#!/usr/bin/env python3
"""
Reads a CSV produced by stage.py (after you've filled it in) and applies
it: moves/renames every row marked status=confirmed, records status=skip
into the shared progress file, and leaves status=pending rows completely
untouched.

Defaults to a DRY RUN — prints what it would do and logs it, but touches
nothing on disk. Add --apply to actually do it.

Usage:
    python3 batch/apply.py /path/to/folder staging.csv            # dry run
    python3 batch/apply.py /path/to/folder staging.csv --apply    # for real
"""

import argparse
import csv
import json
import sys
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parent.parent))

from core import scan, apply_batch, find_duplicate_identities
from core.config import STATE_FILENAME, LOG_FILENAME


REQUIRED_COLUMNS = {
    "status", "current_path", "date_override", "topic", "subtopic",
    "extra", "more", "version", "dest_folder", "keep_filename", "identity",
}


def _read_rows(csv_path: Path) -> list:
    """Reads the CSV defensively: strips a UTF-8 BOM if LibreOffice added
    one, and normalises header casing — a header accidentally typed or
    autocorrected as 'Status' instead of 'status' shouldn't crash the
    whole run."""
    with open(csv_path, newline="", encoding="utf-8-sig") as f:
        reader = csv.DictReader(f)
        rows = [{k.strip().lower(): v for k, v in row.items()} for row in reader]

    if not rows:
        print(f"{csv_path} has no data rows.")
        sys.exit(1)

    missing = REQUIRED_COLUMNS - set(rows[0].keys())
    if missing:
        print(f"{csv_path} is missing expected column(s): {', '.join(sorted(missing))}")
        print(f"Columns actually found: {', '.join(rows[0].keys())}")
        print(f"This usually means the wrong file got opened/saved in the spreadsheet "
              f"(e.g. {LOG_FILENAME} instead of the staging CSV), or a header got "
              f"renamed by accident. Check the file and try again.")
        sys.exit(1)

    return rows
    return str(value).strip().lower() in ("true", "yes", "y", "1")


def _load_state(root: Path) -> dict:
    p = root / STATE_FILENAME
    if p.exists():
        try:
            return json.loads(p.read_text(encoding="utf-8"))
        except Exception:
            return {}
    return {}


def _save_state(root: Path, state: dict):
    (root / STATE_FILENAME).write_text(
        json.dumps(state, indent=2, ensure_ascii=False), encoding="utf-8"
    )


def _state_entry(rec, status: str) -> dict:
    return {
        "status": status,
        "date_override": rec.date_override,
        "topic": rec.topic,
        "subtopic": rec.subtopic,
        "extra": rec.extra,
        "more": rec.more,
        "version": rec.version,
        "dest_folder": rec.dest_folder,
        "keep_filename": rec.keep_filename,
    }


def main():
    ap = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
    ap.add_argument("root", help="Folder that was scanned")
    ap.add_argument("csv_path", help="The filled-in CSV from stage.py")
    ap.add_argument("--apply", action="store_true",
                     help="Actually move/rename files. Without this: dry-run only.")
    args = ap.parse_args()

    root = Path(args.root).expanduser().resolve()
    if not root.is_dir():
        print(f"Not a directory: {root}")
        sys.exit(1)

    csv_path = Path(args.csv_path)
    if not csv_path.is_file():
        print(f"Not a file: {csv_path}")
        sys.exit(1)

    rows = _read_rows(csv_path)
    print(f"Read {len(rows)} rows from {csv_path}")

    records = scan(root)
    duplicates = find_duplicate_identities(records)
    if duplicates:
        print(f"\nWARNING: {len(duplicates)} group(s) of byte-identical files found — "
              f"a CSV row matching one of these may resolve to the wrong twin, since "
              f"they can't be told apart by content:")
        for recs in duplicates.values():
            print("  " + ", ".join(r.rel_path for r in recs))

    by_identity = {rec.identity: rec for rec in records}

    to_confirm, to_skip, not_found = [], [], []
    still_pending = 0

    for row in rows:
        rec = by_identity.get(row["identity"])
        if rec is None:
            not_found.append(row["current_path"])
            continue

        status = row["status"].strip().lower()
        if status == "confirmed":
            rec.date_override = row["date_override"]
            rec.topic = row["topic"]
            rec.subtopic = row["subtopic"]
            rec.extra = row["extra"]
            rec.more = row["more"]
            rec.version = row["version"]
            rec.dest_folder = row["dest_folder"]
            rec.keep_filename = _parse_bool(row["keep_filename"])
            rec.status = "confirmed"
            to_confirm.append(rec)
        elif status == "skip":
            rec.status = "skip"
            to_skip.append(rec)
        else:
            still_pending += 1
            # "pending" (or anything else/blank): left completely alone

    dry_run = not args.apply

    if not_found:
        print(f"\nWARNING: {len(not_found)} row(s) couldn't be matched to a current file — "
              f"probably already moved by another tool since this CSV was made. Skipped:")
        for p in not_found:
            print(f"  - {p}")

    print(f"\nMatched to real files: {len(rows) - len(not_found)} / {len(rows)}")
    print(f"  status=confirmed : {len(to_confirm)}")
    print(f"  status=skip      : {len(to_skip)}")
    print(f"  status=pending   : {still_pending}  (left completely alone — not an error)")

    if len(to_confirm) == 0 and len(to_skip) == 0 and still_pending > 0:
        print(f"\nNothing to do: every matched row is still status=pending.")
        print(f"apply.py only acts on rows you've explicitly set to 'confirmed' (or 'skip').")
        print(f"Open {csv_path.name} and check the status column actually got changed — "
              f"a common slip is editing the topic/folder cells but leaving status untouched.")
        return

    log_rows = apply_batch(to_confirm, dry_run=dry_run, log_path=None)

    log_path = root / LOG_FILENAME
    if log_rows:
        write_header = not log_path.exists()
        with open(log_path, "a", newline="", encoding="utf-8") as f:
            writer = csv.DictWriter(f, fieldnames=list(log_rows[0].keys()))
            if write_header:
                writer.writeheader()
            writer.writerows(log_rows)

    moved = sum(1 for r in log_rows if r["result"] in ("moved", "would move"))
    unchanged = sum(1 for r in log_rows if r["result"] == "unchanged")
    collisions = sum(1 for r in log_rows if r["result"].startswith("SKIPPED"))

    print(f"\n{'Would move' if dry_run else 'Moved'}: {moved}")
    if unchanged:
        print(f"Unchanged (new name+folder computed identical to current): {unchanged}")
    print(f"Skipped — target already exists: {collisions}")
    print(f"Marked as deliberately skipped: {len(to_skip)}")

    if dry_run:
        print(f"\nThis was a DRY RUN — nothing was touched, nothing was saved. "
              f"Review {LOG_FILENAME}, then re-run with --apply to actually do it.")
        return

    state = _load_state(root)
    for rec in to_confirm:
        if rec.status == "done":
            state[rec.identity] = _state_entry(rec, "done")
    for rec in to_skip:
        state[rec.identity] = _state_entry(rec, "skip")
    _save_state(root, state)
    print(f"Progress saved to {STATE_FILENAME} — the GUI will see these as done/skipped too.")


if __name__ == "__main__":
    main()