local astal = require("astal")
local Variable = require("astal").Variable
local Astal = require("astal.gtk3").Astal
local GLib = astal.require("GLib")
local Gtk = require("astal.gtk3").Gtk

local lib

lib = {
	--- get path to file in astal source
	src = function(path)
		local str = debug.getinfo(2, "S").source:sub(2)
		local src = str:match("(.*/)") or str:match("(.*\\)") or "./"
		return src .. path
	end,

	--- map an array with a function
	map = function(array, func)
		local new_arr = {}
		for i, v in ipairs(array) do
			new_arr[i] = func(v, i)
		end
		return new_arr
	end,

	--- filter an array with a function
	filter = function(array, func)
		local new_arr = {}
		for i, v in ipairs(array) do
			if func(v, i) then
				new_arr[i] = v
			end
		end
		return new_arr
	end,

	--- slices a list
	slice = function(array, first, last, step)
		local new_arr = {}

		for i = first or 1, last or #array, step or 1 do
			new_arr[#new_arr+1] = array[i]
		end

		return new_arr
	end,

	--- sort an array of object on a key
	sort = function(array, func)

		-- default func to sort on attr 'id'
		if not func then
			func = 'id'
		end

		-- make function if just provided with attribute
		if type(func) ~= 'function' then
			local key = func
			func = function(a, b) return a[key] < b[key] end
		end

		-- copy to new array
		local new_arr = {}
		for i, v in ipairs(array) do
			new_arr[i] = v
		end

		-- sort and return
		table.sort(new_arr, func)
		return new_arr
	end,

	--- returns if value is an array
	is_array = function(val)
		return type(val) == 'table'
	end,

	--- returns if value is an string
	is_string = function(val)
		return type(val) == 'string'
	end,

	--- returns if value is nil
	is_nil = function(val)
		return val == nil
	end,

	--- returns length of table or string
	count = function(val)
		if lib.is_array(val) then
			return #val
		elseif lib.is_string(val) then
			return val:len()
		elseif lib.is_nil(val) then
			return 0
		else
			return nil
		end
	end,

	--- returns if a table is empty
	empty = function(array)
		return lib.count(array) == 0
	end,

	--- negates value
	neg = function(val)
		return not val
	end,

	--- better truthy function
	is_true = function(val)
		-- zero is false
		if val == 0 then
			return false
		end

		-- empty array or string is false
		if lib.empty(val) then
			return false
		end

		-- default truthyness
		return val and true or false
	end,

	--- better fasly function
	is_false = function(val)
		return not lib.is_true(val)
	end,

	--- checks if a file exists
	file_exists = function(path)
		return GLib.file_test(path, "EXISTS")
	end,

	--- checks if a string is an icon
	is_icon = function(icon)
		return Astal.Icon.lookup_icon(icon) ~= nil
	end,

	--- applies one object onto another
	apply = function(l, r)
		for k,v in pairs(r) do
			l[k] = v
		end
		return l
	end,

	--- returns current unix epoch
	unix = function()
		return os.time(os.date("*t"))
	end,

	--- formats a time
	time = function(t)
		-- default args
		t = lib.apply({
			time = lib.unix(),
			format = "%H:%M"
		}, t or {})
		return GLib.DateTime.new_from_unix_local(t.time):format(t.format)
	end,

	--- astal variable map
	varmap = function(initial)
		local map = initial
		local var = Variable()

		local function notify()
			local arr = {}
			for _, value in pairs(map) do
				table.insert(arr, value)
			end
			var:set(arr)
		end

		local function delete(key)
			if Gtk.Widget:is_type_of(map[key]) then map[key]:destroy() end

			map[key] = nil
		end

		notify()

		return setmetatable({
			set = function(key, value)
				delete(key)
				map[key] = value
				notify()
			end,
			delete = function(key)
				delete(key)
				notify()
			end,
			get = function()
				return var:get()
			end,
			subscribe = function(callback)
				return var:subscribe(callback)
			end,
		}, {
			__call = function() return var() end,
		})
	end,

	--- better or function
	value_or = function(l, r)
		if lib.is_true(l) then
			return l
		else
			return r
		end
	end,

	--- better and function
	value_and = function(l, r)
		if lib.is_false(l) then
			return l
		else
			return r
		end
	end,

}

return lib