"""Per-track image cropping, capture dirs, and full-frame event snapshots."""
from __future__ import annotations

from datetime import datetime
from pathlib import Path
from typing import Dict, Optional

import cv2

from core.detection import STATUSES
from core.geometry import clamp_bbox
from core.paths import CAPTURES_DIR, SNAPSHOTS_DIR


def setup_capture_dirs() -> Dict[str, Path]:
    """runtime/captures/{SAFE,PARTIAL,UNSAFE}/ — latest crop per track."""
    dirs: Dict[str, Path] = {}
    for s in STATUSES:
        d = CAPTURES_DIR / s
        d.mkdir(parents=True, exist_ok=True)
        dirs[s] = d
    return dirs


def setup_snapshot_dirs() -> Dict[str, Path]:
    """runtime/snapshots/{SAFE,PARTIAL,UNSAFE}/ — annotated full frame per transition."""
    dirs: Dict[str, Path] = {}
    for s in STATUSES:
        d = SNAPSHOTS_DIR / s
        d.mkdir(parents=True, exist_ok=True)
        dirs[s] = d
    return dirs


def save_track_image(frame, track, capture_dirs: Dict[str, Path]) -> Optional[Path]:
    """Save the latest crop for a track. Overwritten each frame."""
    h, w = frame.shape[:2]
    x1, y1, x2, y2 = clamp_bbox(track.bbox, w, h)
    if x2 <= x1 or y2 <= y1:
        return None
    crop = frame[y1:y2, x1:x2]
    if crop.size == 0:
        return None

    target = capture_dirs[track.status] / f"track_{track.track_id:04d}.jpg"
    if track.photo_path and track.photo_path != target and track.photo_path.exists():
        try:
            track.photo_path.unlink()
        except OSError:
            pass

    cv2.imwrite(str(target), crop)
    track.photo_path = target
    return target


def save_event_snapshot(annotated_frame, track, snapshot_dirs: Dict[str, Path]) -> Optional[Path]:
    """Save the full annotated frame at the moment of a NEW / STATUS_CHANGE event.

    Timestamped filename so a history is preserved across events.
    """
    if annotated_frame is None or annotated_frame.size == 0:
        return None
    ts = datetime.now().strftime("%Y%m%d_%H%M%S_%f")[:-3]
    target = snapshot_dirs[track.status] / f"track_{track.track_id:04d}_{ts}.jpg"
    cv2.imwrite(str(target), annotated_frame)
    return target