#!/usr/bin/env python3
# -*- coding: utf-8 -*-

from pathlib import Path

import cv2
import numpy as np
from tqdm import tqdm


# =========================
# Parameters
# =========================
DATAMAKER_DIR = Path(__file__).resolve().parent

INPUT_DIR = DATAMAKER_DIR / "02_warp"
OUTPUT_DIR = DATAMAKER_DIR / "03_ckboard"

VIDEO_IDS = [f"{idx:02d}" for idx in range(1, 15)]
BLOCK_SIZE = 50
FOURCC = "mp4v"
OVERWRITE = True
# =========================


def create_checkerboard_mask(height: int, width: int, block_size: int) -> np.ndarray:
    x = np.arange(width)
    y = np.arange(height)
    x_grid, y_grid = np.meshgrid(x, y)
    mask = np.mod(x_grid // block_size + y_grid // block_size, 2)
    return mask.astype(bool)


def fuse_checkerboard(
    ir_frame: np.ndarray,
    vi_frame: np.ndarray,
    block_size: int,
) -> np.ndarray:
    if len(ir_frame.shape) == 2:
        ir_frame = cv2.cvtColor(ir_frame, cv2.COLOR_GRAY2BGR)
    if ir_frame.shape[:2] != vi_frame.shape[:2]:
        raise ValueError(
            f"Frame sizes differ: IR={ir_frame.shape[:2]}, VI={vi_frame.shape[:2]}"
        )

    height, width = ir_frame.shape[:2]
    mask = create_checkerboard_mask(height, width, block_size)
    mask_3d = np.stack([mask] * 3, axis=2)
    return np.where(mask_3d, ir_frame, vi_frame)


def make_checkerboard(ir_path: Path, vi_path: Path, out_path: Path) -> None:
    if not ir_path.exists() or not vi_path.exists():
        raise FileNotFoundError(f"Missing input pair: {ir_path}, {vi_path}")
    if not OVERWRITE and out_path.exists():
        raise FileExistsError(f"Output exists and OVERWRITE=False: {out_path}")

    cap_ir = cv2.VideoCapture(str(ir_path))
    cap_vi = cv2.VideoCapture(str(vi_path))
    if not cap_ir.isOpened() or not cap_vi.isOpened():
        raise IOError(f"Failed to open videos: {ir_path}, {vi_path}")

    width = int(cap_ir.get(cv2.CAP_PROP_FRAME_WIDTH))
    height = int(cap_ir.get(cv2.CAP_PROP_FRAME_HEIGHT))
    fps = cap_ir.get(cv2.CAP_PROP_FPS)
    total_frames = min(
        int(cap_ir.get(cv2.CAP_PROP_FRAME_COUNT)),
        int(cap_vi.get(cv2.CAP_PROP_FRAME_COUNT)),
    )

    out_path.parent.mkdir(parents=True, exist_ok=True)
    writer = cv2.VideoWriter(
        str(out_path),
        cv2.VideoWriter_fourcc(*FOURCC),
        fps,
        (width, height),
    )
    if not writer.isOpened():
        raise IOError(f"Failed to open output writer: {out_path}")

    for _ in tqdm(
        range(total_frames),
        desc=f"Checkerboard {ir_path.parent.name}",
        unit="frame",
        position=1,
        leave=False,
    ):
        ok_ir, frame_ir = cap_ir.read()
        ok_vi, frame_vi = cap_vi.read()
        if not ok_ir or not ok_vi:
            break
        writer.write(fuse_checkerboard(frame_ir, frame_vi, BLOCK_SIZE))

    cap_ir.release()
    cap_vi.release()
    writer.release()


def main() -> None:
    with tqdm(
        total=len(VIDEO_IDS),
        desc="Total checkerboard",
        unit="video",
        position=0,
    ) as progress:
        for video_id in VIDEO_IDS:
            progress.set_postfix(video=video_id)
            out_path = OUTPUT_DIR / f"{video_id}.mp4"
            make_checkerboard(
                ir_path=INPUT_DIR / video_id / "ir.mp4",
                vi_path=INPUT_DIR / video_id / "vi.mp4",
                out_path=out_path,
            )
            tqdm.write(f"Checkerboard {video_id} -> {out_path}")
            progress.update(1)


if __name__ == "__main__":
    main()