termbox-util/termbox_menu.go

package termboxUtil

import "github.com/nsf/termbox-go"

// Menu is a menu with a list of options
type Menu struct {
	title   string
	options []MenuOption
	// If height is -1, then it is adaptive to the menu
	x, y, width, height    int
	showHelp               bool
	cursor                 int
	bg, fg                 termbox.Attribute
	selectedBg, selectedFg termbox.Attribute
	disabledBg, disabledFg termbox.Attribute
	isDone                 bool
	bordered               bool
}

// CreateMenu Creates a menu with the specified attributes
func CreateMenu(title string, options []string, x, y, width, height int, fg, bg termbox.Attribute) *Menu {
	i := Menu{
		title: title,
		x:     x, y: y, width: width, height: height,
		fg: fg, bg: bg, selectedFg: bg, selectedBg: fg,
		disabledFg: bg, disabledBg: bg,
	}
	for _, line := range options {
		i.options = append(i.options, MenuOption{text: line})
	}
	if len(i.options) > 0 {
		i.SetSelectedOption(&i.options[0])
	}
	return &i
}

// GetTitle returns the current title of the menu
func (i *Menu) GetTitle() string { return i.title }

// SetTitle sets the current title of the menu to s
func (i *Menu) SetTitle(s string) *Menu {
	i.title = s
	return i
}

// GetOptions returns the current options of the menu
func (i *Menu) GetOptions() []MenuOption {
	return i.options
}

// SetOptions set the menu's options to opts
func (i *Menu) SetOptions(opts []MenuOption) *Menu {
	i.options = opts
	return i
}

// SetOptionsFromStrings sets the options of this menu from a slice of strings
func (i *Menu) SetOptionsFromStrings(opts []string) *Menu {
	var newOpts []MenuOption
	for _, v := range opts {
		newOpts = append(newOpts, *CreateOptionFromText(v))
	}
	return i.SetOptions(newOpts)
}

// GetX returns the current x coordinate of the menu
func (i *Menu) GetX() int { return i.x }

// SetX sets the current x coordinate of the menu to x
func (i *Menu) SetX(x int) *Menu {
	i.x = x
	return i
}

// GetY returns the current y coordinate of the menu
func (i *Menu) GetY() int { return i.y }

// SetY sets the current y coordinate of the menu to y
func (i *Menu) SetY(y int) *Menu {
	i.y = y
	return i
}

// GetWidth returns the current width of the menu
func (i *Menu) GetWidth() int { return i.width }

// SetWidth sets the current menu width to width
func (i *Menu) SetWidth(width int) *Menu {
	i.width = width
	return i
}

// GetHeight returns the current height of the menu
func (i *Menu) GetHeight() int { return i.height }

// SetHeight set the height of the menu to height
func (i *Menu) SetHeight(height int) *Menu {
	i.height = height
	return i
}

// GetSelectedOption returns the current selected option
func (i *Menu) GetSelectedOption() *MenuOption {
	idx := i.GetSelectedIndex()
	if idx != -1 {
		return &i.options[idx]
	}
	return nil
}

// GetOptionFromIndex Returns the
func (i *Menu) GetOptionFromIndex(idx int) *MenuOption {
	if idx >= 0 && idx < len(i.options) {
		return &i.options[idx]
	}
	return nil
}

// GetOptionFromText Returns the first option with the text v
func (i *Menu) GetOptionFromText(v string) *MenuOption {
	for idx := range i.options {
		testOption := &i.options[idx]
		if testOption.GetText() == v {
			return testOption
		}
	}
	return nil
}

// GetSelectedIndex returns the index of the selected option
// Returns -1 if nothing is selected
func (i *Menu) GetSelectedIndex() int {
	for idx := range i.options {
		if i.options[idx].IsSelected() {
			return idx
		}
	}
	return -1
}

// SetSelectedOption sets the current selected option to v (if it's valid)
func (i *Menu) SetSelectedOption(v *MenuOption) *Menu {
	for idx := range i.options {
		if &i.options[idx] == v {
			i.options[idx].Select()
		} else {
			i.options[idx].Unselect()
		}
	}
	return i
}

// SelectPrevOption Decrements the selected option (if it can)
func (i *Menu) SelectPrevOption() *Menu {
	idx := i.GetSelectedIndex()
	for idx >= 0 {
		idx--
		testOption := i.GetOptionFromIndex(idx)
		if testOption != nil && !testOption.IsDisabled() {
			i.SetSelectedOption(testOption)
			return i
		}
	}
	return i
}

// SelectNextOption Increments the selected option (if it can)
func (i *Menu) SelectNextOption() *Menu {
	idx := i.GetSelectedIndex()
	for idx < len(i.options) {
		idx++
		testOption := i.GetOptionFromIndex(idx)
		if testOption != nil && !testOption.IsDisabled() {
			i.SetSelectedOption(testOption)
			return i
		}
	}
	return i
}

// HelpIsShown returns true or false if the help is displayed
func (i *Menu) HelpIsShown() bool { return i.showHelp }

// ShowHelp sets whether or not to display the help text
func (i *Menu) ShowHelp(b bool) *Menu {
	i.showHelp = b
	return i
}

// GetBackground returns the current background color
func (i *Menu) GetBackground() termbox.Attribute { return i.bg }

// SetBackground sets the background color to bg
func (i *Menu) SetBackground(bg termbox.Attribute) *Menu {
	i.bg = bg
	return i
}

// GetForeground returns the current foreground color
func (i *Menu) GetForeground() termbox.Attribute { return i.fg }

// SetForeground sets the current foreground color to fg
func (i *Menu) SetForeground(fg termbox.Attribute) *Menu {
	i.fg = fg
	return i
}

// IsDone returns whether the user has answered the modal
func (i *Menu) IsDone() bool { return i.isDone }

// SetDone sets whether the modal has completed it's purpose
func (i *Menu) SetDone(b bool) *Menu {
	i.isDone = b
	return i
}

// IsBordered returns true or false if this menu has a border
func (i *Menu) IsBordered() bool { return i.bordered }

// SetBordered sets whether we render a border around the menu
func (i *Menu) SetBordered(b bool) *Menu {
	i.bordered = b
	return i
}

// HandleKeyPress handles the termbox event and returns whether it was consumed
func (i *Menu) HandleKeyPress(event termbox.Event) bool {
	if event.Key == termbox.KeyEnter {
		i.isDone = true
		return true
	}
	currentIdx := i.GetSelectedIndex()
	switch event.Key {
	case termbox.KeyArrowUp:
		i.SelectPrevOption()
	case termbox.KeyArrowDown:
		i.SelectNextOption()
	}
	if i.GetSelectedIndex() != currentIdx {
		return true
	}
	return false
}

// Draw draws the modal
func (i *Menu) Draw() {
	// First blank out the area we'll be putting the menu
	FillWithChar(' ', i.x, i.y, i.x+i.width, i.y+i.height, i.fg, i.bg)
	// Now draw the border
	optionStartX := i.x
	optionStartY := i.y
	optionWidth := i.width
	optionHeight := i.height
	if optionHeight == -1 {
		optionHeight = len(i.options)
	}
	if i.bordered {
		if i.height == -1 {
			DrawBorder(i.x, i.y, i.x+i.width, i.y+optionHeight+1, i.fg, i.bg)
		} else {
			DrawBorder(i.x, i.y, i.x+i.width, i.y+optionHeight, i.fg, i.bg)
		}
		optionStartX = i.x + 1
		optionStartY = i.y + 1
		optionWidth = i.width - 1
	}

	// The title
	if i.title != "" {
		DrawStringAtPoint(AlignText(i.title, optionWidth, AlignCenter), optionStartX, optionStartY, i.fg, i.bg)
		optionStartY++
		if i.bordered {
			FillWithChar('-', optionStartX, optionStartY, optionWidth, optionStartY, i.fg, i.bg)
			optionStartY++
		}
	}

	// Print the options
	if len(i.options) > 0 {
		for idx := range i.options {
			currOpt := &i.options[idx]
			if currOpt.IsDisabled() {
				DrawStringAtPoint(currOpt.GetText(), optionStartX, optionStartY, i.disabledFg, i.disabledBg)
			} else if i.GetSelectedOption() == currOpt {
				DrawStringAtPoint(AlignText(currOpt.GetText(), optionWidth, AlignLeft), optionStartX, optionStartY, i.selectedFg, i.selectedBg)
			} else {
				DrawStringAtPoint(currOpt.GetText(), optionStartX, optionStartY, i.fg, i.bg)
			}
			optionStartY++
		}
	}
}

/* MenuOption Struct & methods */

// MenuOption An option in the menu
type MenuOption struct {
	text     string
	selected bool
	disabled bool
	helpText string
}

// CreateOptionFromText just returns a MenuOption object
// That only has it's text value set.
func CreateOptionFromText(s string) *MenuOption {
	return &MenuOption{text: s}
}

// SetText Sets the text for this option
func (i *MenuOption) SetText(s string) *MenuOption {
	i.text = s
	return i
}

// GetText Returns the text for this option
func (i *MenuOption) GetText() string { return i.text }

// Disable Sets this option to disabled
func (i *MenuOption) Disable() *MenuOption {
	i.disabled = true
	return i
}

// Enable Sets this option to enabled
func (i *MenuOption) Enable() *MenuOption {
	i.disabled = false
	return i
}

// IsDisabled returns whether this option is enabled
func (i *MenuOption) IsDisabled() bool {
	return i.disabled
}

// IsSelected Returns whether this option is selected
func (i *MenuOption) IsSelected() bool {
	return i.selected
}

// Select Sets this option to selected
func (i *MenuOption) Select() *MenuOption {
	i.selected = true
	return i
}

// Unselect Sets this option to not selected
func (i *MenuOption) Unselect() *MenuOption {
	i.selected = false
	return i
}

// SetHelpText Sets this option's help text to s
func (i *MenuOption) SetHelpText(s string) *MenuOption {
	i.helpText = s
	return i
}

// GetHelpText Returns the help text for this option
func (i *MenuOption) GetHelpText() string { return i.helpText }