"""
Download Blueprint
Handles file download endpoints.
"""

from pathlib import Path
from flask import Blueprint, send_file, current_app

from ..shared import _format_response, log_performance, logger

# Create blueprint
download_bp = Blueprint('download', __name__, url_prefix='/download')


@download_bp.route('/<path:filename>')
@log_performance
def download_file(filename):
    """Download a processed file."""
    from flask import request

    logger.info(f"Download request for file: {filename} from IP {request.remote_addr}")

    try:
        # 支持两种路径格式：
        # 1. 绝对路径（以 / 开头，如 /full/path/to/file）
        # 2. 相对路径（task_id/filename）
        if filename.startswith('/'):
            # 绝对路径 - 直接使用
            file_path = Path(filename)
        else:
            # 相对路径 - 相对于 OUTPUT_FOLDER
            output_folder = Path(current_app.config.get('OUTPUT_FOLDER') or '')
            if not output_folder:
                logger.error("OUTPUT_FOLDER not configured")
                return _format_response(500, "服务器配置错误")

            # 解析 task_id/filename 格式
            parts = filename.split('/', 1)
            if len(parts) != 2:
                logger.warning(f"Invalid relative path format: {filename}")
                return _format_response(400, "无效的文件路径")

            task_id, filename_part = parts
            file_path = output_folder / task_id / filename_part

        # Security check - ensure file is within output folder
        file_path = file_path.resolve()
        output_folder = Path(current_app.config.get('OUTPUT_FOLDER') or '').resolve()
        if output_folder and not str(file_path).startswith(str(output_folder)):
            logger.warning(f"Security violation: Attempted to access file outside output folder: {filename}")
            return _format_response(403, "访问被拒绝")

        if not file_path.exists():
            logger.warning(f"File not found: {filename}")
            return _format_response(404, "文件未找到")

        if not file_path.is_file():
            logger.warning(f"Path is not a file: {filename}")
            return _format_response(400, "不是文件")

        file_size = file_path.stat().st_size
        logger.info(f"Serving file: {filename} ({file_size} bytes)")

        return send_file(file_path)

    except Exception as e:
        logger.error(f"Error serving file {filename}: {str(e)}", exc_info=True)
        return _format_response(500, "内部服务器错误")