# /// script
# requires-python = ">=3.10"
# dependencies = ["numpy", "opencv-python"]
# ///
"""
@effect hue_shift
@version 1.0.0
@author artdag

@description
Rotates the hue of all colors by a specified amount (0-360 degrees).
Creates rainbow cycling effects when animated over time.

@param shift float
  @range 0 360
  @default 0
  Hue rotation in degrees. 0/360 = unchanged, 180 = complementary colors.

@example
  (effect hue_shift :shift 180)  ; complementary colors

@example
  ;; Rainbow cycling based on time (use with frame counter in state)
  (effect hue_shift :shift (bind beat_position :range [0 360]))
"""

import numpy as np
import cv2


def process_frame(frame: np.ndarray, params: dict, state: dict) -> tuple:
    """
    Shift hue of a video frame.

    Args:
        frame: Input frame as numpy array (H, W, 3) RGB uint8
        params: Effect parameters
            - shift: hue rotation in degrees (default 0)
        state: Persistent state dict (unused)

    Returns:
        Tuple of (processed_frame, new_state)
    """
    shift = params.get("shift", 0)

    if shift == 0:
        return frame, state

    # Convert RGB to HSV (OpenCV uses H: 0-179, S: 0-255, V: 0-255)
    hsv = cv2.cvtColor(frame, cv2.COLOR_RGB2HSV)

    # Shift hue (OpenCV hue is 0-179, so divide by 2)
    hue_shift = int((shift % 360) / 2)
    hsv[:, :, 0] = (hsv[:, :, 0].astype(np.int16) + hue_shift) % 180

    # Convert back to RGB
    result = cv2.cvtColor(hsv, cv2.COLOR_HSV2RGB)

    return result, state