local inspect = require('inspect')

-- Utility functions for working with Lua in Fungus
local M = {}

------------
-- Debugging
------------

function M.inspect(v)
	print (inspect.inspect(v))
end

-------
-- Time
-------

-- Returns the absolute time
-- Use this timing function to work correctly with the Lua Environment's timeScale property
function M.gettime()
	return M.luautils.getTime()
end

-- Returns the delta time this frame
-- Use this timing function to work correctly with the Lua Environment's timeScale property
function M.getdeltatime()
	return M.luautils.getDeltaTime()
end

function M.settimescale(s)
	M.luautils.timeScale = s
end

-------------
-- Coroutines
-------------

-- Waits for a number of seconds
function M.wait(duration)
	local t = M.gettime()
	while (M.gettime() - t < duration) do
		coroutine.yield()
	end
end

-- Waits until the lamda function provided returns true, or the timeout expires.
-- Returns true if the function succeeded, or false if the timeout expired
-- 
function M.waitfor(fn, timeoutduration)
	local t = M.gettime()
	while (not fn()) do
		coroutine.yield()
		if (M.gettime() - t > timeoutduration) then
			return false
		end
	end
	return true
end

-- Starts a C# coroutine method
function M.run(enumerator)
	-- If the parameter isn't an enumerator then CreateTask will fail
	local status, err = pcall( function() 
		local task = M.luaenvironment.RunUnityCoroutine(enumerator)
	end)

	if (not status) then
		print(debug.traceback("Can't start a coroutine with a c# method that doesn't return IEnumerator", 2))
		error(err)
	end
end

-- Starts a C# coroutine method and waits until it's finished
function M.runwait(enumerator)
	-- If the parameter isn't an enumerator then CreateTask will fail
	local status, err = pcall( function() 
		local task = M.luaenvironment.RunUnityCoroutine(enumerator)
		while (task != nil and task.Running) do
    		coroutine.yield();
		end
	end)

	if (not status) then
		print(debug.traceback("Can't start a coroutine with a c# method that doesn't return IEnumerator", 2))
		error(err)
	end
end

---------------
-- String table
---------------

-- Set active language for string table
function M.setlanguage(languagecode)
	M.luautils.activeLanguage = languagecode
end

-- Get a named string from the string table
function M.getstring(key)
	return M.luautils.GetString(key)
end

-- Substitutes variables and localisation strings into a piece of text
-- e.g. v = 10, "Subbed value is [$v]" => "Subbed value is 10"
function M.sub(text)
	return M.luautils.substitute(text)
end

--------------------------------------------------------------
-- Integration tests
-- These functions require the Unity Test Tools to work.
--------------------------------------------------------------

-- Checks if a condition is true (requires Unity Test Tools)
-- Lua has a built in assert function, so we called this check to avoid conflicting.
function M.check(c, reason)
	if (not c) then
		-- Output a traceback to help track down source
		error( debug.traceback("Assert failed", 2) )
	end
	M.test.assert(c, reason)
end

-- Pass an integration test (requires Unity Test Tools)
function M.pass()
	M.test.pass()
end

-- Fail an integration test (requires Unity Test Tools)
function M.fail(reason)
	error( debug.traceback("Test failed", 2) )
	M.test.fail(reason)
end

---------------------------------------------
-- All functions below require Fungus to work
---------------------------------------------

-------------
-- Say Dialog
-------------

-- Options for configuring Say Dialog behaviour
M.sayoptions = {}
M.sayoptions.saydialog = nil
M.sayoptions.clearprevious = true 
M.sayoptions.waitforinput = true
M.sayoptions.fadewhendone = true
M.sayoptions.stopvoiceover = true

-- Set the active saydialog to use with the say function
function M.setsaydialog(saydialog)
	M.sayoptions.saydialog = saydialog
end

-- Gets the active say dialog, or creates one if none exists yet
function M.getsaydialog()
	if (M.sayoptions.saydialog == nil) then
		local sd = M.luautils.spawn("SayDialog").GetComponent("SayDialog")
		M.setsaydialog(sd)
	end
	return M.sayoptions.saydialog
end

-- Set the active character on the Say Dialog
-- character: A Fungus.Character component
-- portrait: The name of a sprite in the character's portrait list
function M.setcharacter(character, portrait)
	assert(character, "character must not be nil")
	local sd = M.getsaydialog()
	sd.SetCharacter(character)

	-- Do substitution on character name
	local subbed = M.sub(character.nameText)
	M.sayoptions.saydialog.SetCharacterName(subbed, character.nameColor)

	-- Try to set the portrait sprite
	if (portrait) then
		if (portrait == "") then
			M.sayoptions.saydialog.SetCharacterImage(nill)
		else
			for i,v in ipairs(character.portraits) do
				-- Use a case insensitive comparison
				if (string.lower(v.name) == string.lower(portrait)) then
					M.sayoptions.saydialog.SetCharacterImage(v)
				end
			end
		end
	end
end

-- Write text to the active Say Dialog
-- text: A string to write to the say dialog
-- voice: A voiceover audioclip to play
function M.say(text, voiceclip)
   local sd = M.getsaydialog()

   -- Do variable substitution before displaying text
   local subbed = M.sub(text)
   local e = sd.SayInternal(subbed, M.sayoptions.clearprevious, M.sayoptions.waitforinput, M.sayoptions.fadewhendone, M.sayoptions.stopvoiceover, voiceclip)

   M.runwait(e)
end

--------------
-- Menu Dialog
--------------

-- Options for configuring Menu Dialog behaviour
M.menuoptions = {}

-- Set the active menudialog to use with the menu function
function M.setmenudialog(menudialog)
	M.menuoptions.menudialog = menudialog
end

-- Gets the active menu dialog, or creates one if none exists yet
function M.getmenudialog()
	if (M.menuoptions.menudialog == nil) then
		local md = M.luautils.spawn("MenuDialog").GetComponent("MenuDialog")
		M.setmenudialog(md)
	end
	return M.menuoptions.menudialog
end

-- Display a menu button
-- text: text to display on the button
-- callback: function to call when this option is selected
-- interactive (optional): if false, displays the option as disabled
function M.menu(text, callback, interactive)
	local md = M.getmenudialog()

	-- Do variable substitution before displaying text
	local subbed = M.sub(text)
	md.AddOption(subbed, interactive or true, M.luaenvironment, callback)
end

-- Display a timer during which the player has to choose an option.
-- duration: The length of time to display the timer.
-- callback: Function to call if the timer expires before an option is selected.
function M.menutimer(duration, callback)
	local md = M.getmenudialog()

	local e = md.ShowTimer(duration, M.luaenvironment, callback)
	M.runwait(e)
end

-- Clear all currently displayed menu options
function M.clearmenu()
	assert(M.menuoptions.menudialog, "menudialog must not be nil")
	M.menuoptions.menudialog.Clear()
end

------------
-- Flowchart
------------

-- Runs the specified Block in a Flowchart
-- flowchart: The Fungus Flowchart containing the Block to run.
-- blockname: The name of the Block to run.
-- nowait: If false, will yield until the Block finishes execution. If true will continue immediately.
function M.runblock(flowchart, blockname, nowait)
	assert(flowchart, "flowchart must not be nil")
	assert(blockname, "blockname must not be nil")
	local block = flowchart.FindBlock(blockname)
	if (not block) then
		error("Block " .. blockname .. " not found")
		return
	end

	local e = block.Execute();

	if (nowait) then
		M.run( e )
	else
		M.runwait( e )
	end
end

return M