"""
Migration: Replace 26 FK columns on Roster with RosterSlot junction table.

Creates the `rosterslot` table and migrates existing lineup data from the
card_1..card_26 columns.  Safe to re-run (skips rosters already migrated).

Usage:
    python migrations/migrate_roster_junction_table.py
"""

import os
import sys

sys.path.insert(0, os.path.dirname(os.path.dirname(__file__)))

from app.db_engine import db, Roster, RosterSlot

SLOTS = 26


def migrate():
    db.connect(reuse_if_open=True)

    # Create the table if it doesn't exist yet
    db.create_tables([RosterSlot], safe=True)

    # Read raw rows from the old schema via plain SQL so we don't depend on
    # the ORM model knowing about the legacy card_N columns.
    cursor = db.execute_sql("SELECT * FROM roster")
    columns = [desc[0] for desc in cursor.description]

    migrated = 0
    skipped = 0

    with db.atomic():
        for row in cursor.fetchall():
            row_dict = dict(zip(columns, row))
            roster_id = row_dict["id"]

            already_migrated = (
                RosterSlot.select().where(RosterSlot.roster == roster_id).exists()
            )
            if already_migrated:
                skipped += 1
                continue

            slots_to_insert = []
            for slot_num in range(1, SLOTS + 1):
                col = f"card_{slot_num}_id"
                card_id = row_dict.get(col)
                if card_id is not None:
                    slots_to_insert.append(
                        {"roster": roster_id, "slot": slot_num, "card": card_id}
                    )

            if slots_to_insert:
                RosterSlot.insert_many(slots_to_insert).execute()
                migrated += 1

    print(f"Migration complete: {migrated} rosters migrated, {skipped} already done.")
    db.close()


if __name__ == "__main__":
    migrate()