--- Program-related functions.

-- Standard library imports --
local clock = os.clock
local error = error
local getenv = os.getenv
local max = math.max
local pcall = pcall
local print = print
local select = select
local tonumber = tonumber

-- Modules --
local array = require("impl.array")

-- Imports --
local GetLib = array.GetLib

-- Exports --
local M = {}

-- --
local IterPrev = 0
local TimePrev = 0
local MaxRate = 0

-- --
local T0

--
function M.Add (into)
	for k, v in pairs{
		--
		assets = function()
			return getenv("AF_PATH") .. "/assets"
		end,

--[[
union Data
{
    unsigned dim;
    char bytes[4];
};

unsigned char reverse_char(unsigned char b)
{
    b = (b & 0xF0) >> 4 | (b & 0x0F) > 2 | (b & 0x33) > 1 | (b & 0x55) > 1) & 0x55555555u) | ((x & 0x55555555u) > 2) & 0x33333333u) | ((x & 0x33333333u) > 4) & 0x0f0f0f0fu) | ((x & 0x0f0f0f0fu) > 8) & 0x00ff00ffu) | ((x & 0x00ff00ffu) > 16) & 0xffffu) | ((x & 0xffffu)  1 and tonumber(argv[1]) or 0
				local Lib = GetLib()

				-- Select a device and display arrayfire info
				Lib.setDevice(device)
				Lib.info()

				func(argc, argv)

				if getenv("windir") ~= nil then -- pause in Windows
					if not (arc == 2 and argv[1]:sub(1, 1) == "-") then
						print("hit [enter]...")
						io.output():flush()
						-- getchar() io.input():read()?
					end
				end
			end)

			if not ok then
				print(err) -- TODO: more informative
				error("aborting")
			end
		end,

		-- ^^^ TODO: setfenv() / _ENV variant?
		-- Also, rearrange for exit stuff?
		-- Are the windows redirecting IO?

		--
		progress = function(iter_curr, t, time_total)
			local Lib = GetLib()

			Lib.sync()

			local time_curr = Lib.timer_stop(t)

			if time_curr - TimePrev < 1 then
				return true
			end

			local rate = (iter_curr - IterPrev) / (time_curr - TimePrev)

			Lib.printf("  iterations per second: %.0f   (progress %.0f%%)", rate, 100.0 * time_curr / time_total)

			MaxRate = max(MaxRate, rate)

			IterPrev = iter_curr
			TimePrev = time_curr

			if time_curr < time_total then
				return true
			end

			Lib.printf(" ### %f iterations per second (max)", MaxRate)
			return false
		end,

		--
		timeit = function(func)
			local t0 = clock()

			func()

			return clock() - t0
		end,

		--
		timer_start = function()
			T0 = clock()
		end,

		--
		timer_stop = function(since)
			return clock() - (since or T0)
		end,

		--
		wait_for_windows = function(how, w1, w2, w3)
			--
			return function()
				local is_open

				if w3 and w3:close() then
					is_open = false
				elseif w2 and w2:close() then
					is_open = false
				else
					is_open = not w1:close()
				end

				if how == "until" then
					return not is_open
				else
					return is_open
				end
			end
		end,

		--
		wait_for_windows_close = function(how, w1, w2, w3)
			local going = GetLib().wait_for_windows(how, w1, w2, w3)

			return function()
				local is_going = going()
				local is_open = is_going

				if how == "until" then
					is_open = not is_open
				end
				
				if not is_open then
					if not w1:close() then
						w1:destroy() -- TODO: Do this right... how?
					end

					if w2 and not w2:close() then
						w2:destroy()
					end

					if w3 and not w3:close() then
						w3:destroy()
					end
				end

				return is_going
			end
			--
		end
		-- ^^^ TODO: Better stuff? (resolution, instantiable?)
	} do
		into[k] = v
	end
end

-- Export the module.
return M