#!/usr/bin/env python3
# -*- coding: utf-8 -*-

"""
TOWER PATH NORMALIZATION MIGRATION
----------------------------------
✔ Normalizes full_path → NFC canonical
✔ Recalculates path_hash
✔ Uses two DB connections (streaming safe)
✔ Idempotent (safe to rerun)
✔ Production safe
"""

import pymysql
import hashlib
import posixpath
import unicodedata
import time

# =========================
# CONFIG
# =========================

HOST_TO_FIX = "tower"
BATCH_FETCH = 5000
COMMIT_EVERY = 2000

DB_CONFIG = {
    "host": "192.168.1.50",
    "port": 3306,
    "user": "root",
    "password": "Vlado9674+",
    "database": "torrents",
    "charset": "utf8mb4",
    "autocommit": False,
}

# =========================
# CANONICALIZATION
# =========================

def canonical_path(path_str: str) -> str:
    path_str = path_str.replace("\\", "/")
    path_str = posixpath.normpath(path_str)
    path_str = unicodedata.normalize("NFC", path_str)
    return path_str

def md5_bytes(path_str: str) -> bytes:
    return hashlib.md5(path_str.encode("utf-8")).digest()

# =========================
# MAIN
# =========================

def main():

    print("=" * 70)
    print("🚀 TOWER PATH NORMALIZATION MIGRATION")
    print(f"Host: {HOST_TO_FIX}")
    print("=" * 70)

    start = time.time()

    # --- TWO CONNECTIONS ---
    db_read = pymysql.connect(**DB_CONFIG)
    db_write = pymysql.connect(**DB_CONFIG)

    read_cur = db_read.cursor(pymysql.cursors.SSCursor)
    write_cur = db_write.cursor()

    read_cur.execute("""
        SELECT id, full_path, path_hash
        FROM file_md5_index
        WHERE host_name = %s
    """, (HOST_TO_FIX,))

    total = 0
    updated = 0
    skipped = 0
    pending_commit = 0

    while True:

        rows = read_cur.fetchmany(BATCH_FETCH)

        if not rows:
            break

        for rec_id, full_path, stored_hash in rows:

            total += 1

            new_path = canonical_path(full_path)
            new_hash = md5_bytes(new_path)

            if new_path == full_path and new_hash == stored_hash:
                skipped += 1
                continue

            write_cur.execute("""
                UPDATE file_md5_index
                SET full_path = %s,
                    path_hash = %s
                WHERE id = %s
            """, (new_path, new_hash, rec_id))

            updated += 1
            pending_commit += 1

            if pending_commit >= COMMIT_EVERY:
                db_write.commit()
                pending_commit = 0

        print(
            f"Checked {total:,} | Updated {updated:,} | Skipped {skipped:,}"
        )

    if pending_commit:
        db_write.commit()

    elapsed = time.time() - start

    print("\n" + "=" * 70)
    print("✅ MIGRATION FINISHED")
    print("=" * 70)
    print(f"Total checked : {total:,}")
    print(f"Rows updated  : {updated:,}")
    print(f"Rows skipped  : {skipped:,}")
    print(f"Runtime       : {elapsed:.1f}s")
    print("=" * 70)

    read_cur.close()
    write_cur.close()
    db_read.close()
    db_write.close()


if __name__ == "__main__":
    main()