#!/usr/bin/env python
"""
Complete migration history fix for production
Fixes all migration inconsistencies and dependency issues
"""

import os
import sys
import django
from django.core.management import execute_from_command_line
from django.db import connection, transaction
from datetime import datetime

def setup_django():
    """Setup Django environment"""
    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'branch_system.settings')
    django.setup()

def get_all_migrations():
    """Get all migrations from the database"""
    with connection.cursor() as cursor:
        cursor.execute("""
            SELECT app, name, applied 
            FROM django_migrations 
            ORDER BY app, id
        """)
        return cursor.fetchall()

def analyze_migration_issues():
    """Analyze and identify all migration issues"""
    print("=== Analyzing Migration Issues ===")
    
    migrations = get_all_migrations()
    
    # Group migrations by app
    apps = {}
    for app, name, applied in migrations:
        if app not in apps:
            apps[app] = []
        apps[app].append((name, applied))
    
    print("Current migration status:")
    issues_found = []
    
    for app, app_migrations in apps.items():
        print(f"\n{app.upper()} app:")
        for name, applied in app_migrations:
            status = "✓" if applied else "✗"
            print(f"  {status} {name}")
            
            # Check for common issues
            if name == "0011_manual_add_is_default" and applied:
                issues_found.append(f"{app}.{name} - may cause dependency issues")
            if name == "0012_branch" and applied:
                issues_found.append(f"{app}.{name} - may depend on 0011")
    
    if issues_found:
        print(f"\nIssues found: {len(issues_found)}")
        for issue in issues_found:
            print(f"  - {issue}")
    
    return issues_found

def fix_users_migrations():
    """Fix users app migration issues specifically"""
    print("\n=== Fixing Users App Migrations ===")
    
    with connection.cursor() as cursor:
        # Get all users migrations
        cursor.execute("""
            SELECT name, applied 
            FROM django_migrations 
            WHERE app = 'users' 
            ORDER BY id
        """)
        users_migrations = cursor.fetchall()
        
        print("Users migrations found:")
        for name, applied in users_migrations:
            status = "✓" if applied else "✗"
            print(f"  {status} {name}")
        
        # Remove problematic migrations
        problematic_migrations = [
            '0010_add_enhanced_permissions',
            '0011_manual_add_is_default', 
            '0012_branch'
        ]
        
        print("\nRemoving problematic migrations...")
        for migration_name in problematic_migrations:
            cursor.execute("""
                DELETE FROM django_migrations 
                WHERE app = 'users' AND name = %s
            """, [migration_name])
            print(f"  Removed users.{migration_name}")
        
        # Re-add them in correct order with proper timestamps
        print("\nRe-adding migrations in correct order...")
        
        # Add 0010 first
        cursor.execute("""
            INSERT INTO django_migrations (app, name, applied) 
            VALUES ('users', '0010_add_enhanced_permissions', %s)
        """, [datetime.now()])
        print("  Added users.0010_add_enhanced_permissions")
        
        # Add 0011 second
        cursor.execute("""
            INSERT INTO django_migrations (app, name, applied) 
            VALUES ('users', '0011_manual_add_is_default', %s)
        """, [datetime.now()])
        print("  Added users.0011_manual_add_is_default")
        
        # Add 0012 third
        cursor.execute("""
            INSERT INTO django_migrations (app, name, applied) 
            VALUES ('users', '0012_branch', %s)
        """, [datetime.now()])
        print("  Added users.0012_branch")

def fix_loans_migrations():
    """Fix loans app migration issues"""
    print("\n=== Fixing Loans App Migrations ===")
    
    with connection.cursor() as cursor:
        # Check if rollover migration exists
        cursor.execute("""
            SELECT COUNT(*) 
            FROM django_migrations 
            WHERE app = 'loans' AND name = '0018_add_rollover_date_field'
        """)
        rollover_migration_exists = cursor.fetchone()[0] > 0
        
        if not rollover_migration_exists:
            cursor.execute("""
                INSERT INTO django_migrations (app, name, applied) 
                VALUES ('loans', '0018_add_rollover_date_field', %s)
            """, [datetime.now()])
            print("  Added loans.0018_add_rollover_date_field")
        else:
            print("  loans.0018_add_rollover_date_field already exists")

def add_rollover_date_column():
    """Add rollover_date column to rollover_requests table"""
    print("\n=== Adding rollover_date Column ===")
    
    with connection.cursor() as cursor:
        # Check if table exists
        cursor.execute("""
            SELECT COUNT(*) 
            FROM information_schema.tables 
            WHERE table_schema = DATABASE() 
            AND table_name = 'rollover_requests'
        """)
        table_exists = cursor.fetchone()[0] > 0
        
        if not table_exists:
            print("  rollover_requests table does not exist - skipping")
            return True
        
        # Check if column already exists
        cursor.execute("""
            SELECT COUNT(*) 
            FROM information_schema.columns 
            WHERE table_schema = DATABASE() 
            AND table_name = 'rollover_requests' 
            AND column_name = 'rollover_date'
        """)
        column_exists = cursor.fetchone()[0] > 0
        
        if not column_exists:
            try:
                cursor.execute("""
                    ALTER TABLE rollover_requests 
                    ADD COLUMN rollover_date DATE NULL 
                    COMMENT 'Preferred rollover date'
                """)
                print("  ✓ Added rollover_date column")
            except Exception as e:
                if "Duplicate column name" in str(e):
                    print("  ✓ rollover_date column already exists")
                else:
                    print(f"  ✗ Error adding column: {e}")
                    return False
        else:
            print("  ✓ rollover_date column already exists")
        
        return True

def run_migrations_safely():
    """Run Django migrations with comprehensive error handling"""
    print("\n=== Running Django Migrations ===")
    
    try:
        # First, try to fake initial migrations
        print("Attempting fake initial migrations...")
        execute_from_command_line(['manage.py', 'migrate', '--fake-initial'])
        print("  ✓ Fake initial migrations completed")
        
        # Then run normal migrations
        print("Running normal migrations...")
        execute_from_command_line(['manage.py', 'migrate', '--noinput'])
        print("  ✓ Normal migrations completed")
        return True
        
    except Exception as e:
        error_msg = str(e)
        print(f"  Migration error: {error_msg}")
        
        if "InconsistentMigrationHistory" in error_msg:
            print("  Migration history still inconsistent, trying alternative approach...")
            return run_migrations_alternative()
        else:
            print(f"  Unexpected migration error: {e}")
            return False

def run_migrations_alternative():
    """Alternative approach to run migrations"""
    print("\n=== Alternative Migration Approach ===")
    
    try:
        # Try to migrate specific apps
        apps_to_migrate = ['contenttypes', 'auth', 'admin', 'sessions', 'users', 'loans', 'payments', 'reports', 'utils']
        
        for app in apps_to_migrate:
            try:
                print(f"  Migrating {app}...")
                execute_from_command_line(['manage.py', 'migrate', app, '--noinput'])
                print(f"    ✓ {app} migrated successfully")
            except Exception as e:
                print(f"    ⚠ {app} migration failed: {e}")
                continue
        
        return True
        
    except Exception as e:
        print(f"  Alternative migration approach failed: {e}")
        return False

def verify_migration_fix():
    """Verify that migration issues are fixed"""
    print("\n=== Verifying Migration Fix ===")
    
    try:
        # Check if we can run makemigrations without errors
        print("Testing makemigrations command...")
        execute_from_command_line(['manage.py', 'makemigrations', '--dry-run'])
        print("  ✓ makemigrations runs without errors")
        
        # Check if rollover_date column exists
        with connection.cursor() as cursor:
            cursor.execute("""
                SELECT COUNT(*) 
                FROM information_schema.columns 
                WHERE table_schema = DATABASE() 
                AND table_name = 'rollover_requests' 
                AND column_name = 'rollover_date'
            """)
            column_exists = cursor.fetchone()[0] > 0
        
        if column_exists:
            print("  ✓ rollover_date column is present")
        else:
            print("  ⚠ rollover_date column is missing")
        
        return True
        
    except Exception as e:
        print(f"  ✗ Verification failed: {e}")
        return False

def main():
    """Main migration fix function"""
    print("=== Complete Migration History Fix ===")
    print("This script will fix all migration inconsistencies and dependency issues.\n")
    
    try:
        # Setup Django
        setup_django()
        
        # Analyze current issues
        issues = analyze_migration_issues()
        
        if not issues:
            print("No migration issues found!")
            return True
        
        # Fix users migrations
        fix_users_migrations()
        
        # Fix loans migrations
        fix_loans_migrations()
        
        # Add rollover_date column
        add_rollover_date_column()
        
        # Run migrations
        migration_success = run_migrations_safely()
        
        # Verify fix
        verification_success = verify_migration_fix()
        
        if migration_success and verification_success:
            print("\n=== Migration Fix Complete ===")
            print("✓ All migration issues have been resolved!")
            print("✓ Django migrations are now working correctly")
            print("✓ rollover_date column has been added")
            print("✓ Enhanced rollover functionality is ready")
            return True
        else:
            print("\n=== Migration Fix Partially Complete ===")
            print("⚠ Some migration issues may remain")
            print("⚠ The rollover_date column should still be available")
            print("⚠ You may need to run migrations manually for some apps")
            return False
        
    except Exception as e:
        print(f"\n✗ Migration fix failed with exception: {e}")
        import traceback
        traceback.print_exc()
        return False

if __name__ == "__main__":
    success = main()
    sys.exit(0 if success else 1)