local S = minetest.get_translator("mtg_craftguide")
local esc = minetest.formspec_escape
local storage = minetest.get_mod_storage()

local player_data = {}
local init_items = {}
local recipes_cache = {}
local usages_cache = {}

local progressive_mode = minetest.settings:get_bool("progressive_mode", true)

local group_stereotypes = {
	dye = "dye:white",
	wool = "wool:white",
	coal = "default:coal_lump",
	vessel = "vessels:glass_bottle",
	flower = "flowers:dandelion_yellow"
}

local group_names = {
	coal = S("Any coal"),
	sand = S("Any sand"),
	wool = S("Any wool"),
	stick = S("Any stick"),
	vessel = S("Any vessel"),
	wood = S("Any wood planks"),
	stone = S("Any kind of stone block"),

	["color_red,flower"] = S("Any red flower"),
	["color_blue,flower"] = S("Any blue flower"),
	["color_black,flower"] = S("Any black flower"),
	["color_green,flower"] = S("Any green flower"),
	["color_white,flower"] = S("Any white flower"),
	["color_orange,flower"] = S("Any orange flower"),
	["color_violet,flower"] = S("Any violet flower"),
	["color_yellow,flower"] = S("Any yellow flower"),

	["color_red,dye"] = S("Any red dye"),
	["color_blue,dye"] = S("Any blue dye"),
	["color_cyan,dye"] = S("Any cyan dye"),
	["color_grey,dye"] = S("Any grey dye"),
	["color_pink,dye"] = S("Any pink dye"),
	["color_black,dye"] = S("Any black dye"),
	["color_brown,dye"] = S("Any brown dye"),
	["color_green,dye"] = S("Any green dye"),
	["color_white,dye"] = S("Any white dye"),
	["color_orange,dye"] = S("Any orange dye"),
	["color_violet,dye"] = S("Any violet dye"),
	["color_yellow,dye"] = S("Any yellow dye"),
	["color_magenta,dye"] = S("Any magenta dye"),
	["color_dark_grey,dye"] = S("Any dark grey dye"),
	["color_dark_green,dye"] = S("Any dark green dye")
}

local function table_replace(t, val, new)
	for k, v in pairs(t) do
		if v == val then
			t[k] = new
		end
	end
end

local function extract_groups(str)
	if str:sub(1, 6) == "group:" then
		return str:sub(7):split()
	end
	return nil
end

local function item_has_groups(item_groups, groups)
	for _, group in ipairs(groups) do
		if not item_groups[group] then
			return false
		end
	end
	return true
end

local function groups_to_item(groups)
	if #groups == 1 then
		local group = groups[1]
		if group_stereotypes[group] then
			return group_stereotypes[group]
		elseif minetest.registered_items["default:"..group] then
			return "default:"..group
		end
	end

	for name, def in pairs(minetest.registered_items) do
		if item_has_groups(def.groups, groups) then
			return name
		end
	end

	return ":unknown"
end

local function get_craftable_recipes(output)
	local recipes = minetest.get_all_craft_recipes(output)
	if not recipes then
		return nil
	end

	for i = #recipes, 1, -1 do
		for _, item in pairs(recipes[i].items) do
			local groups = extract_groups(item)
			if groups then
				item = groups_to_item(groups)
			end
			if not minetest.registered_items[item] then
				table.remove(recipes, i)
				break
			end
		end
	end

	if #recipes > 0 then
		return recipes
	end
end

local function show_item(def)
	return def.groups.not_in_craft_guide ~= 1 and def.description ~= ""
end

local function cache_usages(recipe)
	local added = {}
	for _, item in pairs(recipe.items) do
		if not added[item] then
			local groups = extract_groups(item)
			if groups then
				for name, def in pairs(minetest.registered_items) do
					if not added[name] and show_item(def)
							and item_has_groups(def.groups, groups) then
						local usage = table.copy(recipe)
						table_replace(usage.items, item, name)
						usages_cache[name] = usages_cache[name] or {}
						table.insert(usages_cache[name], usage)
						added[name] = true
					end
				end
			elseif show_item(minetest.registered_items[item]) then
				usages_cache[item] = usages_cache[item] or {}
				table.insert(usages_cache[item], recipe)
			end
			added[item] = true
		end
	end
end

minetest.register_on_mods_loaded(function()
	for name, def in pairs(minetest.registered_items) do
		if show_item(def) then
			local recipes = get_craftable_recipes(name)
			if recipes then
				recipes_cache[name] = recipes
				for _, recipe in ipairs(recipes) do
					cache_usages(recipe)
				end
			end
		end
	end
	if not progressive_mode then
		for name, def in pairs(minetest.registered_items) do
			if recipes_cache[name] or usages_cache[name] then
				table.insert(init_items, name)
			end
		end
		table.sort(init_items)
	end
end)

local function coords(i, cols)
	return i % cols, math.floor(i / cols)
end

local function is_fuel(item)
	return minetest.get_craft_result({method="fuel", items={item}}).time > 0
end

local function item_button_fs(fs, x, y, item, element_name, groups)
	table.insert(fs, ("item_image_button[%s,%s;1.05,1.05;%s;%s;%s]")
		:format(x, y, item, element_name, groups and "\n"..esc(S("G")) or ""))

	local tooltip
	if groups then
		table.sort(groups)
		tooltip = group_names[table.concat(groups, ",")]
		if not tooltip then
			local groupstr = {}
			for _, group in ipairs(groups) do
				table.insert(groupstr, minetest.colorize("yellow", group))
			end
			groupstr = table.concat(groupstr, ", ")
			tooltip = S("Any item belonging to the group(s): @1", groupstr)
		end
	elseif is_fuel(item) then
		local itemdef = minetest.registered_items[item:match("%S*")]
		local desc = itemdef and itemdef.description or S("Unknown Item")
		tooltip = desc.."\n"..minetest.colorize("orange", S("Fuel"))
	end
	if tooltip then
		table.insert(fs, ("tooltip[%s;%s]"):format(element_name, esc(tooltip)))
	end
end

local function recipe_fs(fs, data)
	local recipe = data.recipes[data.rnum]
	local width = recipe.width
	local cooktime, shapeless

	if recipe.method == "cooking" then
		cooktime, width = width, 1
	elseif width == 0 then
		shapeless = true
		if #recipe.items == 1 then
			width = 1
		elseif #recipe.items <= 4 then
			width = 2
		else
			width = 3
		end
	end

	table.insert(fs, ("label[5.5,1;%s]"):format(esc(data.show_usages
		and S("Usage @1 of @2", data.rnum, #data.recipes)
		or S("Recipe @1 of @2", data.rnum, #data.recipes))))

	if #data.recipes > 1 then
		table.insert(fs,
			"image_button[5.5,1.6;0.8,0.8;craftguide_prev_icon.png;recipe_prev;]"..
			"image_button[6.2,1.6;0.8,0.8;craftguide_next_icon.png;recipe_next;]"..
			"tooltip[recipe_prev;"..esc(S("Previous recipe")).."]"..
			"tooltip[recipe_next;"..esc(S("Next recipe")).."]")
	end

	local rows = math.ceil(table.maxn(recipe.items) / width)
	if width > 3 or rows > 3 then
		table.insert(fs, ("label[0,1;%s]")
			:format(esc(S("Recipe is too big to be displayed."))))
		return
	end

	local base_x = 3 - width
	local base_y = rows == 1 and 1 or 0

	for i, item in pairs(recipe.items) do
		local x, y = coords(i - 1, width)

		local elem_name = item
		local groups = extract_groups(item)
		if groups then
			item = groups_to_item(groups)
			elem_name = esc(item.."."..table.concat(groups, "+"))
		end
		item_button_fs(fs, base_x + x, base_y + y, item, elem_name, groups)
	end

	if shapeless or recipe.method == "cooking" then
		table.insert(fs, ("image[3.2,0.5;0.5,0.5;craftguide_%s.png]")
			:format(shapeless and "shapeless" or "furnace"))
		local tooltip = shapeless and S("Shapeless") or
			S("Cooking time: @1", minetest.colorize("yellow", cooktime))
		table.insert(fs, "tooltip[3.2,0.5;0.5,0.5;"..esc(tooltip).."]")
	end
	table.insert(fs, "image[3,1;1,1;sfinv_crafting_arrow.png]")

	item_button_fs(fs, 4, 1, recipe.output, recipe.output:match("%S*"))
end

local function get_formspec(player)
	local name = player:get_player_name()
	local data = player_data[name]
	data.pagemax = math.max(1, math.ceil(#data.items / 32))

	local fs = {}
	table.insert(fs,
		"style_type[item_image_button;padding=2]"..
		"field[0.3,4.2;2.8,1.2;filter;;"..esc(data.filter).."]"..
		"label[5.8,4.15;"..minetest.colorize("yellow", data.pagenum).." / "..
			data.pagemax.."]"..
		"image_button[2.63,4.05;0.8,0.8;craftguide_search_icon.png;search;]"..
		"image_button[3.25,4.05;0.8,0.8;craftguide_clear_icon.png;clear;]"..
		"image_button[5,4.05;0.8,0.8;craftguide_prev_icon.png;prev;]"..
		"image_button[7.25,4.05;0.8,0.8;craftguide_next_icon.png;next;]"..
		"tooltip[search;"..esc(S("Search")).."]"..
		"tooltip[clear;"..esc(S("Reset")).."]"..
		"tooltip[prev;"..esc(S("Previous page")).."]"..
		"tooltip[next;"..esc(S("Next page")).."]"..
		"field_enter_after_edit[filter;true]"..
		"field_close_on_enter[filter;false]")

	if #data.items == 0 then
		table.insert(fs, "label[3,2;"..esc(S("No items to show.")).."]")
	else
		local first_item = (data.pagenum - 1) * 32
		for i = first_item, first_item + 31 do
			local item = data.items[i + 1]
			if not item then
				break
			end
			local x, y = coords(i % 32, 8)
			item_button_fs(fs, x, y, item, item)
		end
	end

	table.insert(fs, "container[0,5.6]")
	if data.recipes and #data.recipes > 0 then
		recipe_fs(fs, data)
	elseif data.prev_item then
		table.insert(fs, ("label[2,1;%s]"):format(esc(data.show_usages
			and S("No usages.").."\n"..S("Click again to show recipes.")
			or S("No recipes.").."\n"..S("Click again to show usages."))))
	end
	table.insert(fs, "container_end[]")

	return table.concat(fs)
end

local function imatch(str, filter)
	return str:lower():find(filter, 1, true) ~= nil
end

local function execute_search(data)
	local filter = data.filter
	local all_items = init_items
	if progressive_mode then
		all_items = visible_items(data)
	end

	if filter == "" then
		data.items = all_items
		return
	end
	data.items = {}

	for _, item in ipairs(all_items) do
		local def = minetest.registered_items[item]
		local desc = def and minetest.get_translated_string(data.lang_code, def.description)

		if imatch(item, filter) or desc and imatch(desc, filter) then
			table.insert(data.items, item)
		end
	end
end

local function on_receive_fields(player, fields)
	local name = player:get_player_name()
	local data = player_data[name]

	if fields.clear then
		local all_items = init_items
		if progressive_mode then
			all_items = visible_items(data)
		end
		data.filter = ""
		data.pagenum = 1
		data.prev_item = nil
		data.recipes = nil
		data.items = all_items
		return true

	elseif (fields.key_enter_field == "filter" or fields.search)
			and fields.filter then
		local new = fields.filter:sub(1, 128) -- truncate to a sane length
				:gsub("[%z\1-\8\11-\31\127]", "") -- strip naughty control characters (keeps \t and \n)
				:lower() -- search is case insensitive
		if data.filter == new then
			return
		end
		data.filter = new
		data.pagenum = 1
		execute_search(data)
		return true

	elseif fields.prev or fields.next then
		if data.pagemax == 1 then
			return
		end
		data.pagenum = data.pagenum + (fields.next and 1 or -1)
		if data.pagenum > data.pagemax then
			data.pagenum = 1
		elseif data.pagenum == 0 then
			data.pagenum = data.pagemax
		end
		return true

	elseif fields.recipe_next or fields.recipe_prev then
		data.rnum = data.rnum + (fields.recipe_next and 1 or -1)
		if data.rnum > #data.recipes then
			data.rnum = 1
		elseif data.rnum == 0 then
			data.rnum = #data.recipes
		end
		return true

	else
		local item
		for field in pairs(fields) do
			if field:find(":") then
				item = field:match("[%w_:]+")
				break
			end
		end
		if not item then
			return
		end

		if item == data.prev_item then
			data.show_usages = not data.show_usages
		else
			data.show_usages = nil
		end
		if data.show_usages and progressive_mode then
			data.recipes = known_recipes(data, usages_cache[item])
		elseif data.show_usages and not progressive_mode then
			data.recipes = usages_cache[item]
		elseif progressive_mode then
			data.recipes = known_recipes(data, recipes_cache[item])
		else
			data.recipes = recipes_cache[item]
		end
		data.prev_item = item
		data.rnum = 1
		return true
	end
end

sfinv.register_page("mtg_craftguide:craftguide", {
	title = esc(S("Recipes")),
	get = function(self, player, context)
		return sfinv.make_formspec(player, context, get_formspec(player))
	end,
	on_player_receive_fields = function(self, player, context, fields)
		if on_receive_fields(player, fields) then
			sfinv.set_player_inventory_formspec(player)
		end
	end
})

-- ~ Progressive-mode support ~
-- [The vast majority of changes to mtg_craftguide are found here!]
function table_to_str(table)
	local ret = "["
	for k,v in pairs(table) do
		ret = ret .. "; " .. k .. " - "
		if type(v) == "table" then
			ret = ret .. table_to_str(v)
		else
			ret = ret .. v
		end
	end
	return ret .. "]"
end

-- Given a player’s data and a recipe, return whether or not that recipe
-- is “known” by the player. (That is, they have held all necessary inputs.)
function known_recipe(data, recipe)
	for _,input in pairs(recipe.items) do
		if (not data.held_items[input:gsub(" .*", "")]) and (not data.held_groups[input])  then
			return false
		end
	end
	return true
end

-- From a table of recipes, return a sub-table of recipes that are “known.”
function known_recipes(data, recipes)
	local ret = {}
	if recipes then
		for _,recipe in pairs(recipes) do
			if known_recipe(data, recipe) then
				table.insert(ret, recipe)
			end
		end
	end
	return ret
end

-- Given a player’s data and an item-name, return a table of all items the
-- player should “know of” that can be crafted from that item.
function known_crafting_outputs(data, item_name)
	local outputs = {}
	local uses = usages_cache[item_name]
	if uses then
		for _,recipe in pairs(uses) do
			if known_recipe(data, recipe) then
				local out_name = recipe.output
				out_name = out_name:gsub(" .*", "")
				table.insert(outputs, out_name)
			end
		end
	end
	return outputs
end

-- Returns a table of all items that are “known” to the player; either they’ve
-- been held by them, or they’re craftable using solely objects held previously.
function visible_items(data)
	local ret = {}
	for item,_ in pairs(data.held_items) do
		if _ and item ~= "" then
			table.insert(ret, item)
		end
	end
	for item,_ in pairs(data.known_items) do
		if _ and item ~= "" then
			table.insert(ret, item)
		end
	end
	table.sort(ret)
	return ret
end

-- To be executed whenever a player gains/picks up an item.
-- If the item is new, it is added to the player’s held_items table, and then
-- possible outputs from it (and other known items) are added to known_items.
function update_known_items(player, item_name)
	local name = player:get_player_name()
	local data = player_data[name]

	if not data.held_items[item_name] then
		-- Mark the new item as known.
		data.held_items[item_name] = true

		-- Mark the new item’s groups as known.
		local groups = minetest.registered_items[item_name].groups
		for group,rating in pairs(groups) do
			if rating > 0 then
				data.held_groups["group:" .. group] = true
			end
		end

		-- Mark items craftable with this (and other) items as known.
		local new_recipes = 0
		for _,out_item_name in pairs(known_crafting_outputs(data, item_name)) do
			new_recipes = new_recipes + 1
			data.known_items[out_item_name] = true
			if show_item(minetest.registered_items[out_item_name]) then
				new_recipes = new_recipes + 1
				data.known_items[out_item_name] = true
			end
		end

		-- Reset item-list.
		data.items = visible_items(data)

		-- Notify the player.
		if new_recipes == 1 then
			minetest.chat_send_player(name, S("New recipe unlocked!"))
		elseif new_recipes > 1 then
			minetest.chat_send_player(name, S("@1 new recipes unlocked!", new_recipes))
		end
	end
end

if progressive_mode then
	minetest.register_on_item_pickup(function(itemstack, picker)
		update_known_items(picker, itemstack:get_name())
	end)

	minetest.register_on_player_inventory_action(function(player, action, inv, inv_info)
		if action == "put" then
			update_known_items(player, inv_info.stack:get_name())
		end
	end)

	minetest.register_on_dignode(function(pos, oldnode, digger)
		update_known_items(digger, oldnode.name)
	end)

	minetest.register_on_craft(function(itemstack, player)
		update_known_items(player, itemstack:get_name())
	end)
end

-- Go over all items in the player’s inventory for undiscovered recipes.
function check_player_inventory(player)
	local inv = player:get_inventory(player)
	local items = inv:get_list("main")
	if items then
		for _,stack in pairs(items) do
			update_known_items(player, stack:get_name())
		end
	end
end

-- Initialize player-data.
-- If saved data is found, load previous held-items and held-groups data.
function load_player_data(player)
	local name = player:get_player_name()
	local info = minetest.get_player_information(name)

	player_data[name] = {
		filter = "",
		pagenum = 1,
		items = init_items,
		held_items = {},
		held_groups = {},
		known_items = {},
		lang_code = info.lang_code
	}

	local saved_data_str = storage:get_string("player_" .. name)
	local saved_data = minetest.deserialize(saved_data_str or "")
	if saved_data_str and saved_data then
		player_data[name].held_items = saved_data.held_items
		player_data[name].held_groups = saved_data.held_groups
	end
end

-- Go over held items, and make sure any recipes that can be done with
-- them is listed in visible items.
function init_player_known_items(player)
	local name = player:get_player_name()
	local data = player_data[name]

	for item,_ in pairs(data.held_items) do
		local outputs = known_crafting_outputs(data, item)
		if outputs then
			for _,output in pairs(outputs) do
				data.known_items[output] = true
			end
		end
	end
end

-- Save a player’s held-item and held-group data.
function save_player_data(player)
	local name = player:get_player_name()
	local data = player_data[name]
	if data then
		storage:set_string("player_" .. name, minetest.serialize(data))
	end
end

-- Save all players’ held-item and held-group data.
function save_all_player_data()
	for name,data in pairs(player_data) do
		if data then
			storage:set_string("player_" .. name, minetest.serialize(data))
		end
	end
end

minetest.register_on_joinplayer(function(player)
	load_player_data(player)
	if not progressive_mode then
		return
	end

	init_player_known_items(player)
	check_player_inventory(player)

	-- Init displayed items.
	local data = player_data[player:get_player_name()]
	data.items = visible_items(data)
end)

minetest.register_on_leaveplayer(function(player)
	if progressive_mode then
		save_player_data(player)
	end
	player_data[player:get_player_name()] = nil -- Save memory!
end)

if progressive_mode then
	minetest.register_on_shutdown(save_all_player_data)
end