"""
Database migration: Add support for multiple users per chore.

This creates a chore_assignments junction table to allow
multiple users to be assigned to a single chore.
"""

import sys
from pathlib import Path

sys.path.insert(0, str(Path(__file__).parent.parent))

from app.core.database import engine, SessionLocal
from sqlalchemy import text

def create_chore_assignments_table():
    """Create chore_assignments table for many-to-many relationship."""
    db = SessionLocal()
    
    try:
        print("=" * 70)
        print("MIGRATION: Add Multiple Users Per Chore Support")
        print("=" * 70)
        print()
        
        # Check if table already exists
        result = db.execute(text("SELECT name FROM sqlite_master WHERE type='table' AND name='chore_assignments'"))
        if result.fetchone():
            print("✅ chore_assignments table already exists. No migration needed.")
            return
        
        print("📋 Creating chore_assignments table...")
        
        # Create junction table
        db.execute(text("""
            CREATE TABLE chore_assignments (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                chore_id INTEGER NOT NULL,
                user_id INTEGER NOT NULL,
                completed_at DATETIME,
                created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
                FOREIGN KEY (chore_id) REFERENCES chores (id) ON DELETE CASCADE,
                FOREIGN KEY (user_id) REFERENCES users (id) ON DELETE CASCADE,
                UNIQUE(chore_id, user_id)
            )
        """))
        
        print("✅ chore_assignments table created!")
        print()
        
        print("📋 Migrating existing chore assignments...")
        
        # Migrate existing assigned_user_id data to new table
        # For each chore with an assigned_user_id, create an assignment record
        result = db.execute(text("""
            INSERT INTO chore_assignments (chore_id, user_id, completed_at)
            SELECT id, assigned_user_id, completed_at
            FROM chores
            WHERE assigned_user_id IS NOT NULL
        """))
        
        migrated_count = result.rowcount
        db.commit()
        
        print(f"✅ Migrated {migrated_count} existing chore assignments!")
        print()
        print("⚠️  NOTE: The assigned_user_id column in chores table is now deprecated.")
        print("   It will be kept for backwards compatibility but not used.")
        print()
        print("Migration complete!")
        print()
        
    except Exception as e:
        print(f"❌ Migration failed: {e}")
        db.rollback()
        raise
    finally:
        db.close()

if __name__ == "__main__":
    create_chore_assignments_table()