"""
Normalisasi landmark untuk konsistensi across different positions dan scales.

Melakukan normalisasi koordinat landmark sesuai README.
"""

import numpy as np
from typing import Optional


class LandmarkNormalizer:
    """
    Kelas untuk menormalisasi landmark tangan dan wajah.

    Proses normalisasi sesuai README:
    1. Menggeser koordinat ke titik referensi
    2. Scaling
    """

    def __init__(self, scale_factor: Optional[float] = None):
        """
        Inisialisasi normalizer.

        Args:
            scale_factor: Faktor skala tetap. Jika None, dihitung dari data.
        """
        self.scale_factor = scale_factor

    def normalize_hand(self, landmarks: np.ndarray) -> np.ndarray:
        """
        Normalisasi landmark satu tangan.

        Args:
            landmarks: Array shape (21, 3) dari landmark tangan

        Returns:
            Array landmark yang sudah dinormalisasi
        """
        if landmarks is None or landmarks.shape != (21, 3):
            return np.zeros((21, 3))

        # Buat copy
        normalized = landmarks.copy()

        # 1. Translation: Geser ke wrist (origin) - index 0
        wrist = normalized[0]
        normalized -= wrist

        # 2. Scaling: Normalisasi berdasarkan distance dari wrist ke middle finger MCP (index 9)
        middle_mcp = normalized[9]
        distance = np.linalg.norm(middle_mcp)

        if distance > 1e-6:  # Avoid division by zero
            normalized = normalized / distance

            if self.scale_factor is not None:
                normalized *= self.scale_factor

        return normalized

    def normalize_face(self, landmarks: np.ndarray) -> np.ndarray:
        """
        Normalisasi landmark wajah.

        Args:
            landmarks: Array shape (60, 3) dari landmark wajah

        Returns:
            Array landmark yang sudah dinormalisasi
        """
        if landmarks is None or len(landmarks) == 0:
            return np.zeros((60, 3))

        # Buat copy
        normalized = landmarks.copy()

        # 1. Translation: Geser ke nose (center)
        nose = normalized[0]
        normalized -= nose

        # 2. Scaling: Normalisasi berdasarkan max distance from center
        max_distance = np.max(np.linalg.norm(normalized, axis=1))

        if max_distance > 1e-6:
            normalized = normalized / max_distance

            if self.scale_factor is not None:
                normalized *= self.scale_factor

        return normalized

    def normalize_frame(
        self,
        left_hand: np.ndarray,
        right_hand: np.ndarray,
        face: np.ndarray
    ) -> np.ndarray:
        """
        Normalisasi semua landmark dari satu frame.

        Args:
            left_hand: Array (21, 3) landmark tangan kiri
            right_hand: Array (21, 3) landmark tangan kanan
            face: Array (60, 3) landmark wajah

        Returns:
            Array 1D concatenation dari semua landmark yang sudah dinormalisasi
        """
        norm_left = self.normalize_hand(left_hand)
        norm_right = self.normalize_hand(right_hand)
        norm_face = self.normalize_face(face)

        # Concatenate: 63 + 63 + 180 = 306
        return np.concatenate([
            norm_left.flatten(),   # 63 values
            norm_right.flatten(),  # 63 values
            norm_face.flatten()    # 180 values
        ])


def normalize_landmarks(
    left_hand: np.ndarray,
    right_hand: np.ndarray,
    face: np.ndarray,
    scale_factor: Optional[float] = None
) -> np.ndarray:
    """
    Fungsi convenience untuk normalisasi landmark.

    Args:
        left_hand: Landmark tangan kiri
        right_hand: Landmark tangan kanan
        face: Landmark wajah
        scale_factor: Optional scale factor

    Returns:
        Array landmark yang sudah dinormalisasi
    """
    normalizer = LandmarkNormalizer(scale_factor=scale_factor)
    return normalizer.normalize_frame(left_hand, right_hand, face)