local string = string
local table = table
local surface = surface
local tostring = tostring
local pairs = pairs
local Msg = Msg
local setmetatable = setmetatable
local math = math

module("markup")

/*---------------------------------------------------------
    Name: Constants used for text alignment.
          These must be the same values as in the draw module.
---------------------------------------------------------*/
TEXT_ALIGN_LEFT		= 0
TEXT_ALIGN_CENTER	= 1
TEXT_ALIGN_RIGHT	= 2
TEXT_ALIGN_TOP		= 3
TEXT_ALIGN_BOTTOM	= 4

/*---------------------------------------------------------
    Name: Temporary information used when building text frames.
---------------------------------------------------------*/
local colour_stack = { {r=255,g=255,b=255,a=255} }
local font_stack = { "Default" }
local curtag = nil
local blocks = {}

local colourmap = {
// it's all black and white
	["black"] =		{	r=0,	g=0,	b=0,	a=255	},
	["white"] =		{	r=255,	g=255,	b=255,	a=255	},
// it's greys
	["dkgrey"] =	{	r=64,	g=64,	b=64,	a=255	},
	["grey"] =		{	r=128,	g=128,	b=128,	a=255	},
	["ltgrey"] =	{	r=192,	g=192,	b=192,	a=255	},
// account for speeling mistakes
	["dkgray"] =	{	r=64,	g=64,	b=64,	a=255	},
	["gray"] =		{	r=128,	g=128,	b=128,	a=255	},
	["ltgray"] =	{	r=192,	g=192,	b=192,	a=255	},
// normal colours
	["red"] =		{	r=255,	g=0,	b=0,	a=255	},
	["green"] =		{	r=0,	g=255,	b=0,	a=255	},
	["blue"] =		{	r=0,	g=0,	b=255,	a=255	},
	["yellow"] =	{	r=255,	g=255,	b=0,	a=255	},
	["purple"] =	{	r=255,	g=0,	b=255,	a=255	},
	["cyan"] =		{	r=0,	g=255,	b=255,	a=255	},
	["turq"] =		{	r=0,	g=255,	b=255,	a=255	},
// dark variations
	["dkred"] =		{	r=128,	g=0,	b=0,	a=255	},
	["dkgreen"] =	{	r=0,	g=128,	b=0,	a=255	},
	["dkblue"] =	{	r=0,	g=0,	b=128,	a=255	},
	["dkyellow"] =	{	r=128,	g=128,	b=0,	a=255	},
	["dkpurple"] =	{	r=128,	g=0,	b=128,	a=255	},
	["dkcyan"] =	{	r=0,	g=128,	b=128,	a=255	},
	["dkturq"] =	{	r=0,	g=128,	b=128,	a=255	},
// light variations
	["ltred"] =		{	r=255,	g=128,	b=128,	a=255	},
	["ltgreen"] =	{	r=128,	g=255,	b=128,	a=255	},
	["ltblue"] =	{	r=128,	g=128,	b=255,	a=255	},
	["ltyellow"] =	{	r=255,	g=255,	b=128,	a=255	},
	["ltpurple"] =	{	r=255,	g=128,	b=255,	a=255	},
	["ltcyan"] =	{	r=128,	g=255,	b=255,	a=255	},
	["ltturq"] =	{	r=128,	g=255,	b=255,	a=255	},
}

/*---------------------------------------------------------
    Name: colourMatch(c)
    Desc: Match a colour name to an rgb value.
   Usage: ** INTERNAL ** Do not use!
---------------------------------------------------------*/
local function colourMatch(c)
	c = string.lower(c)
	
	return colourmap[c]
end

/*---------------------------------------------------------
    Name: ExtractParams(p1,p2,p3)
    Desc: This function is used to extract the tag information.
   Usage: ** INTERNAL ** Do not use!
---------------------------------------------------------*/
local function ExtractParams(p1,p2,p3)

	if (string.sub(p1, 1, 1) == "/") then
		
		local tag = string.sub(p1, 2)
		
		if (tag == "color" or tag == "colour") then
			table.remove(colour_stack)			
		elseif (tag == "font" or tag == "face") then
			table.remove(font_stack)
		end

	else

		if (p1 == "color" or p1 == "colour") then
			
			local rgba = colourMatch(p2)
			
			if (rgba == nil) then
				rgba = {}
				local x = { "r", "g", "b", "a" }
				n = 1
				for k, v in string.gmatch(p2, "(%d+),?") do
					rgba[ x[n] ] = k
					n = n + 1
				end
			end
						
			table.insert(colour_stack, rgba)
		
		elseif (p1 == "font" or p1 == "face") then

			table.insert(font_stack, tostring(p2))		
		
		end
		
	end
end

/*---------------------------------------------------------
    Name: CheckTextOrTag(p)
    Desc: This function places data in the "blocks" table
          depending of if p is a tag, or some text
   Usage: ** INTERNAL ** Do not use!
---------------------------------------------------------*/
local function CheckTextOrTag(p)
	if (p == "") then return end
	if (p == nil) then return end
	
	if (string.sub(p, 1, 1) == "<") then
		string.gsub(p, "<([/%a]*)=?([^>]*)", ExtractParams)
	else
		
		local text_block = {}
		text_block.text = p 
		text_block.colour = colour_stack[ table.getn(colour_stack) ]
		text_block.font = font_stack[ table.getn(font_stack) ]
		table.insert(blocks, text_block)
		
	end
end

/*---------------------------------------------------------
    Name: ProcessMatches(p1,p2,p3)
    Desc: CheckTextOrTag for 3 parameters. Called by string.gsub
   Usage: ** INTERNAL ** Do not use!
---------------------------------------------------------*/
local function ProcessMatches(p1,p2,p3)
	if (p1) then CheckTextOrTag(p1) end
	if (p2) then CheckTextOrTag(p2) end
	if (p3) then CheckTextOrTag(p3) end
end

local MarkupObject = {}

/*---------------------------------------------------------
    Name: MarkupObject:Create()
    Desc: Called by Parse. Creates a new table, and setups the 
          metatable.
   Usage: ** INTERNAL ** Do not use!
---------------------------------------------------------*/
function MarkupObject:Create()
	local o = {}
	setmetatable(o, self)
	self.__index = self

	return o
end

/*---------------------------------------------------------
    Name: MarkupObject:GetWidth()
    Desc: Returns the width of a markup block
   Usage: ml:GetWidth()
---------------------------------------------------------*/
function MarkupObject:GetWidth()
	return self.totalWidth
end

/*---------------------------------------------------------
    Name: MarkupObject:GetHeight()
    Desc: Returns the height of a markup block
   Usage: ml:GetHeight()
---------------------------------------------------------*/
function MarkupObject:GetHeight()
	return self.totalHeight
end

/*---------------------------------------------------------
---------------------------------------------------------*/
function MarkupObject:Size()
	return self.totalWidth, self.totalHeight
end

/*---------------------------------------------------------
    Name: MarkupObject:Draw(xOffset, yOffset, halign, valign, alphaoverride)
    Desc: Draw the markup text to the screen as position
          xOffset, yOffset. Halign and Valign can be used
          to align the text. Alphaoverride can be used to override
          the alpha value of the text-colour.
   Usage: MarkupObject:Draw(100, 100)
---------------------------------------------------------*/
function MarkupObject:Draw(xOffset, yOffset, halign, valign, alphaoverride)
	for i,blk in pairs(self.blocks) do
		local y = yOffset + (blk.height - blk.thisY) + blk.offset.y
		local x = xOffset
		
		if (halign == TEXT_ALIGN_CENTER) then		x = x - (self.totalWidth / 2) 
		elseif (halign == TEXT_ALIGN_RIGHT) then	x = x - (self.totalWidth)
		end

		x = x + blk.offset.x
	
		if (valign == TEXT_ALIGN_CENTER) then		y = y - (self.totalHeight / 2)
		elseif (valign == TEXT_ALIGN_BOTTOM) then	y = y - (self.totalHeight)
		end
		
		local alpha = blk.colour.a
		if (alphaoverride) then alpha = alphaoverride end
		
		surface.SetFont( blk.font )
		surface.SetTextColor( blk.colour.r, blk.colour.g, blk.colour.b, alpha )
		surface.SetTextPos( x, y )
		surface.DrawText( blk.text )
	end
end

/*---------------------------------------------------------
    Name: Parse(ml, maxwidth)
    Desc: Parses the pseudo-html markup language, and creates a 
          MarkupObject, which can be used to the draw the 
          text to the screen. Valid tags are: font and colour.
          \n and \t are also available to move to the next line,
          or insert a tab character.
          Maxwidth can be used to make the text wrap to a specific
          width.
   Usage: markup.Parse("<font=Default>changed font</font>\n<colour=255,0,255,255>changed colour</colour>")
---------------------------------------------------------*/
function Parse(ml, maxwidth)
	
	colour_stack = { {r=255,g=255,b=255,a=255} }
	font_stack = { "Default" }
	blocks = {}
	
	if (not string.find(ml, "<")) then
		ml = ml .. "<nop>"
	end

	string.gsub(ml, "([^<>]*)(<[^>]+.)([^<>]*)", ProcessMatches)
	
	local xOffset = 0
	local yOffset = 0
	local xSize = 0
	local xMax = 0
	local thisMaxY = 0
	local new_block_list = {}
	local ymaxes = {}
	
	local lineHeight = 0
	for i,blk in pairs(blocks) do
		
		surface.SetFont(blocks[i].font)
		
		local thisY = 0
		local curString = ""
		blocks[i].text = string.gsub(blocks[i].text, "&gt;", ">")
		blocks[i].text = string.gsub(blocks[i].text, "&lt;", "<")
		blocks[i].text = string.gsub(blocks[i].text, "&amp;", "&")
		for j=1,string.len(blocks[i].text) do
			local ch = string.sub(blocks[i].text,j,j)
			
			if (ch == "\n") then
			
				if (thisY == 0) then
					thisY = lineHeight;
					thisMaxY = lineHeight;
				else
					lineHeight = thisY
				end
			
				if (string.len(curString) > 0) then
					local x1,y1 = surface.GetTextSize(curString)

					local new_block = {}
					new_block.text = curString
					new_block.font = blocks[i].font
					new_block.colour = blocks[i].colour
					new_block.thisY = thisY
					new_block.thisX = x1
					new_block.offset = {}
					new_block.offset.x = xOffset
					new_block.offset.y = yOffset
					table.insert(new_block_list, new_block)
					if (xOffset + x1 > xMax) then
						xMax = xOffset + x1
					end
				end
							
				xOffset = 0
				xSize = 0
				yOffset = yOffset + thisMaxY;
				thisY = 0
				curString = ""
				thisMaxY = 0
			elseif (ch == "\t") then
			
				if (string.len(curString) > 0) then
					local x1,y1 = surface.GetTextSize(curString)

					local new_block = {}
					new_block.text = curString
					new_block.font = blocks[i].font
					new_block.colour = blocks[i].colour
					new_block.thisY = thisY
					new_block.thisX = x1
					new_block.offset = {}
					new_block.offset.x = xOffset
					new_block.offset.y = yOffset
					table.insert(new_block_list, new_block)
					if (xOffset + x1 > xMax) then
						xMax = xOffset + x1
					end
				end
				
				local xOldSize = xSize
				xSize = 0
				curString = ""
				local xOldOffset = xOffset
				xOffset = math.ceil( (xOffset + xOldSize) / 50 ) * 50
				
				if (xOffset == xOldOffset) then
					xOffset = xOffset + 50
				end
			else
				local x,y = surface.GetTextSize(ch)
				
				if (x == nil) then return end

				if (maxwidth and maxwidth > x) then
					if (xOffset + xSize + x >= maxwidth) then
					
						-- need to: find the previous space in the curString
						--          if we can't find one, take off the last character
						--          and add a -. add the character to ch
						--          and insert as a new block, incrementing the y etc
						
						local lastSpacePos = string.len(curString)
						for k=1,string.len(curString) do
							local chspace = string.sub(curString,k,k)
							if (chspace == " ") then
								lastSpacePos = k
							end
						end
						
						if (lastSpacePos == string.len(curString)) then
							ch = string.sub(curString,lastSpacePos,lastSpacePos) .. ch
							j = lastSpacePos
							curString = string.sub(curString, 1, lastSpacePos-1)
						else
							ch = string.sub(curString,lastSpacePos+1) .. ch
							j = lastSpacePos+1
							curString = string.sub(curString, 1, lastSpacePos)
						end
						
						local m = 1
						while string.sub(ch, m, m) == " " do
							m = m + 1
						end
						ch = string.sub(ch, m)
						
						local x1,y1 = surface.GetTextSize(curString)
												
						if (y1 > thisMaxY) then thisMaxY = y1; ymaxes[yOffset] = thisMaxY; lineHeight = y1; end

						local new_block = {}
						new_block.text = curString
						new_block.font = blocks[i].font
						new_block.colour = blocks[i].colour
						new_block.thisY = thisY
						new_block.thisX = x1
						new_block.offset = {}
						new_block.offset.x = xOffset
						new_block.offset.y = yOffset
						table.insert(new_block_list, new_block)
						
						if (xOffset + x1 > xMax) then
							xMax = xOffset + x1
						end
					
						xOffset = 0
						xSize = 0
						x,y = surface.GetTextSize(ch)
						yOffset = yOffset + thisMaxY;
						thisY = 0
						curString = ""
						thisMaxY = 0
					end
				end
				
				curString = curString .. ch

				thisY = y
				xSize = xSize + x
								
				if (y > thisMaxY) then thisMaxY = y; ymaxes[yOffset] = thisMaxY; lineHeight = y; end
			end
		end
		
		if (string.len(curString) > 0) then
			
			local x1,y1 = surface.GetTextSize(curString)
	
			local new_block = {}
			new_block.text = curString
			new_block.font = blocks[i].font
			new_block.colour = blocks[i].colour
			new_block.thisY = thisY
			new_block.thisX = x1
			new_block.offset = {}
			new_block.offset.x = xOffset
			new_block.offset.y = yOffset
			table.insert(new_block_list, new_block)
			
			lineHeight = thisY

			if (xOffset + x1 > xMax) then
				xMax = xOffset + x1
			end
			xOffset = xOffset + x1		
		end
		xSize = 0
	end
	
	local totalHeight = 0
	for i,blk in pairs(new_block_list) do
		new_block_list[i].height = ymaxes[new_block_list[i].offset.y]
		
		if (new_block_list[i].offset.y + new_block_list[i].height > totalHeight) then
			totalHeight = new_block_list[i].offset.y + new_block_list[i].height
		end
	end
	
	local newObject = MarkupObject:Create()	
	newObject.totalHeight = totalHeight
	newObject.totalWidth = xMax
	newObject.blocks = new_block_list
	return newObject
end