slope/gui.go

// +build !nogui

package main

import (
	"fmt"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

type GUI struct {
	gui     fyne.App
	windows map[string]fyne.Window
}

func (g GUI) String() string {
	return "GUI"
}

type guiWidget fyne.Widget
type guiContainer fyne.Container

var guiLib = vars{
	"gui-create": func(a ...expression) expression {
		return &GUI{app.New(), make(map[string]fyne.Window)}
	},
	"gui-add-window": func(a ...expression) expression {
		if len(a) < 2 {
			return exception("'gui-add-window' expects a GUI and a string as arguments, too few arguments were given")
		}
		g, ok := a[0].(*GUI)
		if !ok {
			return exception("'gui-add-window' was given a non-GUI value as its first argument")
		}
		s := String(a[1], false)
		g.windows[s] = g.gui.NewWindow(s)
		return true
	},
	"gui-list-windows": func(a ...expression) expression {
		if len(a) == 0 {
			return exception("'gui-list-windows' expects a GUI as an argument, no arguments were given")
		}
		g, ok := a[0].(*GUI)
		if !ok {
			return exception("'gui-list-windows' was given a non-GUI argument")
		}
		out := make([]expression, 0, len(g.windows))
		for k := range g.windows {
			out = append(out, k)
		}
		return out
	},
	"window-set-content": func(a ...expression) expression {
		// (window-set-content window-id content...)
		if len(a) < 3 {
			return exception("'window-set-content' expects a GUI and a string as arguments, too few arguments were given")
		}
		g, ok := a[0].(*GUI)
		if !ok {
			return exception("'window-set-content' was given a non-GUI value as its first argument")
		}
		s := String(a[1], false)
		w, ok := g.windows[s]
		if !ok {
			return exception("'window-show-and-run' was given a window ID that does not exist: " + s)
		}
		w.SetContent(a[2].(fyne.CanvasObject))

		return true
	},
	"window-show-and-run": func(a ...expression) expression {
		// (window-show-and-run window-id)
		if len(a) < 2 {
			return exception("'window-show-and-run' expects a GUI and a string as arguments, too few arguments were given")
		}
		g, ok := a[0].(*GUI)
		if !ok {
			return exception("'window-show-and-run' was given a non-GUI value as its first argument")
		}
		s := String(a[1], false)
		w, ok := g.windows[s]
		if !ok {
			return exception("'window-show-and-run' was given a window ID that does not exist: " + s)
		}
		w.ShowAndRun()
		return true
	},
	"widget-label": func(a ...expression) expression {
		// (widget-label text:string alignment:number wrap:bool)
		if len(a) == 0 {
			return exception("'widget-label' expects at least one argument, a string representing the text of the label, no arguments were given")
		}
		var l guiWidget = widget.NewLabel(String(a[0], false))
		if len(a) >= 2 {
			align, ok := a[1].(number)
			if !ok {
				return exception("'widget-label' expects a number (-1, 0, or 1) as its optional second argument (alignment), a non-number value was given")
			}
			switch int(align) {
			case -1:
				l.(*widget.Label).Alignment = fyne.TextAlignLeading
			case 0:
				l.(*widget.Label).Alignment = fyne.TextAlignCenter
			case 1:
				l.(*widget.Label).Alignment = fyne.TextAlignTrailing
			default:
				return exception("'widget-label' expects a number (-1, 0, or 1) as its optional second argument (alignment), a number outside of the range was given")
			}
		}
		if len(a) >= 3 {
			wrap, ok := a[2].(bool)
			if !ok {
				return exception("'widget-label' expects a bool as its optional third argument (wrap), a non-bool value was given")
			}
			if wrap {
				l.(*widget.Label).Wrapping = fyne.TextWrapWord
			}
		}
		return l
	},
	"widget-button": func(a ...expression) expression {
		// (widget-label text:string alignment:number wrap:bool)
		if len(a) < 2 {
			return exception("'widget-button' expects at least one argument, a string representing the text of the label, no arguments were given")
		}
		var b guiWidget
		switch f := a[1].(type) {
		case func(...expression) expression:
			b = widget.NewButton(String(a[0], false), func() { f() })
		case Callback:
			b = widget.NewButton(String(a[0], false), func() { apply(f.p, []expression{}) })
		default:
			return exception("'widget-button' was given a non-procedure value as its second argument")
		}
		if len(a) >= 3 {
			align, ok := a[2].(number)
			if !ok {
				return exception("'widget-label' expects a number (-1, 0, or 1) as its optional third argument (alignment), a non-number value was given")
			}
			switch int(align) {
			case -1:
				b.(*widget.Button).Alignment = widget.ButtonAlignLeading
			case 0:
				b.(*widget.Button).Alignment = widget.ButtonAlignCenter
			case 1:
				b.(*widget.Button).Alignment = widget.ButtonAlignTrailing
			default:
				return exception("'widget-button' expects a number (-1, 0, or 1) as its optional third argument (alignment), a number outside of the range was given")
			}
		}
		return b
	},
	"container-vertical-box": func(a ...expression) expression {
		list, err := ExpToCanvasObjectList(a)
		if err != nil {
			return exception("'container-vertical-box' was given a list that contained a non widget value")
		}
		return container.NewVBox(list...)
	},
}

func ExpToCanvasObjectList(e []expression) ([]fyne.CanvasObject, error) {
	out := make([]fyne.CanvasObject, len(e))
	for i, v := range e {
		wid, ok := v.(guiWidget)
		if !ok {
			return out, fmt.Errorf("Invalid list")
		}
		out[i] = wid.(fyne.Widget).(fyne.CanvasObject)
	}
	return out, nil
}