--!native
--!optimize 2

local PlacementManager = {}

local ChunkManager = require("./ChunkManager")
local Util = require("./Util")

local DEBUG_PLACEMENT = true
local function debugPlacementLog(...: any)
	if DEBUG_PLACEMENT then
		Util.StudioLog(...)
	end
end

local function debugPlacementWarn(...: any)
	if DEBUG_PLACEMENT then
		Util.StudioWarn(...)
	end
end

PlacementManager.ChunkFolder = ChunkManager.ChunkFolder

local raycastParams = RaycastParams.new()
raycastParams.FilterDescendantsInstances = {PlacementManager.ChunkFolder}
raycastParams.FilterType = Enum.RaycastFilterType.Include
raycastParams.IgnoreWater = true

local Mouse: Mouse = nil
local lastNormalId: Enum.NormalId? = nil
local lastRaycastFailure: string? = nil
local lastSelectedChunkKey: string? = nil
local lastSelectedBlockKey: string? = nil
local BREAK_ROLLBACK_TIMEOUT = 0.6
local pendingBreaks = {}
local clearSelection

if _G.__BLOCKSCRAFT_PLACEMENT_MANAGER then
	return _G.__BLOCKSCRAFT_PLACEMENT_MANAGER
end
_G.__BLOCKSCRAFT_PLACEMENT_MANAGER = PlacementManager

PlacementManager.SelectionBox = script.SelectionBox:Clone()
PlacementManager.SelectionBox.Name = "$SelectionBox"..(game:GetService("RunService"):IsServer() and "_SERVER" or "")
PlacementManager.SelectionBox.Parent = game:GetService("Workspace"):FindFirstChildOfClass("Terrain")
PlacementManager.SelectionBox.Adornee = nil
PlacementManager.SelectionBox:GetPropertyChangedSignal("Adornee"):Connect(function()
	local adornee = PlacementManager.SelectionBox.Adornee
	if not adornee then
		return
	end
	adornee.AncestryChanged:Connect(function(_, parent)
		if not parent then
			clearSelection("adornee destroyed")
		end
	end)
end)

-- Trash method TODO: Fix this
local function findChunkFolderFromDescendant(inst: Instance): Instance?
	local current = inst
	while current and current.Parent do
		if current.Parent == PlacementManager.ChunkFolder then
			return current
		end
		-- Fallback: match by name in case the ChunkFolder reference differs (e.g. recreated/parented later)
		if current.Parent:IsA("Folder") and current.Parent.Name == (PlacementManager.ChunkFolder and PlacementManager.ChunkFolder.Name) then
			return current
		end
		current = current.Parent
	end
	return nil
end

local function findBlockRoot(inst: Instance, chunkFolder: Instance): Instance?
	local current = inst
	while current and current ~= chunkFolder do
		if current:IsA("BasePart") then
			return current
		end
	current = current.Parent
	end
	return nil
end

local function resolveBlockInstance(chunkFolder: Instance, chunkName: string, blockName: string): Instance?
	local chunkInst = chunkFolder:FindFirstChild(chunkName)
	if not chunkInst then
		return nil
	end
	return chunkInst:FindFirstChild(blockName)
end

clearSelection = function(reason: string?)
	PlacementManager.SelectionBox.Adornee = nil
	PlacementManager.SelectionBox.Parent = nil
	lastNormalId = nil
	lastSelectedChunkKey = nil
	lastSelectedBlockKey = nil
	if reason then
		lastRaycastFailure = reason
	end
end

local function setSelection(target: Instance, parent: Instance)
	PlacementManager.SelectionBox.Parent = parent
	PlacementManager.SelectionBox.Adornee = target
end

local function findChunkAndBlock(inst: Instance): (string?, string?)
	local root = PlacementManager.ChunkFolder
	if not root then
		return nil, nil
	end
	local current = inst
	while current and current.Parent do
		-- case: current parent is the chunk folder root; then current is the chunk itself (no block name yet)
		if current.Parent == root then
			return current.Name, inst.Name
		end
		-- case: grandparent is chunk folder root; parent is chunk, current is block/model
		if current.Parent.Parent == root then
			return current.Parent.Name, current.Name
		end
		current = current.Parent
	end
	return nil, nil
end

local function vectorToNormalId(normal: Vector3): Enum.NormalId
	local ax, ay, az = math.abs(normal.X), math.abs(normal.Y), math.abs(normal.Z)
	if ax >= ay and ax >= az then
		return normal.X >= 0 and Enum.NormalId.Right or Enum.NormalId.Left
	elseif ay >= ax and ay >= az then
		return normal.Y >= 0 and Enum.NormalId.Top or Enum.NormalId.Bottom
	else
		return normal.Z >= 0 and Enum.NormalId.Back or Enum.NormalId.Front
	end
end

local function makeChunkKey(cx: number, cy: number, cz: number): string
	return `{cx},{cy},{cz}`
end

local function makeBlockKey(x: number, y: number, z: number): string
	return `{x},{y},{z}`
end

local function getPendingBreak(chunkKey: string, blockKey: string)
	local chunkMap = pendingBreaks[chunkKey]
	if not chunkMap then
		return nil
	end
	return chunkMap[blockKey]
end

local function clearPendingBreak(chunkKey: string, blockKey: string)
	local chunkMap = pendingBreaks[chunkKey]
	if not chunkMap then
		return
	end
	chunkMap[blockKey] = nil
	if not next(chunkMap) then
		pendingBreaks[chunkKey] = nil
	end
end

local function clearPendingBreaksForChunk(chunkKey: string)
	pendingBreaks[chunkKey] = nil
end

local function scheduleBreakRollback(cx: number, cy: number, cz: number, x: number, y: number, z: number)
	task.delay(BREAK_ROLLBACK_TIMEOUT, function()
		local chunkKey = makeChunkKey(cx, cy, cz)
		local blockKey = makeBlockKey(x, y, z)
		local pending = getPendingBreak(chunkKey, blockKey)
		if not pending then
			return
		end
		clearPendingBreak(chunkKey, blockKey)
		local chunk = ChunkManager:GetChunk(cx, cy, cz)
		if pending.data and chunk then
			chunk:CreateBlock(x, y, z, pending.data)
		end
		ChunkManager:RefreshChunk(cx, cy, cz)
	end)
end

local function normalIdToOffset(normal: Enum.NormalId): Vector3
	if normal == Enum.NormalId.Top then
		return Vector3.new(0, 1, 0)
	elseif normal == Enum.NormalId.Bottom then
		return Vector3.new(0, -1, 0)
	elseif normal == Enum.NormalId.Left then
		return Vector3.new(-1, 0, 0)
	elseif normal == Enum.NormalId.Right then
		return Vector3.new(1, 0, 0)
	elseif normal == Enum.NormalId.Back then
		return Vector3.new(0, 0, 1)
	elseif normal == Enum.NormalId.Front then
		return Vector3.new(0, 0, -1)
	end
	return Vector3.new(0, 0, 0)
end

local function offsetChunkBlock(chunk: Vector3, block: Vector3, offset: Vector3)
	local cx, cy, cz = chunk.X, chunk.Y, chunk.Z
	local bx, by, bz = block.X + offset.X, block.Y + offset.Y, block.Z + offset.Z

	if bx < 1 then
		bx = 8
		cx -= 1
	elseif bx > 8 then
		bx = 1
		cx += 1
	end

	if by < 1 then
		by = 8
		cy -= 1
	elseif by > 8 then
		by = 1
		cy += 1
	end

	if bz < 1 then
		bz = 8
		cz -= 1
	elseif bz > 8 then
		bz = 1
		cz += 1
	end

	return Vector3.new(cx, cy, cz), Vector3.new(bx, by, bz)
end

local function getPlayerPosition(): Vector3?
	local player = game:GetService("Players").LocalPlayer
	local character = player and player.Character
	if not character then
		return nil
	end
	local root = character:FindFirstChild("HumanoidRootPart")
	return root and root.Position or nil
end

local MAX_REACH = 512

local function isWithinReach(cx: number, cy: number, cz: number, x: number, y: number, z: number): boolean
	-- Client-side reach loosened; rely on server authority
	return true
end

local function ensureChunkFolder(): Instance?
	if PlacementManager.ChunkFolder and PlacementManager.ChunkFolder.Parent then
		return PlacementManager.ChunkFolder
	end
	local found = workspace:FindFirstChild("$blockscraft_client")
	if found then
		PlacementManager.ChunkFolder = found
		return found
	end
	return nil
end

-- Gets the block and normalid of the block (and surface) the player is looking at
function PlacementManager:Raycast()
	if not Mouse then
		Mouse = game:GetService("Players").LocalPlayer:GetMouse()
	end
	local chunkFolder = ensureChunkFolder()
	if not chunkFolder then
		clearSelection("chunk folder missing")
		script.RaycastResult.Value = nil
		return
	end

	raycastParams.FilterDescendantsInstances = {chunkFolder}
	local cam = workspace.CurrentCamera
	if not cam then
		lastRaycastFailure = "no camera"
		return
	end
	local ray = Mouse.UnitRay
	local result = workspace:Raycast(ray.Origin, ray.Direction * MAX_REACH, raycastParams)
	if not result then
		clearSelection("raycast miss")
		script.RaycastResult.Value = nil
		debugPlacementLog("[PLACE][CLIENT][RAYCAST]", "miss")
		return
	end

	local objLookingAt = result.Instance
	if not objLookingAt then
		clearSelection("raycast nil instance")
		script.RaycastResult.Value = nil
		debugPlacementWarn("[PLACE][CLIENT][RAYCAST]", "nil instance in result")
		return
	end

	local hitChunkFolder = findChunkFolderFromDescendant(objLookingAt)
	if not hitChunkFolder then
		debugPlacementWarn(
			"[PLACE][CLIENT][REJECT]",
			"target not in chunk folder",
			objLookingAt:GetFullName(),
			"parent",
			objLookingAt.Parent and objLookingAt.Parent:GetFullName() or "nil"
		)
		clearSelection("target not in chunk folder")
		script.RaycastResult.Value = nil
		return
	end
	if hitChunkFolder:GetAttribute("ns") == true then
		debugPlacementWarn(
			"[PLACE][CLIENT][REJECT]",
			"chunk flagged ns",
			hitChunkFolder:GetFullName()
		)
		clearSelection("target chunk marked ns")
		script.RaycastResult.Value = nil
		return
	end
	PlacementManager.ChunkFolder = chunkFolder

	local blockRoot = findBlockRoot(objLookingAt, chunkFolder) or objLookingAt
	local chunkName, blockName = findChunkAndBlock(blockRoot)
	if not chunkName or not blockName then
		clearSelection("failed to resolve chunk/block")
		script.RaycastResult.Value = nil
		return
	end
	local okChunk, chunkCoords = pcall(function()
		return Util.BlockPosStringToCoords(chunkName)
	end)
	local okBlock, blockCoords = pcall(function()
		return Util.BlockPosStringToCoords(blockName)
	end)
	if not okChunk or not okBlock then
		clearSelection("failed to parse chunk/block names")
		script.RaycastResult.Value = nil
		return
	end
	local chunkKey = makeChunkKey(chunkCoords.X, chunkCoords.Y, chunkCoords.Z)
	local blockKey = makeBlockKey(blockCoords.X, blockCoords.Y, blockCoords.Z)

	-- block is being optimistically broken, do not highlight it
	if getPendingBreak(chunkKey, blockKey) then
		clearSelection("block pending break")
		script.RaycastResult.Value = nil
		return
	end

	-- hide selection if block no longer exists (air/removed)
	local chunk = ChunkManager:GetChunk(chunkCoords.X, chunkCoords.Y, chunkCoords.Z)
	local blockData = chunk and chunk:GetBlockAt(blockCoords.X, blockCoords.Y, blockCoords.Z)
	if not blockData or blockData == 0 or blockData.id == 0 then
		clearSelection("block missing/air")
		script.RaycastResult.Value = nil
		return
	end
	local blockInstance = resolveBlockInstance(chunkFolder, chunkName, blockName) or blockRoot
	if not blockInstance then
		clearSelection("missing block instance")
		script.RaycastResult.Value = nil
		return
	end

	lastRaycastFailure = nil
	if lastSelectedChunkKey ~= chunkKey or lastSelectedBlockKey ~= blockKey then
		setSelection(blockInstance, PlacementManager.ChunkFolder)
		lastSelectedChunkKey = chunkKey
		lastSelectedBlockKey = blockKey
	end
	script.RaycastResult.Value = objLookingAt
	lastNormalId = vectorToNormalId(result.Normal)
	debugPlacementLog(
		"[PLACE][CLIENT][RAYCAST][HIT]",
		blockInstance:GetFullName(),
		"chunkFolder",
		hitChunkFolder:GetFullName(),
		"blockName",
		blockInstance.Name,
		"normal",
		lastNormalId.Name
	)
	return objLookingAt, lastNormalId
end

function PlacementManager:RaycastGetResult()
	return script.RaycastResult.Value
end

local remotes = game:GetService("ReplicatedStorage"):WaitForChild("Remotes")
local placeRemote = remotes:WaitForChild("PlaceBlock")
local breakRemote = remotes:WaitForChild("BreakBlock")
local tickRemote = game:GetService("ReplicatedStorage").Tick

-- FIRES REMOTE
function PlacementManager:PlaceBlock(cx, cy, cz, x, y, z, blockId: string)
	debugPlacementLog("[PLACE][CLIENT][PLACE_CALL]", "chunk", cx, cy, cz, "block", x, y, z, "blockId", blockId)
	if typeof(cx) ~= "number" or typeof(cy) ~= "number" or typeof(cz) ~= "number" then
		debugPlacementWarn("[PLACE][CLIENT][REJECT]", "chunk type", cx, cy, cz, x, y, z, blockId)
		return
	end
	if typeof(x) ~= "number" or typeof(y) ~= "number" or typeof(z) ~= "number" then
		debugPlacementWarn("[PLACE][CLIENT][REJECT]", "block type", cx, cy, cz, x, y, z, blockId)
		return
	end
	if x < 1 or x > 8 or y < 1 or y > 8 or z < 1 or z > 8 then
		debugPlacementWarn("[PLACE][CLIENT][REJECT]", "block bounds", cx, cy, cz, x, y, z, blockId)
		return
	end
	if not isWithinReach(cx, cy, cz, x, y, z) then
		debugPlacementWarn("[PLACE][CLIENT][REJECT]", "reach", cx, cy, cz, x, y, z, blockId)
		return
	end

	-- ensure chunk is present/rendered client-side
	local chunk = ChunkManager:GetChunk(cx, cy, cz)
	if chunk and not chunk.loaded then
		ChunkManager:LoadChunk(cx, cy, cz)
	end
	if not chunk then
		debugPlacementWarn("[PLACE][CLIENT][REJECT]", "missing chunk", cx, cy, cz, x, y, z, blockId)
		return
	end

	-- if the client already thinks this block is the same id, skip sending
	if chunk then
		local existing = chunk:GetBlockAt(x, y, z)
		local existingId = existing and existing.id
		if existingId and tostring(existingId) == tostring(blockId) then
			debugPlacementLog(
				"[PLACE][CLIENT][SKIP]",
				"duplicate id",
				"chunk",
				cx,
				cy,
				cz,
				"block",
				x,
				y,
				z,
				"existingId",
				existingId,
				"blockId",
				blockId
			)
			return
		else
			debugPlacementLog(
				"[PLACE][CLIENT][EXISTING]",
				"chunk",
				cx,
				cy,
				cz,
				"block",
				x,
				y,
				z,
				"existingId",
				existingId
			)
		end
	end

	-- optimistic local apply; server will correct on tick
	if chunk then
		chunk:CreateBlock(x, y, z, {
			id = tonumber(blockId) or blockId,
			state = {},
		})
	end

	debugPlacementLog("[PLACE][CLIENT][SEND]", cx, cy, cz, x, y, z, blockId)
	placeRemote:FireServer(cx, cy, cz, x, y, z, blockId)
end

-- FIRES REMOTE
function PlacementManager:BreakBlock(cx, cy, cz, x, y, z)
	if typeof(cx) ~= "number" or typeof(cy) ~= "number" or typeof(cz) ~= "number" then
		return
	end
	if typeof(x) ~= "number" or typeof(y) ~= "number" or typeof(z) ~= "number" then
		debugPlacementWarn("[BREAK][CLIENT][REJECT]", "block type", cx, cy, cz, x, y, z)
		return
	end
	if x < 1 or x > 8 or y < 1 or y > 8 or z < 1 or z > 8 then
		debugPlacementWarn("[BREAK][CLIENT][REJECT]", "block bounds", cx, cy, cz, x, y, z)
		return
	end
	if not isWithinReach(cx, cy, cz, x, y, z) then
		debugPlacementWarn("[BREAK][CLIENT][REJECT]", "reach", cx, cy, cz, x, y, z)
		return
	end

	local chunk = ChunkManager:GetChunk(cx, cy, cz)
	local blockData = chunk and chunk:GetBlockAt(x, y, z) or nil
	local chunkKey = makeChunkKey(cx, cy, cz)
	local blockKey = makeBlockKey(x, y, z)
	if getPendingBreak(chunkKey, blockKey) then
		debugPlacementLog("[BREAK][CLIENT][SKIP]", "pending rollback", cx, cy, cz, x, y, z)
		return
	end
	pendingBreaks[chunkKey] = pendingBreaks[chunkKey] or {}
	pendingBreaks[chunkKey][blockKey] = {
		data = blockData,
		time = tick(),
	}
	if blockData then
		chunk:RemoveBlock(x, y, z)
	end
	scheduleBreakRollback(cx, cy, cz, x, y, z)
	debugPlacementLog("[BREAK][CLIENT][SEND]", cx, cy, cz, x, y, z)
	breakRemote:FireServer(cx, cy, cz, x, y, z)
end

-- CLIENTSIDED: only apply server-validated changes
local function applyPlaceBlockLocal(cx, cy, cz, x, y, z, blockData)
	local chunk = ChunkManager:GetChunk(cx, cy, cz)
	if chunk and not chunk.loaded then
		ChunkManager:LoadChunk(cx, cy, cz)
	end
	chunk:CreateBlock(x, y, z, blockData)
end

-- CLIENTSIDED: only apply server-validated changes
local function applyBreakBlockLocal(cx, cy, cz, x, y, z)
	local chunk = ChunkManager:GetChunk(cx, cy, cz)
	if chunk and not chunk.loaded then
		ChunkManager:LoadChunk(cx, cy, cz)
	end
	if not chunk then
		return
	end
	local chunkKey = makeChunkKey(cx, cy, cz)
	local blockKey = makeBlockKey(x, y, z)
	if getPendingBreak(chunkKey, blockKey) then
		clearPendingBreak(chunkKey, blockKey)
		return
	end
	chunk:RemoveBlock(x, y, z)
end

function PlacementManager:GetBlockAtMouse(): nil | {chunk:Vector3, block: Vector3}
	pcall(function()
		PlacementManager:Raycast()
	end)
	local selectedPart = PlacementManager:RaycastGetResult()
	--print(selectedPart and selectedPart:GetFullName() or nil)
	if selectedPart == nil then
		clearSelection()
		script.RaycastResult.Value = nil
		debugPlacementLog("[PLACE][CLIENT][TARGET]", "no selectedPart after raycast", lastRaycastFailure)
		return nil
	end
	local chunkName, blockName = findChunkAndBlock(selectedPart)
	if not chunkName or not blockName then
		debugPlacementWarn(
			"[PLACE][CLIENT][TARGET]",
			"failed to find chunk/block from selection",
			selectedPart:GetFullName()
		)
		return nil
	end

	local okChunk, chunkCoords = pcall(function()
		return Util.BlockPosStringToCoords(chunkName :: string)
	end)
	local okBlock, blockCoords = pcall(function()
		return Util.BlockPosStringToCoords(blockName :: string)
	end)
	if not okChunk or not okBlock then
		debugPlacementWarn(
			"[PLACE][CLIENT][TARGET]",
			"failed to parse names",
			"chunkName",
			chunkName,
			"blockName",
			blockName
		)
		return nil
	end
	debugPlacementLog(
		"[PLACE][CLIENT][TARGET]",
		"chunk",
		chunkName,
		"block",
		blockName,
		"normal",
		(lastNormalId and lastNormalId.Name) or "nil"
	)

	return {
		chunk = chunkCoords,
		block = blockCoords
	}

end

function PlacementManager:GetTargetAtMouse(): nil | {chunk:Vector3, block: Vector3, normal: Enum.NormalId}
	local hit = PlacementManager:GetBlockAtMouse()
	if not hit then
		return nil
	end
	local normal = lastNormalId or Enum.NormalId.Top

	return {
		chunk = hit.chunk,
		block = hit.block,
		normal = normal
	}
end

function PlacementManager:GetPlacementAtMouse(): nil | {chunk:Vector3, block: Vector3}
	local hit = PlacementManager:GetTargetAtMouse()
	if not hit then
		return nil
	end
	local offset = normalIdToOffset(hit.normal)
	local placeChunk, placeBlock = offsetChunkBlock(hit.chunk, hit.block, offset)
	debugPlacementLog(
		"[PLACE][CLIENT][PLACE_TARGET]",
		"target chunk",
		hit.chunk,
		"target block",
		hit.block,
		"normal",
		hit.normal.Name,
		"place chunk",
		placeChunk,
		"place block",
		placeBlock
	)
	return {
		chunk = placeChunk,
		block = placeBlock
	}
end

function PlacementManager:DebugGetPlacementOrWarn()
	local placement = PlacementManager:GetPlacementAtMouse()
	if not placement then
		debugPlacementWarn("[PLACE][CLIENT][REJECT]", "no placement target under mouse", lastRaycastFailure)
	end
	return placement
end

function PlacementManager:Init()
	game:GetService("RunService").RenderStepped:Connect(function()
		local a,b = pcall(function()
			PlacementManager:Raycast()
		end)
		if not a then
			clearSelection("raycast error")
			script.RaycastResult.Value = nil
		end
	end)
	tickRemote.OnClientEvent:Connect(function(m, cx, cy, cz, x, y, z, d)
		--warn("PROPOGATED TICK", m, cx, cy, cz, x, y, z, d)
		if m == "B_C" then
			applyPlaceBlockLocal(cx, cy, cz, x, y ,z, d)
		end
		if m == "B_D" then
			applyBreakBlockLocal(cx, cy, cz, x, y ,z)
		end
		if m == "C_R" then
			clearPendingBreaksForChunk(makeChunkKey(cx, cy, cz))
			ChunkManager:RefreshChunk(cx, cy, cz)
		end
	end)
end

return PlacementManager