"""
Database migration for Story 3.2: Find Tiered Links

This script adds:
1. money_site_url column to projects table
2. article_links table for tracking link relationships

Run this script BEFORE deploying Story 3.2 code to production.

Usage:
    python scripts/migrate_story_3.2.py
"""

import sys
from pathlib import Path

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

from sqlalchemy import text, inspect
from src.database.session import db_manager
from src.core.config import get_config


def check_column_exists(inspector, table_name: str, column_name: str) -> bool:
    """Check if a column exists in a table"""
    columns = inspector.get_columns(table_name)
    return any(col['name'] == column_name for col in columns)


def check_table_exists(inspector, table_name: str) -> bool:
    """Check if a table exists"""
    return table_name in inspector.get_table_names()


def migrate_add_money_site_url(connection):
    """Add money_site_url column to projects table"""
    print("\n[1/2] Adding money_site_url to projects table...")
    
    inspector = inspect(connection)
    
    if not check_table_exists(inspector, 'projects'):
        print("  [ERROR] projects table does not exist!")
        return False
    
    if check_column_exists(inspector, 'projects', 'money_site_url'):
        print("  [INFO] Column money_site_url already exists, skipping")
        return True
    
    try:
        connection.execute(text("""
            ALTER TABLE projects ADD COLUMN money_site_url VARCHAR(500) NULL
        """))
        print("  [OK] Added money_site_url column")
        
        connection.execute(text("""
            CREATE INDEX idx_projects_money_site_url ON projects(money_site_url)
        """))
        print("  [OK] Created index on money_site_url")
        
        connection.commit()
        return True
        
    except Exception as e:
        print(f"  [ERROR] {e}")
        connection.rollback()
        return False


def migrate_create_article_links_table(connection):
    """Create article_links table"""
    print("\n[2/2] Creating article_links table...")
    
    inspector = inspect(connection)
    
    if check_table_exists(inspector, 'article_links'):
        print("  [INFO] Table article_links already exists, skipping")
        return True
    
    try:
        connection.execute(text("""
            CREATE TABLE article_links (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                from_content_id INTEGER NOT NULL,
                to_content_id INTEGER NULL,
                to_url TEXT NULL,
                link_type VARCHAR(20) NOT NULL,
                created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
                FOREIGN KEY (from_content_id) REFERENCES generated_content(id) ON DELETE CASCADE,
                FOREIGN KEY (to_content_id) REFERENCES generated_content(id) ON DELETE CASCADE,
                CHECK (to_content_id IS NOT NULL OR to_url IS NOT NULL)
            )
        """))
        print("  [OK] Created article_links table")
        
        connection.execute(text("""
            CREATE INDEX idx_article_links_from ON article_links(from_content_id)
        """))
        print("  [OK] Created index on from_content_id")
        
        connection.execute(text("""
            CREATE INDEX idx_article_links_to ON article_links(to_content_id)
        """))
        print("  [OK] Created index on to_content_id")
        
        connection.execute(text("""
            CREATE INDEX idx_article_links_type ON article_links(link_type)
        """))
        print("  [OK] Created index on link_type")
        
        connection.commit()
        return True
        
    except Exception as e:
        print(f"  [ERROR] {e}")
        connection.rollback()
        return False


def verify_migration(connection):
    """Verify the migration was successful"""
    print("\n[Verification] Checking migration results...")
    
    inspector = inspect(connection)
    
    success = True
    
    if check_column_exists(inspector, 'projects', 'money_site_url'):
        print("  [OK] projects.money_site_url exists")
    else:
        print("  [ERROR] projects.money_site_url MISSING")
        success = False
    
    if check_table_exists(inspector, 'article_links'):
        print("  [OK] article_links table exists")
        
        columns = inspector.get_columns('article_links')
        expected_columns = ['id', 'from_content_id', 'to_content_id', 'to_url', 'link_type', 'created_at']
        actual_columns = [col['name'] for col in columns]
        
        for col in expected_columns:
            if col in actual_columns:
                print(f"    [OK] article_links.{col} exists")
            else:
                print(f"    [ERROR] article_links.{col} MISSING")
                success = False
        
        indexes = inspector.get_indexes('article_links')
        index_names = [idx['name'] for idx in indexes]
        print(f"    [INFO] Indexes: {index_names}")
    else:
        print("  [ERROR] article_links table MISSING")
        success = False
    
    return success


def main():
    """Run the migration"""
    print("=" * 60)
    print("Story 3.2 Database Migration")
    print("=" * 60)
    
    try:
        config = get_config()
        print(f"\nDatabase: {config.database.url}")
    except Exception as e:
        print(f"[ERROR] Error loading configuration: {e}")
        sys.exit(1)
    
    try:
        db_manager.initialize()
        engine = db_manager.get_engine()
        connection = engine.connect()
    except Exception as e:
        print(f"[ERROR] Error connecting to database: {e}")
        sys.exit(1)
    
    try:
        success = True
        
        if not migrate_add_money_site_url(connection):
            success = False
        
        if not migrate_create_article_links_table(connection):
            success = False
        
        if success:
            if verify_migration(connection):
                print("\n" + "=" * 60)
                print("[SUCCESS] Migration completed successfully!")
                print("=" * 60)
            else:
                print("\n" + "=" * 60)
                print("[WARNING] Migration completed with warnings")
                print("=" * 60)
        else:
            print("\n" + "=" * 60)
            print("[FAILED] Migration failed!")
            print("=" * 60)
            sys.exit(1)
            
    except Exception as e:
        print(f"\n[ERROR] Unexpected error during migration: {e}")
        import traceback
        traceback.print_exc()
        sys.exit(1)
    finally:
        connection.close()
        db_manager.close()


if __name__ == "__main__":
    main()