package main

import (
	"bufio"
	"crypto/tls"
	"fmt"
	"net"
	"net/url"
	"strings"
	"time"
	"unicode/utf8"
)

var reloadTime time.Time

func startServer() {
	for {
		ln, err := listenTLSServer(config.Listen)
		if err != nil {
			fmt.Println("Error starting server", err)
			return
		}
		defer ln.Close()

		go waitForCertReload(ln)

		fmt.Println("Accepting new connections on", ln.Addr())
		for {
			conn, err := ln.Accept()
			if err != nil {
				fmt.Println("Error accepting connections", err)
				break
			}
			go handleConnection(conn)
		}
	}
}

func waitForCertReload(ln net.Listener) {
	fmt.Println("Will reload certs on", reloadTime)
	<-time.After(time.Until(reloadTime))
	fmt.Println("Certificates expired, reloading server")
	ln.Close()
}

func listenTLSServer(addr string) (net.Listener, error) {
	cfg := getTLSConfig()
	addr = parseAddr(addr)
	return tls.Listen("tcp", addr, cfg)
}

func handleConnection(c net.Conn) {
	defer c.Close()

	req, err := bufio.NewReader(c).ReadString('\r')
	if err != nil {
		return
	}

	rawURL := strings.TrimSpace(req)
	if rawURL == "" {
		sendError(c, BadRequest, "Empty URL")
		return
	} else if !utf8.ValidString(rawURL) {
		sendError(c, BadRequest, "Non UTF-8 Request")
		return
	} else if len(rawURL) > MaxURLSize {
		sendError(c, BadRequest, "URL Larger than 1024 bytes")
		return
	}

	parsedURL, err := url.Parse(rawURL)
	if err != nil {
		sendError(c, BadRequest, "Bad URL")
	}
	if parsedURL.Scheme == "" {
		parsedURL.Scheme = "gemini"
	}
	if parsedURL.Scheme != "gemini" {
		sendError(c, ProxyRequestRefused, fmt.Sprintf("Unknown scheme '%s'", parsedURL.Scheme))
		return
	} else if parsedURL.Host == "" {
		sendError(c, BadRequest, "Host not supplied")
		return
	}
	_, port, _ := net.SplitHostPort(c.LocalAddr().String())
	if parsedURL.Port() != "" && parsedURL.Port() != port {
		sendError(c, ProxyRequestRefused, "Wrong port")
		return
	}

	for i := 0; i < len(config.Domain); i++ {
		if config.Domain[i].Name == parsedURL.Hostname() {
			handleRequest(c, i, parsedURL)
			return
		}
	}
	sendError(c, ProxyRequestRefused, fmt.Sprintf("Host not found '%s'",
		parsedURL.Host))
}