import json
import re
import urllib.request

import goodreads
from jsonfile import PROJECT_ROOT

SCRAPE_CACHE_DIR = PROJECT_ROOT / "tools" / "content" / ".cache" / "goodreads"
COVERS_DIR = PROJECT_ROOT / "static" / "covers" / "books"
COVERS_PUBLIC_PATH = "/covers/books"
IMAGE_EXTENSION_PATTERN = re.compile(r"\.(jpe?g|png|webp|gif)(?:$|\?)", re.I)


def scrape_cache_path(identifier: str):
    return SCRAPE_CACHE_DIR / f"{identifier}.json"


def cached_scrape(identifier: str) -> dict | None:
    path = scrape_cache_path(identifier)
    if not path.exists():
        return None
    try:
        return json.loads(path.read_text(encoding="utf-8"))
    except ValueError:
        return None


def store_scrape(scraped: dict) -> None:
    SCRAPE_CACHE_DIR.mkdir(parents=True, exist_ok=True)
    scrape_cache_path(scraped["goodreadsId"]).write_text(json.dumps(scraped, ensure_ascii=False, indent=2), encoding="utf-8")


def scrape_book(url: str, fresh: bool = False) -> dict:
    identifier = goodreads.book_id(url)
    cached = None if fresh or not identifier else cached_scrape(identifier)
    if cached:
        return cached
    scraped = goodreads.scrape_book(url)
    if scraped.get("title"):
        store_scrape(scraped)
    return scraped


def is_local_cover(cover: str | None) -> bool:
    return bool(cover) and cover.startswith(COVERS_PUBLIC_PATH)


def existing_cover(identifier: str):
    return next(iter(sorted(COVERS_DIR.glob(f"{identifier}.*"))), None) if COVERS_DIR.exists() else None


def cache_cover(identifier: str, source_url: str | None, fresh: bool = False) -> str | None:
    existing = existing_cover(identifier)
    if existing and not fresh:
        return f"{COVERS_PUBLIC_PATH}/{existing.name}"
    if not source_url or is_local_cover(source_url):
        return f"{COVERS_PUBLIC_PATH}/{existing.name}" if existing else None

    match = IMAGE_EXTENSION_PATTERN.search(source_url)
    extension = match.group(1).lower().replace("jpeg", "jpg") if match else "jpg"
    request = urllib.request.Request(source_url, headers=goodreads.REQUEST_HEADERS)
    with urllib.request.urlopen(request, timeout=15) as response:
        image = response.read()

    COVERS_DIR.mkdir(parents=True, exist_ok=True)
    if existing:
        existing.unlink()
    (COVERS_DIR / f"{identifier}.{extension}").write_bytes(image)
    return f"{COVERS_PUBLIC_PATH}/{identifier}.{extension}"


def remove_cover(identifier: str) -> None:
    existing = existing_cover(identifier)
    if existing:
        existing.unlink()