"""Register a Telegram chat_id for a farmer by updating the instance DB.

This is a small admin helper which writes the chat id directly into
`instance/farm_management.db` to avoid needing to authenticate via the
web admin UI. Usage:

  python scripts/register_telegram_chat.py --farmer-id 1 --chat-id 123456789

It will print what it changed and exit with a non-zero code on error.
"""
import argparse
import sqlite3
import os
import sys


def register_chat(farmer_id: int, chat_id: str, db_path: str):
    if not os.path.exists(db_path):
        print(f"Database not found: {db_path}")
        return 2

    con = sqlite3.connect(db_path)
    cur = con.cursor()

    # Check farmer exists
    cur.execute("SELECT id, name, telegram_chat_id FROM farmers WHERE id = ?", (farmer_id,))
    row = cur.fetchone()
    if not row:
        print(f"Farmer id {farmer_id} not found in {db_path}")
        con.close()
        return 3

    old = row[2]
    cur.execute("UPDATE farmers SET telegram_chat_id = ? WHERE id = ?", (str(chat_id), farmer_id))
    con.commit()
    con.close()

    print(f"Updated farmer {farmer_id} telegram_chat_id: {old} -> {chat_id}")
    return 0


def main():
    p = argparse.ArgumentParser()
    p.add_argument('--farmer-id', '-f', type=int, required=False, help='Farmer id to update')
    p.add_argument('--chat-id', '-c', required=True, help='Telegram chat id to set')
    p.add_argument('--all', '-a', action='store_true', help='Apply chat id to all farmers')
    p.add_argument('--db', default=os.path.join('instance', 'farm_management.db'), help='Path to instance DB')
    args = p.parse_args()

    if args.all:
        # Update all farmers
        if not os.path.exists(args.db):
            print(f"Database not found: {args.db}")
            sys.exit(2)
        con = sqlite3.connect(args.db)
        cur = con.cursor()
        cur.execute("UPDATE farmers SET telegram_chat_id = ?", (str(args.chat_id),))
        con.commit()
        con.close()
        print(f"Updated telegram_chat_id for ALL farmers -> {args.chat_id}")
        rc = 0
    else:
        if not args.farmer_id:
            print('Either --farmer-id or --all must be provided')
            sys.exit(1)
        rc = register_chat(args.farmer_id, args.chat_id, args.db)
    sys.exit(rc)


if __name__ == '__main__':
    main()