"""
JSON to SQLite Migration
========================

Automatically migrates existing feature_list.json files to SQLite database.
"""

import json
import shutil
from datetime import datetime
from pathlib import Path
from typing import Optional

from sqlalchemy.orm import Session, sessionmaker

from api.database import Feature


def migrate_json_to_sqlite(
    project_dir: Path,
    session_maker: sessionmaker,
) -> bool:
    """
    Detect existing feature_list.json, import to SQLite, rename to backup.

    This function:
    1. Checks if feature_list.json exists
    2. Checks if database already has data (skips if so)
    3. Imports all features from JSON
    4. Renames JSON file to feature_list.json.backup.<timestamp>

    Args:
        project_dir: Directory containing the project
        session_maker: SQLAlchemy session maker

    Returns:
        True if migration was performed, False if skipped
    """
    json_file = project_dir / "feature_list.json"

    if not json_file.exists():
        return False  # No JSON file to migrate

    # Check if database already has data
    session: Session = session_maker()
    try:
        existing_count = session.query(Feature).count()
        if existing_count > 0:
            print(
                f"Database already has {existing_count} features, skipping migration"
            )
            return False
    finally:
        session.close()

    # Load JSON data
    try:
        with open(json_file, "r", encoding="utf-8") as f:
            features_data = json.load(f)
    except json.JSONDecodeError as e:
        print(f"Error parsing feature_list.json: {e}")
        return False
    except IOError as e:
        print(f"Error reading feature_list.json: {e}")
        return False

    if not isinstance(features_data, list):
        print("Error: feature_list.json must contain a JSON array")
        return False

    # Import features into database
    session = session_maker()
    try:
        imported_count = 0
        for i, feature_dict in enumerate(features_data):
            # Handle both old format (no id/priority/name) and new format
            feature = Feature(
                id=feature_dict.get("id", i + 1),
                priority=feature_dict.get("priority", i + 1),
                category=feature_dict.get("category", "uncategorized"),
                name=feature_dict.get("name", f"Feature {i + 1}"),
                description=feature_dict.get("description", ""),
                steps=feature_dict.get("steps", []),
                passes=feature_dict.get("passes", False),
            )
            session.add(feature)
            imported_count += 1

        session.commit()

        # Verify import
        final_count = session.query(Feature).count()
        print(f"Migrated {final_count} features from JSON to SQLite")

    except Exception as e:
        session.rollback()
        print(f"Error during migration: {e}")
        return False
    finally:
        session.close()

    # Rename JSON file to backup
    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
    backup_file = project_dir / f"feature_list.json.backup.{timestamp}"

    try:
        shutil.move(json_file, backup_file)
        print(f"Original JSON backed up to: {backup_file.name}")
    except IOError as e:
        print(f"Warning: Could not backup JSON file: {e}")
        # Continue anyway - the data is in the database

    return True


def export_to_json(
    project_dir: Path,
    session_maker: sessionmaker,
    output_file: Optional[Path] = None,
) -> Path:
    """
    Export features from database back to JSON format.

    Useful for debugging or if you need to revert to the old format.

    Args:
        project_dir: Directory containing the project
        session_maker: SQLAlchemy session maker
        output_file: Output file path (default: feature_list_export.json)

    Returns:
        Path to the exported file
    """
    if output_file is None:
        output_file = project_dir / "feature_list_export.json"

    session: Session = session_maker()
    try:
        features = (
            session.query(Feature)
            .order_by(Feature.priority.asc(), Feature.id.asc())
            .all()
        )

        features_data = [f.to_dict() for f in features]

        with open(output_file, "w", encoding="utf-8") as f:
            json.dump(features_data, f, indent=2)

        print(f"Exported {len(features_data)} features to {output_file}")
        return output_file

    finally:
        session.close()