from fastapi import APIRouter, HTTPException
from fastapi.responses import FileResponse
from pathlib import Path
from typing import List
import os

router = APIRouter(prefix="/api", tags=["photos"])

PHOTOS_BASE_DIR = Path("data/photos")


@router.get("/unit/{unit_id}/photos")
def get_unit_photos(unit_id: str):
    """
    Reads /data/photos/<unit_id>/ and returns list of image filenames.
    Primary photo = most recent file.
    """
    unit_photo_dir = PHOTOS_BASE_DIR / unit_id

    if not unit_photo_dir.exists():
        # Return empty list if no photos directory exists
        return {
            "unit_id": unit_id,
            "photos": [],
            "primary_photo": None
        }

    # Get all image files
    image_extensions = {".jpg", ".jpeg", ".png", ".gif", ".webp"}
    photos = []

    for file_path in unit_photo_dir.iterdir():
        if file_path.is_file() and file_path.suffix.lower() in image_extensions:
            photos.append({
                "filename": file_path.name,
                "path": f"/api/unit/{unit_id}/photo/{file_path.name}",
                "modified": file_path.stat().st_mtime
            })

    # Sort by modification time (most recent first)
    photos.sort(key=lambda x: x["modified"], reverse=True)

    # Primary photo is the most recent
    primary_photo = photos[0]["filename"] if photos else None

    return {
        "unit_id": unit_id,
        "photos": [p["filename"] for p in photos],
        "primary_photo": primary_photo,
        "photo_urls": [p["path"] for p in photos]
    }


@router.get("/unit/{unit_id}/photo/{filename}")
def get_photo(unit_id: str, filename: str):
    """
    Serves a specific photo file.
    """
    file_path = PHOTOS_BASE_DIR / unit_id / filename

    if not file_path.exists() or not file_path.is_file():
        raise HTTPException(status_code=404, detail="Photo not found")

    return FileResponse(file_path)