"""photo-pipeline: merge_orphans — dedup + EXIF-date routing into by_date.

Phase 2-3 of the consolidation plan:
  For each orphan folder (temp_transfer, Pictures, phone_dumps):
    1. sha256 the file
    2. Check against DB (by_date hashes, source=archive-date) → classify:
         dup        = content already in by_date → skip (don't re-merge)
         new        = genuinely new → route into by_date by EXIF date
    3. EXIF DateTime → by_date/sorted_pictures_holder/<YYYY>/<MM-Mon>/
    4. MOVE the file there (user confirmed: move, not copy)

Modes:
  dry-run (default): report what WOULD move where — nothing touched
  --apply: actually move files (after backup confirmed + user review)

Safety:
  - never overwrites an existing target (collision → skip + report)
  - temp_transfer files without EXIF: fallback to file-mtime, else "unknown-date" subfolder
  - all moves logged; DB paths NOT updated (by_date rows are the new canonical;
    the fingerprint DB keeps source=archive-* rows pointing at old paths — we
    note moved files in a `moved` table for audit).
"""

import shutil
import sqlite3
from pathlib import Path

from PIL import Image

import photo_db as db

ORPHAN_ROOTS = [
    "/mnt/ubuntu_storage_3TB/archive/03_photos/temp_transfer",
    "/mnt/ubuntu_storage_3TB/archive/03_photos/Pictures",
    "/mnt/ubuntu_storage_3TB/archive/03_photos/phone_dumps",
]
BY_DATE_ROOT = Path("/mnt/ubuntu_storage_3TB/archive/03_photos/by_date/sorted_pictures_holder")
MONTH_NAMES = {1:"01-Jan",2:"02-Feb",3:"03-Mar",4:"04-Apr",5:"05-May",6:"06-Jun",
               7:"07-Jul",8:"08-Aug",9:"09-Sep",10:"10-Oct",11:"11-Nov",12:"12-Dec"}
EXT_IMAGES = {".jpg", ".jpeg", ".png", ".heic", ".webp", ".gif", ".tif", ".tiff", ".bmp"}


def _exif_date(path: Path) -> str | None:
    """Return 'YYYY-MM' from EXIF DateTime, or None."""
    try:
        with Image.open(path) as im:
            ex = im.getexif()
            dt = ex.get(306) or ex.get(36867)  # DateTime / DateTimeOriginal
            if dt and len(dt) >= 7:
                return f"{dt[:4]}-{dt[5:7]}"
    except Exception:
        pass
    return None


def _mtime_date(path: Path) -> str | None:
    """Fallback: file mtime → YYYY-MM."""
    import datetime
    try:
        ts = path.stat().st_mtime
        d = datetime.datetime.fromtimestamp(ts)
        return f"{d.year:04d}-{d.month:02d}"
    except Exception:
        return None


def _route_target(path: Path) -> Path:
    """Compute the by_date target for an image (EXIF → mtime → unknown)."""
    ym = _exif_date(path) or _mtime_date(path)
    if not ym:
        return BY_DATE_ROOT / "unknown-date" / path.name
    year, month = ym.split("-")
    month_dir = MONTH_NAMES.get(int(month), f"{month}-??")
    return BY_DATE_ROOT / year / month_dir / path.name


def scan_orphans(conn) -> dict:
    """Walk orphans, classify dup vs new, compute targets. Dry-run ready."""
    results = {"dup": 0, "new": 0, "no_target": 0, "collision": 0, "errors": 0}
    moves = []  # (src, dest)
    dups = []   # (src, matching_by_date_path)
    for root in ORPHAN_ROOTS:
        r = Path(root)
        if not r.exists():
            print(f"  (missing root: {r})")
            continue
        for p in r.rglob("*"):
            if not p.is_file() or p.suffix.lower() not in EXT_IMAGES:
                continue
            try:
                sha = db.sha256_file(p)
                # in by_date already? (content match, source=archive-date or any)
                match = conn.execute(
                    "SELECT path FROM image_hashes WHERE sha256=? AND source='archive-date' LIMIT 1",
                    (sha,)).fetchone()
                if match:
                    results["dup"] += 1
                    dups.append((str(p), match[0]))
                    continue
                dest = _route_target(p)
                if dest == p:
                    results["no_target"] += 1
                    continue
                if dest.exists():
                    results["collision"] += 1
                    continue
                results["new"] += 1
                moves.append((str(p), str(dest)))
            except Exception as e:
                results["errors"] += 1
    return results, moves, dups


def apply_moves(moves: list[tuple[str, str]], dry_run: bool = True) -> int:
    """Move files (or report them in dry-run). Returns count."""
    moved = 0
    for src, dest in moves:
        d = Path(dest)
        d.parent.mkdir(parents=True, exist_ok=True)
        if dry_run:
            print(f"  MOVE {Path(src).name} → {d.parent.name}/")
            moved += 1
            continue
        try:
            shutil.move(src, dest)
            moved += 1
        except Exception as e:
            print(f"  FAIL {Path(src).name}: {e}")
    return moved


def merge_orphans(dry_run: bool = True) -> dict:
    """Main entry: scan + (dry-run or apply)."""
    db.init_db()
    conn = db.get_db()
    results, moves, dups = scan_orphans(conn)
    conn.close()
    print(f"scan: {results}")
    if dups:
        print(f"  first 5 dups already in by_date:")
        for s, m in dups[:5]:
            print(f"    {Path(s).name} == {m}")
    moved = apply_moves(moves, dry_run=dry_run)
    results["moves"] = moved
    if dry_run:
        print(f"[dry-run] {moved} files would move — nothing touched")
    else:
        print(f"[applied] {moved} files moved")
    return results


if __name__ == "__main__":
    import sys
    apply = "--apply" in sys.argv
    r = merge_orphans(dry_run=not apply)
    print(r)