// Copyright 2015 Hajime Hoshi
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// +build example

package main

import (
	"log"
	"strconv"

	"github.com/hajimehoshi/ebiten"
	"github.com/hajimehoshi/ebiten/ebitenutil"
	"github.com/hajimehoshi/ebiten/examples/keyboard/keyboard"
)

const (
	screenWidth  = 320
	screenHeight = 240
)

var keyboardImage *ebiten.Image

func init() {
	var err error
	keyboardImage, _, err = ebitenutil.NewImageFromFile("_resources/images/keyboard/keyboard.png", ebiten.FilterNearest)
	if err != nil {
		log.Fatal(err)
	}
}

var keyNames = map[ebiten.Key]string{
	ebiten.KeyBackspace:    "BS",
	ebiten.KeyComma:        ",",
	ebiten.KeyEnter:        "Enter",
	ebiten.KeyEscape:       "Esc",
	ebiten.KeyPeriod:       ".",
	ebiten.KeySpace:        "Space",
	ebiten.KeyTab:          "Tab",
	ebiten.KeyMinus:        "-",
	ebiten.KeyEqual:        "=",
	ebiten.KeyBackslash:    "\\",
	ebiten.KeyGraveAccent:  "`",
	ebiten.KeyLeftBracket:  "[",
	ebiten.KeyRightBracket: "]",
	ebiten.KeySemicolon:    ";",
	ebiten.KeyApostrophe:   "'",
	ebiten.KeySlash:        "/",

	// Arrows
	ebiten.KeyDown:  "Down",
	ebiten.KeyLeft:  "Left",
	ebiten.KeyRight: "Right",
	ebiten.KeyUp:    "Up",

	// Mods
	ebiten.KeyShift:   "Shift",
	ebiten.KeyControl: "Ctrl",
	ebiten.KeyAlt:     "Alt",
}

func update(screen *ebiten.Image) error {
	// Collect pressed keys' names.
	pressed := []string{}
	for i := 0; i <= 9; i++ {
		if ebiten.IsKeyPressed(ebiten.Key(i) + ebiten.Key0) {
			pressed = append(pressed, string(i+'0'))
		}
	}
	for c := 'A'; c <= 'Z'; c++ {
		if ebiten.IsKeyPressed(ebiten.KeyA + ebiten.Key(c-'A')) {
			pressed = append(pressed, string(c))
		}
	}
	for i := 1; i <= 12; i++ {
		if ebiten.IsKeyPressed(ebiten.KeyF1 + ebiten.Key(i-1)) {
			pressed = append(pressed, "F"+strconv.Itoa(i))
		}
	}
	for key, name := range keyNames {
		if ebiten.IsKeyPressed(key) {
			pressed = append(pressed, name)
		}
	}

	if ebiten.IsRunningSlowly() {
		return nil
	}

	const (
		offsetX = 24
		offsetY = 40
	)

	// Draw the base (grayed) keyboard image.
	op := &ebiten.DrawImageOptions{}
	op.GeoM.Translate(offsetX, offsetY)
	op.ColorM.Scale(0.5, 0.5, 0.5, 1)
	screen.DrawImage(keyboardImage, op)

	// Draw the highlighted keys.
	op = &ebiten.DrawImageOptions{}
	for _, p := range pressed {
		op.GeoM.Reset()
		r, ok := keyboard.KeyRect(p)
		if !ok {
			continue
		}
		op.GeoM.Translate(float64(r.Min.X), float64(r.Min.Y))
		op.GeoM.Translate(offsetX, offsetY)
		op.SourceRect = &r
		screen.DrawImage(keyboardImage, op)
	}

	return nil
}

func main() {
	if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Keyboard (Ebiten Demo)"); err != nil {
		log.Fatal(err)
	}
}