local storage = minetest.get_mod_storage()

playersettings = {}

playersettings.registered = {}

playersettings.settingslist = {}

playersettings.highlighted = {}

playersettings.form = "formspec_version[4]"..
	"size[15,15]" ..
	"button[12.5,13.5;2,1;quit;Save and Exit]"..
	"textlist[0.5,0.5;7,14;settinglist;%s;%d;false]"..
	"label[8,2;%s]"..
	"label[8,3;%s]"..
	"%s"

function playersettings.openform(player)
	if type(player) == "string" then player = minetest.get_player_by_name(player) end
	local name = player:get_player_name()
	if #playersettings.settingslist < 1 then
		local form = "formspec_version[4]"..
		             "size[12,3.5]"..
		             "label[0.5,1;No settings currently exist.]"..
		             "label[0.5,1.5;To use the settings menu, one or more mods that provide some settings must be installed.]"..
		             "button_exit[5,2;2,1;quit;Close]"
		minetest.show_formspec(name,"playersettings:nosettings",form)
		return
	end
	if not playersettings.highlighted[name] then playersettings.highlighted[name] = 1 end
	local settingslist = ""
	for _,setting in ipairs(playersettings.settingslist) do
		settingslist = settingslist..minetest.formspec_escape(playersettings.registered[setting].shortdesc)..","
	end
	settingslist = settingslist:sub(1,-2)
	local settingname = playersettings.settingslist[playersettings.highlighted[name]]
	local def = playersettings.registered[settingname]
	local extras = ""
	if def.type == "boolean" then
		extras = "checkbox[8,8;checkbox;Enabled;%s]"
		extras = extras:format(playersettings.get(name,settingname) and "true" or "false")
	elseif def.type == "string" then
		extras = "field[8,8;6,1;field;Enter value:;%s]label[8,9.5;Allowed values: %s]field_close_on_enter[field;false]"
		extras = extras:format(minetest.formspec_escape(playersettings.get(name,settingname)),minetest.formspec_escape(def.values or "any string"))
	elseif def.type == "number" then
		extras = "field[8,8;6,1;field;Enter value:;%s]label[8,9.5;Allowed values: %s]field_close_on_enter[field;false]"
		local allowed = "any number"
		if def.min and def.max then
			allowed = "numbers "..def.min.." to "..def.max
		elseif def.max then
			allowed = "numbers up to "..def.max
		elseif def.min then
			allowed = "numbers "..def.min.." and up"
		end
		if def.integer then
			allowed = allowed.." (whole numbers only)"
		end
		extras = extras:format(minetest.formspec_escape(playersettings.get(name,settingname)),allowed)
	elseif def.type == "enum" then
		extras = "dropdown[8,8;6,1;dropdown;%s;%d;false]"
		local choices = ""
		local current = playersettings.get(name,settingname)
		local selected = 1
		for k,v in ipairs(def.values) do
			choices = choices..minetest.formspec_escape(v)..","
			if v == current then selected = k end
		end
		choices = choices:sub(1,-2)
		extras = extras:format(choices,selected)
	end
	local highlighted = playersettings.highlighted[name]
	local shortdesc = minetest.formspec_escape(def.shortdesc)
	local longdesc = minetest.formspec_escape(def.longdesc)
	local form = playersettings.form:format(settingslist,highlighted,shortdesc,longdesc,extras)
	minetest.show_formspec(name,"playersettings:settings",form)
end

function playersettings.handleform(player,form,fields)
	if form ~= "playersettings:settings" then return end
	local name = player:get_player_name()
	local settingname = playersettings.settingslist[playersettings.highlighted[name]]
	local def = playersettings.registered[settingname]
	if def.type == "boolean" and fields.checkbox then
		playersettings.set(name,settingname,fields.checkbox == "true")
	elseif def.type == "enum" and fields.dropdown then
		playersettings.set(name,settingname,fields.dropdown)
	elseif def.type == "number" and fields.field then
		local value = tonumber(fields.field)
		if value
			and ((not def.max) or (value <= def.max))
			and ((not def.min) or (value >= def.min)) then
			if def.integer then value = math.floor(value) end
			playersettings.set(name,settingname,value)
		end
	elseif def.type == "string" and fields.field then
		playersettings.set(name,settingname,fields.field)
	end
	if fields.settinglist then
		local exp = minetest.explode_textlist_event(fields.settinglist)
		if exp.type == "CHG" then
			playersettings.highlighted[name] = exp.index
			playersettings.openform(player)
		end
	end
	if fields.quit then
		minetest.close_formspec(name,"playersettings:settings")
	end
end

function playersettings.getdefault(setting)
	local def = playersettings.registered[setting]
	if def.default ~= nil then return def.default end
	if def.type == "boolean" then
		return false
	elseif def.type == "number" then
		return def.min or 0
	elseif def.type == "string" then
		return ""
	end
end

function playersettings.get(name,setting)
	assert(type(name) == "string",string.format("Invalid player name (expected string, got %s)",type(name)))
	assert(type(setting) == "string",string.format("Invalid setting name (expected string, got %s)",type(setting)))
	assert(playersettings.registered[setting],"No such setting: "..setting)
	local value = minetest.deserialize(storage:get_string(string.format("%s|%s",name,setting)))
	if value then
		return value
	else
		return playersettings.getdefault(setting)
	end
end

function playersettings.set(name,setting,value)
	assert(type(name) == "string",string.format("Invalid player name (expected string, got %s)",type(name)))
	assert(type(setting) == "string",string.format("Invalid setting name (expected string, got %s)",type(setting)))
	assert(playersettings.registered[setting],"No such setting: "..setting)
	local old = playersettings.get(name,setting)
	local def = playersettings.registered[setting]
	if def.onchange then
		if not def.onchange(name,old,value) then return end
	end
	storage:set_string(string.format("%s|%s",name,setting),minetest.serialize(value))
	if def.afterchange then def.afterchange(name,old,value) end
end

function playersettings.register(setting,def)
	assert(type(setting) == "string",string.format("Invalid setting name (expected string, got %s)",type(setting)))
	assert(not playersettings.registered[setting],string.format("Setting %s already defined",setting))
	assert(type(def) == "table",string.format("Invalid setting definition (expected table, got %s)",type(def)))
	table.insert(playersettings.settingslist,setting)
	table.sort(playersettings.settingslist)
	playersettings.registered[setting] = def
end

function playersettings.onjoin(player)
	local name = player:get_player_name()
	for setting,def in pairs(playersettings.registered) do
		if type(def.onjoin) == "function" then
			def.onjoin(name,playersettings.get(name,setting))
		end
	end
end

if minetest.global_exists("unified_inventory") then
	unified_inventory.register_button("playersettings",
		{
			action = playersettings.openform,
			tooltip = "Settings",
			type = "image",
			image = "playersettings_settings_button.png"
		}
	)
end

minetest.register_chatcommand("settings",{
	description = "Open player settings menu",
	func = playersettings.openform,
})

minetest.register_on_joinplayer(playersettings.onjoin)
minetest.register_on_player_receive_fields(playersettings.handleform)