# /// script
# requires-python = '>=3.12'
# dependencies = ['pillow']
# ///
'''Render a Task A episode as a video with the agent's decisions burnt in.

The point of the clip is to make the agent auditable: for every frame you can
see what it said and what it did, so a reader can check the table rather than
take it on trust. Same intent as the Task B and C overlays.

    uv run render_wt.py experiments/wt_live/island_local/ep_000
'''

import json
import subprocess
from argparse import ArgumentParser
from pathlib import Path

from PIL import Image, ImageDraw, ImageFont


def font(sz):
    for p in ('/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf',
              '/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf'):
        if Path(p).exists():
            return ImageFont.truetype(p, sz)
    return ImageFont.load_default()


_COLOUR = {'fire': (255, 90, 90), 'mouse': (255, 210, 90), 'aim': (255, 210, 90),
           'look': (255, 210, 90), 'key': (120, 210, 255),
           'none': (150, 160, 180)}


def render(ep: Path, out: Path, fps: int = 4) -> Path:
    rec = json.loads((ep / 'record.json').read_text())
    by_frame = {d['frame_id']: d for d in rec['decisions']}
    work = ep / '_overlay'
    work.mkdir(exist_ok=True)
    big, small = font(30), font(21)

    k = 0
    for fp in sorted((ep / 'frames').glob('*.jpg')):
        try:
            im = Image.open(fp).convert('RGB')
        except OSError:
            # frames are written while the episode is still running, so the
            # last one can be caught half-written. Skipping it loses a frame;
            # aborting the render loses the whole recording.
            print(f'  skipped unreadable frame {fp.name}')
            continue
        d = by_frame.get(fp.stem, {})
        act = (d.get('action') or {}).get('kind', 'none')
        dr = ImageDraw.Draw(im)
        dr.rectangle([0, 0, im.width, 96], fill=(10, 12, 20))
        dr.text((16, 8), f't = {d.get("t", 0):5.1f} s', font=big,
                fill=(230, 236, 245))
        dr.text((190, 12), act.upper(), font=big, fill=_COLOUR.get(act, (200,) * 3))
        if act in ('aim', 'mouse', 'look'):
            dr.text((300, 16), f'dx={d["action"].get("dx")} dy={d["action"].get("dy")}',
                    font=small, fill=(255, 210, 90))
        elif act == 'key':
            dr.text((300, 16), (d['action'].get('key') or '').upper(),
                    font=small, fill=(120, 210, 255))
        dr.text((16, 58), (d.get('text') or '')[-110:], font=small,
                fill=(150, 160, 180))
        dr.text((im.width - 260, 58), f'{d.get("model_ms", 0):.0f} ms/decision',
                font=small, fill=(150, 160, 180))
        # a ring round the gun sight so the reader can see where the agent is pointing
        cx, cy = im.width // 2, im.height // 2
        dr.ellipse([cx - 26, cy - 26, cx + 26, cy + 26],
                   outline=_COLOUR.get(act, (200,) * 3), width=3)
        im.save(work / f'{k:05d}.jpg', quality=88)
        k += 1

    out.parent.mkdir(parents=True, exist_ok=True)
    subprocess.run(['ffmpeg', '-y', '-loglevel', 'error', '-framerate', str(fps),
                    '-i', str(work / '%05d.jpg'), '-c:v', 'libx264',
                    '-pix_fmt', 'yuv420p', '-movflags', '+faststart', str(out)],
                   check=True)
    for f in work.glob('*.jpg'):
        f.unlink()
    work.rmdir()
    return out


def main() -> int:
    ap = ArgumentParser(description='Render a Task A episode with overlays.')
    ap.add_argument('episode', type=Path)
    ap.add_argument('--out', type=Path, default=None)
    ap.add_argument('--fps', type=int, default=4)
    args = ap.parse_args()
    out = args.out or (args.episode / 'overlay.mp4')
    print('wrote', render(args.episode, out, args.fps))
    return 0


if __name__ == '__main__':
    raise SystemExit(main())