package main

import (
	"bufio"
	"fmt"
	"io"
	"log"
	"time"
	//	"math"
	"container/ring"
	"os/exec"

	"github.com/jroimartin/gocui"
	"github.com/pelletier/go-toml"
)

var settings *toml.Tree
var stdout_ring *ring.Ring
var srv_stdin io.WriteCloser

// reload settings (and maybe other things too)
func reload() {
	settings, _ = toml.LoadFile("serverwrapper.toml")
}

//builds the cmd which is called to run the server
func build_cmd() (string, []string) {
	return "ping", []string{"-t", "8.8.8.8"}
}

//run the server-thread
func server_run() {
	//create the command
	cmd_str, cmd_args := build_cmd()
	cmd := exec.Command(cmd_str, cmd_args...)

	//connect pipes
	stdout, err := cmd.StdoutPipe()
	cmd.Stderr = cmd.Stdout
	srv_stdin, err = cmd.StdinPipe() //this one is global, because we write to it elsewhere

	// run the process
	err = cmd.Start()
	if err != nil {
		log.Panicln("Failed to call server command \"" + cmd.String() + "\"")
	}

	//read pipes and write them to the ring buffer
	buf := bufio.NewScanner(stdout)
	for {
		if buf.Scan() {
			stdout_ring.Value = buf.Text()
			stdout_ring = stdout_ring.Next()
		} else {
			time.Sleep(300 * time.Millisecond)
		}
	}

}

//refresh the screen
func refresh(g *gocui.Gui) error {
	v, err := g.View("srv_log")
	if err != nil {
		log.Panicln(err)
	}
	v.Clear()

	_, vH := v.Size()

	r := stdout_ring

	v.Overwrite = true

	for i := 0; i < vH; i++ {
		v.SetCursor(4, vH - i)
		if r.Value != nil {
			fmt.Fprint(v, r.Value)
		}
		r = r.Prev()
	}

	return nil
}

func main() {
	//initialize settings by "re"loading them from disk
	reload()

	//initialize the stdout/err ringbuffer
	stdout_ring = ring.New(255)

	//init the CUI
	g, err := gocui.NewGui(gocui.OutputNormal)
	if err != nil {
		log.Panicln(err)
	}
	defer g.Close()

	g.SetManagerFunc(layout)

	if err := g.SetKeybinding("", gocui.KeyCtrlC, gocui.ModNone, quit); err != nil {
		log.Panicln(err)
	}

	go server_run()

	//run the CUI main loop
	if err := g.MainLoop(); err != nil && err != gocui.ErrQuit {
		log.Panicln(err)
	}
}

//create the CUI layout
func layout(g *gocui.Gui) error {
	maxX, maxY := g.Size()

	if _, err := g.SetView("srv_log", 0, 0, maxX-1, int(float32(maxY) * 0.8)); err != nil {
		if err != gocui.ErrUnknownView {
			return err
		}
	}

	refresh(g)

	return nil
}

func quit(g *gocui.Gui, v *gocui.View) error {
	return gocui.ErrQuit
}