// xh.go JGL (yiyus). 2010
// xgb Hello World
// 8g xh.go && 8l -o xh xh.8 && ./xh

package main

import (
	"fmt"
	"os"
	"xgb"
)

func hello(c *xgb.Conn, win, gc xgb.Id) {
	c.ImageText8(win, gc, 50, 50, []byte("Hello World!"))
}

func main() {
	c, err := xgb.Dial("")
	if err != nil {
		fmt.Fprintf(os.Stderr, "cannot connect: %v\n", err)
		os.Exit(1)
	}

	screen := c.DefaultScreen()
	win := c.NewId()

	c.CreateWindow(
		screen.RootDepth, win, screen.Root,
		0, 0, 300, 200, 2,
		xgb.WindowClassCopyFromParent,
		xgb.WindowClassCopyFromParent,
		xgb.CWBackPixel|xgb.CWEventMask,
		[]uint32{screen.BlackPixel, xgb.EventMaskExposure | xgb.EventMaskButtonPress},
	)

	gc := c.NewId()
	font := c.NewId()

	c.OpenFont(font, "7x13")
	c.CreateGC(gc, win,
		xgb.GCBackground|xgb.GCForeground|xgb.GCFont,
		[]uint32{screen.WhitePixel, screen.BlackPixel, uint32(font)},
	)
	c.CloseFont(font)
	r := xgb.Rectangle{0, 0, 300, 200}
	c.PolyFillRectangle(win, gc, []xgb.Rectangle{r})
	hello(c, win, gc)

	c.MapWindow(win)

Loop: for {
		reply, err := c.WaitForEvent()
		switch {
		case err != nil:
			fmt.Printf("error: %v\n", err)
			os.Exit(1)
		}
		switch event := reply.(type) {
		case xgb.ExposeEvent:
			hello(c, win, gc)
		case xgb.ButtonPressEvent:
			fmt.Println("Button", event.Detail, "pressed. Bye!")
			break Loop
		}
	}

	c.Close()
}