from __future__ import annotations

import hashlib
import os
from pathlib import Path
from typing import Tuple
from urllib.parse import urlparse

import httpx
from fastapi import FastAPI, UploadFile, File, HTTPException
from fastapi.responses import FileResponse
from pydantic import BaseModel

# Хранилище картинок только для этого сервиса
MEDIA_ROOT = Path(os.getenv("NYANIMEDB_MEDIA_ROOT", "media")).resolve()
MEDIA_ROOT.mkdir(parents=True, exist_ok=True)

app = FastAPI()


def _guess_ext_from_url(url: str) -> str:
    path = urlparse(url).path
    _, ext = os.path.splitext(path)
    if ext and len(ext) <= 5:
        return ext
    return ".jpg"


def _guess_ext_from_name(name: str) -> str:
    _, ext = os.path.splitext(name)
    if ext and len(ext) <= 5:
        return ext
    return ".jpg"


def _build_rel_path_from_hash(h: str, ext: str, subdir: str = "posters") -> Tuple[str, Path]:
    """
    Строим путь вида subdir/ab/cd/<hash>.ext по sha1-хешу содержимого.
    """
    level1 = h[:2]
    level2 = h[2:4]
    rel = f"{subdir}/{level1}/{level2}/{h}{ext}"
    abs_path = MEDIA_ROOT / rel
    return rel, abs_path


async def _save_bytes(data: bytes, *, filename_hint: str, subdir: str = "posters") -> str:
    # sha1 по содержимому
    h = hashlib.sha1(data).hexdigest()
    # расширение либо из имени, либо .jpg
    ext = _guess_ext_from_name(filename_hint)

    rel, abs_path = _build_rel_path_from_hash(h, ext, subdir=subdir)

    if abs_path.exists():
        return rel

    abs_path.parent.mkdir(parents=True, exist_ok=True)
    tmp_path = abs_path.with_suffix(abs_path.suffix + ".tmp")

    with open(tmp_path, "wb") as f:
        f.write(data)
    os.replace(tmp_path, abs_path)

    return rel


class DownloadByUrlRequest(BaseModel):
    url: str
    subdir: str = "posters"


@app.post("/upload")
async def upload_image(
    file: UploadFile = File(...),
    subdir: str = "posters",
):
    """
    Загрузка файла от клиента (ETL/админка/бекенд).
    Возвращает относительный путь (subdir/ab/cd/hash.ext).
    """
    data = await file.read()
    rel = await _save_bytes(data, filename_hint=file.filename or "", subdir=subdir)
    return {"path": rel}


@app.post("/download-by-url")
async def download_by_url(payload: DownloadByUrlRequest):
    """
    Скачивает картинку по URL и сохраняет по тем же правилам, что downloader.py.
    """
    async with httpx.AsyncClient(timeout=20.0) as client:
        r = await client.get(payload.url)
        r.raise_for_status()
        data = r.content

    # filename_hint берём из URL
    rel = await _save_bytes(data, filename_hint=payload.url, subdir=payload.subdir)
    return {"path": rel}


@app.get("/media/{path:path}")
async def get_image(path: str):
    """
    Отдаёт файл по относительному пути (например, posters/ab/cd/hash.jpg).
    """
    abs_path = MEDIA_ROOT / path
    if not abs_path.is_file():
        raise HTTPException(status_code=404, detail="Image not found")
    return FileResponse(abs_path)