#pragma once
#include "types.hpp"

#include <opencv2/calib3d.hpp>
#include <opencv2/imgproc.hpp>

#include <cmath>

// ── align_face ────────────────────────────────────────────────────────────────
// Produces a 112×112 BGR crop using the ArcFace 5-point similarity transform.
// Returns an empty Mat if the affine fit fails (degenerate detection).
inline cv::Mat align_face(const cv::Mat& img,
                           const std::array<cv::Point2f, 5>& landmarks) {
    std::vector<cv::Point2f> src(landmarks.begin(), landmarks.end());
    std::vector<cv::Point2f> dst(5);
    for (int i = 0; i < 5; ++i) dst[i] = {kArcFaceRef[i][0], kArcFaceRef[i][1]};

    cv::Mat M = cv::estimateAffinePartial2D(src, dst, cv::noArray(), cv::RANSAC, 3.0);
    if (M.empty()) return {};

    cv::Mat crop;
    cv::warpAffine(img, crop, M, {112, 112},
                   cv::INTER_LINEAR, cv::BORDER_CONSTANT, {0, 0, 0});
    return crop;
}

// ── enhance_for_retry ────────────────────────────────────────────────────────
// Used when initial face detection finds nothing. Pads the image by 50%
// (border-replicated, so the detector doesn't see a hard edge) and applies
// CLAHE to boost local contrast, giving the detector a second try.
inline cv::Mat enhance_for_retry(const cv::Mat& img) {
    cv::Mat padded;
    const int pad_x = img.cols / 4;
    const int pad_y = img.rows / 4;
    cv::copyMakeBorder(img, padded, pad_y, pad_y, pad_x, pad_x, cv::BORDER_REPLICATE);

    cv::Mat lab;
    cv::cvtColor(padded, lab, cv::COLOR_BGR2Lab);
    std::vector<cv::Mat> channels;
    cv::split(lab, channels);
    cv::createCLAHE(2.0, cv::Size(8, 8))->apply(channels[0], channels[0]);
    cv::merge(channels, lab);

    cv::Mat out;
    cv::cvtColor(lab, out, cv::COLOR_Lab2BGR);
    return out;
}

// ── l2_normalise ──────────────────────────────────────────────────────────────
inline Embedding l2_normalise(const float* row) {
    float norm = 0.f;
    for (int d = 0; d < 512; ++d) norm += row[d] * row[d];
    norm = std::sqrt(norm);
    if (norm < 1e-6f) norm = 1e-6f;
    Embedding emb;
    for (int d = 0; d < 512; ++d) emb[d] = row[d] / norm;
    return emb;
}