"""火山引擎 Open API 客户端（HMAC-SHA256 签名）"""

import datetime
import hashlib
import hmac
import logging
from urllib.parse import quote

import requests

logger = logging.getLogger(__name__)


class VolcengineAPIError(Exception):
    def __init__(self, action: str, code: str, message: str):
        self.action = action
        self.code = code
        super().__init__(f"[{action}] {code}: {message}")


class VolcengineClient:
    """火山引擎 API 客户端"""

    def __init__(self, ak: str, sk: str, service: str, host: str,
                 region: str = "cn-north-1", version: str = "2018-01-01"):
        self.ak = ak
        self.sk = sk
        self.service = service
        self.host = host
        self.region = region
        self.version = version

    def _norm_query(self, params: dict) -> str:
        query = ""
        for key in sorted(params.keys()):
            if isinstance(params[key], list):
                for v in params[key]:
                    query += quote(key, safe="-_.~") + "=" + quote(str(v), safe="-_.~") + "&"
            else:
                query += quote(key, safe="-_.~") + "=" + quote(str(params[key]), safe="-_.~") + "&"
        return query[:-1].replace("+", "%20") if query else ""

    def _hmac_sha256(self, key: bytes, content: str) -> bytes:
        return hmac.new(key, content.encode("utf-8"), hashlib.sha256).digest()

    def _hash_sha256(self, content: str) -> str:
        return hashlib.sha256(content.encode("utf-8")).hexdigest()

    def call(self, action: str, params: dict = None, body: str = "") -> dict:
        params = params or {}
        now = datetime.datetime.now(datetime.timezone.utc)
        x_date = now.strftime("%Y%m%dT%H%M%SZ")
        short_date = x_date[:8]

        x_content_sha256 = self._hash_sha256(body)
        all_params = {"Action": action, "Version": self.version, **params}

        signed_headers_str = "content-type;host;x-content-sha256;x-date"
        canonical_headers = (
            f"content-type:application/x-www-form-urlencoded\n"
            f"host:{self.host}\n"
            f"x-content-sha256:{x_content_sha256}\n"
            f"x-date:{x_date}"
        )
        query_string = self._norm_query(all_params)
        canonical_request = "\n".join([
            "GET", "/", query_string,
            canonical_headers, "", signed_headers_str, x_content_sha256
        ])

        credential_scope = f"{short_date}/{self.region}/{self.service}/request"
        string_to_sign = "\n".join([
            "HMAC-SHA256", x_date, credential_scope,
            self._hash_sha256(canonical_request)
        ])

        k_date = self._hmac_sha256(self.sk.encode("utf-8"), short_date)
        k_region = self._hmac_sha256(k_date, self.region)
        k_service = self._hmac_sha256(k_region, self.service)
        k_signing = self._hmac_sha256(k_service, "request")
        signature = self._hmac_sha256(k_signing, string_to_sign).hex()

        headers = {
            "Host": self.host,
            "X-Date": x_date,
            "X-Content-Sha256": x_content_sha256,
            "Content-Type": "application/x-www-form-urlencoded",
            "Authorization": (
                f"HMAC-SHA256 Credential={self.ak}/{credential_scope}, "
                f"SignedHeaders={signed_headers_str}, Signature={signature}"
            ),
        }

        url = f"https://{self.host}/?{query_string}"
        try:
            r = requests.get(url, headers=headers, timeout=30)
            resp = r.json()
        except Exception as e:
            raise VolcengineAPIError(action, "NetworkError", str(e))

        error = resp.get("ResponseMetadata", {}).get("Error")
        if error:
            raise VolcengineAPIError(
                action, error.get("Code", "Unknown"), error.get("Message", "")
            )
        return resp


def get_iam_client(ak: str, sk: str) -> VolcengineClient:
    return VolcengineClient(ak, sk, "iam", "iam.volcengineapi.com")


def get_billing_client(ak: str, sk: str) -> VolcengineClient:
    return VolcengineClient(ak, sk, "billing", "billing.volcengineapi.com",
                            version="2022-01-01")


def get_resource_client(ak: str, sk: str) -> VolcengineClient:
    return VolcengineClient(ak, sk, "iam", "iam.volcengineapi.com",
                            version="2021-08-01")