--[[
Copyright (c) 2013 Julius Riecke

This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

   1. The origin of this software must not be misrepresented; you must not
   claim that you wrote the original software. If you use this software
   in a product, an acknowledgment in the product documentation would be
   appreciated but is not required.

   2. Altered source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

   3. This notice may not be removed or altered from any source
   distribution.
]]

--[[
A Compilation of general-purpose functions.

-]]
M_UTILS_VERSION = 0

--initialization
if(FCEU) then
	EMU = FCEU
elseif(snes9x) then
	EMU = snes9x
elseif(gens) then
	EMU = gens
end
if(EMU == nil) then
	error("Unsupported environment. This script runs on Lua-capable emulators only - FCEUX, Snes9x or Gens.")
end




--[[	m_require
	"require" with version checking
	
	Similar to the approach in Xk's x_functions.lua, but supports loading and automatic version checking of
	"compatible" modules, too. A central version checking function does have its advantages.
	
A compatible module looks like this:
	if(REQUIRED_MODULE_VERSION==0) then --global variable = the second parameter of m_require
		error("This module isn't backwards compatible to version 0.")
	end
	module("modulename")
	MODULE_VERSION = 3
	function test()
	end
	return _M
	
using it in your code:
	m_require("modulefile.lua",3) --second parameter being > MODULE_VERSION would raise an error
	modulename.test()
-]]
function m_require(module,requiredver)
	if(module==nil or module=="m_utils") then
		if(M_UTILS_VERSION>=requiredver) then
			return true
		else
			error("\n\nThis script requires m_utils version "..requiredver..".\n"..
					"Your m_utils.lua is version "..M_UTILS_VERSION.."\n"..
					"Check http://morphcat.de/lua/ for a newer version.")
		end
	else
		--give the module the possibility to be backwards compatible
		--not very elegant, but there seems to be no other way using require
		REQUIRED_MODULE_VERSION = requiredver
		local ret = require(module)
		if(requiredver==nil) then --got no version checking to do
			return ret
		elseif(ret==nil or ret==false) then
			error("Could not load module "..module.." or module invalid.")
		elseif(type(ret)~="table") then
			error("Invalid module "..module..", doesn't return itself.")
		elseif(ret.MODULE_VERSION==nil) then
			error("Invalid module "..module..", missing version information.")
		elseif(ret.MODULE_VERSION < requiredver) then
			error("\n\nThis script requires "..module.." version "..requiredver..".\n"..
					"Your "..module.." module is version "..ret.MODULE_VERSION..".\n"..
					"If it's one of miau's Lua modules check\n"..
					"http://morphcat.de/lua/ for a newer version.\n")
		else
			return ret
		end
	end
end


--drawing functions with bounds checking
function bcbox(x1,y1,x2,y2,color1)
	if(x1>=0 and y1>=0 and x2<=255 and y2<=255) then
		gui.drawbox(x1, y1, x2, y2, color1, 0)
	end
end

function bcpixel(x,y,color)
	if(x>=0 and y>=0 and x<=255 and y<=255) then
		gui.drawpixel(x,y,color)
	end
end

function bcline(x1,y1,x2,y2,color)
	if(x1>=0 and y1>=0 and x2<=255 and y2<=255
		and x2>=0 and y2>=0 and x1<=255 and y1<=255) then
		gui.drawline(x1, y1, x2, y2, color)
	end
end


--bc + clipping, just make sure x2,y2 is the point that will most likely leave the screen first
function bcline2(x1,y1,x2,y2,color)
	if(x1>=0 and y1>=0 and x1<=255 and y1<=255) then
		if(x2>255 or y2>255 or x2<0 or y2<0) then	
			local vx,vy=getvdir(x1,y1,x2,y2)
			--TODO: replace brute force-y method  with line intersection formula
			if(math.abs(vx)==1 or math.abs(vy)==1) then
				local x=x1
				local y=y1
				while(x<254 and x>1 and y<254 and y>1) do
					x = x + vx
					y = y + vy
				end
				x = math.floor(x)
				y = math.floor(y)
				--logf(" ("..x1..","..y1..")-("..x..","..y..")\r\n")
				gui.drawline(x1,y1,x,y,color)
			end
		else
			gui.drawline(x1,y1,x2,y2,color)
		end
	end
end

function bctext(x,y,text)
	if(x>=0 and y>=0 and x<=255 and y<=255) then
		--make sure the text is always visible or else... possible memory leaks(?) and crashes on FCEUX <= 2.0.3
		local len=string.len(text)*8+1
		if(x+len > 255) then
			x = 255-len
		end
		if(x < 0) then
			x = 0
		end
		
		if(y > 222) then --NTSC
			y=222
		end
		gui.text(x, y, text)
	end
end


function getdistance(x1,y1,x2,y2)
	return math.floor(math.sqrt((x1-x2)^2+(y1-y2)^2))
end

--returns direction vector of a line
function getvdir(srcx,srcy,destx,desty)
	local x1 = srcx
	local x2 = destx
	local y1 = srcy
	local y2 = desty
	local xc = x2-x1
	local yc = y2-y1
	if(math.abs(xc)>math.abs(yc)) then
		yc = yc/math.abs(xc)
		xc = xc/math.abs(xc)
	elseif(math.abs(yc)>math.abs(xc)) then
		xc = xc/math.abs(yc)
		yc = yc/math.abs(yc)
	else
		if(xc<0) then
			xc=-1
		elseif(xc>0) then
			xc=1
		else
			xc=0
		end
		if(yc<0) then
			yc=-1
		elseif(yc>0) then
			yc=1
		else
			yc=0
		end
	end
	
	return xc,yc
end


local m_cursor = {
	{1,0,0,0,0,0,0,0},
	{1,1,0,0,0,0,0,0},
	{1,2,1,0,0,0,0,0},
	{1,2,2,1,0,0,0,0},
	{1,2,2,2,1,0,0,0},
	{1,2,2,2,2,1,0,0},
	{1,2,2,2,2,2,1,0},
	{1,2,1,1,1,1,1,1},
	{1,1,0,0,0,0,0,0},
	{1,0,0,0,0,0,0,0},
}
function drawcursor(px,py,col1,col2)
	if(px>0 and py>0 and px<256-8 and py<256-10) then
		for y=1,10 do
			if(m_cursor[y]) then
				for x=1,8 do
					if(m_cursor[y][x]==1) then
						gui.drawpixel(px+x,py+y,col1)
					elseif(m_cursor[y][x]==2) then
						gui.drawpixel(px+x,py+y,col2)
					end
				end
			end
		end
	end
end

--debug functions
function logf(s)
	local fo = io.open("E:/emu/nes/fceux-2.0.4.win32-unofficial/lua/log.txt", "ab")
	if(fo~=nil) then
		fo:write(s)
		fo:close()
		return true
	end
end

function logtable(a)
	for i,v in pairs(a) do
		if(type(v)=="table") then
			printarrrec(v)
		else
			if(v==false) then
				v="false"
			elseif(v==true) then
				v="true"
			end
			logf(i.." = "..v.."\r\n")
		end
	end
end