from pathlib import Path
import math

EPS_DIST = 1e-4      # distância mínima entre pontos
MIN_AREA = 1e-6      # área mínima do polígono


def clamp(v: float) -> float:
    # remove -0.0 e garante [0,1]
    v = 0.0 if abs(v) < 1e-12 else v
    return max(0.0, min(1.0, v))


def polygon_area(pts):
    # fórmula do polígono (shoelace)
    area = 0.0
    for i in range(len(pts)):
        x1, y1 = pts[i]
        x2, y2 = pts[(i + 1) % len(pts)]
        area += x1 * y2 - x2 * y1
    return abs(area) * 0.5


def dist(a, b):
    return math.hypot(a[0] - b[0], a[1] - b[1])


def dedupe_and_simplify(pts):
    # remove pontos duplicados / muito próximos
    clean = []
    for p in pts:
        if not clean or dist(p, clean[-1]) > EPS_DIST:
            clean.append(p)

    # fecha polígono se necessário
    if len(clean) > 2 and dist(clean[0], clean[-1]) < EPS_DIST:
        clean.pop()

    return clean


def convert_label_file(path: Path):
    text = path.read_text().strip()
    if not text:
        print(f"[WARN] {path.name} vazio, pulando.")
        return

    new_lines = []

    for line in text.splitlines():
        parts = line.strip().split()
        if len(parts) < 7:
            continue  # menos que 3 pontos

        cls_id = int(float(parts[0]))
        nums = list(map(float, parts[1:]))

        if len(nums) % 2 != 0:
            continue

        pts = []
        for x, y in zip(nums[0::2], nums[1::2]):
            pts.append((clamp(x), clamp(y)))

        pts = dedupe_and_simplify(pts)

        if len(pts) < 3:
            continue

        area = polygon_area(pts)
        if area < MIN_AREA:
            continue

        flat = []
        for x, y in pts:
            flat.append(f"{x:.6f}")
            flat.append(f"{y:.6f}")

        new_lines.append(" ".join([str(cls_id)] + flat))

    if not new_lines:
        print(f"[WARN] {path.name} ficou sem polígonos válidos.")
        return

    # backup
    backup = path.with_suffix(path.suffix + ".bak")
    if not backup.exists():
        backup.write_text(text)

    path.write_text("\n".join(new_lines) + "\n")
    print(f"[OK] Corrigido: {path.name}")


def main():
    root = Path(".").resolve()

    for sub in ["labels/train", "labels/val"]:
        d = root / sub
        if not d.exists():
            continue

        for txt in sorted(d.glob("*.txt")):
            convert_label_file(txt)


if __name__ == "__main__":
    main()