finish up minimal replacement for admin console with no deps

admin.go

@@ -20,6 +20,7 @@ package main
 */
 import "C"
 import (
+	"bufio"
 	"fmt"
 	"io/ioutil"
 	"log"
@@ -28,27 +29,72 @@ import (
 
 func adminscreen() {
 	log.SetOutput(ioutil.Discard)
-	stdout := os.Stdout
+	stdout := bufio.NewWriter(os.Stdout)
 	esc := "\x1b"
 	smcup := esc + "[?1049h"
 	rmcup := esc + "[?1049l"
 
+	messages := []*struct {
+		name  string
+		label string
+		text  string
+	}{
+		{
+			name:  "servermsg",
+			label: "server",
+			text:  string(serverMsg),
+		},
+		{
+			name:  "aboutmsg",
+			label: "about",
+			text:  string(aboutMsg),
+		},
+		{
+			name:  "loginmsg",
+			label: "login",
+			text:  string(loginMsg),
+		},
+	}
+	cursel := 0
+
 	hidecursor := func() {
+		stdout.WriteString(esc + "[?25l")
 	}
 	showcursor := func() {
+		stdout.WriteString(esc + "[?12;25h")
 	}
 	movecursor := func(x, y int) {
-		stdout.WriteString(fmt.Sprintf(esc+"[%d;%dH", x, y))
+		stdout.WriteString(fmt.Sprintf(esc+"[%d;%dH", y, x))
+	}
+	moveleft := func() {
+		stdout.WriteString(esc + "[1D")
 	}
 	clearscreen := func() {
 		stdout.WriteString(esc + "[2J")
 	}
+	clearline := func() {
+		stdout.WriteString(esc + "[2K")
+	}
+	colorfn := func(code int) func(string) string {
+		return func(s string) string {
+			return fmt.Sprintf(esc+"[%dm"+"%s"+esc+"[0m", code, s)
+		}
+	}
+	reverse := colorfn(7)
+	magenta := colorfn(35)
+	readchar := func() byte {
+		var buf [1]byte
+		os.Stdin.Read(buf[:])
+		c := buf[0]
+		return c
+	}
 
 	savedtio := new(C.struct_termios)
 	C.tcgetattr(1, savedtio)
 	restore := func() {
 		stdout.WriteString(rmcup)
 		showcursor()
+		stdout.Flush()
 		C.tcsetattr(1, C.TCSAFLUSH, savedtio)
 	}
 	defer restore()
@@ -63,19 +109,98 @@ func adminscreen() {
 		stdout.WriteString(smcup)
 		clearscreen()
 		movecursor(1, 1)
+		stdout.Flush()
+	}
+
+	msglineno := func(idx int) int {
+		return 4 + idx*2
+	}
+
+	drawmessage := func(idx int) {
+		line := msglineno(idx)
+		movecursor(4, line)
+		label := messages[idx].label
+		if idx == cursel {
+			label = reverse(label)
+		}
+		stdout.WriteString(fmt.Sprintf("%s %s", label, messages[idx].text))
+	}
+
+	drawscreen := func() {
+		clearscreen()
+		movecursor(4, msglineno(-1))
+		stdout.WriteString(magenta(serverName + " admin panel"))
+		for i := range messages {
+			drawmessage(i)
+		}
+		movecursor(4, msglineno(len(messages)))
+		stdout.WriteString(magenta("j/k to move - q to quit - enter to edit"))
+		stdout.Flush()
+	}
+
+	selectnext := func() {
+		if cursel < len(messages)-1 {
+			cursel++
+		}
+		drawscreen()
+	}
+	selectprev := func() {
+		if cursel > 0 {
+			cursel--
+		}
+		drawscreen()
+	}
+	editsel := func() {
+		movecursor(4, msglineno(cursel))
+		clearline()
+		m := messages[cursel]
+		stdout.WriteString(reverse(magenta(m.label)))
+		text := m.text
+		stdout.WriteString(" ")
+		stdout.WriteString(text)
+		showcursor()
+		stdout.Flush()
+	loop:
+		for {
+			c := readchar()
+			switch c {
+			case '\n':
+				break loop
+			case 127:
+				if len(text) > 0 {
+					moveleft()
+					stdout.WriteString(" ")
+					moveleft()
+					text = text[:len(text)-1]
+				}
+			default:
+				text = text + string(c)
+				stdout.WriteString(string(c))
+			}
+			stdout.Flush()
+		}
+		m.text = text
+		updateconfig(m.name, m.text)
+		hidecursor()
+		drawscreen()
 	}
 
 	init()
+	drawscreen()
 
 	for {
-		var buf [1]byte
-		os.Stdin.Read(buf[:])
-		c := buf[0]
+		c := readchar()
 		switch c {
 		case 'q':
 			return
+		case 'j':
+			selectnext()
+		case 'k':
+			selectprev()
+		case '\n':
+			editsel()
 		default:
-			os.Stdout.Write(buf[:])
+
 		}
 	}
 }