--  Windon't
-- enhanced window API by LDDestroier
-- intended for general use within all me new programs
--
-- Unique features:
--  + Transparency within windows
--  + Built-in window layering

-- stores all local values to make drag-and-dropping into other programs less conflict-prone
local lval = {
	to_blit = {},
	to_colors = {},
	oldScreenBuffer = {},

	expect = function(value, default, valueType)
		if value == nil or (valueType and type(value) ~= valueType) then
			return default
		else
			return value
		end
	end,

	getTime = function()
		return 24 * os.day() + os.time()
	end,

	-- check if space on screenBuffer is transparent

	check = function(buffer, x, y, blitLayer)
		if buffer[blitLayer or 1][y] then
			if blitLayer then
				return (buffer[blitLayer][y][x] and buffer[blitLayer][y][x] ~= "-")
			else
				if (not buffer[2][y][x] or buffer[2][y][x] == "-") and (not buffer[3][y][x] or buffer[3][y][x] == "-") then
					return false
				elseif (not buffer[3][y][x] or buffer[3][y][x] == "-") and buffer[1][y][x] == " " then
					return false
				else
					return buffer[1][y][x] and buffer[2][y][x] and buffer[3][y][x]
				end
			end
		end
	end
}

local table_insert = table.insert
local table_concat = table.concat
local math_floor = math.floor

for i = 1, 16 do
	lval.to_blit[2 ^ (i - 1)] = ("0123456789abcdef"):sub(i, i)
	lval.to_colors[("0123456789abcdef"):sub(i, i)] = 2 ^ (i - 1)
end
lval.to_blit[0], lval.to_colors["-"] = "-", 0

local windont = {
	doClearScreen = false,				-- if true, will clear the screen during render
	ignoreUnchangedLines = true,		-- if true, the render function will check each line it renders against the last framebuffer and ignore it if they are the same
	useSetVisible = false,				-- if true, sets the base terminal's visibility to false before rendering
	default = {
		baseTerm = term.current(),		-- default base terminal for all windows
		textColor = "0",				-- default text color (what " " corresponds to in term.blit's second argument)
		backColor = "f",				-- default background color (what " " corresponds to in term.blit's third argument)
		blink = true,
		visible = true,
		alwaysRender = true,			-- if true, new windows will always render if they are written to
	},
	info = {
		BLIT_CALLS = 0,				-- amount of term.blit calls during the last render
		LAST_RENDER_TIME = 0,		-- last time in which render was called
		LAST_RENDER_AMOUNT = 0,		-- amount of windows drawn during last render
		LAST_RENDER_WINDOWS = {},	-- table of the last window objects that were rendered
	}
}

-- draws one or more windon't objects
-- should not draw over any terminal space that isn't occupied by a window

windont.render = function(options, ...)
--	potential options:
--		number:		onlyX1
--		number:		onlyX2
--		number:		onlyY
--		boolean:	force		(forces render / ignores optimiztaion that compares current framebuffer to old one)
--		terminal:	baseTerm	(forces to render onto this terminal instead of the window's base terminal)

	local windows = {...}
	options = options or {}
	local bT, scr_x, scr_y

	-- checks if "options" is actually the first window, just in case
	if type(options.meta) == "table" then
		if (
			type(options.meta.buffer) == "table" and
			type(options.meta.x) == "number" and
			type(options.meta.y) == "number" and
			type(options.meta.newBuffer) == "function"
		) then
			table_insert(windows, 1, options)
		end
	end

	local check = lval.check

	local screenBuffer = {{}, {}, {}}
	local blitList = {}	-- list of blit commands per line
	local c	= 1 		-- current blitList entry

	local cTime = lval.getTime()

	local AMNT_OF_BLITS = 0	-- how many blit calls are there?

	local cx, cy							-- each window's absolute X and Y
	local char_cx, text_cx, back_cx			-- each window's transformed absolute X's in table form
	local char_cy, text_cy, back_cy			-- each window's transformed absolute X's in table form
	local buffer							-- each window's buffer
	local newChar, newText, newBack			-- if the transformation function declares a new dot, this is it
	local oriChar, oriText, oriBack

	local baseTerms = {}
	if type(options.baseTerm) == "table" then
		for i = 1, #windows do
			baseTerms[options.baseTerm] = baseTerms[options.baseTerm] or {}
			baseTerms[options.baseTerm][i] = true
		end
	else
		for i = 1, #windows do
			baseTerms[windows[i].meta.baseTerm] = baseTerms[windows[i].meta.baseTerm] or {}
			baseTerms[windows[i].meta.baseTerm][i] = true
		end
	end

	for bT, bT_list in pairs(baseTerms) do
		if bT == output then
			bT = output.meta.baseTerm
		end
		if windont.useSetVisible and bT.setVisible then
			bT.setVisible(false)
		end
		scr_x, scr_y = bT.getSize()
		-- try entire buffer transformations
		for i = #windows, 1, -1 do
			if bT_list[i] then
				if windows[i].meta.metaTransformation then
					-- metaTransformation functions needn't return a value
					windows[i].meta.metaTransformation(windows[i].meta)
				end
			end
		end
		for y = options.onlyY or 1, options.onlyY or scr_y do
			screenBuffer[1][y] = {}
			screenBuffer[2][y] = {}
			screenBuffer[3][y] = {}
			blitList = {}
			c = 1
			for x = options.onlyX1 or 1, math.min(scr_x, options.onlyX2 or scr_x) do
				for i = #windows, 1, -1 do
					if bT_list[i] then
						newChar, newText, newBack = nil
						if windows[i].meta.visible then
							buffer = windows[i].meta.buffer

							cx = 1 + x + -windows[i].meta.x
							cy = 1 + y + -windows[i].meta.y
							char_cx, text_cx, back_cx = cx, cx, cx
							char_cy, text_cy, back_cy = cy, cy, cy

							oriChar = (buffer[1][cy] or {})[cx]
							oriText = (buffer[2][cy] or {})[cx]
							oriBack = (buffer[3][cy] or {})[cx]

							-- try char transformation
							if windows[i].meta.charTransformation then
								char_cx, char_cy, newChar = windows[i].meta.charTransformation(cx, cy, {oriChar, oriText, oriBack}, windows[i].meta)
								if char_cx ~= math_floor(char_cx) or char_cy ~= math_floor(char_cy) then
									newChar = " "
								end
								char_cx = math_floor(char_cx or cx)
								char_cy = math_floor(char_cy or cy)
							end

							-- try text transformation
							if windows[i].meta.textTransformation then
								text_cx, text_cy, newText = windows[i].meta.textTransformation(cx, cy, {oriChar, oriText, oriBack}, windows[i].meta)
								text_cx = math_floor(text_cx or cx)
								text_cy = math_floor(text_cy or cy)
							end

							-- try back transformation
							if windows[i].meta.backTransformation then
								back_cx, back_cy, newBack = windows[i].meta.backTransformation(cx, cy, {oriChar, oriText, oriBack}, windows[i].meta)
								back_cx = math_floor(back_cx or cx)
								back_cy = math_floor(back_cy or cy)
							end

							if check(buffer, char_cx, char_cy) or check(buffer, text_cx, text_cy) or check(buffer, back_cx, back_cy) then
								screenBuffer[1][y][x] = newChar or check(buffer, char_cx, char_cy   ) and (buffer[1][char_cy][char_cx]) or screenBuffer[1][y][x]
								screenBuffer[2][y][x] = newText or check(buffer, text_cx, text_cy, 2) and (buffer[2][text_cy][text_cx]) or screenBuffer[3][y][x]
								screenBuffer[3][y][x] = newBack or check(buffer, back_cx, back_cy, 3) and (buffer[3][back_cy][back_cx]) or screenBuffer[3][y][x]
							end
						end
					end
				end

				if windont.doClearScreen then
					screenBuffer[1][y][x] = screenBuffer[1][y][x] or " "
				end
				screenBuffer[2][y][x] = screenBuffer[2][y][x] or windont.default.backColor	-- intentionally not the default text color
				screenBuffer[3][y][x] = screenBuffer[3][y][x] or windont.default.backColor

				if check(screenBuffer, x, y) then
					if check(screenBuffer, -1 + x, y) then
						blitList[c][1] = blitList[c][1] .. screenBuffer[1][y][x]
						blitList[c][2] = blitList[c][2] .. screenBuffer[2][y][x]
						blitList[c][3] = blitList[c][3] .. screenBuffer[3][y][x]
					else
						c = x
						blitList[c] = {
							screenBuffer[1][y][x],
							screenBuffer[2][y][x],
							screenBuffer[3][y][x]
						}
					end
				end
			end
			if (not lval.oldScreenBuffer[bT]) or (not windont.ignoreUnchangedLines) or (options.force) or (
				table_concat(screenBuffer[1][y]) ~= table_concat(lval.oldScreenBuffer[bT][1][y]) or
				table_concat(screenBuffer[2][y]) ~= table_concat(lval.oldScreenBuffer[bT][2][y]) or
				table_concat(screenBuffer[3][y]) ~= table_concat(lval.oldScreenBuffer[bT][3][y])
			) then
				for k,v in pairs(blitList) do
					bT.setCursorPos(k, y)
					bT.blit(v[1], v[2], v[3])
					AMNT_OF_BLITS = 1 + AMNT_OF_BLITS
				end
			end
		end
		lval.oldScreenBuffer[bT] = screenBuffer
		if windont.useSetVisible and bT.setVisible then
			if not multishell then
				bT.setVisible(true)
			elseif multishell.getFocus() == multishell.getCurrent() then
				bT.setVisible(true)
			end
		end
	end

	windont.info.LAST_RENDER_AMOUNT = #windows
	windont.info.BLIT_CALLS = AMNT_OF_BLITS
	windont.info.LAST_RENDER_WINDOWS = windows
	windont.info.LAST_RENDER_TIME = cTime
	windont.info.LAST_RENDER_DURATION = lval.getTime() + -cTime

end

-- creates a new windon't object that can be manipulated the same as a regular window

windont.newWindow = function( x, y, width, height, misc )

	-- check argument types
	assert(type(x) == "number", "argument #1 must be number, got " .. type(x))
	assert(type(y) == "number", "argument #2 must be number, got " .. type(y))
	assert(type(width) == "number", "argument #3 must be number, got " .. type(width))
	assert(type(height) == "number", "argument #4 must be number, got " .. type(height))

	-- check argument validity
	assert(x > 0, "x position must be above zero")
	assert(y > 0, "y position must be above zero")
	assert(width > 0, "width must be above zero")
	assert(height > 0, "height must be above zero")

	local output = {}
	misc = misc or {}
	local meta = {
		x 				= lval.expect(x, 1),												-- x position of the window
		y 				= lval.expect(y, 1),												-- y position of the window
		width 			= width,															-- width of the buffer
		height			= height,															-- height of the buffer
		buffer 			= lval.expect(misc.buffer, {}, "table"),							-- stores contents of terminal in buffer[1][y][x] format
		renderBuddies 	= lval.expect(misc.renderBuddies, {}, "table"),						-- renders any other window objects stored here after rendering here
		baseTerm 		= lval.expect(misc.baseTerm, windont.default.baseTerm, "table"),	-- base terminal for which this window draws on
		isColor 		= lval.expect(misc.isColor, term.isColor(), "boolean"),				-- if true, then it's an advanced computer

		charTransformation = lval.expect(misc.charTransformation, nil, "function"),			-- function that transforms the characters of the window
		textTransformation = lval.expect(misc.textTransformation, nil, "function"),			-- function that transforms the text colors of the window
		backTransformation = lval.expect(misc.backTransformation, nil, "function"),			-- function that transforms the BG colors of the window
		metaTransformation = lval.expect(misc.miscTransformation, nil, "function"),			-- function that transforms the whole output.meta function

		cursorX 		= lval.expect(misc.cursorX, 1),
		cursorY 		= lval.expect(misc.cursorY, 1),

		textColor 		= lval.expect(misc.textColor, windont.default.textColor, "string"),			-- current text color
		backColor 		= lval.expect(misc.backColor, windont.default.backColor, "string"),			-- current background color

		blink 			= lval.expect(misc.blink, windont.default.blink, "boolean"),				-- cursor blink
		alwaysRender 	= lval.expect(misc.alwaysRender, windont.default.alwaysRender, "boolean"),	-- render after every terminal operation
		visible 		= lval.expect(misc.visible, windont.default.visible, "boolean"),			-- if false, don't render ever

		-- make a new buffer (optionally uses an existing buffer as a reference)
		newBuffer = function(width, height, char, text, back, drawAtop)
			local output = drawAtop or {{}, {}, {}}
			for y = 1, height do
				output[1][y] = output[1][y] or {}
				output[2][y] = output[2][y] or {}
				output[3][y] = output[3][y] or {}
				for x = 1, width do
					output[1][y][x] = output[1][y][x] or (char or " ")
					output[2][y][x] = output[2][y][x] or (text or "0")
					output[3][y][x] = output[3][y][x] or (back or "f")
				end
			end
			return output
		end
	}

	bT = meta.baseTerm

	-- initialize the buffer
	meta.buffer = meta.newBuffer(meta.width, meta.height, " ", meta.textColor, meta.backColor)

	output.meta = meta

	output.write = function(text)
		assert(type(text) == "string" or type(text) == "number", "expected string, got " .. type(text))
		local initX = meta.cursorX
		for i = 1, #tostring(text) do
			if meta.cursorX >= 1 and meta.cursorX <= meta.width and meta.cursorY >= 1 and meta.cursorY <= meta.height then
				if not meta.buffer[1] then
					error("what the fuck happened")
				end
				meta.buffer[1][meta.cursorY][meta.cursorX] = tostring(text):sub(i,i)
				meta.buffer[2][meta.cursorY][meta.cursorX] = meta.textColor
				meta.buffer[3][meta.cursorY][meta.cursorX] = meta.backColor
			end
			meta.cursorX = meta.cursorX + 1
		end
		if meta.alwaysRender then
			output.redraw(
				-1 + meta.x + initX,
				-1 + meta.x + meta.cursorX,
				-1 + meta.y + meta.cursorY
			)
		end
	end

	output.blit = function(char, text, back)
		assert(type(char) == "string" and type(text) == "string" and type(back) == "string", "all arguments must be strings")
		assert(#char == #text and #text == #back, "arguments must be same length")
		local initX = meta.cursorX
		for i = 1, #char do
			if meta.cursorX >= 1 and meta.cursorX <= meta.width and meta.cursorY >= 1 and meta.cursorY <= meta.height then
				meta.buffer[1][meta.cursorY][meta.cursorX] = char:sub(i,i)
				meta.buffer[2][meta.cursorY][meta.cursorX] = text:sub(i,i) == " " and windont.default.textColor or text:sub(i,i)
				meta.buffer[3][meta.cursorY][meta.cursorX] = back:sub(i,i) == " " and windont.default.backColor or back:sub(i,i)
				meta.cursorX = meta.cursorX + 1
			end
		end
		if meta.alwaysRender then
			output.redraw(
				-1 + meta.x + initX,
				-1 + meta.x + meta.cursorX,
				-1 + meta.y + meta.cursorY
			)
		end
	end

	output.setCursorPos = function(x, y)
		assert(type(x) == "number", "argument #1 must be number, got " .. type(x))
		assert(type(y) == "number", "argument #2 must be number, got " .. type(y))
		meta.cursorX, meta.cursorY = math.floor(x), math.floor(y)
		if meta.alwaysRender then
			if bT == output then
				bT = output.meta.baseTerm
			end
			bT.setCursorPos(
				-1 + meta.x + meta.cursorX,
				-1 + meta.y + meta.cursorY
			)
		end
	end

	output.getCursorPos = function()
		return meta.cursorX, meta.cursorY
	end

	output.setTextColor = function(color)
		if lval.to_blit[color] then
			meta.textColor = lval.to_blit[color]
		else
			error("Invalid color (got " .. color .. ")")
		end
	end
	output.setTextColour = output.setTextColor

	output.setBackgroundColor = function(color)
		if lval.to_blit[color] then
			meta.backColor = lval.to_blit[color]
		else
			error("Invalid color (got " .. color .. ")")
		end
	end
	output.setBackgroundColour = output.setBackgroundColor

	output.getTextColor = function()
		return lval.to_colors[meta.textColor]
	end
	output.getTextColour = output.getTextColor

	output.getBackgroundColor = function()
		return lval.to_colors[meta.backColor]
	end
	output.getBackgroundColour = output.getBackgroundColor

	output.setVisible = function(visible)
		assert(type(visible) == "boolean", "bad argument #1 (expected boolean, got " .. type(visible) .. ")")
		meta.visible = visible and true or false
	end

	output.clear = function()
		meta.buffer = meta.newBuffer(meta.width, meta.height, " ", meta.textColor, meta.backColor)
		if meta.alwaysRender then
			output.redraw()
		end
	end

	output.clearLine = function()
		meta.buffer[1][meta.cursorY] = nil
		meta.buffer[2][meta.cursorY] = nil
		meta.buffer[3][meta.cursorY] = nil
		meta.buffer = meta.newBuffer(meta.width, meta.height, " ", meta.textColor, meta.backColor, meta.buffer)
		if meta.alwaysRender then
			bT.setCursorPos(meta.x, -1 + meta.y + meta.cursorY)
			bT.blit(
				(" "):rep(meta.width),
				(meta.textColor):rep(meta.width),
				(meta.backColor):rep(meta.width)
			)
		end
	end

	output.getLine = function(y)
		assert(type(y) == "number", "bad argument #1 (expected number, got " .. type(y) .. ")")
		assert(meta.buffer[1][y], "Line is out of range.")
		return table_concat(meta.buffer[1][y]), table_concat(meta.buffer[2][y]), table_concat(meta.buffer[3][y])
	end

	output.scroll = function(amplitude)
		if math.abs(amplitude) < meta.height then	-- minor optimization
			local blank = {{}, {}, {}}
			for x = 1, meta.width do
				blank[1][x] = " "
				blank[2][x] = meta.textColor
				blank[3][x] = meta.backColor
			end
			for y = 1, meta.height do
				meta.buffer[1][y] = meta.buffer[1][y + amplitude] or blank[1]
				meta.buffer[2][y] = meta.buffer[2][y + amplitude] or blank[2]
				meta.buffer[3][y] = meta.buffer[3][y + amplitude] or blank[3]
			end
		else
			meta.buffer = meta.newBuffer(meta.width, meta.height, " ", meta.textColor, meta.backColor)
		end
		if meta.alwaysRender then
			if math_floor(amplitude) ~= 0 then
				output.redraw()
			end
		end
	end

	output.getSize = function()
		return width, height
	end

	output.isColor = function()
		return meta.isColor
	end
	output.isColour = output.isColor

	output.reposition = function(x, y, width, height)
		assert(type(x) == "number", "bad argument #1 (expected number, got " .. type(x) .. ")")
		assert(type(y) == "number", "bad argument #2 (expected number, got " .. type(y) .. ")")
		meta.x = math_floor(x)
		meta.y = math_floor(y)
		if width then
			assert(type(width) == "number", "bad argument #3 (expected number, got " .. type(width) .. ")")
			assert(type(height) == "number", "bad argument #4 (expected number, got " .. type(height) .. ")")
			meta.width = width
			meta.height = height
			meta.buffer = meta.newBuffer(meta.width, meta.height, " ", meta.textColor, meta.backColor, meta.buffer)
		end
		if meta.alwaysRender then
			output.redraw()
		end
	end

	output.restoreCursor = function()
		bT.setCursorPos(
			math.max(0, -1 + meta.x + meta.cursorX),
			math.max(0, -1 + meta.y + meta.cursorY)
		)
		bT.setCursorBlink(meta.blink)
	end

	output.getPosition = function()
		return meta.x, meta.y
	end

	output.setCursorBlink = function(blink)
		meta.blink = blink and true or false
	end

	output.getCursorBlink = function(blink)
		return meta.blink
	end

	output.setPaletteColor = bT.setPaletteColor
	output.setPaletteColour = bT.setPaletteColour
	output.getPaletteColor = bT.getPaletteColor
	output.getPaletteColour = bT.getPaletteColour

	output.redraw = function(x1, x2, y)
		if #meta.renderBuddies > 0 then
			windont.render({onlyX1 = x1, onlyX2 = x2, onlyY = y}, output, table.unpack(meta.renderBuddies))
		else
			windont.render({onlyX1 = x1, onlyX2 = x2, onlyY = y}, output)
		end
		output.restoreCursor()
	end

	if meta.alwaysRender then
		output.redraw()
	end

	return output

end

return windont