"""Pre-generate OG track images for all activities.

Writes 400×400 PNGs to {www_root}/og-image/{user}/{activity_id}.png.
Skips activities that already have an up-to-date image (mtime check).
Safe to run repeatedly — only processes new/changed activities.

Usage:
    uv run scripts/generate_og_images.py [--data-dir /var/bincio/data] [--www-root /var/www/activity]
"""

from __future__ import annotations

import argparse
import json
import sys
from pathlib import Path


def generate_all(data_dir: Path, www_root: Path) -> None:
    out_root = www_root / "og-image"
    out_root.mkdir(parents=True, exist_ok=True)

    from bincio.render.ogimage import generate

    total = generated = skipped = errors = 0

    users = sorted(
        d.name for d in data_dir.iterdir()
        if d.is_dir() and not d.name.startswith("_") and d.name != "segments"
    )

    for handle in users:
        user_dir   = data_dir / handle
        acts_dir   = user_dir / "activities"
        img_dir    = out_root / handle
        if not acts_dir.exists():
            continue
        img_dir.mkdir(exist_ok=True)
        u_gen = u_skip = u_err = 0

        for ts_path in sorted(acts_dir.glob("*.timeseries.json")):
            activity_id = ts_path.name.replace(".timeseries.json", "")
            out_path    = img_dir / f"{activity_id}.png"
            total += 1

            # Skip if image is newer than timeseries
            if out_path.exists() and out_path.stat().st_mtime >= ts_path.stat().st_mtime:
                skipped += 1
                u_skip  += 1
                continue

            try:
                ts      = json.loads(ts_path.read_text(encoding="utf-8"))
                lat_arr = ts.get("lat") or []
                lon_arr = ts.get("lon") or []
                ele_arr = ts.get("elevation_m") or []
                png     = generate(lat_arr, lon_arr, ele_arr)
                out_path.write_bytes(png)
                generated += 1
                u_gen     += 1
            except Exception as exc:
                errors += 1
                u_err  += 1
                print(f"  ERROR {handle}/{activity_id}: {exc}", file=sys.stderr)

        if u_gen or u_err:
            print(f"{handle:<25} generated={u_gen:4d}  skipped={u_skip:4d}  errors={u_err}")
        else:
            print(f"{handle:<25} skipped={u_skip:4d} (all up to date)")

    print(f"\nDone — {generated} generated, {skipped} skipped, {errors} errors  (total {total})")


def main() -> None:
    ap = argparse.ArgumentParser(description="Pre-generate OG track images")
    ap.add_argument("--data-dir",  default="/var/bincio/data",   type=Path)
    ap.add_argument("--www-root",  default="/var/www/activity",  type=Path)
    args = ap.parse_args()

    if not args.data_dir.exists():
        print(f"ERROR: data dir not found: {args.data_dir}", file=sys.stderr)
        sys.exit(1)

    print(f"data-dir : {args.data_dir}")
    print(f"www-root : {args.www_root}")
    print(f"output   : {args.www_root}/og-image/\n")
    generate_all(args.data_dir, args.www_root)


if __name__ == "__main__":
    main()