-- takes a 2 dimensional table with strings, returns a string
-- padding is used to make rows distinguishable
local function column(t, padding)
	padding = padding or "  "

	-- collect lengths
	local h = #t
	local w = #t[1]
	local maxlen = {}
	for j = 1,w do
		local col_width = 0
		for i = 1,h do
			-- length instead of # for UTF-8 support
			local l = t[i][j]:len()
			if l > col_width then
				col_width = l
			end
		end
		maxlen[j] = col_width
	end

	-- generate the string
	local lines = {}
	for i = 1,h do
		local line = {}
		for j = 1,w do
			local text = t[i][j]
			local l = text:len()
			local col_width = maxlen[j]
			-- align right
			line[j] = string.rep(" ", col_width - l) .. text
		end
		lines[i] = table.concat(line, padding)
	end
	return table.concat(lines, "\n")
end

local function analyze(item)
	local name = item:get_name()
	local def = minetest.registered_tools[name]
	assert(def, "not a tool")
	local caps = item:get_tool_capabilities()

	local groupcaps = caps.groupcaps
	local groups = {}
	for group, data in pairs(groupcaps) do
		local lvstats = {}
		for level = 0,data.maxlevel do
			local result = {}
			for v in pairs(data.times) do
				local p = minetest.get_dig_params(
					{[group] = v, level = level},
					caps
				)
				if p.diggable then
					if p.time ~= 0 then
						p.time = string.format("%-5.3g", p.time)
					else
						p.time = "0.15 (immediate)"
					end
				else
					p.time = "not diggable"
				end
				result[v] = p
			end
			lvstats[level] = result
		end
		groups[#groups+1] = {group, lvstats}
	end

	-- TODO format date
	local msg =
		'# Stats for the tool "' .. name .. '" (' .. os.date() .. ")\n\n" ..
		"## Digging speed and maximum uses\n\n" ..
		"The following tables show digging time and maximum number of\n" ..
		"nodes that can be dug for each supported group and level.\n\n"

	-- TODO show whether tool capabilities are overridden in item metadata
	-- add digging speed and wear for each group and level
	local sort_func = function(a, b)
		return a[1] < b[1]
	end
	table.sort(groups, sort_func)
	for i = 1,#groups do
		local v = groups[i]
		local groupname = v[1]
		msg = msg .. "### Group " .. groupname ..
			", values show the digging time\n\n"

		local w = 0
		local w_l = 3
		local lines = {}
		local lvstats = v[2]
		for i = 0, #lvstats do
			local line = {string.format("level=%d", i)}
			local stats = lvstats[i]
			local wear
			for i,v in pairs(stats) do
				wear = v.wear
				line[i + 2] = v.time
				if i > w then
					w = i
				elseif i < w_l then
					w_l = i
				end
			end
			line[2] = string.format("%.3g", 65535 / wear)
			lines[i + 2] = line
		end

		-- add description
		lines[1] = {"", "max uses"}
		for i = 3, 3 + w - w_l do
			lines[1][i] = string.format("%s=%d", groupname, i + w_l - 3)
		end

		-- fill in missings with empty string
		for i = 2,#lines do
			local line = lines[i]
			for i = 3, w + 2 do
				line[i] = line[i + w_l - 1] or ""
			end
		end
		msg = msg .. column(lines) .. "\n\n\n"
	end

	-- add damage
	if caps.damage_groups then
		msg = msg .. "## Damage\n\n"
		for name,v in pairs(caps.damage_groups) do
			msg = msg .. name .. ":\t" .. v .. "\n"
		end
		msg = msg .. "\n\n"
	end

	msg = msg .. "## Other stats\n\n"

	-- full punch interval TODO what is this
	if caps.full_punch_interval then
		msg = msg .. string.format("full_punch_interval: %.3g\n",
			caps.full_punch_interval)
	end

	-- TODO what is max_drop_level

	-- add range
	if def.range then
		msg = msg .. "range: " .. def.range .. "\n"
	end

	if def.liquids_pointable then
		msg = msg .. "This tool points liquids.\n"
	end

	return msg
end

minetest.register_node("magic_sys:tool_analyzer", {
	description = "Tool Analyzer",
	tiles = {"default_wood.png"},
	groups = {cracky=3},
	on_construct = function(pos)
		local meta = minetest.get_meta(pos)
		meta:set_string("formspec",
			"size[8,8]" ..
			"label[1,0.5;Tool:]" ..
			"list[context;tool;2,0.5;1,1;]" ..
			"button[3,0.5;2,2;analyze;Analyze tool]" ..
			"label[1,1.5;Book:]" ..
			"list[context;book;2,1.5;1,1;]" ..
			"list[current_player;main;0,3;8,4;]" ..
			"listring[context;book]" ..
			"listring[current_player;main]" ..
			"listring[context;tool]" ..
			"listring[current_player;main]"
		)
		meta:set_string("infotext", "Tool Analyzer")
		local inv = meta:get_inventory()
		inv:set_size("tool", 1)
		inv:set_size("book", 1)
	end,
	can_dig = function(pos)
		local inv = minetest.get_meta(pos):get_inventory()
		return inv:is_empty"tool" and inv:is_empty"book"
	end,
	allow_metadata_inventory_put = function(pos, listname, _, stack, player)
		if minetest.is_protected(pos, player:get_player_name()) then
			return 0
		end
		local itemname = stack:get_name()
		if listname == "book" then
			if itemname == "default:book" then
				-- TODO: multiple books
				return 1
			end
			return 0
		end
		if listname == "tool" then
			if minetest.registered_tools[itemname] then
				return 1
			end
			return 0
		end
		return 0
	end,
	-- TODO: fix items can be put by swapping
	allow_metadata_inventory_take = function(pos, _, _, stack, player)
		if minetest.is_protected(pos, player:get_player_name()) then
			return 0
		end
		return stack:get_count()
	end,
	on_receive_fields = function(pos, _, fields, player)
		if not fields.analyze then
			return
		end
		local pname = player:get_player_name()
		if minetest.is_protected(pos, pname) then
			return
		end
		local inv = minetest.get_meta(pos):get_inventory()
		local book = inv:get_stack("book", 1)
		if book:to_string() ~= "default:book" then
			return
		end
		local tool = inv:get_stack("tool", 1)
		local toolname = tool:get_name()
		if not minetest.registered_tools[toolname] then
			return
		end

		if not magic_sys.before_tool_analyze(player) then
			return
		end

		local text = analyze(tool)

		book:set_name"default:book_written"
		book:get_meta():from_table{fields = {
			title = "Analyzed " .. toolname,
			owner = pname,
			description = "Analyzed " .. toolname,
			text = text,
			page = 1,
			page_max = 1,
		}}
		inv:set_stack("book", 1, book)
	end,
})