorCode::InversionFailed, "Inverter received empty image"));
    }

    switch (data.film_type) {
        case FilmType::ColorNegative:
            std::cout << "[Invert] Inverting color negative (C-41)" << std::endl;
            return invert_color_negative(std::move(data));

        case FilmType::BWNegative:
            std::cout << "[Invert] Inverting B&W negative" << std::endl;
            return invert_bw_negative(std::move(data));

        case FilmType::ColorPositive:
        case FilmType::BWPositive:
            std::cout << "[Invert] Positive detected, skipping inversion" << std::endl;
            return data;

        case FilmType::Unknown:
            std::cout << "[Invert] Unknown film type, applying default inversion" << std::endl;
            return invert_color_negative(std::move(data));
    }

    return data; // Unreachable, but satisfies compiler
}

StageResult Inverter::invert_color_negative(ImageData data) {
    // TODO: Implement proper C-41 orange mask removal.
    // Strategy:
    // 1. Sample unexposed border regions to characterize the orange mask
    // 2. Compute per-channel mask color (typically R > G > B)
    // 3. Subtract mask contribution from each channel
    // 4. Apply bitwise_not inversion
    // 5. Apply per-channel scaling to normalize levels

    // Basic inversion for now
    cv::bitwise_not(data.rgb, data.rgb);

    return data;
}

StageResult Inverter::invert_bw_negative(ImageData data) {
    cv::bitwise_not(data.rgb, data.rgb);
    return data;
}

} // namespace photoconv