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

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

const server = fastify();

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

server.register(fastifyView, { engine: { handlebars }, root: path.resolve(__dirname, 'views') });

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}`);
});