// Example copy shows how to place text data in the CLIPBOARD selection.
package main

import "os"
import "io"
import "log"
import "bytes"
import "github.com/jezek/xgbutil"
import "github.com/jezek/xgb/xproto"
import "git.tebibyte.media/tomo/xgbsel"
import "github.com/jezek/xgbutil/xprop"
import "github.com/jezek/xgbutil/xevent"
import "github.com/jezek/xgbutil/xwindow"

// data is a very basic implementation of xgbsel.Data that only serves data of
// one type.
type data struct {
	buffer io.ReadSeekCloser
	mime   string
}

func (this *data) Convert (target xgbsel.Target) (io.ReadSeekCloser, bool) {
	if mime, _ := target.ToMime(); mime == this.mime {
		return this.buffer, true
	} else {
		return nil, false
	}
}

func (this *data) Supported () []xgbsel.Target {
	return xgbsel.MimeToTargets(this.mime)
}

// nopSeekCloser is like io.NopCloser but for an io.ReadSeeker.
type nopSeekCloser struct { io.ReadSeeker }
func (nopSeekCloser) Close () error { return nil }

func main () {
	// get data from user
	log.Println("enter data, ^D when done: ")
	buffer, _ := io.ReadAll(os.Stdin)
	data := &data {
		buffer: nopSeekCloser {
			ReadSeeker: bytes.NewReader(buffer),
		},
		mime: "text/plain",
	}

	// establish connection
	X, err := xgbutil.NewConn()
	if err != nil {
		log.Fatal(err)
	}

	// create window
	window, err := xwindow.Generate(X)
	if err != nil {
		log.Fatalln("could not generate a new window X id:", err)
	}
	window.Create(X.RootWin(), 0, 0, 500, 500, xproto.CwBackPixel, 0xffffffff)

	// obtain claim on CLIPBOARD
	log.Println("obtaining claim")
	clipboard, _ := xprop.Atm(X, "CLIPBOARD")
	claim := xgbsel.NewClaim(window, clipboard, data)

	// listen for events
	window.Listen(xproto.EventMaskPropertyChange)
	xevent.SelectionRequestFun(claim.HandleSelectionRequest).Connect(X, window.Id)
	
	log.Println("running main event loop")
	xevent.Main(X)
}