// Copyright 2014 The gocui Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package gocui

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

// handleEdit manages the edition mode.
func (g *Gui) handleEdit(v *View, ev *termbox.Event) error {
	switch {
	case ev.Ch != 0 && ev.Mod == 0:
		return v.editWrite(ev.Ch)
	case ev.Key == termbox.KeySpace:
		return v.editWrite(' ')
	case ev.Key == termbox.KeyBackspace || ev.Key == termbox.KeyBackspace2:
		return v.editDelete(true)
	case ev.Key == termbox.KeyDelete:
		return v.editDelete(false)
	case ev.Key == termbox.KeyInsert:
		v.overwrite = !v.overwrite
	case ev.Key == termbox.KeyEnter:
		return v.editLine()
	}
	return nil
}

// editWrite writes a rune at the cursor position.
func (v *View) editWrite(ch rune) error {
	v.writeRune(v.cx, v.cy, ch)
	if err := v.SetCursor(v.cx+1, v.cy); err != nil {
		if err := v.SetOrigin(v.ox+1, v.oy); err != nil {
			return err
		}
	}
	return nil
}

// editDelete deletes a rune at the cursor position. back determines
// the direction.
func (v *View) editDelete(back bool) error {
	if back {
		v.deleteRune(v.cx-1, v.cy)
		if err := v.SetCursor(v.cx-1, v.cy); err != nil && v.ox > 0 {
			if err := v.SetOrigin(v.ox-1, v.oy); err != nil {
				return err
			}
		}
	} else {
		v.deleteRune(v.cx, v.cy)
	}
	return nil
}

// editLine inserts a new line under the cursor.
func (v *View) editLine() error {
	v.breakLine(v.cx, v.cy)
	if err := v.SetCursor(v.cx, v.cy+1); err != nil {
		if err := v.SetOrigin(v.ox, v.oy+1); err != nil {
			return err
		}
	}
	if err := v.SetCursor(0, v.cy); err != nil {
		return err
	}
	if err := v.SetOrigin(0, v.oy); err != nil {
		return err
	}
	return nil
}