import os
import re
import mimetypes
from fastapi import APIRouter, HTTPException, Response
from fastapi.responses import FileResponse, RedirectResponse
import httpx

from ..runtime import get_runtime_settings

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

_TMDB_BASE = "https://image.tmdb.org/t/p"
_ALLOWED_SIZES = {"w92", "w154", "w185", "w342", "w500", "w780", "original"}


def _safe_filename(path: str) -> str:
    trimmed = path.strip("/")
    trimmed = trimmed.replace("/", "_")
    safe = re.sub(r"[^A-Za-z0-9_.-]", "_", trimmed)
    return safe or "image"


async def cache_tmdb_image(path: str, size: str = "w342") -> bool:
    if not path or "://" in path or ".." in path:
        return False
    if not path.startswith("/"):
        path = f"/{path}"
    if size not in _ALLOWED_SIZES:
        return False

    runtime = get_runtime_settings()
    cache_mode = (runtime.artwork_cache_mode or "remote").lower()
    if cache_mode != "cache":
        return False

    cache_dir = os.path.join(os.getcwd(), "data", "artwork", "tmdb", size)
    os.makedirs(cache_dir, exist_ok=True)
    file_path = os.path.join(cache_dir, _safe_filename(path))
    if os.path.exists(file_path):
        return True

    url = f"{_TMDB_BASE}/{size}{path}"
    async with httpx.AsyncClient(timeout=20) as client:
        response = await client.get(url)
        response.raise_for_status()
        content = response.content
    with open(file_path, "wb") as handle:
        handle.write(content)
    return True


@router.get("/tmdb")
async def tmdb_image(path: str, size: str = "w342"):
    if not path or "://" in path or ".." in path:
        raise HTTPException(status_code=400, detail="Invalid image path")
    if not path.startswith("/"):
        path = f"/{path}"
    if size not in _ALLOWED_SIZES:
        raise HTTPException(status_code=400, detail="Invalid size")

    runtime = get_runtime_settings()
    cache_mode = (runtime.artwork_cache_mode or "remote").lower()
    url = f"{_TMDB_BASE}/{size}{path}"
    if cache_mode != "cache":
        return RedirectResponse(url=url)

    cache_dir = os.path.join(os.getcwd(), "data", "artwork", "tmdb", size)
    os.makedirs(cache_dir, exist_ok=True)
    file_path = os.path.join(cache_dir, _safe_filename(path))
    headers = {"Cache-Control": "public, max-age=86400"}
    if os.path.exists(file_path):
        media_type = mimetypes.guess_type(file_path)[0] or "image/jpeg"
        return FileResponse(file_path, media_type=media_type, headers=headers)

    try:
        await cache_tmdb_image(path, size)
        if os.path.exists(file_path):
            media_type = mimetypes.guess_type(file_path)[0] or "image/jpeg"
            return FileResponse(file_path, media_type=media_type, headers=headers)
        raise HTTPException(status_code=502, detail="Image cache failed")
    except httpx.HTTPError as exc:
        raise HTTPException(status_code=502, detail=f"Image fetch failed: {exc}") from exc