"""WooCommerce REST v3 client (stdlib urllib). Basic-auth, HTTPS-only, paginated.

Creds come from Settings (wp_username plain, app_password AES-GCM). Missing creds
raise WooCredentialsMissing (a fail-closed condition the caller maps to ok:false),
distinct from WooAuthError (a 401 from the store).
"""

import base64
import json
import urllib.error
import urllib.request
from typing import Any, Callable

from .crypto import DecryptError, decrypt


class WooError(Exception):
    """Base for all Woo client failures."""


class WooCredentialsMissing(WooError):
    """Woo base URL or credentials are not configured (fail-closed)."""


class WooAuthError(WooError):
    """The store rejected the credentials (401)."""


class WooNotFoundError(WooError):
    pass


class WooServerError(WooError):
    pass


class WooConnectionError(WooError):
    """Store unreachable (DNS, TLS, timeout)."""


def _default_request(url: str, method: str, data: bytes | None, headers: dict[str, str]):
    req = urllib.request.Request(url, method=method, data=data)
    for k, v in headers.items():
        req.add_header(k, v)
    try:
        with urllib.request.urlopen(req, timeout=15) as r:
            return r.getcode(), dict(r.headers.items()), r.read()
    except urllib.error.HTTPError as e:
        body = e.read()
        try:
            parsed = json.loads(body)
        except (ValueError, json.JSONDecodeError):
            parsed = {}
        msg = parsed.get("message") if isinstance(parsed, dict) else None
        if e.code == 401:
            raise WooAuthError(msg or "authentication rejected (401)") from e
        if e.code == 404:
            raise WooNotFoundError(msg or "not found (404)") from e
        raise WooServerError(f"server error {e.code}: {msg}") from e
    except (urllib.error.URLError, OSError, TimeoutError) as e:
        raise WooConnectionError(f"store unreachable: {e}") from e


class WooClient:
    def __init__(self, username: str, password: str, base_url: str,
                 request: Callable[..., tuple[int, dict, bytes]] = _default_request) -> None:
        if not base_url or not base_url.startswith("https://"):
            raise WooCredentialsMissing("WOO_BASE_URL must be https:// (SETTINGS-10)")
        self.base_url = base_url.rstrip("/")
        self._request = request
        self._auth = base64.b64encode(f"{username}:{password}".encode("utf-8")).decode("ascii")

    @classmethod
    def from_settings(cls, base_url: str, username: str | None, encrypted_password: str | None,
                      request: Callable[..., tuple[int, dict, bytes]] | None = None) -> "WooClient":
        """Build from Settings values; raise WooCredentialsMissing if incomplete (fail-closed)."""
        if not username:
            raise WooCredentialsMissing("woo_wp_username not set (SETTINGS-15)")
        if not encrypted_password:
            raise WooCredentialsMissing("woo_app_password not configured (SETTINGS-15)")
        try:
            password = decrypt(encrypted_password)
        except DecryptError as e:
            raise WooCredentialsMissing("woo_app_password cannot be decrypted (re-enter it)") from e
        if request is None:
            request = _default_request
        return cls(username, password, base_url, request)

    def _get(self, path: str) -> tuple[int, dict, bytes]:
        url = f"{self.base_url}/wp-json/wc/v3{path}"
        return self._request(
            url, "GET", None,
            {"Authorization": f"Basic {self._auth}", "Accept": "application/json"},
        )

    def _fetch_all(self, path: str) -> list[dict[str, Any]]:
        page = 1
        results: list[dict[str, Any]] = []
        while True:
            code, headers, body = self._get(f"{path}?per_page=100&page={page}")
            if code != 200:
                raise WooServerError(f"expected 200, got {code}")
            results.extend(json.loads(body))
            total_pages = int(headers.get("X-WP-TotalPages") or headers.get("x-wp-totalpages") or 1)
            if page >= total_pages:
                return results
            page += 1

    def get_categories(self) -> list[dict[str, Any]]:
        return self._fetch_all("/products/categories")

    def get_tags(self) -> list[dict[str, Any]]:
        return self._fetch_all("/products/tags")

    def get_attributes(self) -> list[dict[str, Any]]:
        return self._fetch_all("/products/attributes")

    def get_attribute_terms(self, attr_id: int) -> list[dict[str, Any]]:
        return self._fetch_all(f"/products/attributes/{attr_id}/terms")

    def upload_media(self, png_bytes: bytes, filename: str) -> int:
        """POST a PNG to WordPress core media; return the attachment id."""
        boundary = "----slabuploader-media-boundary"
        body = (
            f"--{boundary}\r\n"
            f'Content-Disposition: form-data; name="file"; filename="{filename}"\r\n'
            "Content-Type: image/png\r\n\r\n"
        ).encode("utf-8") + png_bytes + f"\r\n--{boundary}--\r\n".encode("utf-8")
        url = f"{self.base_url}/wp-json/wp/v2/media"
        code, _headers, resp = self._request(
            url, "POST", body,
            {
                "Authorization": f"Basic {self._auth}",
                "Content-Type": f"multipart/form-data; boundary={boundary}",
            },
        )
        if code not in (200, 201):
            raise WooServerError(f"media upload returned {code}")
        return int(json.loads(resp)["id"])