const Service = "DNS";
const Version = "2018-08-01";
const Region = "cn-north-1";
const Host = "dns.volcengineapi.com";

interface Credential {
  access_key_id: string;
  secret_access_key: string;
  service: string;
  region: string;
}

interface RequestParam {
  body: string;
  host: string;
  path: string;
  method: string;
  content_type: string;
  date: Date;
  query: Record<string, any>;
}

interface SignResult {
  Host: string;
  'X-Content-Sha256': string;
  'X-Date': string;
  'Content-Type': string;
  Authorization?: string;
}

/**
 * 字符串转ArrayBuffer
 */
function stringToArrayBuffer(str: string): ArrayBuffer {
  const encoder = new TextEncoder();
  return encoder.encode(str).buffer;
}

/**
 * ArrayBuffer转十六进制字符串
 */
function arrayBufferToHex(buffer: ArrayBuffer): string {
  const hashArray = Array.from(new Uint8Array(buffer));
  return hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
}

/**
 * URL编码函数，类似Python的quote函数
 */
function encodeURIComponentSafe(str: string): string {
  return encodeURIComponent(str)
    .replace(/[!'()*]/g, (c) => '%' + c.charCodeAt(0).toString(16).toUpperCase())
    .replace(/%20/g, '%20');
}

/**
 * 规范化查询参数
 */
function normQuery(params: Record<string, any>): string {
  let query = "";
  const sortedKeys = Object.keys(params).sort();
  
  for (const key of sortedKeys) {
    if (Array.isArray(params[key])) {
      for (const k of params[key]) {
        query += encodeURIComponentSafe(key) + "=" + encodeURIComponentSafe(k) + "&";
      }
    } else {
      query += encodeURIComponentSafe(key) + "=" + encodeURIComponentSafe(params[key]) + "&";
    }
  }
  
  query = query.slice(0, -1);
  return query.replace(/\+/g, "%20");
}

/**
 * HMAC-SHA256 加密 (使用Web Crypto API)
 */
async function hmacSha256(key: ArrayBuffer, content: string): Promise<ArrayBuffer> {
  const cryptoKey = await crypto.subtle.importKey(
    'raw',
    key,
    { name: 'HMAC', hash: 'SHA-256' },
    false,
    ['sign']
  );
  return crypto.subtle.sign('HMAC', cryptoKey, stringToArrayBuffer(content));
}

/**
 * SHA256 哈希算法 (使用Web Crypto API)
 */
async function hashSha256(content: string): Promise<string> {
  const hashBuffer = await crypto.subtle.digest('SHA-256', stringToArrayBuffer(content));
  return arrayBufferToHex(hashBuffer);
}

/**
 * 获取签名
 */
export async function getSignature(
  method: string,
  query: Record<string, any>,
  header: Record<string, string>,
  ak: string,
  sk: string,
  action: string,
  body: any
): Promise<SignResult> {
  const credential: Credential = {
    access_key_id: ak,
    secret_access_key: sk,
    service: Service,
    region: Region,
  };

  const fullQuery = { Action: action, Version: Version, ...query };
  const sortedQuery: Record<string, any> = {};
  Object.keys(fullQuery).sort().forEach(key => {
    sortedQuery[key] = (fullQuery as any)[key];
  });

  const requestParam: RequestParam = {
    body: "",
    host: Host,
    path: "/",
    method: method,
    content_type: "application/json",
    date: new Date(),
    query: sortedQuery,
  };

  if (method === "POST") {
    requestParam.body = JSON.stringify(body);
  }

  const xDate = requestParam.date.toISOString().replace(/[:\-]|\.\d{3}/g, '').slice(0, -1) + 'Z';
  const shortXDate = xDate.slice(0, 8);
  const xContentSha256 = await hashSha256(requestParam.body);
  
  const signResult: SignResult = {
    Host: requestParam.host,
    'X-Content-Sha256': xContentSha256,
    'X-Date': xDate,
    'Content-Type': requestParam.content_type,
  };

  const signedHeadersStr = ["content-type", "host", "x-content-sha256", "x-date"].join(";");
  
  const canonicalRequestStr = [
    requestParam.method,
    requestParam.path,
    normQuery(requestParam.query),
    [
      "content-type:" + requestParam.content_type,
      "host:" + requestParam.host,
      "x-content-sha256:" + xContentSha256,
      "x-date:" + xDate,
    ].join("\n"),
    "",
    signedHeadersStr,
    xContentSha256,
  ].join("\n");

  const hashedCanonicalRequest = await hashSha256(canonicalRequestStr);
  const credentialScope = [shortXDate, credential.region, credential.service, "request"].join("/");
  const stringToSign = ["HMAC-SHA256", xDate, credentialScope, hashedCanonicalRequest].join("\n");
  
  const secretKeyBuffer = stringToArrayBuffer(credential.secret_access_key);
  const kDate = await hmacSha256(secretKeyBuffer, shortXDate);
  const kRegion = await hmacSha256(kDate, credential.region);
  const kService = await hmacSha256(kRegion, credential.service);
  const kSigning = await hmacSha256(kService, "request");
  const signatureBuffer = await hmacSha256(kSigning, stringToSign);
  const signature = arrayBufferToHex(signatureBuffer);
  
  signResult.Authorization = `HMAC-SHA256 Credential=${credential.access_key_id}/${credentialScope}, SignedHeaders=${signedHeadersStr}, Signature=${signature}`;
  
  return signResult;
}

/**
 * 发送API请求
 */
export async function request(
  method: string,
  query: Record<string, any>,
  header: Record<string, string>,
  ak: string,
  sk: string,
  action: string,
  body: any
): Promise<any> {
  const signResult = await getSignature(method, query, header, ak, sk, action, body);
  const finalHeader = { ...header, ...signResult };

  const requestParam: RequestParam = {
    body: method === "POST" ? JSON.stringify(body) : "",
    host: Host,
    path: "/",
    method: method,
    content_type: "application/json",
    date: new Date(),
    query: { Action: action, Version: Version, ...query },
  };

  const url = new URL(`https://${requestParam.host}${requestParam.path}`);
  Object.keys(requestParam.query).forEach(key => {
    url.searchParams.append(key, requestParam.query[key]);
  });

  const fetchOptions: RequestInit = {
    method: method,
    headers: finalHeader,
  };

  if (method === "POST") {
    fetchOptions.body = requestParam.body;
  }

  try {
    const response = await fetch(url.toString(), fetchOptions);
    return await response.json();
  } catch (error) {
    throw new Error(`Request failed: ${error}`);
  }
}

/**
 * 使用示例
 */
export async function example(ak: string, sk: string) {
  try {
    // POST 请求示例 - 调用 UpdateZone API
    const requestBody = {
      ZID: 100,
      Remark: "example",
    };
    const updateZoneResult = await request("POST", {}, {}, ak, sk, "UpdateZone", requestBody);
    console.log(updateZoneResult);

    // GET 请求示例 - 调用 CheckZone API
    const requestQuery = { ZoneName: "example.com" };
    const checkZoneResult = await request("GET", requestQuery, {}, ak, sk, "CheckZone", {});
    console.log(checkZoneResult);
  } catch (error) {
    console.error('API request failed:', error);
  }
}