package main

import (
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"os"

	"github.com/dchest/uniuri"
	"github.com/ewhal/pygments"
)

const (
	DIRECTORY = "/tmp/"
	ADDRESS   = "http://localhost:8080/"
	LENGTH    = 4
	TEXT      = "$ <command> | curl -F 'p=<-' lang='python'" + ADDRESS + "\n"
	PORT      = ":8080"
)

func check(err error) {
	if err != nil {
		fmt.Println(err)
	}
}

func exists(location string) bool {
	if _, err := os.Stat(location); err != nil {
		if os.IsNotExist(err) {
			return false
		}
	}
	return true

}

func generateName() string {
	s := uniuri.NewLen(LENGTH)
	file := exists(DIRECTORY + s)
	if file == true {
		generateName()
	}

	return s

}
func save(raw []byte) string {
	paste := raw[85 : len(raw)-46]

	s := generateName()
	location := DIRECTORY + s

	err := ioutil.WriteFile(location, paste, 0644)
	check(err)

	return s
}

func pasteHandler(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case "GET":
		param1 := r.URL.Query().Get("p")
		param2 := r.URL.Query().Get("lang")
		if param1 != "" {
			d := DIRECTORY + param1
			s, err := ioutil.ReadFile(d)
			if err != nil {
				http.Error(w, err.Error(), 500)
			}

			if param2 != "" {
				highlight := pygments.Highlight(string(s), param2, "html", "full, style=autumn,linenos=True, lineanchors=True,anchorlinenos=True,", "utf-8")
				io.WriteString(w, string(highlight))

			} else {
				io.WriteString(w, string(s))
			}
		} else {
			io.WriteString(w, TEXT)
		}
	case "POST":
		buf, err := ioutil.ReadAll(r.Body)
		if err != nil {
			http.Error(w, err.Error(), 500)
		}
		io.WriteString(w, ADDRESS+"?p="+save(buf)+"\n")
	case "DELETE":
		// Remove the record.
	}
}

func main() {
	http.HandleFunc("/", pasteHandler)
	err := http.ListenAndServe(PORT, nil)
	if err != nil {
		panic(err)
	}

}