/*
Copyright 2014 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.
*/

package blocks

import (
	"github.com/hajimehoshi/ebiten"
	"image/color"
	"math/rand"
	"time"
)

func init() {
	texturePaths["empty"] = "images/blocks/empty.png"
}

type GameScene struct {
	field             *Field
	rand              *rand.Rand
	currentPiece      *Piece
	currentPieceX     int
	currentPieceY     int
	currentPieceAngle Angle
	nextPiece         *Piece
	landingCount      int
}

func NewGameScene() *GameScene {
	return &GameScene{
		field: NewField(),
		rand:  rand.New(rand.NewSource(time.Now().UnixNano())),
	}
}

const emptyWidth = 16
const emptyHeight = 16
const fieldWidth = blockWidth * fieldBlockNumX
const fieldHeight = blockHeight * fieldBlockNumY

func (s *GameScene) choosePiece() *Piece {
	num := NormalBlockTypeNum
	blockType := BlockType(s.rand.Intn(num) + 1)
	return Pieces[blockType]
}

func (s *GameScene) initCurrentPiece(piece *Piece) {
	s.currentPiece = piece
	x, y := s.currentPiece.InitialPosition()
	s.currentPieceX = x
	s.currentPieceY = y
	s.currentPieceAngle = Angle0
}

func (s *GameScene) Update(state *GameState) {
	const maxLandingCount = 60

	if s.currentPiece == nil {
		s.initCurrentPiece(s.choosePiece())
	}
	if s.nextPiece == nil {
		s.nextPiece = s.choosePiece()
	}
	piece := s.currentPiece
	x := s.currentPieceX
	y := s.currentPieceY
	angle := s.currentPieceAngle
	moved := false
	if state.Input.StateForKey(ebiten.KeySpace) == 1 {
		s.currentPieceAngle = s.field.RotatePieceRight(piece, x, y, angle)
		moved = angle != s.currentPieceAngle
	}
	if l := state.Input.StateForKey(ebiten.KeyLeft); l == 1 || (10 <= l && l%2 == 0) {
		s.currentPieceX = s.field.MovePieceToLeft(piece, x, y, angle)
		moved = x != s.currentPieceX
	}
	if r := state.Input.StateForKey(ebiten.KeyRight); r == 1 || (10 <= r && r%2 == 0) {
		s.currentPieceX = s.field.MovePieceToRight(piece, x, y, angle)
		moved = y != s.currentPieceX
	}
	if d := state.Input.StateForKey(ebiten.KeyDown); (d-1)%2 == 0 {
		s.currentPieceY = s.field.DropPiece(piece, x, y, angle)
		moved = y != s.currentPieceY
	}
	if moved {
		s.landingCount = 0
	} else if !s.field.PieceDroppable(piece, x, y, angle) {
		if 0 < state.Input.StateForKey(ebiten.KeyDown) {
			s.landingCount += 10
		} else {
			s.landingCount++
		}
		if maxLandingCount <= s.landingCount {
			s.field.AbsorbPiece(piece, x, y, angle)
			s.initCurrentPiece(s.nextPiece)
			s.nextPiece = nil
			s.landingCount = 0
		}
	}
}

func (s *GameScene) Draw(context ebiten.GraphicsContext, textures *Textures) {
	context.Fill(0xff, 0xff, 0xff)

	field := textures.GetTexture("empty")
	geoMat := ebiten.GeometryMatrixI()
	geoMat.Scale(
		float64(fieldWidth)/float64(emptyWidth),
		float64(fieldHeight)/float64(emptyHeight))
	geoMat.Translate(20, 20) // magic number?
	colorMat := ebiten.ColorMatrixI()
	colorMat.Scale(color.RGBA{0, 0, 0, 0x80})
	ebiten.DrawWhole(context.Texture(field), emptyWidth, emptyHeight, geoMat, colorMat)

	geoMat = ebiten.GeometryMatrixI()
	geoMat.Translate(20, 20)
	s.field.Draw(context, textures, geoMat)

	if s.currentPiece != nil {
		s.currentPiece.Draw(context, textures, 20, 20, s.currentPieceX, s.currentPieceY, s.currentPieceAngle)
	}
}