import http, { IncomingMessage, ServerResponse } from "node:http";
import { URL } from "node:url";
import querystring from "node:querystring";

import Router, { Request, Response, Handler } from "./router.js";
import Container from "./container.js";
import Tpl from "./template.js";

export { Router, Tpl, Request, Response, Handler };

export default class Flummpress {
  private server?: http.Server;
  private container: Container;
  private middleware: Handler[];
  public router: Router;

  constructor() {
    this.container = new Container();
    this.router = new Router();
    this.middleware = [];
  }

  public use<T>(plugin: string | Router | Handler, factory?: () => T): this {
    if(typeof plugin === "string" && factory)
      this.container.register(plugin, factory);
    else if(plugin instanceof Router)
      this.router.use(plugin);
    else if(typeof plugin === "function")
      this.middleware.push(plugin);
    else
      throw new TypeError("Invalid arguments provided to use()");
    return this;
  }
  public resolve<T>(name: string): T {
    return this.container.resolve(name);
  }

  private async processPipeline(handlers: Handler[], req: Request, res: Response) {
    for(const handler of handlers) {
      if(typeof handler !== "function")
        throw new TypeError(`Handler is not a function: ${handler}`);

      let nextCalled = false;
      await handler(req, res, () => nextCalled = true);
      if(!nextCalled || res.writableEnded)
        return;
    }
  }

  public listen(...args: any[]): this {
    this.server = http.createServer(async (request: IncomingMessage, response: ServerResponse) => {
      const req: Request = this.parseRequest(request);
      const res: Response = this.createResponse(response);
      const start = process.hrtime();
  
      try {
        await this.processPipeline(this.middleware, req, res);
  
        const route = this.router.getRoute(req.url.pathname, req.method!);
  
        if(route) {
          const handler = route.methods[req.method?.toLowerCase()!];
  
          req.params = req.url.pathname.match(new RegExp(route.path))?.groups || {};
          req.post = await this.readBody(req);
          await this.processPipeline(handler, req, res);
        }
        else {
          res.writeHead(404).end("404 - Not Found");
        }
      }
      catch(err: any) {
        console.error(err);
        res.writeHead(500).end("500 - Internal Server Error");
      }
  
      console.log([
        `[${new Date().toISOString()}]`,
        `${(process.hrtime(start)[1] / 1e6).toFixed(2)}ms`,
        `${req.method} ${res.statusCode}`,
        req.url.pathname,
      ].join(" | "));
    })
    this.server.listen(...args);
  
    return this;
  }

  private parseRequest(request: IncomingMessage): Request {
    const url = new URL(request.url!.replace(/(?!^.)(\/+)?$/, ""), "http://localhost");
    const req = request as unknown as Request;
    req.url = {
      pathname: url.pathname,
      split: url.pathname.split("/").slice(1),
      searchParams: url.searchParams,
      qs: Object.fromEntries(url.searchParams.entries()),
    };

    req.cookies = {};
    if(req.headers.cookie) {
      req.headers.cookie.split("; ").forEach(cookie => {
        const [key, value] = cookie.split("=");
        req.cookies![key] = decodeURIComponent(value);
      });
    }
    return req;
  }

  private async readBody(req: Request): Promise<Record<string, string>> {
    return new Promise((resolve, reject) => {
      let body: string = "";

      req.on("data", (chunk: string) => {
        body += chunk;
      });

      req.on("end", () => {
        try {
          resolve(
            req.headers["content-type"] === "application/json"
              ? JSON.parse(body)
              : querystring.parse(body)
          );
        }
        catch(err: any) {
          reject(err);
        }
      });

      req.on("error", reject);
    });
  }

  private createResponse(response: ServerResponse): Response {
    const res: Response = response as Response;

    res.reply = ({ code = 200, type = "text/html", body }) => {
      res.writeHead(code, { "Content-Type": `${type}; charset=utf-8` });
      res.end(body);
    };

    res.status = (code = 200) => {
      return res.writeHead(code);
    };

    res.json = (body: any, code = 200) => {
      res.reply({ code, type: "application/json", body: JSON.stringify(body) });
    };

    res.html = (body, code = 200) => {
      res.reply({ code, type: "text/html", body });
    };

    res.redirect = (target, code = 302) => {
      res.writeHead(code, { Location: encodeURI(target) });
      res.end();
    };

    return res;
  }
}