local term_stack = require("term-stack")
local ensure_width = require("cc.strings").ensure_width
local ui = require("ui")
local main_view = {}

local function clamp(x, min, max)
	return math.min(math.max(x, min), max)
end

local function rect(x, y, w, h)
	return { x = x, y = y, w = w, h = h or w }
end

local function list_items(inventories)
	local item_registry = {}
	for _, name in ipairs(inventories) do
		for slot, item in pairs(peripheral.call(name, "list")) do
			item_registry[item.name] = item_registry[item.name] or {}
			table.insert(item_registry[item.name], {
				count = item.count,
				slot = slot,
				peripheral = name
			})
		end
	end

	for _, items in pairs(item_registry) do
		items.count = 0
		for _, slot in ipairs(items) do
			items.count = items.count + slot.count
		end
	end

	return item_registry
end

local function populate_item_details(item_details, item_registry)
	for name, items in pairs(item_registry) do
		local item = items[1]
		if item and not item_details[name] then
			local detail = peripheral.call(item.peripheral, "getItemDetail", item.slot)
			item_details[name] = {
				display_name = detail.displayName,
				stack_size = detail.maxCount
			}
		end
	end
end

local function remove_value(array, value)
	for i, v in ipairs(array) do
		if v == value then
			table.remove(array, i)
			return
		end
	end
end

local function vsplit(area, x)
	local left_area = rect(area.x, area.y, x - area.x, area.h)
	local right_area = rect(area.x + left_area.w+1, area.y, area.w - left_area.w-1, area.h)
	return left_area, right_area
end

local function vline(x, y, height)
	for i=1, height do
		term.setCursorPos(x, y+i-1)
		term.write("|")
	end
end

local function get_item_counts(items)
	local item_counts = {}
	for name, item_collection in pairs(items) do
		item_counts[name] = item_collection.count
	end
	return item_counts
end

function main_view:prepare(inventories, result_inventory)
	self.event = {}

	self.is_left_active = true

	self.main_area = rect(1, 1, term.getSize())
	self.split_x = math.floor(self.main_area.w*0.5)
	self.left_area, self.right_area = vsplit(self.main_area, self.split_x)

	self.result_inventory = result_inventory
	self.inventories = inventories
	remove_value(self.inventories, result_inventory)

	self.item_registry = list_items(self.inventories)
	self.item_details = {}
	populate_item_details(self.item_details, self.item_registry)

	local all_item_counts = get_item_counts(self.item_registry)
	self.left_store = {
		all_items = all_item_counts,
		filtered_names = self:list_filtered_names(all_item_counts, ""),
		search_bar = "",
		selected_idx = 1,
		scroll = 0
	}
	self.right_store = {
		all_items = {},
		filtered_names = {},
		search_bar = "",
		selected_idx = 1,
		scroll = 0
	}
end

function main_view:list_filtered_names(all_items, name_filter)
	name_filter = name_filter:lower()

	local names = {}
	for name, count in pairs(all_items) do
		local display_name = self.item_details[name].display_name:lower()
		if display_name:find(name_filter) and count > 0 then
			table.insert(names, name)
		end
	end

	table.sort(names, function(a, b)
		if all_items[a] == all_items[b] then
			return a < b
		else
			return all_items[a] > all_items[b]
		end
	end)

	return names
end

function main_view:display_item_list(store, area, active)
	term_stack.push_cursor(area.x, area.y)

	local filtered_names = store.filtered_names
	local shown_count = #filtered_names

	local max_count = 0
	for i=1, math.min(area.h, shown_count) do
		local name = filtered_names[i + store.scroll]
		local count = store.all_items[name]
		max_count = math.max(max_count, count)
	end
	local max_count_width = math.floor(math.log(max_count, 10) + 1)

	for row=1, math.min(area.h, shown_count) do
		local i = row + store.scroll
		local name = filtered_names[i]
		local count = store.all_items[name]
		local item_info = self.item_details[name]
		local count_width = math.floor(math.log(count, 10) + 1)
		if i == store.selected_idx and active then
			term.setTextColor(colors.yellow)
		else
			term.setTextColor(colors.white)
		end
		term.setCursorPos((max_count_width+1 - count_width), row)
		term.write(count)
		term.setCursorPos(max_count_width+2, row)
		term.write(ensure_width(item_info.display_name, area.w-max_count_width-1))
	end

	if shown_count > area.h then
		local scroll_height = math.max(1, area.h/shown_count*area.h)
		local y = 1+store.scroll/shown_count*area.h
		paintutils.drawLine(area.w, y, area.w, y+scroll_height-1, colors.lightGray)
	end

	term_stack.pop_cursor()
end

function main_view:move_item(item_name, amount, destination)
	local item_collection = self.item_registry[item_name]

	local moved_amount = 0
	while moved_amount < amount and item_collection.count > 0 do
		local slot_details = item_collection[#item_collection]

		local needed_amount = amount - moved_amount
		local transferred_amount = peripheral.call(slot_details.peripheral, "pushItems", destination, slot_details.slot, needed_amount)
		if transferred_amount == 0 then break end

		moved_amount = moved_amount + transferred_amount
		slot_details.count = slot_details.count - transferred_amount
		item_collection.count = item_collection.count - transferred_amount
		if slot_details.count == 0 then
			table.remove(item_collection)
		end
	end

	return moved_amount
end

function main_view:update_selected_item(store, area, idx)
	local filtered_count = #store.filtered_names
	store.selected_idx = clamp(idx, 1, filtered_count)

	local margin = 2
	local item_list_height = area.h-1
	if store.selected_idx > store.scroll+item_list_height-margin then
		store.scroll = math.min(store.selected_idx-item_list_height+margin, filtered_count-item_list_height)
	elseif store.selected_idx <= store.scroll+margin then
		store.scroll = math.max(store.selected_idx-1-margin, 0)
	end
end

function main_view:select_item(store, area, item_name)
	for i, name in ipairs(store.filtered_names) do
		if name == item_name then
			self:update_selected_item(store, area, i)
			return
		end
	end
end

function main_view:refresh_filtered_names(store, area)
	store.filtered_names = main_view:list_filtered_names(store.all_items, store.search_bar or "")
	self:update_selected_item(store, area, store.selected_idx)
end

function main_view:display_items_with_search(store, area, active)
	term_stack.push_cursor(area.x, area.y)

	local new_search_bar = ui:textbox(area.w, active, "Search", store.search_bar)
	if new_search_bar ~= store.search_bar then
		store.search_bar = new_search_bar
		self:refresh_filtered_names(store, area)
	end

	if active then
		if ui.event[1] == "key" then
			local key = ui.event[2]
			if key == keys.down or (main_view.ctrl_down and key == keys.j) then
				store.selected_idx = math.min(store.selected_idx + 1, #store.filtered_names)
			elseif key == keys.up or (main_view.ctrl_down and key == keys.k) then
				store.selected_idx = math.max(store.selected_idx - 1, 1)
			end

			local margin = 2
			local item_list_height = area.h-1
			if store.selected_idx > store.scroll+item_list_height-margin then
				store.scroll = math.min(store.selected_idx-item_list_height+margin, #store.filtered_names - item_list_height)
			elseif store.selected_idx <= store.scroll+margin then
				store.scroll = math.max(store.selected_idx-1-margin, 0)
			end
		end
	end

	term.setBackgroundColor(colors.black)
	main_view:display_item_list(store, rect(1, 2, area.w, area.h-1), active)

	term_stack.pop_cursor()
end

function main_view:has_selected_items()
	for _, count in pairs(main_view.right_store.all_items) do
		if count > 0 then
			return true
		end
	end

	return false
end

function main_view:refresh_items()
	self.item_registry = list_items(self.inventories)
	populate_item_details(self.item_details, self.item_registry)

	self.left_store.all_items = get_item_counts(self.item_registry)
	self.right_store.all_items = {}
	self:refresh_filtered_names(self.left_store, self.left_area)
	self:refresh_filtered_names(self.right_store, self.right_area)
end

function main_view:deposit_items()
	for slot, item in pairs(peripheral.call(self.result_inventory, "list")) do
		local total_transferred = 0
		for _, inventory in ipairs(self.inventories) do
			local transferred = peripheral.call(self.result_inventory, "pushItems", inventory, slot)
			total_transferred = total_transferred + transferred

			if total_transferred == item.count then break end
		end
	end
	self:refresh_items()
end

function main_view:draw()
	term.setBackgroundColor(colors.black)
	term.clear()

	local has_selected_items = self:has_selected_items()
	if has_selected_items then
		term.setTextColor(colors.lightGray)
		vline(self.split_x, self.main_area.y, self.main_area.h)

		main_view:display_items_with_search(self.left_store, self.left_area, self.is_left_active)
		main_view:display_items_with_search(self.right_store, self.right_area, not self.is_left_active)
	else
		main_view:display_items_with_search(self.left_store, self.main_area, true)
	end
end

function main_view:on_event(event, ...)
	local has_selected_items = self:has_selected_items()
	if not has_selected_items and not self.is_left_active then
		self.is_left_active = true
	end

	if event == "key" then
		self:on_key(...)
	elseif event == "key_up" then
		self:on_key_up(...)
	end
end

function main_view:on_key(key)
	local left_selected = self.left_store.filtered_names[self.left_store.selected_idx]
	local right_selected = self.right_store.filtered_names[self.right_store.selected_idx]

	if key == keys.rightCtrl or key == keys.leftCtrl then
		self.ctrl_down = true
	elseif key == keys.rightAlt or key == keys.leftAlt then
		self.alt_down = true
	elseif key == keys.tab then
		self.is_left_active = not self.is_left_active
	elseif key == keys.f5 then
		self:refresh_items()
	end

	if self.ctrl_down then
		local has_selected_items = self:has_selected_items()
		if key == keys.space then
			if has_selected_items then
				for name, count in pairs(self.right_store.all_items) do
					local transferred = self:move_item(name, count, self.result_inventory)
					self.left_store.all_items[name] = self.left_store.all_items[name] - transferred
				end
				self.right_store.all_items = {}
				self:refresh_filtered_names(self.left_store, self.left_area)
				self:refresh_filtered_names(self.right_store, self.right_area)
			else
				if left_selected then
					local item = left_selected
					local stack_size = self.item_details[item].stack_size
					local transferred_count = self:move_item(item, stack_size, self.result_inventory)
					self.left_store.all_items[item] = self.left_store.all_items[item] - transferred_count
					self:refresh_filtered_names(self.left_store, self.left_area)
					self:select_item(self.left_store, self.left_area, item)
				end
			end
		elseif key == keys.d then
			self:deposit_items()
		end

		if self.is_left_active then
			if key == keys.l and left_selected then
				local item = left_selected
				local stack_size = self.item_details[item].stack_size
				local transferred = math.min(self.left_store.all_items[item], stack_size)
				self.left_store.all_items[item] = self.left_store.all_items[item] - transferred
				self.right_store.all_items[item] = (self.right_store.all_items[item] or 0) + transferred
				self:refresh_filtered_names(self.left_store, self.left_area)
				self:refresh_filtered_names(self.right_store, self.right_area)
				self:select_item(self.left_store, self.left_area, item)
			end
		else
			if key == keys.h and right_selected then
				local item = right_selected
				local stack_size = self.item_details[item].stack_size
				local transferred = math.min(self.right_store.all_items[item], stack_size)
				self.left_store.all_items[item] = self.left_store.all_items[item] + transferred
				self.right_store.all_items[item] = self.right_store.all_items[item] - transferred
				self:refresh_filtered_names(self.left_store, self.left_area)
				self:refresh_filtered_names(self.right_store, self.right_area)
				self:select_item(self.right_store, self.right_area, item)
			end
		end
	end
end

function main_view:on_key_up(key)
	if key == keys.rightCtrl or key == keys.leftCtrl then
		self.ctrl_down = false
	elseif key == keys.rightAlt or key == keys.leftAlt then
		self.alt_down = false
	end
end

return main_view