import * as path from "@std/path";

import fastify from "fastify";
import fastifyView from "@fastify/view";
import fastifyStatic from "@fastify/static";
import handlebars from "handlebars";
import mime from "mime/lite";

const server = fastify();

const __dirname = new URL(".", import.meta.url).pathname;

// 处理视图资源
server.register(fastifyView, {
  engine: { handlebars },
  root: path.resolve(__dirname, "views"),
});

// 处理静态资源 maxAge 30天
server.register(fastifyStatic, {
  prefix: "/static/",
  root: path.resolve(__dirname, "static"),
  cacheControl: true,
  maxAge: 2592000,
});

enum Headers {
  FormatHeader = "x-format",
  CodeHeader = "x-code",
  OriginalURI = "x-original-uri",
  ContentType = "content-type",
  Namespace = "x-namespace",
  IngressName = "x-ingress-name",
  ServiceName = "x-service-name",
  ServicePort = "x-service-port",
  RequestId = "x-request-id",
}

const CodeMessageMap: Record<number, string> = {
  403: "禁止访问此内容: 抱歉，由于安全问题您被禁止访问此内容。如果您认为这是个错误，请联系我们获取帮助。",
  404: "内容未找到: 您正在寻找的内容可能已被删除、名称已更改或暂时不可用。",
  500: "服务器错误: 请稍后再试，或者返回主页。如果问题持续存在，请联系我们，我们会尽快修复。",
};

// 默认处理函数
server.all("/", (request, reply) => {
  const headers = request.headers;

  // 获取OriginalURI的文件后缀
  const originalURI: string = headers[Headers.OriginalURI] || "";
  const urlExtWithDot = path.extname(originalURI);

  // 获取FormatHeader对应的文件后缀
  const format: string = headers[Headers.FormatHeader] || "";
  // 排除format存在多个的情况 目前只支持一个
  const firstFormat = format.split(",")[0];
  const formatExt = mime.getExtension(firstFormat);
  const formatExtWithDot = formatExt ? `.${formatExt}` : "";

  const ext = formatExtWithDot || urlExtWithDot || ".html";

  // 获取header中的其他内容
  const requestId: string = headers[Headers.RequestId] || "";

  // 获取CodeHeader对应的状态码
  const code: number = Number(headers[Headers.CodeHeader] || 404);

  // 获取兼容code 比如没有403的code，就使用404 没有502的code，就使用500 取第一位相同的但是最小的code
  let compatibleCode = code;

  const isCodeExist = Reflect.has(CodeMessageMap, code);

  if (!isCodeExist) {
    const codeList = Object.keys(CodeMessageMap).map(Number).sort((a, b) =>
      a - b
    );
    compatibleCode = Number(
      codeList.find((c) => String(c).startsWith(String(code).charAt(0))) || 404,
    );
  }

  const message = CodeMessageMap[compatibleCode];

  const data = { code, requestId, message };

  console.log(
    `[${
      new Date().toISOString()
    }] code:${code} url:'${originalURI}' ext:'${ext}' requestId:'${requestId}'`,
  );

  // 根据后缀渲染不同的内容
  if (ext === ".html" || ext === ".htm") {
    const [title, content] = message.split(":");

    const htmlContent = content.trim().replace(/。(?=.+)/, "。<br>");

    reply.code(code).view("error.hbs", {
      ...data,
      title,
      content: htmlContent,
    });
  } else if (ext === ".json") {
    reply.code(code).send(data);
  } else {
    reply.code(code).send(message);
  }
});

// 提供健康检查接口
server.get("/healthz", (_request, reply) => reply.send("OK"));

server.listen({ port: 8080, host: "0.0.0.0" }, (_err, address) => {
  if (_err) throw _err;

  console.log(`Server listening at ${address}`);
});