package main

import (
	"bufio"
	"fmt"
	"io/ioutil"
	"net"
	"net/url"
	"os"
	"strconv"
	"strings"
)

// SpartanURL parses u and calls SpartanParsedURL with the parsed url
func SpartanURL(u string) bool {
	// Parse URL
	parsed, err := url.Parse(u)
	if err != nil {
		fmt.Println("invalid url")
		return false
	}
	if parsed.Scheme == "" {
		// have to parse again
		// ignoring err since it shouldn't fail here if it succeeded above
		parsed, _ = url.Parse("spartan://" + u)
	}
	if parsed.Scheme != "spartan" {
		fmt.Printf("Unsupported scheme %s", parsed.Scheme)
		return false
	}
	return SpartanParsedURL(*parsed)
}

// SpartanParsedURL fetches u and displays the page
func SpartanParsedURL(u url.URL) bool {
	host := u.Host
	// Connect to server
	if u.Port() == "" {
		host += ":300"
	}
	conn, err := net.Dial("tcp", host)
	if err != nil {
		fmt.Println("unable to connect to " + u.Host)
		fmt.Println(err.Error())
		return false
	}
	defer conn.Close()
	// Send request
	path := u.Path
	if u.Path == "" {
		path = "/"
	}
	conn.Write([]byte(fmt.Sprintf("%s %s 0\r\n", u.Hostname(), path)))
	// Receive and parse response header
	reader := bufio.NewReader(conn)
	header, err := reader.ReadString(byte('\n'))
	if err != nil {
		fmt.Println("Error reading response header")
		return false
	}
	// Parse header
	statusParts := strings.SplitN(header, " ", 2)
	status, err := strconv.Atoi(statusParts[0])
	if err != nil {
		fmt.Println("invalid status code:" + statusParts[0])
		return false
	}
	meta := statusParts[1]

	// Handle status
	switch status {
	case 1:
		fmt.Println("[INPUT]")
		fmt.Println(meta)
	case 2:
		// TODO: handle mime type
		bodyBytes, err := ioutil.ReadAll(reader)
		if err != nil {
			fmt.Println("Error reading body")
			return false
		}
		body := string(bodyBytes)
		fmt.Print(body)
	case 3:
		SpartanURL("spartan://" + u.Host + meta)
	case 4:
		fmt.Println("Error: " + meta)
	case 5:
		fmt.Println("Server error: " + meta)
	}

	return true
}

func main() {
	args := os.Args
	if len(args) == 0 || args[1] == "--help" {
		fmt.Println("Usage: <program> [--help] [URL]")
		return
	}
	// TODO: support multiple args
	SpartanURL(args[1])
}