import numpy as np

LUTS = {
    "cinematic": {
        "name": "🎬 电影橙青",
        "matrix": np.array([[1.1, 0.0, -0.1], [0.0, 1.05, 0.0], [-0.05, 0.0, 1.15]]),
        "warmth": (5, 0, -5), "contrast": 1.15,
    },
    "bw": {
        "name": "⬛ 经典黑白",
        "matrix": np.array([[0.3, 0.59, 0.11], [0.3, 0.59, 0.11], [0.3, 0.59, 0.11]]),
        "warmth": (0, 0, 0), "contrast": 1.3,
    },
    "cyberpunk": {
        "name": "🌆 赛博朋克",
        "matrix": np.array([[0.8, 0.0, 0.3], [0.0, 0.9, 0.1], [0.1, 0.0, 1.3]]),
        "warmth": (-10, 0, 15), "contrast": 1.2,
    },
    "warm": {
        "name": "☀️ 日系暖阳",
        "matrix": np.array([[1.1, 0.05, 0.0], [0.0, 1.0, -0.05], [-0.05, -0.05, 0.9]]),
        "warmth": (15, 5, -10), "contrast": 0.95,
    },
    "noir": {
        "name": "🌙 夜景蓝调",
        "matrix": np.array([[0.7, 0.0, 0.2], [0.0, 0.8, 0.1], [0.1, 0.0, 1.2]]),
        "warmth": (-15, -5, 10), "contrast": 1.25,
    },
}

def apply_lut(frame, lut_name):
    lut = LUTS.get(lut_name)
    if not lut:
        return frame

    h, w = frame.shape[:2]
    pixels = frame.astype(np.float32).reshape(-1, 3)
    transformed = np.clip(pixels @ lut["matrix"].T, 0, 255).reshape(h, w, 3)

    # 分离 BGR 通道，加 warmth 偏移（warmth 顺序是 R, G, B）
    b = np.clip(transformed[:, :, 0] + lut["warmth"][2], 0, 255)
    g = np.clip(transformed[:, :, 1] + lut["warmth"][1], 0, 255)
    r = np.clip(transformed[:, :, 2] + lut["warmth"][0], 0, 255)

    frame = np.stack([b, g, r], axis=2)
    frame = (frame - 128) * lut["contrast"] + 128
    return np.clip(frame, 0, 255).astype(np.uint8)