#!/usr/bin/env python3
"""Switch the default instance used by all skills.

Usage:
    python3 scripts/switch_default_instance.py <instance-name>
    python3 scripts/switch_default_instance.py          # lists available instances
"""

import argparse
import os
import sys

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

from lib.config import get_instance_names, get_default_instance_name, paths


def main():
    parser = argparse.ArgumentParser(description="Switch the default instance")
    parser.add_argument("instance", nargs="?", help="Instance name to switch to")
    args = parser.parse_args()

    instances = get_instance_names()
    current = get_default_instance_name()

    if not args.instance:
        print(f"Current default: {current}")
        print(f"Available instances: {', '.join(instances)}")
        sys.exit(0)

    if args.instance not in instances:
        print(f"Error: '{args.instance}' is not a valid instance.")
        print(f"Available instances: {', '.join(instances)}")
        sys.exit(1)

    if args.instance == current:
        print(f"Already set to '{current}', nothing to do.")
        sys.exit(0)

    settings_path = paths.WORKSPACE / "settings.toml"
    text = settings_path.read_text()
    new_text = text.replace(
        f'default_instance = "{current}"',
        f'default_instance = "{args.instance}"',
    )
    settings_path.write_text(new_text)

    # Verify
    # Re-import to bust any caches wouldn't work, so just read back
    verify = settings_path.read_text()
    if f'default_instance = "{args.instance}"' in verify:
        print(f"Switched default instance: {current} -> {args.instance}")
    else:
        print("Error: failed to update settings.toml")
        sys.exit(1)


if __name__ == "__main__":
    main()