from pathlib import Path

import cv2 as cv


source_path = Path("input/scene.png")
output_path = Path("output/still-demo.mp4")
fps = 24
duration_seconds = 3
frame_count = fps * duration_seconds

image = cv.imread(str(source_path))
if image is None:
    raise SystemExit(f"Could not read source image: {source_path}")

height, width = image.shape[:2]
width -= width % 2
height -= height % 2
frame_size = (width, height)
base = cv.resize(image, frame_size, interpolation=cv.INTER_AREA)

output_path.parent.mkdir(parents=True, exist_ok=True)
fourcc = cv.VideoWriter_fourcc(*"mp4v")
writer = cv.VideoWriter(str(output_path), fourcc, fps, frame_size)
if not writer.isOpened():
    raise SystemExit(f"Could not open VideoWriter for: {output_path}")

for index in range(frame_count):
    frame = base.copy()
    progress = index / max(frame_count - 1, 1)
    bar_width = int(progress * (width - 40))
    overlay = frame.copy()

    cv.rectangle(overlay, (20, height - 45), (20 + bar_width, height - 25), (0, 180, 255), -1)
    frame = cv.addWeighted(overlay, 0.35, frame, 0.65, 0)
    cv.putText(
        frame,
        f"Frame {index + 1:02d}/{frame_count}",
        (20, 40),
        cv.FONT_HERSHEY_SIMPLEX,
        1,
        (255, 255, 255),
        2,
        cv.LINE_AA,
    )

    writer.write(frame)

writer.release()

capture = cv.VideoCapture(str(output_path))
if not capture.isOpened():
    raise SystemExit(f"Could not reopen video: {output_path}")

saved_frames = int(capture.get(cv.CAP_PROP_FRAME_COUNT))
saved_fps = capture.get(cv.CAP_PROP_FPS)
saved_width = int(capture.get(cv.CAP_PROP_FRAME_WIDTH))
saved_height = int(capture.get(cv.CAP_PROP_FRAME_HEIGHT))
capture.release()

duration = saved_frames / saved_fps if saved_fps else 0
size_kib = output_path.stat().st_size / 1024

print(f"wrote: {output_path}")
print(f"frames: {saved_frames}")
print(f"fps: {saved_fps:.1f}")
print(f"size: {saved_width}x{saved_height}")
print(f"duration: {duration:.2f}s")
print(f"file size: {size_kib:.1f} KiB")