Emanuele Feronato

local WIDTH = 6
local HEIGHT = 6

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

local LEVELS = {
	{ -- level 1
		{0, 0, 0, 0, 0, 0},
		{3, 2, 3, 2, 2, 2},
		{0, 0, 2, 3, 2, 2},
		{2, 0, 2, 2, 0, 0},
		{0, 2, 3, 0, 2, 2},
		{2, 3, 0, 2, 0, 4}
	},
	{ -- level 2
		{0, 2, 3, 3, 2, 1},
		{2, 0, 3, 3, 0, 2},
		{1, 4, 3, 3, 0, 1},
		{1, 4, 3, 3, 0, 1},
		{2, 0, 3, 3, 0, 2},
		{0, 2, 3, 3, 2, 1}
	},
	{ -- level 3
		{0, 2, 2, 2, 0, 2},
		{1, 1, 1, 1, 1, 1},
		{1, 3, 0, 3, 3, 1},
		{1, 3, 3, 3, 3, 1},
		{1, 1, 1, 1, 1, 1},
		{4, 4, 0, 4, 0, 1}
	},
	{ -- level 4
		{3, 4, 2, 2, 0, 2},
		{1, 1, 1, 1, 1, 1},
		{0, 1, 3, 0, 3, 1},
		{1, 3, 1, 3, 1, 1},
		{1, 1, 1, 1, 1, 1},
		{3, 0, 0, 4, 0, 1}
	},
	{ -- level 5
		{4, 2, 1, 2, 1, 4},
		{1, 2, 1, 1, 2, 1},
		{1, 3, 2, 3, 3, 1},
		{1, 1, 2, 2, 3, 1},
		{1, 0, 1, 1, 2, 1},
		{4, 0, 0, 4, 1, 4}
	},
	{ -- level 6
		{3, 2, 1, 1, 2, 1},
		{1, 2, 1, 0, 2, 2},
		{2, 1, 1, 1, 2, 1},
		{1, 2, 1, 1, 2, 1},
		{0, 2, 1, 1, 2, 4},
		{3, 0, 0, 4, 0, 4}
	},
	{ -- level 7
		{2, 0, 2, 3, 0, 2},
		{0, 2, 1, 3, 2, 1},
		{2, 0, 1, 3, 0, 2},
		{0, 2, 3, 3, 2, 1},
		{2, 0, 1, 3, 0, 2},
		{0, 2, 0, 3, 2, 1}
	},
	{ -- level 8
		{1, 3, 0, 1, 1, 2},
		{0, 4, 0, 0, 2, 3},
		{3, 1, 0, 0, 3, 1},
		{1, 2, 0, 0, 1, 2},
		{4, 3, 1, 0, 4, 3},
		{2, 4, 1, 1, 2, 4}
	},
	{ -- level 9
		{4, 1, 0, 0, 2, 4},
		{2, 4, 2, 4, 1, 0},
		{0, 0, 2, 0, 4, 2},
		{1, 1, 0, 0, 4, 2},
		{2, 4, 1, 4, 0, 1},
		{3, 0, 4, 1, 0, 4}
	},
	{ -- level 10
		{3, 2, 2, 0, 2, 0},
		{2, 3, 2, 3, 2, 0},
		{0, 1, 3, 1, 2, 2},
		{1, 1, 0, 0, 0, 1},
		{2, 2, 1, 3, 3, 1},
		{3, 2, 1, 1, 2, 2}
	}
}

local function play_animation(id, animation)
	msg.post(msg.url(nil, id, "sprite"), "play_animation", { id = animation })
end

-- update the visual representation of the cell based on its state
local function update_cell(cell, pressed)
	if cell.number and cell.number > 0 then
		label.set_text(msg.url(nil, cell.square_id, "label"), cell.number)
		if pressed then
			play_animation(cell.square_id, hash("buttonSquare_lightblue"))
		elseif cell.locked then
			play_animation(cell.square_id, hash("buttonSquare_darkblue_pressed"))
		else
			play_animation(cell.square_id, hash("buttonSquare_blue"))
		end
	else
		label.set_text(msg.url(nil, cell.square_id, "label"), "")
		play_animation(cell.square_id, hash("buttonSquare_darkblue_pressed"))
	end
end

-- find a cell on the map based on the game object id of the square
local function find_cell(board, square_id)
	for x=1,WIDTH do
		for y=1,HEIGHT do
			local cell = board[x][y]
			if cell.square_id == square_id then
				return cell
			end
		end
	end
end

-- find empty target cells at the correct distance from a specific cell
-- containing a number
local function find_targets(board, cell)
	local targets = {}
	for _,dir in pairs(DIRECTIONS) do
		local tx = cell.x + cell.number * dir.x
		local ty = cell.y + cell.number * dir.y
		if tx > 0 and tx <= WIDTH and ty > 0 and ty <= HEIGHT then
			local target = board[tx][ty]
			if not target.number then
				table.insert(targets, target)
			end
		end
	end
	return targets
end

-- highlight target cells
local function highlight_targets(board, cell)
	local targets = find_targets(board, cell)
	for _,target in ipairs(targets) do
		play_animation(target.square_id, hash("buttonSquare_grey_pressed"))
	end
end

-- reset target cells
local function reset_targets(board, cell)
	local targets = find_targets(board, cell)
	for _,target in ipairs(targets) do
		play_animation(target.square_id, hash("buttonSquare_darkblue_pressed"))
	end
end

local function random(max, fillrate)
	if math.random() > fillrate then return 0 end
	local n = 1
	for i=1,max-1 do
		n = n + math.random(0, 1)
	end
	return n
end

local function new_level(self, level, additional_delay)
	self.level = level
	self.board = {}
	self.numbers_left = 0
	for x=1,WIDTH do
		self.board[x] = {}
		for y=1,HEIGHT do
			local cell = { x = x, y = y, locked = false }
			self.board[x][y] = cell

			-- create the square and let it fall down to it's position
			local duration = 1
			local delay = math.random(1,10) * 0.05 + x * 0.05 + y * 0.1 + (additional_delay or 0)
			local to = vmath.vector3(140 + x * 48, 360 + y * 48, 1 - y / 10)
			cell.square_id = factory.create("#squarefactory", to + vmath.vector3(0, 1000, 0))
			go.animate(cell.square_id, "position", go.PLAYBACK_ONCE_FORWARD, to, go.EASING_OUTBOUNCE, duration, delay)

			-- possibly assign a number
			local number = random(4, 0.5)
			if level <= #LEVELS then
				number = LEVELS[level][x][y]
			end
			if number > 0 then
				cell.number = number
				self.numbers_left = self.numbers_left + 1
			end

			update_cell(cell, false)
		end
	end
end

local function end_level(board)
	local down = vmath.vector3(0, 1000, 0)
	for x=1,WIDTH do
		for y=1,HEIGHT do
			local cell = board[x][y]
			local duration = 0.5
			local delay = math.random(1,10) * 0.05 + x * 0.05 + y * 0.1
			local to = go.get_position(cell.square_id) - down
			go.animate(cell.square_id, "position", go.PLAYBACK_ONCE_FORWARD, to, go.EASING_INQUAD, duration, delay, function()
				go.delete(cell.square_id)
			end)
		end
	end
end

function init(self)
	msg.post(".", "acquire_input_focus")
	msg.post("@render:", "clear_color", { color = vmath.vector4(0.15, 0.15, 0.15, 1.0) })
	math.randomseed(os.time())
	new_level(self, 1)
end

function on_message(self, message_id, message, sender)
	-- keep track of which cell we're currently pointing at
	if message_id == hash("trigger_response") then
		if message.enter then
			self.over_id = message.other_id
		elseif self.over_id == message.other_id then
			self.over_id = nil
		end
	elseif message_id == hash("restart") then
		end_level(self.board)
		new_level(self, self.level, 2)
	end
end

function on_input(self, action_id, action)
	-- move the cursor
	go.set_position(vmath.vector3(action.x, action.y, 0))

	-- handle clicks
	if action_id == hash("touch") and action.released then
		-- get which cell we clicked on
		local current = find_cell(self.board, self.over_id)
		if self.selected_id then
			-- get the cell that the user has selected to move
			local selected = find_cell(self.board, self.selected_id)
			
			-- deselect if clicking on the same as the selected cell
			if selected == current then
				reset_targets(self.board, selected)
				update_cell(selected, false)
				self.selected_id = nil
			-- deselect and select a new one
			elseif not current.locked and current.number then
				reset_targets(self.board, selected)
				update_cell(selected, false)
				self.selected_id = self.over_id
				update_cell(current, true)
				highlight_targets(self.board, current)
			-- try to move the selected cell to the one we clicked on
			else
				local targets = find_targets(self.board, selected)
				for _,target in ipairs(targets) do
					if target == current then
						reset_targets(self.board, selected)
						self.selected_id = nil
						target.number = selected.number
						target.locked = true
						selected.number = nil
						go.set_position(go.get_position(target.square_id), target.number_id)
						update_cell(selected, false)
						update_cell(target, false)
						self.numbers_left = self.numbers_left - 1
						if self.numbers_left == 0 then
							end_level(self.board)
							new_level(self, self.level + 1, 2)
						end
						break
					end
				end
			end
		-- clicked on a non-locked cell with a number
		elseif self.over_id and not current.locked and current.number then
			self.selected_id = self.over_id
			update_cell(current, true)
			highlight_targets(self.board, current)
		end
	end
end