World = class("World")

local Movement = require "movement"

-- The world is deliberately only a layout: rooms continue to own their puzzle
-- state.  Keeping the two separate lets the editor move a room without
-- rewriting its level file.
function World:initialize()
	self.width, self.height = 18, 18
	self.rooms = {}
	self.roomByName = {}
	self.previewCache = {}
	self.lastRoom = nil
	self:load()
	self:loadRuntimeState()
	self.levels = {}

end

function World:loadLevels()
	-- Gameplay saves go to LÖVE's runtime directory. Seed every world slice
	-- through the same runtime-first loader, not just the initially visible one.
	for _, placed in ipairs(self.rooms) do self.levels[placed.name] = Room:new{name = placed.name, runtime = true} end
	self:rebuildCollision()
end

-- The editor can replace a level with a freshly loaded authored Room. Keep the
-- global simulation pointing at that exact instance, not a stale preload.
function World:setLevel(room)
	if not room or not room.name or not self:roomLocation(room.name) then return false end
	self.levels[room.name] = room
	self:rebuildCollision()
	return true
end

-- Runtime state is one logical world snapshot: each level slice is written to
-- LÖVE's save directory, and this companion file says which slice was active.
-- The authored world layout remains source-only for the editor.
function World:loadRuntimeState()
	local raw = love.filesystem.read("rooms/world.sav")
	if not raw then return end
	local ok, state = pcall(TSerial.unpack, raw)
	if ok and type(state) == "table" and state.lastRoom and self:roomLocation(state.lastRoom) then
		self.lastRoom = state.lastRoom
	end
end

function World:saveRuntime(dirtyRooms)
	for room in pairs(dirtyRooms or {}) do room:save() end
	return love.filesystem.write("rooms/world.sav", TSerial.pack({lastRoom = currentRoom and currentRoom.name}, nil, true))
end

function World:markDirty(room)
	self.dirtyRooms = self.dirtyRooms or {}
	self.dirtyRooms[room] = true
end

function World:flushRuntime()
	self:saveRuntime(self.dirtyRooms)
	self.dirtyRooms = {}
end

function World:listRoomNames()
	local names = {}
	for _, file in ipairs(love.filesystem.getDirectoryItems("rooms")) do
		local name = file:match("^(.+)%.sav$")
		if name and name ~= "world" then table.insert(names, name) end
	end
	table.sort(names)
	return names
end

function World:load()
	local raw = readFromSource("rooms/world.sav")
	if not raw then return end
	local ok, save = pcall(TSerial.unpack, raw)
	if not ok or type(save) ~= "table" then return end
	self.lastRoom = save.lastRoom
	for _, room in ipairs(save.rooms or {}) do
		if room.name and self:isInBounds(room.x, room.y) then
			self:_putRoom(room.name, room.x, room.y)
		end
	end
end

function World:save()
	local rooms = {}
	for _, room in ipairs(self.rooms) do
		table.insert(rooms, { name = room.name, x = room.x, y = room.y })
	end
	return writeToSource("rooms/world.sav", TSerial.pack({ width = self.width, height = self.height, lastRoom = self.lastRoom, rooms = rooms }, nil, true))
end

function World:isInBounds(x, y)
	return x and y and x >= 1 and x <= self.width and y >= 1 and y <= self.height
end

function World:roomAt(x, y)
	for _, room in ipairs(self.rooms) do
		if room.x == x and room.y == y then return room.name end
	end
	return nil
end

function World:roomLocation(name)
	return self.roomByName[name]
end

function World:_putRoom(name, x, y)
	local existing = self.roomByName[name]
	if existing then
		for i = #self.rooms, 1, -1 do
			if self.rooms[i] == existing then table.remove(self.rooms, i) end
		end
	end
	for i = #self.rooms, 1, -1 do
		if self.rooms[i].x == x and self.rooms[i].y == y then
			self.roomByName[self.rooms[i].name] = nil
			table.remove(self.rooms, i)
		end
	end
	local room = { name = name, x = x, y = y }
	table.insert(self.rooms, room)
	self.roomByName[name] = room
	return room
end

function World:placeRoom(name, x, y)
	if not name or not self:isInBounds(x, y) then return false end
	self:_putRoom(name, x, y)
	return self:save()
end

function World:removeRoom(x, y)
	for i = #self.rooms, 1, -1 do
		local room = self.rooms[i]
		if room.x == x and room.y == y then
			self.roomByName[room.name] = nil
			table.remove(self.rooms, i)
			if self.lastRoom == room.name then self.lastRoom = nil end
			return self:save(), room.name
		end
	end
	return false
end

function World:renameRoom(oldName, newName)
	local room = self:roomLocation(oldName)
	if not room or oldName == newName then return false end
	self.roomByName[oldName] = nil
	room.name = newName
	self.roomByName[newName] = room
	if self.lastRoom == oldName then self.lastRoom = newName end
	self:invalidatePreview(oldName)
	self:invalidatePreview(newName)
	return self:save()
end

function World:setLastRoom(name)
	if name and self.lastRoom ~= name then
		self.lastRoom = name
	end
	return true
end

function World:getNeighbor(name, exit)
	local room = self:roomLocation(name)
	if not room then return nil end
	local directions = {
		left = { x = -1, y = 0 }, right = { x = 1, y = 0 },
		top = { x = 0, y = -1 }, bottom = { x = 0, y = 1 },
	}
	local direction = directions[exit]
	if not direction then return nil end
	return self:roomAt(room.x + direction.x, room.y + direction.y)
end

-- All placed levels share these sparse matrices.  Rendering still uses the
-- selected Room, whose ordinary local matrices remain unchanged.
function World:rebuildCollision()
	self.collidableMatrices = {red = {}, green = {}, blue = {}}
	self.playerBlockerMatrices = {red = {}, green = {}, blue = {}}
	self.entityRooms = {}
	local function put(matrix, cell, entity)
		matrix[cell.y] = matrix[cell.y] or {}
		matrix[cell.y][cell.x] = entity
	end
	for name, room in pairs(self.levels) do
		local location = self:roomLocation(name)
		if location then
			for color, entities in pairs(room.collideables) do
				for _, entity in pairs(entities) do
					self.entityRooms[entity] = room
					for _, cell in ipairs(entity:getOccupiedCells()) do
						put(self.collidableMatrices[color], {
							x = (location.x - 1) * gridWidth + cell.x,
							y = (location.y - 1) * gridHeight + cell.y,
						}, entity)
					end
				end
			end
			-- NPCs are local room state, but globally collidable: a movement lookup
			-- must find them so its normal bump() path can open dialogue.
			for _, npc in ipairs(room.npcs) do
				self.entityRooms[npc] = room
				for _, cell in ipairs(npc:getOccupiedCells()) do
					local worldCell = {
						x = (location.x - 1) * gridWidth + cell.x,
						y = (location.y - 1) * gridHeight + cell.y,
					}
					for color in pairs(self.collidableMatrices) do put(self.collidableMatrices[color], worldCell, npc) end
				end
			end
			for color, entities in pairs(room.playerBlockers) do
				for _, entity in pairs(entities) do
					for _, cell in ipairs(entity:getOccupiedCells()) do
						put(self.playerBlockerMatrices[color], {
							x = (location.x - 1) * gridWidth + cell.x,
							y = (location.y - 1) * gridHeight + cell.y,
						}, entity)
					end
				end
			end
		end
	end
end

function World:worldCell(room, cell)
	local location = self:roomLocation(room.name)
	return location and {x = (location.x - 1) * gridWidth + cell.x, y = (location.y - 1) * gridHeight + cell.y}
end

function World:roomCell(cell)
	local roomX = math.floor((cell.x - 1) / gridWidth) + 1
	local roomY = math.floor((cell.y - 1) / gridHeight) + 1
	local name = self:roomAt(roomX, roomY)
	local room = name and self.levels[name]
	return room, {x = cell.x - (roomX - 1) * gridWidth, y = cell.y - (roomY - 1) * gridHeight}
end

function World:movementContext(room, color)
	local proxies = {}
	local world = self
	local context = {}
	function context:worldCell(cell) return world:worldCell(room, cell) end
	function context:isInBounds(cell) return world:roomCell(cell) ~= nil end
	function context:entityAt(cell)
		local row = world.collidableMatrices[color][cell.y]
		local entity = row and row[cell.x]
		if not entity then return nil end
		if proxies[entity] then return proxies[entity] end
		local owner = world.entityRooms[entity]
		local position = world:worldCell(owner, entity:getGridPos())
		local proxy = {entity = entity, room = owner, color = color, x = position.x, y = position.y}
		function proxy:canMove() return self.entity:canMove() end
		function proxy:canPassOver() return self.entity:canPassOver() end
		function proxy:isSticky() return self.entity:isSticky() end
		function proxy:isSkewer() return self.entity:isSkewer() end
		function proxy:isSpiky() return self.entity:isSpiky() end
		function proxy:bump() return self.entity:bump() end
		function proxy:getOccupiedCells(offset)
			offset = offset or {x = 0, y = 0}
			local cells = {}
			for _, shapeCell in ipairs(self.entity:getCellShape()) do
				table.insert(cells, {x = self.x + shapeCell.x - 1 + offset.x, y = self.y + shapeCell.y - 1 + offset.y})
			end
			return cells
		end
		proxies[entity] = proxy
		return proxy
	end
	function context:playerBlockerAt(cell)
		local row = world.playerBlockerMatrices[color][cell.y]
		return row and row[cell.x]
	end
	return context
end

-- Player copies live in room files, but joining is a world-coordinate rule.
-- This also lets a copy rejoin immediately when the player crosses into its
-- room, rather than waiting for one more local move.
function World:playerJoinCheck(room, previousPositions, newPositions)
	local activeColors = room:getActiveColors()
	local deactivate, activate = {}, {}
	if previousPositions and newPositions and #activeColors > 1 then
		for _, color in ipairs(activeColors) do
			if Entity.positionsAreEqual(previousPositions[color], newPositions[color]) then
				table.insert(deactivate, color)
			end
		end
	end
	for color, player in pairs(room.player) do
		if not room:colorIsActive(color) then
			local playerCell = self:worldCell(room, player:getGridPos())
			local overlaps = playerCell and #activeColors > 0
			for _, activeColor in ipairs(activeColors) do
				local activeCell = self:worldCell(room, room.player[activeColor]:getGridPos())
				if not activeCell or activeCell.x ~= playerCell.x or activeCell.y ~= playerCell.y then overlaps = false; break end
			end
			if overlaps then table.insert(activate, color) end
		end
	end
	for _, color in ipairs(activate) do room:setActiveColor(color, true) end
	for _, color in ipairs(deactivate) do room:setActiveColor(color, false) end
end

function World:movePlayer(room, key)
	local directions = {
		up = {x = 0, y = -1, axis = "y"}, down = {x = 0, y = 1, axis = "y"},
		left = {x = -1, y = 0, axis = "x"}, right = {x = 1, y = 0, axis = "x"},
	}
	local dir = directions[key]
	if not dir then return end
	local moved, previous, current = false, {}, {}
	for _, color in ipairs(room:getActiveColors()) do
		local player = room.player[color]
		local pos = player:getGridPos()
		previous[color] = pos
		local context = self:movementContext(room, color)
		local target = context:worldCell({x = pos.x + dir.x, y = pos.y + dir.y})
		local targetEntity = context:entityAt(target)
		if targetEntity then targetEntity:bump() end
		local blocker = context:playerBlockerAt(target)
		local canMove, pushing = true, {}
		if context:isInBounds(target) and not (blocker and blocker:blocksPlayer()) then
			canMove, pushing = Movement.findMovableGroup({target}, dir,
				function(cell) return context:entityAt(cell) end,
				function(cell) return context:isInBounds(cell) end)
		elseif blocker then
			canMove = false
		end

		local pulling, pullingGroup = false, {}
		local behind = context:worldCell({x = pos.x - dir.x, y = pos.y - dir.y})
		if context:isInBounds(behind) then
			pulling, pullingGroup = Movement.findMovableGroup({behind}, dir,
				function(cell) return context:entityAt(cell) end,
				function(cell) return context:isInBounds(cell) end)
		end
		if canMove then
			local group = {}
			for entity in pairs(pushing) do group[entity] = entity end
			if pulling then for entity in pairs(pullingGroup) do group[entity] = entity end end
			self:moveGroup(group, dir)
			player:move(dir.axis, dir[dir.axis])
			moved = true
		end
		current[color] = player:getGridPos()
	end
	if moved then
		self:markDirty(room)
		self:playerJoinCheck(room, previous, current)
		self:tick(room)
		self:flushRuntime()
	end
end

function World:switchPlayerColor(room, color)
	local player = room.player[color]
	if not player then return false end
	local activeColors = room:getActiveColors()
	local canSwitch = #activeColors ~= 1 or activeColors[1] ~= color
	if canSwitch then
		for _, possibleColor in ipairs(room:getPossibleColors()) do
			room:setActiveColor(possibleColor, possibleColor == color)
		end
	end
	player:playSwitchSound(canSwitch)
	if canSwitch then self:markDirty(room); self:flushRuntime() end
	return canSwitch
end

function World:tick(room)
	room:tickLocal()
	self:rebuildCollision()
	self:nextRoomCheck(room)
end

function World:nextRoomCheck(room)
	for _, color in ipairs(room:getActiveColors()) do
		local player = room.player[color]
		if player and not room:isInBounds(player:getGridPos()) then
			self:nextRoom(room, player:getGridPos())
			return
		end
	end
end

function World:nextRoom(room, pos)
	local exit, entry = nil, {x = pos.x, y = pos.y}
	if pos.x > gridWidth then exit, entry.x = "right", 1
	elseif pos.x < 1 then exit, entry.x = "left", gridWidth
	elseif pos.y > gridHeight then exit, entry.y = "bottom", 1
	elseif pos.y < 1 then exit, entry.y = "top", gridHeight end
	local nextName = self:getNeighbor(room.name, exit) or room.name
	local activeColors = room:getActiveColors()
	self:markDirty(room)
	local destination = self.levels[nextName]
	for _, color in ipairs(activeColors) do
		local player = room.player[color]
		-- Active copies travel with the player. Inactive copies are deliberately
		-- left in their room so World:playerJoinCheck can merge them later.
		room.player[color] = nil
		for i = #room.colorsPlayerHas, 1, -1 do
			if room.colorsPlayerHas[i] == color then table.remove(room.colorsPlayerHas, i) end
		end
		if destination.player[color] then
			for i = #destination.colorsPlayerHas, 1, -1 do
				if destination.colorsPlayerHas[i] == color then table.remove(destination.colorsPlayerHas, i) end
			end
		end
		destination.player[color] = player
		table.insert(destination.colorsPlayerHas, color)
	end
	room.activeColors = {red = false, green = false, blue = false}
	currentRoom = destination
	self:markDirty(currentRoom)
	for _, color in ipairs(activeColors) do
		currentRoom.player[color].x, currentRoom.player[color].y = entry.x, entry.y
		currentRoom:setActiveColor(color, true)
	end
	self:playerJoinCheck(currentRoom)
	self.lastRoom = currentRoom.name
	setEditorRoomName(currentRoom.name)
end

function World:moveGroup(group, direction)
	local changed = {}
	for proxy in pairs(group) do
		changed[proxy.room] = true
		for _, cell in ipairs(proxy:getOccupiedCells()) do
			local room = self:roomCell(cell)
			if room then changed[room] = true end
		end
		for _, cell in ipairs(proxy:getOccupiedCells(direction)) do
			local room = self:roomCell(cell)
			if room then changed[room] = true end
		end
		local destination, localCell = self:roomCell({x = proxy.x + direction.x, y = proxy.y + direction.y})
		if destination then
			if destination ~= proxy.room then
				for i = #proxy.room.collideables[proxy.color], 1, -1 do
					if proxy.room.collideables[proxy.color][i] == proxy.entity then table.remove(proxy.room.collideables[proxy.color], i); break end
				end
				table.insert(destination.collideables[proxy.color], proxy.entity)
				self.entityRooms[proxy.entity] = destination
				changed[proxy.room], changed[destination] = true, true
			end
			proxy.entity.x, proxy.entity.y = localCell.x, localCell.y
		end
	end
	self:rebuildCollision()
	for room in pairs(changed) do room:resolveSwitchesAndDoors() end
	self:rebuildCollision()
	for room in pairs(changed) do self:markDirty(room) end
end

function World:drawOverlaps(room, color)
	local location = self:roomLocation(room.name)
	if not location then return end
	local drawn = {}
	for y = 1, gridHeight do
		local row = self.collidableMatrices[color][(location.y - 1) * gridHeight + y]
		if row then
			for x = 1, gridWidth do
				local entity = row[(location.x - 1) * gridWidth + x]
				local owner = entity and self.entityRooms[entity]
				if entity and owner ~= room and not drawn[entity] then
					drawn[entity] = true
					local ownerLocation = self:roomLocation(owner.name)
					love.graphics.push()
					love.graphics.translate((ownerLocation.x - location.x) * width, (ownerLocation.y - location.y) * height)
					entity:draw(color)
					love.graphics.pop()
				end
			end
		end
	end
end

function World:getCellFromMousePos(mouseX, mouseY)
	return math.floor(mouseX / (width / self.width)) + 1, math.floor(mouseY / (height / self.height)) + 1
end

function World:getRoomData(name)
	-- The current room is live: its preview reflects unsaved edits immediately.
	if currentRoom and currentRoom.name == name then return currentRoom:serialize() end
	if not self.previewCache[name] then
		local raw = readFromSource("rooms/" .. name .. ".sav")
		if not raw then return nil end
		local ok, room = pcall(TSerial.unpack, raw)
		if not ok then return nil end
		self.previewCache[name] = room
	end
	return self.previewCache[name]
end

function World:invalidatePreview(name)
	self.previewCache[name] = nil
end

function World:drawRoomPreview(name, x, y, size)
	local room = self:getRoomData(name)
	if not room then return end
	local scale = size / (gridWidth * 16)
	love.graphics.setScissor(x, y, size, size)
	for _, object in ipairs(room.objects or {}) do
		if object.class == "npc" then
			love.graphics.setColor(1, 1, 1, 1)
			love.graphics.print("?", x + (object.x - 1) * 16 * scale, y + (object.y - 1) * 16 * scale, 0, scale, scale)
		else
			local props = globalAssetProperties[object.class]
			if props and props.sprites then
				local colors
				if object.class == "door" then
					colors = object.color and { object.color } or { "red", "green", "blue" }
				else
					colors = { object.color }
				end
				for _, color in ipairs(colors) do
					local path = props.sprites[color]
					if path then
						love.graphics.setColor(gColor[color]:set())
						local sprite = loadSprite(path)
						if props.goopy and drawGoopySprite then
							drawGoopySprite(sprite, x + (object.x - 1) * 16 * scale, y + (object.y - 1) * 16 * scale, scale)
						elseif props.skewer and drawSkewerSprite then
							drawSkewerSprite(sprite, props.cells and props.cells[color], x + (object.x - 1) * 16 * scale, y + (object.y - 1) * 16 * scale, scale)
						elseif props.spiky and drawSpikySprite then
							drawSpikySprite(sprite, props.cells and props.cells[color], x + (object.x - 1) * 16 * scale, y + (object.y - 1) * 16 * scale, scale)
						else
							love.graphics.draw(sprite, x + (object.x - 1) * 16 * scale, y + (object.y - 1) * 16 * scale, 0, scale, scale)
						end
					end
				end
			end
		end
	end
	love.graphics.setScissor()
end

function World:drawHoveredRoomName()
	local mouseX, mouseY = love.mouse.getPosition()
	local cellX, cellY = self:getCellFromMousePos(mouseX, mouseY)
	local name = self:isInBounds(cellX, cellY) and self:roomAt(cellX, cellY)
	if not name then return end

	local font = love.graphics.getFont()
	local padding = 6
	local tooltipW = math.min(font:getWidth(name) + padding * 2, width - 8)
	local tooltipH = font:getHeight() + padding * 2
	local tooltipX = math.min(mouseX + 14, width - tooltipW - 4)
	local tooltipY = math.min(mouseY + 14, height - tooltipH - 4)
	tooltipX = math.max(4, tooltipX)
	tooltipY = math.max(4, tooltipY)

	-- Keep the label anchored beside the pointer, while keeping it entirely in
	-- the playable map rather than allowing it to spill into the editor panel.
	love.graphics.setColor(0, 0, 0, 0.9)
	love.graphics.rectangle("fill", tooltipX, tooltipY, tooltipW, tooltipH)
	love.graphics.setColor(1, 1, 1, 1)
	love.graphics.rectangle("line", tooltipX, tooltipY, tooltipW, tooltipH)
	love.graphics.printf(name, tooltipX + padding, tooltipY + padding, tooltipW - padding * 2, "left")
end

function World:draw()
	local cell = width / self.width
	love.graphics.setColor(12 / 255, 12 / 255, 20 / 255, 1)
	love.graphics.rectangle("fill", 0, 0, width, height)
	for y = 1, self.height do
		for x = 1, self.width do
			local screenX, screenY = (x - 1) * cell, (y - 1) * cell
			local name = self:roomAt(x, y)
			if name then self:drawRoomPreview(name, screenX, screenY, cell) end
			love.graphics.setColor(name and 1 or 70 / 255, name and 1 or 70 / 255, name and 1 or 90 / 255, 1)
			love.graphics.rectangle("line", screenX, screenY, cell, cell)
		end
	end
	self:drawHoveredRoomName()
end