// SPDX-License-Identifier: Unlicense OR MIT

package main

// A simple Gio program. See https://gioui.org for more information.

import (
	"fmt"
	"log"
	"time"

	"gioui.org/app"
	"gioui.org/layout"
	"gioui.org/text"
	"gioui.org/text/shape"
	"gioui.org/unit"

	"golang.org/x/image/font/gofont/goregular"
	"golang.org/x/image/font/sfnt"
)

func main() {
	go func() {
		w := app.NewWindow()
		if err := loop(w); err != nil {
			log.Fatal(err)
		}
	}()
	app.Main()
}

func loop(w *app.Window) error {
	regular, err := sfnt.Parse(goregular.TTF)
	if err != nil {
		panic("failed to load font")
	}
	family := &shape.Family{Regular: regular}
	gtx := &layout.Context{Queue: w.Queue()}
	lst := &layout.List{Axis: layout.Vertical}
	for {
		e := <-w.Events()
		switch e := e.(type) {
		case app.DestroyEvent:
			return e.Err
		case app.UpdateEvent:
			stime := time.Now()
			gtx.Reset(&e.Config, e.Size)
			for i := 0; i < 200; i++ {
				lst.Layout(gtx, 200, func(i int) {
					text.Label{Size: unit.Dp(16), Text: fmt.Sprintf("label %d", i)}.Layout(gtx, family)
				})
			}
			w.Update(gtx.Ops)
			log.Printf("Frame time: %s\n", time.Since(stime))
		}
	}
}