"""
scripts/repair_unknown_serials.py — re-attribute events stuck under
`serial = 'UNKNOWN'` to their correct serial by decoding the BW filename.

Why this is needed
──────────────────
The /db/import/blastware_file endpoint had a bug (fixed in commit a032fa5+1
on the ach-report-ingestion branch) where every forwarded event was inserted
with serial='UNKNOWN' because the endpoint's `_serial_from_event(ev)` stub
returned None and never consulted the BW-filename serial that
`WaveformStore.save_imported_bw()` had already decoded.

Effect on a server that ran a buggy version: every forwarded event's
SeismoDb row has `serial='UNKNOWN'`, even though the on-disk waveform
store has correctly bucketed the files into `BE<NNNN>/` folders.  So
the BW binaries / sidecars / HDF5s are fine, but `/db/units` and
`/db/events?serial=...` queries don't surface the events.

This script
───────────
Walks the events table looking for rows with `serial='UNKNOWN'` and
re-attributes each one to the serial decoded from its
`blastware_filename` column.  If the row's serial would collide with
an existing row (already-correct duplicate from a later re-forward),
the UNKNOWN row is deleted.  Otherwise the row's `serial` column is
updated in-place.

Idempotent: re-running after a successful repair finds zero matching
rows and exits cleanly.

Usage
─────
  # Dry-run (default): print what would change, don't touch the DB
  python -m scripts.repair_unknown_serials --db bridges/captures/seismo_relay.db

  # Apply the repair
  python -m scripts.repair_unknown_serials --db bridges/captures/seismo_relay.db --apply
"""

from __future__ import annotations

import argparse
import sqlite3
import sys
from pathlib import Path

# Reach into sfm.waveform_store for the serial decoder.  This script
# is run from the repo root via `python -m scripts.repair_unknown_serials`.
sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
from sfm.waveform_store import _serial_from_bw_filename


def main(argv: list[str] | None = None) -> int:
    p = argparse.ArgumentParser(
        description="Re-attribute events stuck under serial='UNKNOWN'.",
    )
    p.add_argument(
        "--db", required=True, type=Path,
        help="Path to seismo_relay.db (e.g. bridges/captures/seismo_relay.db)",
    )
    p.add_argument(
        "--apply", action="store_true",
        help="Apply the repair.  Without this flag the script runs in "
             "dry-run mode and only reports what would change.",
    )
    args = p.parse_args(argv)

    if not args.db.exists():
        print(f"DB not found: {args.db}", file=sys.stderr)
        return 2

    conn = sqlite3.connect(str(args.db))
    conn.row_factory = sqlite3.Row

    rows = list(conn.execute(
        "SELECT id, serial, timestamp, blastware_filename "
        "  FROM events "
        " WHERE serial = 'UNKNOWN' "
        " ORDER BY timestamp",
    ))
    print(f"Found {len(rows)} UNKNOWN-serial rows in events table.")
    if not rows:
        return 0

    updated   = 0
    deleted   = 0
    unresolved = 0
    by_serial: dict[str, int] = {}

    for row in rows:
        rid       = row["id"]
        ts        = row["timestamp"]
        bw_name   = row["blastware_filename"]
        new_serial = _serial_from_bw_filename(bw_name) if bw_name else None
        if not new_serial:
            print(f"  ⚠ id={rid[:8]} ts={ts} filename={bw_name!r} — "
                  f"cannot decode serial from filename; skipping")
            unresolved += 1
            continue

        # Check for an existing row at the target (serial, timestamp).
        existing = conn.execute(
            "SELECT id FROM events WHERE serial = ? AND timestamp = ?",
            (new_serial, ts),
        ).fetchone()
        action: str
        if existing is None:
            # Safe to UPDATE in place.
            if args.apply:
                conn.execute(
                    "UPDATE events SET serial = ? WHERE id = ?",
                    (new_serial, rid),
                )
            action = "UPDATE"
            updated += 1
        else:
            # A correctly-attributed row already exists.  Drop the
            # UNKNOWN duplicate.
            if args.apply:
                conn.execute("DELETE FROM events WHERE id = ?", (rid,))
            action = "DELETE (dup)"
            deleted += 1

        by_serial[new_serial] = by_serial.get(new_serial, 0) + 1
        print(f"  {action:14s}  id={rid[:8]}  ts={ts}  "
              f"filename={bw_name}  →  {new_serial}")

    if args.apply:
        conn.commit()
    conn.close()

    print()
    print(f"Summary:")
    print(f"  UNKNOWN rows scanned:       {len(rows)}")
    print(f"  Updated to real serial:     {updated}")
    print(f"  Deleted (duplicate of an    ")
    print(f"   already-correct row):      {deleted}")
    print(f"  Unresolved (bad filename):  {unresolved}")
    print()
    if by_serial:
        print(f"Per-serial breakdown of repaired rows:")
        for serial, count in sorted(by_serial.items()):
            print(f"  {serial:12s}  {count}")
    if not args.apply:
        print()
        print("(dry-run — re-run with --apply to commit)")
    return 0


if __name__ == "__main__":
    sys.exit(main())