import hashlib
import logging
import mimetypes
from pathlib import Path

import requests

import db
from config import CalibreConfig

log = logging.getLogger(__name__)

MIME_TYPES = {
    ".epub": "application/epub+zip",
    ".pdf": "application/pdf",
}


class CalibreClient:
    def __init__(self, cfg: CalibreConfig):
        self._cfg = cfg
        self._session = requests.Session()
        self._authenticated = False

    def _ensure_auth(self) -> None:
        if self._authenticated:
            return
        resp = self._session.post(
            f"{self._cfg.url}/login",
            data={"username": self._cfg.user, "password": self._cfg.password},
            allow_redirects=True,
            timeout=30,
        )
        resp.raise_for_status()
        # Calibre-Web redirects to / on success; a 200 on /login means bad creds
        if resp.url.endswith("/login"):
            raise RuntimeError("Calibre-Web authentication failed — check credentials")
        self._authenticated = True
        log.info("Authenticated to Calibre-Web at %s", self._cfg.url)

    def upload(self, book_path: Path, zip_source: str) -> str:
        """Upload a book file. Returns status: 'uploaded' | 'skipped_duplicate' | 'error'."""
        file_hash = _sha256(book_path)

        if db.is_book_uploaded(file_hash):
            log.info("Skipping duplicate: %s (hash %s)", book_path.name, file_hash[:8])
            db.record_book(book_path.name, file_hash, zip_source, "skipped_duplicate")
            return "skipped_duplicate"

        try:
            self._ensure_auth()
            mime = MIME_TYPES.get(book_path.suffix.lower(), "application/octet-stream")
            with book_path.open("rb") as fh:
                resp = self._session.post(
                    f"{self._cfg.url}/upload",
                    files={"btn-upload": (book_path.name, fh, mime)},
                    timeout=120,
                )
            resp.raise_for_status()
            log.info("Uploaded: %s", book_path.name)
            db.record_book(book_path.name, file_hash, zip_source, "uploaded")
            return "uploaded"
        except Exception as e:
            log.error("Upload failed for %s: %s", book_path.name, e)
            db.record_book(book_path.name, file_hash, zip_source, "error")
            return "error"


def _sha256(path: Path) -> str:
    h = hashlib.sha256()
    with path.open("rb") as f:
        for chunk in iter(lambda: f.read(65536), b""):
            h.update(chunk)
    return h.hexdigest()