Don't allow pieces to be moved after they're dropped

Tetris/ContentView.swift

@@ -22,35 +22,50 @@ struct ContentView: View {
     var body: some View {
         GeometryReader { (geometry) in
             VStack {
-                HStack {
-                    Text("Held:")
-                    if self.controller.heldTetromino != nil {
-                        Group {
-                            TetrominoView(tetromino: self.controller.heldTetromino!)
-                        }.frame(width: 50, height: 50, alignment: .center)
-                    } else {
-                        Rectangle().foregroundColor(.clear).frame(width: 50, height: 50)
+                Spacer()
+                HStack(alignment: .top, spacing: 8) {
+                    VStack {
+                        Text("Held")
+                        if self.controller.heldTetromino != nil {
+                            Group {
+                                TetrominoView(tetromino: self.controller.heldTetromino!)
+                            }.frame(width: 50, height: 50, alignment: .center)
+                        } else {
+                            Rectangle().foregroundColor(.clear).frame(width: 50, height: 50)
+                        }
                     }
+                        .padding(.leading, 8)
+                    BoardView(board: self.$controller.board, currentPiece: self.$controller.currentPiece, droppedPiece: self.$controller.currentPieceAtDropPoint)
+                        .aspectRatio(CGSize(width: self.controller.width, height: self.controller.height), contentMode: .fit)
+                        .onAppear(perform: self.startTimer)
+                        .onDisappear(perform: self.stopTimer)
+                        .onTapGesture(perform: self.onTap)
+                        .gesture(self.horizDragGesture(geometry: geometry).simultaneously(with: self.verticalDragGesture))
+                    //        .gesture(ExclusiveGesture(horizDragGesture, verticalDragGesture))
+                    //            .gesture(horizDragGesture.simultaneously(with: verticalDragGesture))
+                    
+                    VStack {
+                        Text("Next")
+                        NextTetromioesView(tetrominoes: self.controller.nextTetrominoes).frame(width: 50)
+                    }
+                        .padding(.trailing, 8)
                 }
-                BoardView(board: self.$controller.board, currentPiece: self.$controller.currentPiece, droppedPiece: self.$controller.currentPieceAtDropPoint)
-                    .aspectRatio(CGSize(width: self.controller.width, height: self.controller.height), contentMode: .fit)
-                    .onAppear(perform: self.startTimer)
-                    .onDisappear(perform: self.stopTimer)
-                    .onTapGesture(perform: self.onTap)
-                    .gesture(self.horizDragGesture(geometry: geometry).simultaneously(with: self.verticalDragGesture))
-                //        .gesture(ExclusiveGesture(horizDragGesture, verticalDragGesture))
-                //            .gesture(horizDragGesture.simultaneously(with: verticalDragGesture))
-
+                Spacer()
                 HStack {
+                    Button(action: { self.controller.rotate(direction: .counterClockwise) }) {
+                        Image(systemName: "gobackward").resizable().frame(width: 50, height: 50)
+                    }
+                        .padding(.leading, 25)
                     Button(action: self.onTap) {
                         Image(systemName: "goforward").resizable().frame(width: 50, height: 50)
                     }
-                        .padding(.leading, 50)
+                        .padding(.leading, 25)
                     Spacer()
                     DPadView(up: self.controller.hold, down: self.controller.drop, left: self.controller.left, right: self.controller.right)
                         .frame(width: 150, height: 150)
-                        .padding(.trailing, 50)
+                        .padding(.trailing, 25)
                 }
+                Spacer()
             }
         }
     }
@@ -58,7 +73,8 @@ struct ContentView: View {
     func horizDragGesture(geometry: GeometryProxy) -> some Gesture {
         DragGesture(coordinateSpace: .global)
             .onChanged { (state) in
-                guard let currentPiece = self.controller.currentPiece else { return }
+                guard case .playing(.normal) = self.controller.state,
+                    let currentPiece = self.controller.currentPiece else { return }
                 if self.initialXPosition == nil {
                     self.initialXPosition = currentPiece.topLeft.0
                 }

TetrisKit/GameController.swift

@@ -12,9 +12,9 @@ import Combine
 public class GameController: ObservableObject {
     
     public let width = 10
-    public let height = 16
+    public let height = 20
     
-    var state: GameState = .waitingForStart
+    public var state: GameState = .waitingForStart
     
     @Published public var board: GameBoard
 
@@ -24,6 +24,7 @@ public class GameController: ObservableObject {
         }
     }
     @Published public var currentPieceAtDropPoint: GamePiece?
+    @Published public var nextTetrominoes: [Tetromino] = [.random(), .random(), .random()]
     @Published public var heldTetromino: Tetromino?
 
     public var ended: Bool {
@@ -41,8 +42,9 @@ public class GameController: ObservableObject {
     }
     
     func nextPiece() {
-        let tetromino = Tetromino.random()
+        let tetromino = nextTetrominoes.removeFirst()
         currentPiece = GamePiece(tetromino: tetromino, topLeft: ((width - tetromino.shape.count) / 2, 0))
+        nextTetrominoes.append(.random())
     }
     
     func finalizePiece() {
@@ -153,12 +155,12 @@ public class GameController: ObservableObject {
 
 }
 
-enum GameState {
+public enum GameState {
     case waitingForStart
     case playing(PlayState)
 }
 
-enum PlayState {
+public enum PlayState {
     case normal
     case dropped
     case switched

TetrisUI/NextTetrominoesView.swift

@@ -0,0 +1,32 @@
+//
+//  NextTetrominoesView.swift
+//  Tetris
+//
+//  Created by Shadowfacts on 10/16/19.
+//  Copyright © 2019 Shadowfacts. All rights reserved.
+//
+
+import SwiftUI
+import TetrisKit
+
+public struct NextTetromioesView: View {
+    let tetrominoes: [Tetromino]
+    
+    public init(tetrominoes: [Tetromino]) {
+        self.tetrominoes = tetrominoes
+    }
+    
+    public var body: some View {
+        VStack {
+            ForEach(0..<self.tetrominoes.count, id: \.self) { (index) in
+                TetrominoView(tetromino: self.tetrominoes[index]).aspectRatio(1, contentMode: .fit)
+            }
+        }
+    }
+}
+
+struct NextTetrominoesView_Previews: PreviewProvider {
+    static var previews: some View {
+        NextTetromioesView(tetrominoes: [.t, .l, .z])
+    }
+}