Hazard Pits Map (#108)

* added the new hazard map with custom start locations

* tweaked comments/logic

* cleaning up functionality

* unit test plus bug fixes

* fixing unnecessary error

maps/hazard_pits.go

@@ -0,0 +1,138 @@
+package maps
+
+import (
+	"github.com/BattlesnakeOfficial/rules"
+)
+
+func init() {
+	globalRegistry.RegisterMap("hz_hazard_pits", HazardPitsMap{})
+}
+
+type HazardPitsMap struct{}
+
+func (m HazardPitsMap) ID() string {
+	return "hz_hazard_pits"
+}
+
+func (m HazardPitsMap) Meta() Metadata {
+	return Metadata{
+		Name:        "hz_hazard_pits",
+		Description: "A map that that fills in grid-like pattern of squares with pits filled with hazard sauce. Every N turns the pits will fill with another layer of sauce up to a maximum of 4 layers which last a few cycles, then the pits drain and the pattern repeats",
+		Author:      "Battlesnake",
+		Version:     1,
+		MinPlayers:  1,
+		MaxPlayers:  4,
+		BoardSizes:  FixedSizes(Dimensions{11, 11}),
+		Tags:        []string{TAG_FOOD_PLACEMENT, TAG_HAZARD_PLACEMENT, TAG_SNAKE_PLACEMENT},
+	}
+}
+
+func (m HazardPitsMap) AddHazardPits(board *rules.BoardState, settings rules.Settings, editor Editor) {
+	for x := 0; x < board.Width; x++ {
+		for y := 0; y < board.Height; y++ {
+			if x%2 == 1 && y%2 == 1 {
+				point := rules.Point{X: x, Y: y}
+				isStartPosition := false
+				for _, startPos := range hazardPitStartPositions {
+					if startPos == point {
+						isStartPosition = true
+					}
+				}
+				if !isStartPosition {
+					editor.AddHazard(point)
+				}
+			}
+		}
+	}
+}
+
+func (m HazardPitsMap) SetupBoard(initialBoardState *rules.BoardState, settings rules.Settings, editor Editor) error {
+	if !m.Meta().BoardSizes.IsAllowable(initialBoardState.Width, initialBoardState.Height) {
+		return rules.RulesetError("This map can only be played on a 11x11 board")
+	}
+
+	if len(initialBoardState.Snakes) > len(hazardPitStartPositions) {
+		return rules.ErrorTooManySnakes
+	}
+
+	rand := settings.GetRand(0)
+
+	rand.Shuffle(len(hazardPitStartPositions), func(i int, j int) {
+		hazardPitStartPositions[i], hazardPitStartPositions[j] = hazardPitStartPositions[j], hazardPitStartPositions[i]
+	})
+	snakeIDs := make([]string, 0, len(initialBoardState.Snakes))
+	for _, snake := range initialBoardState.Snakes {
+		snakeIDs = append(snakeIDs, snake.ID)
+	}
+
+	tempBoardState := rules.NewBoardState(initialBoardState.Width, initialBoardState.Height)
+	tempBoardState.Snakes = make([]rules.Snake, len(snakeIDs))
+
+	for i := 0; i < len(snakeIDs); i++ {
+		tempBoardState.Snakes[i] = rules.Snake{
+			ID:     snakeIDs[i],
+			Health: rules.SnakeMaxHealth,
+		}
+	}
+
+	for index, snake := range initialBoardState.Snakes {
+		head := hazardPitStartPositions[index]
+		err := rules.PlaceSnake(tempBoardState, snake.ID, []rules.Point{head, head, head})
+		if err != nil {
+			return err
+		}
+	}
+
+	err := rules.PlaceFoodFixed(rand, tempBoardState)
+	if err != nil {
+		return err
+	}
+
+	// Copy food from temp board state
+	for _, f := range tempBoardState.Food {
+		editor.AddFood(f)
+	}
+
+	// Copy snakes from temp board state
+	for _, snake := range tempBoardState.Snakes {
+		editor.PlaceSnake(snake.ID, snake.Body, snake.Health)
+	}
+
+	return nil
+}
+
+func (m HazardPitsMap) UpdateBoard(lastBoardState *rules.BoardState, settings rules.Settings, editor Editor) error {
+	err := StandardMap{}.UpdateBoard(lastBoardState, settings, editor)
+	if err != nil {
+		return err
+	}
+
+	// Cycle 0 - no hazards
+	// Cycle 1 - 1 layer
+	// Cycle 2 - 2 layers
+	// Cycle 3 - 3 layers
+	// Cycle 4-6 - 4 layers of hazards
+
+	if lastBoardState.Turn%settings.RoyaleSettings.ShrinkEveryNTurns == 0 {
+		// Is it time to update the hazards
+		layers := (lastBoardState.Turn / settings.RoyaleSettings.ShrinkEveryNTurns) % 7
+		if layers > 4 {
+			layers = 4
+		}
+
+		editor.ClearHazards()
+
+		// Add 1-4 layers of hazard pits depending on the cycle
+		for n := 0; n < layers; n++ {
+			m.AddHazardPits(lastBoardState, settings, editor)
+		}
+	}
+	return nil
+}
+
+var hazardPitStartPositions = []rules.Point{
+	{X: 1, Y: 1},
+	{X: 9, Y: 1},
+	{X: 1, Y: 9},
+	{X: 9, Y: 9},
+}