from flask import Blueprint, jsonify, send_from_directory
from server.database import Session
from models.models import EventMedia
import os

# Blueprint for direct file downloads by media ID
files_bp = Blueprint("files", __name__, url_prefix="/api/files")

# Reuse the same media root convention as eventmedia.py
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
MEDIA_ROOT = os.path.join(BASE_DIR, "media")


@files_bp.route("/<int:media_id>/<path:filename>", methods=["GET"])
def download_media_file(media_id: int, filename: str):
    """
    Download the stored media file for a given EventMedia ID.

    URL format example:
      /api/files/26/LPUV4I_Folien_Nowitzki_Bewertungskriterien.pptx

    Behavior:
      - Looks up EventMedia by ID
      - Validates requested filename against stored metadata (best-effort)
      - Serves the file from server/media using the stored relative file_path
    """
    session = Session()
    media = session.query(EventMedia).get(media_id)
    if not media:
        session.close()
        return jsonify({"error": "Not found"}), 404

    # Prefer the stored relative file_path; fall back to the URL/filename
    rel_path = media.file_path or media.url

    # Basic filename consistency check to avoid leaking other files
    # Only enforce if media.url is present
    if media.url and os.path.basename(filename) != os.path.basename(media.url):
        session.close()
        return jsonify({
            "error": "Filename mismatch",
            "expected": os.path.basename(media.url),
            "got": os.path.basename(filename),
        }), 400

    abs_path = os.path.join(MEDIA_ROOT, rel_path)

    # Ensure file exists
    if not os.path.isfile(abs_path):
        session.close()
        return jsonify({"error": "File not found on server"}), 404

    # Serve as attachment (download)
    directory = os.path.dirname(abs_path)
    served_name = os.path.basename(abs_path)
    session.close()
    return send_from_directory(directory, served_name, as_attachment=True)