@page "/snake"

<div @onkeydown="OnKeyDown" tabindex="0" style="background-color: #333;" >
    <h1 id="Score" style="width: 100%; text-align: center; color:#fff;">Score : 0</h1>
    <div id="BODY" style="position: relative; margin-bottom: 5px; margin-left: 50%; right: 300px; background-color: #666; width: 600px; height: 600px;">
        <!-- Game -->

        @foreach(SnakePart part in SnakeParts ) {
            <div style="position: absolute; left: @part.getX(); top: @part.getY(); width: 10px; height: 10px; background-color: #111; border: 0; padding: 0; margin: 0;"></div>
        }
        <div style="position: absolute; left: @Collectable.getX(); top: @Collectable.getY(); width: 10px; height: 10px; background-color: #f00; border: 0; padding: 0; margin: 0;"></div>
        
        <!-- End Game -->
    </div>
    <div id="PauseScreen"style="position: relative; display: none; width: 500px; margin-left: 50%; right: 250px;">
        <h2 style="text-align: center; color: #f00; ">Game Paused</h2>
    </div>
    <div style="margin: 0 40px; width: calc(100% - 80px); background-color: #777;">
        <h3 style="text-align: center; font-size: 25px; color: #0f0; padding: 0; margin: 0; border: 0;">LEADERBOARD</h3>
    </div>
    <hr style="margin: 0px; width:calc(100% - 82px);" />
    <div id="Scoreboard" style="margin: 0 40px; width: calc(100% - 80px); background-color: #777;"></div>
    <h3 style="position: absolute; right: 10px; bottom: 3px; color: #fff;">Designed by Derek in California</h3>
</div>



@code {

    struct SnakePart {
        public int X{ get; set; }
        public int Y{ get; set; }
        public int Hue{ get; set; }

        public string getX() {
            return X * 10 + "px";
        }
        public string getY() {
            return Y * 10 + "px";
        }
    }
    enum Direction {
        Up,
        Down,
        Left,
        Right
    }

    List<SnakePart> SnakeParts = new List<SnakePart>(){
        new SnakePart{ X = 5, Y = 10 },                      // Tail
        new SnakePart{ X = 6, Y = 10 },
        new SnakePart{ X = 7, Y = 10 },
        new SnakePart{ X = 8, Y = 10 }                       // Head
    };
    int Score = 0;
    bool Paused = false;
    Direction SnakeDirection = Direction.Right;
    int FrameRate = 1000 / 10;
    int HueRate = 5;

    SnakePart Collectable = new SnakePart{ X = 15, Y = 15 };


    void OnKeyDown(KeyboardEventArgs e) {
        Console.WriteLine(e.Key);
        if (e.Key.ToLower() == "w" ) {
            SnakeDirection = Direction.Up;
        }else if (e.Key.ToLower() == "a" ) {
            SnakeDirection = Direction.Left;
        }else if (e.Key.ToLower() == "s" ) {
            SnakeDirection = Direction.Down;
        }else if (e.Key.ToLower() == "d" ) {
            SnakeDirection = Direction.Right;
        }
    }

    bool CheckSelfHit() {
        foreach(SnakePart cur in SnakeParts ) {
            if (SnakeParts[SnakeParts.Count-1].X == cur.X ) {
                if (SnakeParts[SnakeParts.Count-1].Y == cur.Y ) {
                    return false;
                }
            }
        }
        return true;
    }

    bool CheckBounds() {
        if (SnakeParts[SnakeParts.Count-1].X > 0 && SnakeParts[SnakeParts.Count-1].X < 50 ) {
            if (SnakeParts[SnakeParts.Count-1].Y > 0 && SnakeParts[SnakeParts.Count-1].Y < 50 ) {
                return true;
            }
        }
        return false;
    }

    bool CheckCollectibleHit() { // return true if hit
        if (SnakeParts[SnakeParts.Count-1].X == Collectable.X ) {
            if (SnakeParts[SnakeParts.Count-1].Y == Collectable.Y ) {
                return true;
            }
        }
        return false;
    }

    void ResetCollectable() {
        Collectable.X = new Random().Next(1, 40);
        Collectable.Y = new Random().Next(1, 40);
    }

    void Die() {

    }

    void Update() {
        // Get Next Position
        if( SnakeDirection == Direction.Up ) {
            SnakeParts.Add( new SnakePart {
                X = SnakeParts[SnakeParts.Count-1].X,
                Y = SnakeParts[SnakeParts.Count-1].Y - 1,
                Hue = SnakeParts[SnakeParts.Count-1].Hue + HueRate
            });
        }else if (SnakeDirection == Direction.Right ) {
            SnakeParts.Add( new SnakePart {
                X = SnakeParts[SnakeParts.Count-1].X + 1,
                Y = SnakeParts[SnakeParts.Count-1].Y,
                Hue = SnakeParts[SnakeParts.Count-1].Hue + HueRate
            });
        }else if (SnakeDirection == Direction.Down ) {
            SnakeParts.Add( new SnakePart {
                X = SnakeParts[SnakeParts.Count-1].X,
                Y = SnakeParts[SnakeParts.Count-1].Y + 1,
                Hue = SnakeParts[SnakeParts.Count-1].Hue + HueRate
            });
        }else if (SnakeDirection == Direction.Left ) {
            SnakeParts.Add( new SnakePart {
                X = SnakeParts[SnakeParts.Count-1].X - 1,
                Y = SnakeParts[SnakeParts.Count-1].Y,
                Hue = SnakeParts[SnakeParts.Count-1].Hue + HueRate
            });
        }
        if (CheckSelfHit() && CheckBounds() ) {
            if( CheckCollectibleHit() ) {
                Score += 1;
                ResetCollectable();
            } else {
                SnakeParts.RemoveAt( 0 );
            }
        } else {
            Die();
        }
        StateHasChanged();
    }

    protected override void OnInitialized() {
        ResetCollectable();
        var timer = new System.Threading.Timer((e) => {
            if (!Paused){
                Update();
            }
        }, null, 0, FrameRate );
    }

}