"""Service for exporting and importing trivia questions with media files"""
import os
import json
import shutil
import tempfile
import zipfile
from datetime import datetime
from pathlib import Path
from typing import Tuple, Optional

from flask import current_app
from backend.models import db, Question, Category, QuestionType, Score, Team, GameQuestion, Game


def export_questions_to_zip() -> Tuple[bytes, str]:
    """
    Export all questions and categories to a ZIP file with images and audio.

    Returns:
        Tuple of (zip_bytes, filename)
    """
    # Query all data
    questions = Question.query.order_by(Question.created_at).all()
    categories = Category.query.order_by(Category.name).all()

    # Create temporary directory
    temp_dir = tempfile.mkdtemp()

    try:
        # Create subdirectories
        images_dir = os.path.join(temp_dir, 'images')
        audio_dir = os.path.join(temp_dir, 'audio')
        os.makedirs(images_dir, exist_ok=True)
        os.makedirs(audio_dir, exist_ok=True)

        # Prepare manifest data
        manifest = {
            'export_version': '1.0',
            'export_timestamp': datetime.utcnow().isoformat() + 'Z',
            'questions_count': len(questions),
            'categories_count': len(categories),
            'categories': [],
            'questions': []
        }

        # Export categories
        for category in categories:
            manifest['categories'].append({
                'name': category.name,
                'created_at': category.created_at.isoformat() if category.created_at else None
            })

        # Get base folder for file operations
        base_folder = Path(current_app.config.get('UPLOAD_FOLDER')).parent.parent

        # Export questions with media files
        missing_files = []

        for question in questions:
            question_data = {
                'type': question.type.value,
                'question_content': question.question_content,
                'answer': question.answer,
                'category': question.category,
                'created_at': question.created_at.isoformat() if question.created_at else None,
                'image_path': question.image_path,
                'image_filename': None,
                'audio_path': question.audio_path,
                'audio_filename': None,
                'youtube_url': question.youtube_url,
                'start_time': question.start_time,
                'end_time': question.end_time
            }

            # Handle image files
            if question.image_path:
                image_filename = os.path.basename(question.image_path)
                question_data['image_filename'] = image_filename

                # Copy image file to temp directory
                source_path = os.path.join(base_folder, question.image_path.lstrip('/'))
                dest_path = os.path.join(images_dir, image_filename)

                if os.path.exists(source_path):
                    try:
                        shutil.copy2(source_path, dest_path)
                    except Exception as e:
                        print(f"Warning: Failed to copy image {source_path}: {e}")
                        missing_files.append(question.image_path)
                else:
                    print(f"Warning: Image file not found: {source_path}")
                    missing_files.append(question.image_path)

            # Handle audio files
            if question.audio_path:
                audio_filename = os.path.basename(question.audio_path)
                question_data['audio_filename'] = audio_filename

                # Copy audio file to temp directory
                source_path = os.path.join(base_folder, question.audio_path.lstrip('/'))
                dest_path = os.path.join(audio_dir, audio_filename)

                if os.path.exists(source_path):
                    try:
                        shutil.copy2(source_path, dest_path)
                    except Exception as e:
                        print(f"Warning: Failed to copy audio {source_path}: {e}")
                        missing_files.append(question.audio_path)
                else:
                    print(f"Warning: Audio file not found: {source_path}")
                    missing_files.append(question.audio_path)

            manifest['questions'].append(question_data)

        # Add missing files info to manifest if any
        if missing_files:
            manifest['missing_files'] = missing_files

        # Write manifest.json
        manifest_path = os.path.join(temp_dir, 'manifest.json')
        with open(manifest_path, 'w') as f:
            json.dump(manifest, f, indent=2)

        # Create ZIP file
        timestamp = datetime.now().strftime('%Y-%m-%d_%H%M%S')
        zip_filename = f'trivia-export-{timestamp}.zip'
        zip_path = os.path.join(temp_dir, zip_filename)

        with zipfile.ZipFile(zip_path, 'w', zipfile.ZIP_DEFLATED) as zipf:
            # Add manifest
            zipf.write(manifest_path, 'manifest.json')

            # Add all images
            for filename in os.listdir(images_dir):
                file_path = os.path.join(images_dir, filename)
                zipf.write(file_path, f'images/{filename}')

            # Add all audio files
            for filename in os.listdir(audio_dir):
                file_path = os.path.join(audio_dir, filename)
                zipf.write(file_path, f'audio/{filename}')

        # Read ZIP into memory
        with open(zip_path, 'rb') as f:
            zip_bytes = f.read()

        return zip_bytes, zip_filename

    finally:
        # Clean up temp directory
        try:
            shutil.rmtree(temp_dir)
        except Exception as e:
            print(f"Warning: Failed to clean up temp directory {temp_dir}: {e}")


def validate_import_zip(zip_path: str) -> Tuple[bool, Optional[str]]:
    """
    Validate an import ZIP file.

    Args:
        zip_path: Path to ZIP file

    Returns:
        Tuple of (is_valid, error_message)
    """
    try:
        # Check if file exists
        if not os.path.exists(zip_path):
            return False, "ZIP file not found"

        # Try to open as ZIP
        try:
            with zipfile.ZipFile(zip_path, 'r') as zipf:
                # Check for manifest.json
                if 'manifest.json' not in zipf.namelist():
                    return False, "Missing manifest.json in ZIP"

                # Read and parse manifest
                with zipf.open('manifest.json') as f:
                    manifest = json.load(f)

                # Validate required fields
                required_fields = ['export_version', 'questions', 'categories']
                for field in required_fields:
                    if field not in manifest:
                        return False, f"Missing required field in manifest: {field}"

                # Validate version compatibility
                if manifest['export_version'] != '1.0':
                    return False, f"Unsupported export version: {manifest['export_version']}"

                # Validate each question has required fields
                for i, question in enumerate(manifest['questions']):
                    required_q_fields = ['type', 'question_content', 'answer']
                    for field in required_q_fields:
                        if field not in question:
                            return False, f"Question {i} missing required field: {field}"

                    # Validate type is valid
                    if question['type'] not in ['text', 'image', 'youtube_audio']:
                        return False, f"Question {i} has invalid type: {question['type']}"

                    # Verify referenced files exist in ZIP
                    if question.get('image_filename'):
                        expected_path = f"images/{question['image_filename']}"
                        if expected_path not in zipf.namelist():
                            return False, f"Missing referenced image: {expected_path}"

                    if question.get('audio_filename'):
                        expected_path = f"audio/{question['audio_filename']}"
                        if expected_path not in zipf.namelist():
                            return False, f"Missing referenced audio: {expected_path}"

                return True, None

        except zipfile.BadZipFile:
            return False, "Invalid ZIP file format"
        except json.JSONDecodeError:
            return False, "Invalid JSON in manifest.json"

    except Exception as e:
        return False, f"Validation error: {str(e)}"


def clear_all_data():
    """Clear all questions, categories, games, teams, and scores from database."""
    # Delete in dependency order to avoid FK errors
    Score.query.delete()
    Team.query.delete()
    GameQuestion.query.delete()
    Game.query.delete()
    Question.query.delete()
    Category.query.delete()
    db.session.commit()


def clear_all_media_files():
    """Delete all images and audio files from static directories."""
    base_folder = Path(current_app.config.get('UPLOAD_FOLDER')).parent.parent

    # Clear images
    images_dir = os.path.join(base_folder, 'backend', 'static', 'images')
    if os.path.exists(images_dir):
        for filename in os.listdir(images_dir):
            if filename == '.gitkeep':
                continue
            file_path = os.path.join(images_dir, filename)
            try:
                if os.path.isfile(file_path):
                    os.remove(file_path)
            except Exception as e:
                print(f"Warning: Failed to delete {file_path}: {e}")

    # Clear audio
    audio_dir = os.path.join(base_folder, 'backend', 'static', 'audio')
    if os.path.exists(audio_dir):
        for filename in os.listdir(audio_dir):
            if filename == '.gitkeep':
                continue
            file_path = os.path.join(audio_dir, filename)
            try:
                if os.path.isfile(file_path):
                    os.remove(file_path)
            except Exception as e:
                print(f"Warning: Failed to delete {file_path}: {e}")


def import_questions_from_zip(zip_path: str) -> dict:
    """
    Import questions and media from a ZIP file.

    Args:
        zip_path: Path to ZIP file to import

    Returns:
        Dict with import summary

    Raises:
        ValueError: If validation fails
        Exception: If import fails
    """
    temp_dir = None

    try:
        # Validate ZIP
        is_valid, error_msg = validate_import_zip(zip_path)
        if not is_valid:
            raise ValueError(error_msg)

        # Extract ZIP to temp directory
        temp_dir = tempfile.mkdtemp()

        with zipfile.ZipFile(zip_path, 'r') as zipf:
            zipf.extractall(temp_dir)

        # Load manifest
        manifest_path = os.path.join(temp_dir, 'manifest.json')
        with open(manifest_path, 'r') as f:
            manifest = json.load(f)

        # Get base folder for file operations
        base_folder = Path(current_app.config.get('UPLOAD_FOLDER')).parent.parent
        images_dest_dir = os.path.join(base_folder, 'backend', 'static', 'images')
        audio_dest_dir = os.path.join(base_folder, 'backend', 'static', 'audio')

        # Ensure destination directories exist
        os.makedirs(images_dest_dir, exist_ok=True)
        os.makedirs(audio_dest_dir, exist_ok=True)

        # Begin transaction
        # Clear existing data
        clear_all_data()

        # Clear existing media files
        clear_all_media_files()

        # Copy media files from extracted ZIP
        images_src_dir = os.path.join(temp_dir, 'images')
        if os.path.exists(images_src_dir):
            for filename in os.listdir(images_src_dir):
                src = os.path.join(images_src_dir, filename)
                dst = os.path.join(images_dest_dir, filename)
                shutil.copy2(src, dst)

        audio_src_dir = os.path.join(temp_dir, 'audio')
        if os.path.exists(audio_src_dir):
            for filename in os.listdir(audio_src_dir):
                src = os.path.join(audio_src_dir, filename)
                dst = os.path.join(audio_dest_dir, filename)
                shutil.copy2(src, dst)

        # Import categories
        for cat_data in manifest['categories']:
            category = Category(name=cat_data['name'])
            # Preserve created_at if provided
            if cat_data.get('created_at'):
                try:
                    category.created_at = datetime.fromisoformat(cat_data['created_at'].replace('Z', '+00:00'))
                except:
                    pass  # Use default if parsing fails
            db.session.add(category)

        # Import questions
        for q_data in manifest['questions']:
            # Reconstruct paths from filenames
            image_path = None
            if q_data.get('image_filename'):
                image_path = f"/static/images/{q_data['image_filename']}"

            audio_path = None
            if q_data.get('audio_filename'):
                audio_path = f"/static/audio/{q_data['audio_filename']}"

            question = Question(
                type=QuestionType(q_data['type']),
                question_content=q_data['question_content'],
                answer=q_data['answer'],
                category=q_data.get('category'),
                image_path=image_path,
                audio_path=audio_path,
                youtube_url=q_data.get('youtube_url'),
                start_time=q_data.get('start_time'),
                end_time=q_data.get('end_time')
            )

            # Preserve created_at if provided
            if q_data.get('created_at'):
                try:
                    question.created_at = datetime.fromisoformat(q_data['created_at'].replace('Z', '+00:00'))
                except:
                    pass  # Use default if parsing fails

            db.session.add(question)

        # Commit transaction
        db.session.commit()

        return {
            'success': True,
            'questions_imported': len(manifest['questions']),
            'categories_imported': len(manifest['categories'])
        }

    except Exception as e:
        # Rollback database changes
        db.session.rollback()
        # Note: File operations cannot be rolled back
        raise

    finally:
        # Clean up temp directory
        if temp_dir:
            try:
                shutil.rmtree(temp_dir)
            except Exception as e:
                print(f"Warning: Failed to clean up temp directory {temp_dir}: {e}")