-- gui.lua

--(( Settings ))--

--(( Variables ))--

local termW,termH = term.getSize()
local pageW,pageH = 25,21

local lockedSender = "kalle"

local grid = {}

--(( Functions ))--

function updateGrid()
	-- Add lost parts
	for x = 1,termW do
		if type(grid[x]) ~= "table" then
			grid[x] = {}
		end
		for y = 1,termH do
			if type(grid[x][y]) ~= "table" then
				grid[x][y] = {
					fg = util.colorToHex(colors.white),
					bg = util.colorToHex(colors.black),
					char = " ",
				}
			end
		end
	end

	-- Remove excess
	for x in pairs(grid) do
		if type(x) ~= "number"
		or (x < 1 or x > termW) then
			grid[x] = nil
		else
			for y in pairs(grid[x]) do
				if type(y) ~= "number"
				or (y < 1 or y > termH) then
					grid[x][y] = nil
				end
			end
		end
	end
end

-- Get each row seperatly
-- so you can draw it with term.blit
function blitReadyGrid()
	local rows = {}
	-- note that I'm looping Y first
	for y = 1,termH do
		local row = {"","",""}
		for x = 1,termW do
			local pixel = getPixel(x,y)
			row[1] = row[1] .. pixel.char
			row[2] = row[2] .. pixel.fg
			row[3] = row[3] .. pixel.bg
		end
		rows[y] = row
	end

	return rows
end

function drawGrid()
	updateGrid()
	local rows = blitReadyGrid()
	for y,row in ipairs(rows) do
		term.setCursorPos(1,y)
		term.blit(unpack(row))
	end
end

function validPixel(x,y)
	return (x >= 1 and x <= termW)
	and (y >= 1 and y <= termH)
	and (x%1==0) and (y%1==0)
end

function getPixel( x,y )
	if validPixel(x,y) then
		return grid[x][y]
	end
end

function setPixel(char,x,y,fg,bg)
	if type(fg) == "number" then fg = util.colorToHex(fg) end
	if type(bg) == "number" then bg = util.colorToHex(bg) end

	if validPixel(x,y) then
		grid[x][y].char = ((char or grid[x][y].char or "") .. " "):sub(1,1)
		grid[x][y].fg = fg or grid[x][y].fg
		grid[x][y].bg = bg or grid[x][y].bg
	end
end

function setRect(char,x1,y1,x2,y2,fg,bg)
	for x = x1,x2 or x1 do
		for y = y1,y2 or y1 do
			setPixel(char,x,y,fg,bg)
		end
	end
end

function writeText(text,x,y,fg,bg)
	text = tostring(text)
	for i = 1,#text do
		setPixel(text:sub(i,i),x+i-1,y,fg,bg)
	end
end

function writeCentered(text,y,fg,bg)
	writeText(text,math.floor(termW/2-#text/2),y,fg,bg)
end

function previewMail(data)
	local tPages = mail.splitPages(mail.prepareMessage(data))
	local nPage = 1
	local pageTitle = mail.getTitle(data,nPage,#tPages)

	local scroll = -1
	local scrollbarH = 4

	local pageX = 20
	local pageY = 3

	-- height of visable area
	local viewH = 17

	local running = true
	local redraw = true

	local function changePage(newPage)
		nPage = math.max(1,math.min(#tPages, newPage))
		scroll = -1
		redraw = true
		pageTitle = mail.getTitle(data,nPage,#tPages)
	end

	local function nextPage() changePage(nPage+1) end
	local function prevPage() changePage(nPage-1) end

	local function draw()
		-- Draw header
		setRect(" ",1,1,termW,2,_,colors.cyan)
		writeCentered("Preview of",1,colors.white)
		writeCentered(pageTitle,2,colors.white)

		-- Draw background
		setRect(" ",1,3,termW,termH,_,colors.lightBlue)
		-- paper edge
		local y2 = scroll == 5 and termH-1 or termH
		setRect("|",pageX-1,3,_,y2,colors.lightBlue,colors.white)
		setRect("|",pageX+pageW,3,_,y2,colors.lightBlue,colors.white)

		-- Draw message
		local tPage = tPages[nPage]
		for nRow = 1+scroll, termH-2+scroll do
			-- filler char
			if nRow == 0 then
				-- row before page
				setRect("~",pageX,3,pageX+pageW-1,_,colors.lightBlue,colors.white)
			elseif nRow == pageH+1 then
				-- row after page
				setRect("~",pageX,termH,pageX+pageW-1,_,colors.white,colors.lightBlue)
			else
				-- get page
				sRow = tPage[nRow] or ""
				-- fill out so it redraws the entire thing
				sRow = sRow .. string.rep(" ", pageW - #sRow)

				-- write it out
				local y = pageY+nRow-scroll-1
				writeText(sRow,pageX,y,colors.gray,colors.white)
			end
		end

		-- Draw scrollbar
		local y = math.floor(pageY+(viewH-scrollbarH)*(scroll+1)/(6))
		setRect(" ", termW, 3, _, termH, _, colors.lightGray)
		setRect(" ", termW, y, _, y+scrollbarH-1, _, colors.gray)
		setPixel("^", termW, y, colors.lightGray)
		setPixel("v", termW, y+scrollbarH-1,colors.lightGray)

		-- Draw buttons
		setRect(" ", 1, pageY, 13, termH, _, colors.gray)
		writeText("Page", 2, termH-4, colors.lightGray)
		local txt = nPage.."/"..#tPages
		writeText(txt, 13-#txt, termH-4, colors.lightGray)
		writeText("  <  ", 2, termH-3, colors.white, (nPage > 1) and colors.cyan or colors.lightGray)
		writeText("  >  ", 8, termH-3, colors.white, (nPage < #tPages) and colors.cyan or colors.lightGray)

		writeText("   Back    ", 2, termH-1, colors.white, colors.cyan)

		-- Draw to screen
		drawGrid()
	end

	local function changeScroll(delta)
		scroll = math.min(math.max(math.floor(scroll + delta),-1),pageH-viewH+1)
		redraw = true
	end

	local function handleEvents(ev,p1,p2,p3,p4,p5)
		if ev == "key" then
			if p1 == keys.down then
				changeScroll(1)
			elseif p1 == keys.up then
				changeScroll(-1)
			elseif p1 == keys.q then
				running = false
			end
		end
		if ev == "mouse_scroll" then
			changeScroll(p1)
		end
		if ev == "mouse_click" and p1 == 1 then
			if p3 == termH-3 then
				-- prev page
				if p2 >= 2 and p2 <= 6 and nPage > 1 then
					prevPage()
				end
				-- next page
				if p2 >= 8 and p2 <= 12 and nPage < #tPages then
					nextPage()
				end
			end
			-- exit
			if p3 == termH-1 and p2 >= 2 and p2 <= 12 then
				running = false
			end
		end
	end

	-- Main loop
	while running do
		if redraw then
			draw()
		end
		handleEvents(os.pullEvent())
	end
end

function writeMail()

	local running = true
	local redraw = true
	local selected = false
	local fields = {}

	local lshift = false
	local rshift = false
	local rctrl = false
	local lctrl = false
	local tabJump = false

	local diskAvailable = false
	local anyReceivers = false

	local function newTextArea(x1,y1,x2,y2,multiline)
		x2 = x2 or x1
		y2 = y2 or y1

		local textArea = {
			x1 = x1, x2 = x2,
			y1 = y1, y2 = y2,
			w = x2 - x1 + 1, h = y2 - y1 + 1,
			multiline = multiline,
			scrollX = 0, scrollY = 0,
			cursorX = 1, cursorY = 1,
			visableCursor = false,
			enabled = true,

			onSelect = false,
			onDeselect = false,
			lateDraw = false,
			elemType = "textArea",

			nextElem = false,
			prevElem = false,

			text = {""}
		}
		table.insert(fields,textArea)

		function textArea.destroy(self)
			for i,v in ipairs(fields) do
				if v == self then
					table.remove(fields, i)
					break
				end
			end
		end

		function textArea.localToWorld(self,x,y)
			return x + self.x1 - self.scrollX - 1, y + self.y1 - self.scrollY - 1
		end

		function textArea.worldtoLocal(self,x,y)
			return x - self.x1 + self.scrollX + 1, y - self.y1 + self.scrollY + 1
		end

		function textArea.pointInArea(self,x,y)
			return x >= self.x1 and x <= self.x2
			and y >= self.y1 and y <= self.y2
		end

		function textArea.draw(self)
			local bg = self==selected and colors.black or colors.gray
			local fg = self==selected and colors.white or colors.lightGray

			if self.elemType == "button" then
				bg = self.enabled and colors.cyan or colors.gray
				fg = self.enabled and colors.white or colors.lightGray
			end

			setRect(" ",self.x1,self.y1,self.x2,self.y2,_,bg)

			for row = 1 + self.scrollY, self.h + self.scrollY do
				if row <= #self.text then
					local x = self.x1
					local y = self.y1 + row - self.scrollY - 1
					local text = self.text[row]
					if row == 1 and self.elemType == "textArea" and not self.enabled then
						text = "(locked) "..text
					end
					writeText(text:sub(1+self.scrollX,self.scrollX+self.w),x,y,fg)
				end
			end

			if selected == self then
				local x,y = self:localToWorld(self.cursorX,self.cursorY)
				self.visableCursor = self:pointInArea(self:localToWorld(self.cursorX,self.cursorY))
			end
		end

		function textArea.setScroll(self, x,y)
			local maxW = 0
			for _,line in ipairs(self.text) do
				maxW = math.max(maxW, #line)
			end

			-- lock
			self.scrollX = math.max(math.min(maxW-1,x),0)
			self.scrollY = math.max(math.min(y,#self.text-self.h),0)
		end

		function textArea.changeScroll(self,dx,dy)
			self:setScroll(self.scrollX+dx,self.scrollY+dy)
		end

		function textArea.focusCursor(self)
			self:setScroll(
				math.min(math.max(self.scrollX,self.cursorX-self.w),self.cursorX-1),
				math.min(math.max(self.scrollY,self.cursorY-self.h),self.cursorY-1)
			)
		end

		function textArea.getText(self)
			local text = ""
			for row,str in ipairs(self.text) do
				text = text .. str
				if row < #self.text then -- not last row
					text = text .. " \n"
				end
			end
			return text
		end

		function textArea.isChecked(self)
			return self.elemType == "checkbox" and self.text[1] == "[x]"
		end

		function textArea.handleEvents(self,ev,p1,p2,p3,p4,p5)
			if not self.enabled then
				return false
			end
			if self==selected then
				if ev == "char" or ev == "paste" then
					-- Add character
					local line = self.text[self.cursorY]

					self.text[self.cursorY] = line:sub(1,self.cursorX) .. p1 .. line:sub(self.cursorX + 1,-1)
					self.cursorX = self.cursorX + 1
					self:focusCursor()
					return true
				elseif ev == "key" then
					if p1 == keys.left then
						if lctrl or rctrl then
							self:changeScroll(-1,0)
						else
							-- left
							self.cursorX = self.cursorX - 1
							if self.cursorX < 1 then
								if self.cursorY > 1 then -- not first row
									self.cursorY = self.cursorY - 1
									self.cursorX = #self.text[self.cursorY] + 1
								else
									self.cursorX = 1
								end
							end
							self:focusCursor()
						end
						return true
					elseif p1 == keys.right then
						if lctrl or rctrl then
							self:changeScroll(1,0)
						else
							-- right
							self.cursorX = self.cursorX + 1
							if self.cursorX > #self.text[self.cursorY] + 1 then
								if self.cursorY < #self.text then -- not last row
									self.cursorY = self.cursorY + 1
									self.cursorX = 1
								else
									self.cursorX = #self.text[self.cursorY] + 1
								end
							end
							self:focusCursor()
						end
						return true
					elseif p1 == keys.up then
						if lctrl or rctrl then
							self:changeScroll(0,1)
						else
							-- up
							if self.cursorY > 1 then -- not first row
								self.cursorX = math.min(self.cursorX,#self.text[self.cursorY - 1] + 1)
								self.cursorY = self.cursorY - 1
							else
								self.cursorX = 1
							end
							self:focusCursor()
						end
						return true
					elseif p1 == keys.down then
						if lctrl or rctrl then
							self:changeScroll(0,-1)
						else
							-- down
							if self.cursorY < #self.text then -- not last row
								self.cursorX = math.min(self.cursorX,#self.text[self.cursorY + 1] + 1)
								self.cursorY = self.cursorY + 1
							else
								self.cursorX = #self.text[self.cursorY] + 1
							end
							self:focusCursor()
						end
						return true
					elseif p1 == keys.backspace then
						if self.cursorX > 1 then
							-- remove a char
							local line = self.text[self.cursorY]
							self.text[self.cursorY] = line:sub(1,self.cursorX - 2) .. line:sub(self.cursorX,-1)
							self.cursorX = self.cursorX - 1
							self:focusCursor()
							return true
						else
							if self.cursorY > 1 then
								-- compress two lines
								self.text[self.cursorY - 1] = self.text[self.cursorY - 1] .. self.text[self.cursorY]
								table.remove(self.text,self.cursorY)
								self.cursorY = self.cursorY - 1
								self.cursorX = #self.text[self.cursorY] + 1
								self:focusCursor()
								return true
							end
						end
					elseif p1 == keys.delete then
						if self.cursorX < #self.text[self.cursorY]+1 then
							-- remove a char
							local line = self.text[self.cursorY]
							self.text[self.cursorY] = line:sub(1,self.cursorX - 1) .. line:sub(self.cursorX + 1,-1)
							return true
						else
							if self.cursorY < #self.text then
								-- compress two lines
								self.text[self.cursorY] = self.text[self.cursorY] .. self.text[self.cursorY + 1]
								table.remove(self.text,self.cursorY + 1)
								self:focusCursor()
								return true
							end
						end
					elseif p1 == keys.enter then
						if self.multiline then
							-- split into new line
							local line = self.text[self.cursorY]
							self.text[self.cursorY] = line:sub(1, self.cursorX - 1)
							line = line:sub(self.cursorX, -1)

							table.insert(self.text, self.cursorY + 1, line)
							self.cursorY = self.cursorY + 1
							self.cursorX = 1
							self:focusCursor()
							return true
						end
					elseif p1 == keys["end"] then
						self.cursorX = #self.text[self.cursorY] + 1
						self:focusCursor()
						return true
					elseif p1 == keys.home then
						self.cursorX = 1
						self:focusCursor()
						return true
					elseif p1 == keys.tab then
						if not tabJump then
							if rshift or lshift then
								-- prev
								if self.prevElem then
									if type(self.onDeselect) == "function" then
										self:onDeselect()
									end
									selected = self.prevElem
									if type(selected.onSelect) == "function" then
										selected:onSelect()
									end
									tabJump = true
									return true
								end
							else
								-- next
								if self.nextElem then
									if type(self.onDeselect) == "function" then
										self:onDeselect()
									end
									selected = self.nextElem
									if type(selected.onSelect) == "function" then
										selected:onSelect()
									end
									tabJump = true
									return true
								end
							end
						end
					end
				elseif ev == "mouse_scroll" then
					self:changeScroll(0,p1)
					return true
				end
			end
			if ev == "mouse_click" and p1 == 1 then
				if self:pointInArea(p2,p3) then
					if self.elemType == "textArea" then
						selected = self
						local x,y = self:worldtoLocal(p2,p3)
						self.cursorY = math.min(#self.text, y)
						self.cursorX = math.min(#self.text[self.cursorY]+1, x)
						self:focusCursor()
					elseif self.elemType == "checkbox" then
						local checked = self:isChecked()
						self.text[1] = checked and "[ ]" or "[x]"
					end
					if type(self.onSelect) == "function" then
						self:onSelect()
					end
					return true
				elseif selected == self then
					if type(self.onDeselect) == "function" then
						self:onDeselect()
					end
					selected = false
					return true
				end
			end

			return false
		end

		return textArea
	end

	local function newCheckbox( x,y,checked )
		local textArea = newTextArea(x,y,x+2,_,false)
		textArea.elemType = "checkbox"
		textArea.text[1] = checked and "[x]" or "[ ]"
		return textArea
	end

	local function newButton(x1,y1,x2,y2,str,onSelect)
		local button = newTextArea(x1,y1,x2,y2,true)
		button.elemType = "button"
		button.onSelect = onSelect
		button.enabled = true

		button.text = {}
		for i=1,button.h do
			if i == math.floor(button.h/2)+1 then
				table.insert(button.text,string.rep(" ",math.floor(button.w/2-#str/2))..str)
			else
				table.insert(button.text,"")
			end
		end

		return button
	end

	local exitField = newButton(termW,1,_,_,"X")
	local fromField = newTextArea(10,4,termW-1,_,false)
	local subjectField = newTextArea(10,6,termW-1,_,false)
	local messageField = newTextArea(10,8,termW-1,14,true)
	local previewField = newButton(termW - 14,termH-3,termW-1,_,"Preview")
	local sendField = newButton(termW - 14,termH-1,termW-1,_,"Send")

	fromField.nextElem = subjectField
	fromField.prevElem = messageField
	subjectField.nextElem = messageField
	subjectField.prevElem = fromField
	messageField.nextElem = fromField
	messageField.prevElem = subjectField
	sendField.enabled = false

	if type(lockedSender) == "string" and #lockedSender > 0 then
		fromField.enabled = false
		fromField.text[1] = lockedSender

		subjectField.prevElem = messageField
		messageField.nextElem = subjectField
	end

	local jagField = newCheckbox(10,termH - 3)
	local knautField = newCheckbox(10,termH - 2)
	local bejnoField = newCheckbox(10,termH - 1)

	local function getReceivers()
		local receivers = {}
		if jagField:isChecked() then table.insert(receivers,"jag") end
		if knautField:isChecked() then table.insert(receivers,"knaut") end
		if bejnoField:isChecked() then table.insert(receivers,"bejno") end
		return receivers
	end

	local function checkForErrors()
		local oldA,oldB = diskAvailable,anyReceivers
		diskAvailable = mail.getDrive().hasData()
		anyReceivers = #getReceivers() > 0
		sendField.enabled = diskAvailable and anyReceivers
		if diskAvailable ~= oldA or anyReceivers ~= oldB then redraw = true end
	end

	local function getMailData()
		return {
			sender = fromField:getText(),
			receivers = getReceivers(),
			message = messageField:getText(),
			subject = subjectField:getText(),
		}
	end

	previewField.onSelect = function(self)
		previewMail(getMailData())
	end

	sendField.onSelect = function(self)
		if self.enabled then
			mail.writeMail(getMailData())
		end
	end

	exitField.onSelect = function(self)
		running = false
	end

	local function draw()
		term.setCursorBlink(false)

		-- draw background
		setRect(" ",1,1,termW,2,_,colors.cyan)
		setRect(" ",1,3,termW,termH, _, colors.lightBlue)

		-- Draw text
		writeCentered("Write new mail",2,colors.white)

		writeText("From", 2, 4, colors.gray)
		writeText("Subject", 2, 6, colors.gray)
		writeText("Message", 2, 8, colors.gray)

		writeText("Send to", 2, termH - 3, colors.gray)
		writeText("- jag", 14, termH - 3, jagField:isChecked() and colors.black or colors.gray)
		writeText("- knaut", 14, termH - 2, knautField:isChecked() and colors.black or colors.gray)
		writeText("- bejno", 14, termH - 1, bejnoField:isChecked() and colors.black or colors.gray)

		if not diskAvailable then
			writeText("Requires disk in disk drive!",23,termH,colors.red)
		elseif not anyReceivers then
			writeText("   Need at least 1 receiver!",23,termH,colors.red)
		end

		-- Draw fields
		for _,field in pairs(fields) do
			if type(field.draw) == "function" then
				field:draw()
			end
		end

		for _,field in pairs(fields) do
			if type(field.lateDraw) == "function" then
				field:lateDraw()
			end
		end

		-- Draw to screen
		drawGrid()

		-- Show cursor
		if selected and selected.visableCursor then
			term.setCursorPos(selected:localToWorld(selected.cursorX,selected.cursorY))
			term.setCursorBlink(true)
		else
			term.setCursorBlink(false)
		end
	end

	local function handleEvents(ev,p1,p2,p3,p4,p5)
		checkForErrors()

		if ev == "key" then
			if p1 == keys.leftShift then lshift = true end
			if p1 == keys.rightShift then rshift = true end
			if p1 == keys.leftCtrl then lctrl = true end
			if p1 == keys.rightCtrl then rctrl = true end
		end
		if ev == "key_up" then
			if p1 == keys.leftShift then lshift = false end
			if p1 == keys.rightShift then rshift = false end
			if p1 == keys.leftCtrl then lctrl = false end
			if p1 == keys.rightCtrl then rctrl = false end
		end

		-- Update fields
		tabJump = false
		for _,field in pairs(fields) do
			if field:handleEvents(ev,p1,p2,p3,p4,p5) then
				redraw = true
			end
		end
	end

	-- Main loop
	checkForErrors()
	while running do
		if redraw then
			draw()
			redraw = false
		end
		handleEvents(os.pullEvent())
	end

	term.setBackgroundColor(colors.black)
	term.clear()
	term.setCursorPos(1,1)

	return data
end

-- eof