local S = minetest.get_translator("cmdtool")
local F = minetest.formspec_escape

local NEWLINE = "\n"
local DESCRIPTION = S("Command Tool")
local MAX_CMD_TOOLTIP_LEN = 48

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

local split_commands = function(commands_string)
	return string.split(commands_string, NEWLINE)
end

local set_commands = function(itemstack, commands_string)
	local meta = itemstack:get_meta()
	meta:set_string("cmd", commands_string)
	local cmds = split_commands(commands_string)
	local first_cmd
	if #cmds >= 1 then
		first_cmd = cmds[1]
		if string.len(first_cmd) > MAX_CMD_TOOLTIP_LEN then
			first_cmd = string.sub(first_cmd, 1, MAX_CMD_TOOLTIP_LEN) .. " (…)"
		end
		local tooltip = DESCRIPTION .. NEWLINE .. first_cmd
		if #cmds == 2 then
			tooltip = tooltip .. NEWLINE .. S("… and 1 more command")
		elseif #cmds > 2 then
			tooltip = tooltip .. NEWLINE .. S("… and @1 more command(s)", #cmds - 1)
		end
		meta:set_string("description", tooltip)
	else
		meta:set_string("description", "")
	end
	return itemstack
end

-- Returns a table of commands in a command tool itemstack
local get_commands = function(itemstack)
	local meta = itemstack:get_meta()
	local cmd_str = meta:get_string("cmd")
	local cmds = split_commands(cmd_str)
	return cmds
end

--[[ Takes a command and substitutes placeholders like “@playername” with the actual values.
This operation might fail.
Returns the substituted command on success.
Returns false on failure. ]]
local substitute_placeholders = function(command, itemstack, player, pointed_thing)
	local pos_pt, pos_pl
	pos_pl = player:get_pos()
	if pointed_thing.type == "node" then
		pos_pt = pointed_thing.under

		command = string.gsub(command, "@ptx", pos_pt.x)
		command = string.gsub(command, "@pty", pos_pt.y)
		command = string.gsub(command, "@ptz", pos_pt.z)

		local node = minetest.get_node(pos_pt)
		command = string.gsub(command, "@nodename", node.name)
		command = string.gsub(command, "@param2", node.param2)
	else
		-- If one of the coordinate parameters is in the command, but
		-- the pointed thing is not a node, we have to fail as the placeholders
		-- are meaningless.
		local coord = {"@ptx", "@pty", "@ptz", "@nodename", "@param2", "@light"}
		for c=1, #coord do
			if string.find(command, coord[c]) ~= nil then
				return false
			end
		end
	end

	command = string.gsub(command, "@plx", pos_pl.x)
	command = string.gsub(command, "@ply", pos_pl.y)
	command = string.gsub(command, "@plz", pos_pl.z)

	command = string.gsub(command, "@playername", player:get_player_name())

	command = string.gsub(command, "@@", "@")

	return command
end

local execute_command = function(itemstack, player, pointed_thing)
	local player_name = player:get_player_name()
	local cmds = get_commands(itemstack)
	if not cmds then
		return
	end
	local player_privs = minetest.get_player_privs(player_name)
	for c=1, #cmds do
		local cmd = cmds[c]
		-- Substitution successful?
		-- Split command string into command name and parameters
		local cmd_split = string.split(cmd, " ", false, 1)
		local cmd_name
		-- Perform some checks:
		-- 1. Command exists
		-- 2. Player has all required privileges
		if cmd_split then
			-- Get command name
			cmd_name = cmd_split[1]
			local cmd_params = ""
			if cmd_split[2] then
				cmd_params = cmd_split[2]
			end
			cmd_params = substitute_placeholders(cmd_params, itemstack, player, pointed_thing)
			local def = minetest.registered_chatcommands[cmd_name]
			-- Command exists? Placeholder substitution successful?
			if def then
				if cmd_params then
					local required_privs = def.privs
					for priv, _ in pairs(required_privs) do
						if player_privs[priv] ~= true then
							minetest.chat_send_player(player_name, minetest.colorize("#FF0000", S("Insufficient privileges for command “@1”! You need the “@2” privilege.", cmd_name, priv)))
							return
						end
					end
					-- All tests survived!
					-- Call the command
					local retval, msg = def.func(player_name, cmd_params)

					-- Print return value and message
					if print_result then
						if retval == true then
							-- Command successfull
							minetest.chat_send_player(player_name, minetest.colorize("#00FF00", "["..S("OK").."] ".. cmd))
						elseif retval == false then
							-- Command failed
							minetest.chat_send_player(player_name, minetest.colorize("#FF0000", "["..S("FAIL").."] ".. cmd))
						elseif retval == nil then
							-- Command result unknown
							minetest.chat_send_player(player_name, minetest.colorize("#FF8800", "["..S("UNKN").."] ".. cmd))
						end
					end
					if msg ~= nil and msg ~= "" then
						local out = msg
						if print_result then
							local out = "> " .. msg
						end
						minetest.chat_send_player(player_name, out)
					end
				else
					minetest.chat_send_player(player_name, minetest.colorize("#FF0000", S("Nothing pointed!")))
				end
			else
				minetest.chat_send_player(player_name, minetest.colorize("#FF0000", S("The command “@1” does not exist!", cmd_name)))
				return
			end
		else
			minetest.chat_send_player(player_name, minetest.colorize("#FF0000", S("Invalid command!")))
			return
		end
		-- One iteration is done. We continue with the next command.
	end
end

local open_command_configuration = function(itemstack, player, pointed_thing)
	local player_name = player:get_player_name()
	local commands = get_commands(itemstack)
	local commands_str = ""
	if commands then
		for c=1, #commands do
			commands_str = commands_str .. commands[c]
			if c < #commands then
				commands_str = commands_str .. "\n"
			end
		end
	end
	local formspec =
			"size[12,6]"..
			"textarea[0.25,0.25;12,5;commands;"..F(S("Commands:"))..";"..F(commands_str).."]"..
			"button_exit[0.5,5;2,1;ok;"..F(S("OK")).."]"..
			"button_exit[3.5,5;2,1;cancel;"..F(S("Cancel")).."]"
	minetest.show_formspec(player_name, "cmdtool", formspec)
end

minetest.register_tool("cmdtool:cmdtool", {
	description = DESCRIPTION,
	_doc_items_longdesc = S("This is a programmable tool which can be used to run server commands."),
	_doc_items_usagehelp = S("This tool is very mighty, so handle with care!").."\n"..
S("Use the [Place] key to set the commands. Write a list of server commands you wish to execute (with one command per line), in that order, but without the trailing slash like in the chat. Confirm with the OK button.").."\n"..
S("To run the commands, use the attack key. Note that commands might fail if you lack the required privileges or you made a mistake.").."\n\n"..

S("Optionally, you can use the following placeholders to insert variable values into your commands:").."\n"..
S("• @playername: Your player name").."\n"..
S("• @plx, @ply and @plz: Your player coordinates").."\n"..
S("• @@: Literal at sign").."\n\n"..

S("These placeholders only work when you use the tool on a block.").."\n"..
S("• @ptx, @pty and @ptz: Coordinates of the pointed node (i.e. block)").."\n"..
S("• @nodename: Itemstring of the pointed node").."\n"..
S("• @param2: param2 of the pointed node").."\n\n"..

S("Refer to “Advancd usage > Server commands” to learn more about server commands.").."\n\n\n"..


S([[Example 1:
    time 12000
→ Sets time to midday.]]).."\n\n"..

S([[Example 2:
    teleport @plx 9 @plz
    giveme default:apple
→ Teleports you to Y=9 without changing the X and Z coordinates, then gives you an apple.]]),
	inventory_image = "cmdtool_cmdtool.png",
	wield_imagee = "cmdtool_cmdtool.png",
	groups = { disable_repair = 1 },
	on_use = execute_command,
	on_place = open_command_configuration,
	on_secondary_use = open_command_configuration,
})

-- Set commands
minetest.register_on_player_receive_fields(function(player, formname, fields)
	if formname == "cmdtool" and fields.ok and fields.commands ~= nil then
		local wield_tool = player:get_wielded_item()
		if wield_tool:get_name() == "cmdtool:cmdtool" then
			local updated_tool = set_commands(wield_tool, fields.commands)
			player:set_wielded_item(updated_tool)
		end
	end
end)