#!/usr/bin/env python3
"""
Migration script for existing speakers to new format
Adds tts_backend and reference_text fields to existing speaker data
"""
import sys
import yaml
from pathlib import Path
from datetime import datetime

# Add project root to path
project_root = Path(__file__).parent.parent.parent
sys.path.append(str(project_root))

from backend.app.services.speaker_service import SpeakerManagementService
from backend.app.models.speaker_models import Speaker

def backup_speakers_file(speakers_file_path: Path) -> Path:
    """Create a backup of the existing speakers file"""
    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
    backup_path = speakers_file_path.parent / f"speakers_backup_{timestamp}.yaml"
    
    if speakers_file_path.exists():
        with open(speakers_file_path, 'r') as src, open(backup_path, 'w') as dst:
            dst.write(src.read())
        print(f"✓ Created backup: {backup_path}")
        return backup_path
    else:
        print("⚠ No existing speakers file to backup")
        return None

def analyze_existing_speakers(service: SpeakerManagementService) -> dict:
    """Analyze current speakers data structure"""
    analysis = {
        "total_speakers": len(service.speakers_data),
        "needs_migration": 0,
        "already_migrated": 0,
        "sample_speaker_data": None,
        "missing_fields": set()
    }
    
    for speaker_id, speaker_data in service.speakers_data.items():
        needs_migration = False
        
        # Check for missing fields
        if "tts_backend" not in speaker_data:
            analysis["missing_fields"].add("tts_backend")
            needs_migration = True
        
        if "reference_text" not in speaker_data:
            analysis["missing_fields"].add("reference_text")
            needs_migration = True
        
        if needs_migration:
            analysis["needs_migration"] += 1
            if not analysis["sample_speaker_data"]:
                analysis["sample_speaker_data"] = {
                    "id": speaker_id,
                    "current_data": speaker_data.copy()
                }
        else:
            analysis["already_migrated"] += 1
    
    return analysis

def interactive_migration_prompt(analysis: dict) -> bool:
    """Ask user for confirmation before migrating"""
    print("\n=== Speaker Migration Analysis ===")
    print(f"Total speakers: {analysis['total_speakers']}")
    print(f"Need migration: {analysis['needs_migration']}")
    print(f"Already migrated: {analysis['already_migrated']}")
    
    if analysis["missing_fields"]:
        print(f"Missing fields: {', '.join(analysis['missing_fields'])}")
    
    if analysis["sample_speaker_data"]:
        print("\nExample current speaker data:")
        sample_data = analysis["sample_speaker_data"]["current_data"]
        for key, value in sample_data.items():
            print(f"  {key}: {value}")
        
        print("\nAfter migration will have:")
        print(f"  tts_backend: chatterbox (default)")
        print(f"  reference_text: null (default)")
    
    if analysis["needs_migration"] == 0:
        print("\n✓ All speakers are already migrated!")
        return False
    
    print(f"\nThis will migrate {analysis['needs_migration']} speakers.")
    response = input("Continue with migration? (y/N): ").lower().strip()
    return response in ['y', 'yes']

def validate_migrated_speakers(service: SpeakerManagementService) -> dict:
    """Validate all speakers after migration"""
    print("\n=== Validating Migrated Speakers ===")
    validation_results = service.validate_all_speakers()
    
    print(f"✓ Valid speakers: {validation_results['valid_speakers']}")
    
    if validation_results['invalid_speakers'] > 0:
        print(f"❌ Invalid speakers: {validation_results['invalid_speakers']}")
        for error in validation_results['validation_errors']:
            print(f"  - {error['speaker_name']} ({error['speaker_id']}): {error['error']}")
    
    return validation_results

def show_backend_statistics(service: SpeakerManagementService):
    """Show speaker distribution across backends"""
    print("\n=== Backend Distribution ===")
    stats = service.get_backend_statistics()
    
    print(f"Total speakers: {stats['total_speakers']}")
    for backend, backend_stats in stats['backends'].items():
        print(f"\n{backend.upper()} Backend:")
        print(f"  Count: {backend_stats['count']}")
        print(f"  With reference text: {backend_stats['with_reference_text']}")
        print(f"  Without reference text: {backend_stats['without_reference_text']}")

def main():
    """Run the migration process"""
    print("=== Speaker Data Migration Tool ===")
    print("This tool migrates existing speaker data to support multiple TTS backends\n")
    
    try:
        # Initialize service
        print("Loading speaker data...")
        service = SpeakerManagementService()
        
        # Analyze current state
        analysis = analyze_existing_speakers(service)
        
        # Show analysis and get confirmation
        if not interactive_migration_prompt(analysis):
            print("Migration cancelled.")
            return 0
        
        # Create backup
        print("\nCreating backup...")
        from backend.app import config
        backup_path = backup_speakers_file(config.SPEAKERS_YAML_FILE)
        
        # Perform migration
        print("\nPerforming migration...")
        migration_stats = service.migrate_existing_speakers()
        
        print(f"\n=== Migration Results ===")
        print(f"Total speakers processed: {migration_stats['total_speakers']}")
        print(f"Speakers migrated: {migration_stats['migrated_count']}")
        print(f"Already migrated: {migration_stats['already_migrated']}")
        
        if migration_stats['migrations_performed']:
            print(f"\nMigrated speakers:")
            for migration in migration_stats['migrations_performed']:
                print(f"  - {migration['speaker_name']}: {', '.join(migration['migrations'])}")
        
        # Validate results
        validation_results = validate_migrated_speakers(service)
        
        # Show backend distribution
        show_backend_statistics(service)
        
        # Final status
        if validation_results['invalid_speakers'] == 0:
            print(f"\n✅ Migration completed successfully!")
            print(f"All {migration_stats['total_speakers']} speakers are now using the new format.")
            if backup_path:
                print(f"Original data backed up to: {backup_path}")
        else:
            print(f"\n⚠ Migration completed with {validation_results['invalid_speakers']} validation errors.")
            print("Please check the error details above.")
            return 1
        
        return 0
        
    except Exception as e:
        print(f"\n❌ Migration failed: {e}")
        import traceback
        traceback.print_exc()
        return 1

if __name__ == "__main__":
    exit(main())