require "entity"

GenericSkewer = class("GenericSkewer", Entity)

local edgeDirections = {
	{x = 1, y = 0}, {x = -1, y = 0},
	{x = 0, y = 1}, {x = 0, y = -1},
}

local function shapeHasCell(shape, x, y)
	for _, cell in ipairs(shape) do
		if cell.x == x and cell.y == y then return true end
	end
	return false
end

-- Draw two teeth on every exposed cell edge. The art remains synthetic: the
-- underlying box sprite and its collision shape are still the authored base.
function drawSkewerSprite(sprite, cellShape, x, y, scale)
	cellShape = cellShape or {{x = 1, y = 1}}
	local cellSize = 16 * scale
	local inset = scale
	local reach = 3 * scale
	local halfBase = 1.5 * scale

	for _, cell in ipairs(cellShape) do
		local left = x + (cell.x - 1) * cellSize
		local top = y + (cell.y - 1) * cellSize
		for _, direction in ipairs(edgeDirections) do
			if not shapeHasCell(cellShape, cell.x + direction.x, cell.y + direction.y) then
				for _, along in ipairs({5, 11}) do
					if direction.x ~= 0 then
						local edgeX = direction.x > 0 and left + cellSize - inset or left + inset
						local centerY = top + along * scale
						love.graphics.polygon("fill",
							edgeX, centerY - halfBase,
							edgeX + direction.x * reach, centerY,
							edgeX, centerY + halfBase
						)
					else
						local edgeY = direction.y > 0 and top + cellSize - inset or top + inset
						local centerX = left + along * scale
						love.graphics.polygon("fill",
							centerX - halfBase, edgeY,
							centerX, edgeY + direction.y * reach,
							centerX + halfBase, edgeY
						)
					end
				end
			end
		end
	end

	love.graphics.draw(sprite, x, y, 0, scale, scale)
end

function GenericSkewer:initialize(x, y, color, sprite, name, cellShape)
	Entity.initialize(self, {
		name = name,
		x = x,
		y = y,
		color = color,
		collision = "moveable",
		skewer = true,
		sprite = sprite,
		cellShape = cellShape
	})
end

function GenericSkewer:update()

end

function GenericSkewer:draw(channel)
	local sprite = self.sprites[channel]
	if not sprite then return end
	love.graphics.setColor(gColor[channel]:set())
	local p = self:getDrawPos()
	drawSkewerSprite(
		sprite, self:getCellShape(),
		p.x + self.drawOffset.x * drawScale,
		p.y + self.drawOffset.y * drawScale,
		drawScale
	)
end

function GenericSkewer:tick()

end