"""
User Role Migration Script (Phase 3)

This script migrates existing users from the legacy role enum to the new dynamic role system.
For each user, it maps their current role enum value to the corresponding role_id in the roles table.

Usage:
    python migrate_users_to_dynamic_roles.py

Environment Variables:
    DATABASE_URL - PostgreSQL connection string
"""

import os
import sys
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from database import Base
from models import User, Role, UserRole
from dotenv import load_dotenv

# Load environment variables
load_dotenv()

# Database connection
DATABASE_URL = os.getenv("DATABASE_URL")
if not DATABASE_URL:
    print("Error: DATABASE_URL environment variable not set")
    sys.exit(1)

engine = create_engine(DATABASE_URL)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)


def migrate_users():
    """Migrate users from enum role to role_id"""
    db = SessionLocal()

    try:
        print("🚀 Starting user role migration (Phase 3)...")
        print("="*60)

        # Step 1: Load all roles into a map
        print("\n📋 Loading roles from database...")
        roles = db.query(Role).all()
        role_map = {role.code: role for role in roles}

        print(f"✓ Loaded {len(roles)} roles:")
        for role in roles:
            print(f"  • {role.name} ({role.code}) - ID: {role.id}")

        # Step 2: Get all users
        print("\n👥 Loading users...")
        users = db.query(User).all()
        print(f"✓ Found {len(users)} users to migrate")

        # Step 3: Check if any users already have role_id set
        users_with_role_id = [u for u in users if u.role_id is not None]
        if users_with_role_id:
            print(f"\n⚠️  Warning: {len(users_with_role_id)} users already have role_id set")
            response = input("Do you want to re-migrate these users? (yes/no): ")
            if response.lower() != 'yes':
                print("Skipping users that already have role_id set...")
                users = [u for u in users if u.role_id is None]
                print(f"Will migrate {len(users)} users without role_id")

        if not users:
            print("\n✅ No users to migrate!")
            return

        # Step 4: Migrate users
        print(f"\n🔄 Migrating {len(users)} users...")

        migration_stats = {
            UserRole.guest: 0,
            UserRole.member: 0,
            UserRole.admin: 0,
            UserRole.superadmin: 0
        }

        for user in users:
            # Get the enum role code (e.g., "guest", "member", "admin", "superadmin")
            role_code = user.role.value

            # Find the matching role in the roles table
            if role_code not in role_map:
                print(f"  ⚠️  Warning: No matching role found for '{role_code}' (user: {user.email})")
                continue

            # Set the role_id
            user.role_id = role_map[role_code].id
            migration_stats[user.role] = migration_stats.get(user.role, 0) + 1

        # Commit all changes
        db.commit()
        print(f"✓ Migrated {len(users)} users")

        # Step 5: Display migration summary
        print("\n" + "="*60)
        print("📊 Migration Summary:")
        print("="*60)
        print("\nUsers migrated by role:")
        for role_enum, count in migration_stats.items():
            if count > 0:
                print(f"  • {role_enum.value}: {count} users")

        # Step 6: Verify migration
        print("\n🔍 Verifying migration...")
        users_without_role_id = db.query(User).filter(User.role_id == None).count()
        users_with_role_id = db.query(User).filter(User.role_id != None).count()

        print(f"  • Users with role_id: {users_with_role_id}")
        print(f"  • Users without role_id: {users_without_role_id}")

        if users_without_role_id > 0:
            print(f"\n⚠️  Warning: {users_without_role_id} users still don't have role_id set!")
        else:
            print("\n✅ All users successfully migrated!")

        print("\n" + "="*60)
        print("✅ User migration completed successfully!")
        print("="*60)

        print("\n📝 Next Steps:")
        print("  1. Migrate role_permissions table")
        print("  2. Update auth.py to use dynamic roles")
        print("  3. Update server.py role checks")
        print("  4. Verify system still works with new roles")

    except Exception as e:
        db.rollback()
        print(f"\n❌ Error migrating users: {str(e)}")
        import traceback
        traceback.print_exc()
        raise
    finally:
        db.close()


if __name__ == "__main__":
    migrate_users()