package objects

import "image"
import "git.tebibyte.media/tomo/tomo"
import "git.tebibyte.media/tomo/tomo/text"
import "git.tebibyte.media/tomo/tomo/input"
import "git.tebibyte.media/tomo/tomo/event"

// TextInput is a single-line editable text box.
type TextInput struct {
	tomo.TextBox
	text []rune
	on struct {
		enter event.FuncBroadcaster
		edit  event.FuncBroadcaster
	}
}

// NewTextInput creates a new text input containing the specified text.
func NewTextInput (text string) *TextInput {
	this := &TextInput { TextBox: tomo.NewTextBox() }
	tomo.Apply(this, tomo.R("objects", "TextInput", ""))
	this.SetAlign(tomo.AlignStart, tomo.AlignMiddle)
	this.SetText(text)
	this.SetFocusable(true)
	this.SetSelectable(true)
	this.SetOverflow(true, false)
	this.OnKeyDown(this.handleKeyDown)
	this.OnScroll(this.handleScroll)
	return this
}

// SetText sets the text content of the input.
func (this *TextInput) SetText (text string) {
	this.text = []rune(text)
	this.TextBox.SetText(text)
}

// Text returns the text content of the input.
func (this *TextInput) Text () string {
	return string(this.text)
}

// OnEnter specifies a function to be called when the user presses enter within
// the text input.
func (this *TextInput) OnEnter (callback func ()) event.Cookie {
	return this.on.enter.Connect(callback)
}

// OnEdit specifies a function to be called when the user edits the input text.
func (this *TextInput) OnEdit (callback func ()) event.Cookie {
	return this.on.edit.Connect(callback)
}

func (this *TextInput) handleKeyDown (key input.Key, numpad bool) {
	dot       := this.Dot()
	modifiers := this.Modifiers()
	word      := modifiers.Control
	sel       := modifiers.Shift
	changed   := false

	// TODO all dot control (movement, selection, etc) should be done in the
	// backend. (editing should be done here, though)

	switch {
	case key == input.KeyEnter:
		this.on.enter.Broadcast()
	case key == input.KeyHome || (modifiers.Alt && key == input.KeyLeft):
		dot.End = 0
		if !sel { dot.Start = dot.End }
	case key == input.KeyEnd || (modifiers.Alt && key == input.KeyRight):
		dot.End = len(this.text)
		if !sel { dot.Start = dot.End }
	case key == input.KeyLeft:
		if sel {
			dot = text.SelectLeft(this.text, dot, word)
		} else {
			dot = text.MoveLeft(this.text, dot, word)
		}
	case key == input.KeyRight:
		if sel {
			dot = text.SelectRight(this.text, dot, word)
		} else {
			dot = text.MoveRight(this.text, dot, word)
		}
	case key == input.KeyBackspace:
		this.text, dot = text.Backspace(this.text, dot, word)
		changed = true
	case key == input.KeyDelete:
		this.text, dot = text.Delete(this.text, dot, word)
		changed = true
	case key == input.Key('a') && modifiers.Control:
		dot.Start = 0
		dot.End   = len(this.text)
	case key.Printable():
		this.text, dot = text.Type(this.text, dot, rune(key))
		changed = true
	}

	this.Select(dot)
	if changed {
		this.SetText(string(this.text))
		this.on.edit.Broadcast()
	}
}

// Type types a character at the current dot position.
func (this *TextInput) Type (char rune) {
	dot := this.Dot()
	this.text, dot = text.Type(this.text, dot, rune(char))
	this.Select(dot)
	this.SetText(string(this.text))
}

func (this *TextInput) handleScroll (x, y float64) {
	this.ScrollTo(this.ContentBounds().Min.Add(image.Pt(int(x), int(y))))
}