BobCatAPI

do
  Object = { __name = "Object" }

  function Object:init(...) end

  function Object:super(class)
    local obj = self
    return setmetatable({ }, { __index = function(t, k)
        return function(...)
            while class do
                local method = class[k]
                if method then
                    return method(obj, ...)
                end
                class = class.__super
            end
        end
    end })
  end
  function Object:createTable()
    local obj = self
    local class = obj:getClass()
    return setmetatable({ }, { __index = function(t, k)
        return function(...)
            local method = class[k]
            return method(obj, ...)
        end
    end })
  end

  function Object:getSuper()
    return rawget(self:getClass(), "__super")
  end

  function Object:getClass()
    return rawget(self, "__class")
  end

  function Object:instanceof(targetType)
    local objectType = self:getClass()
    while objectType do
        if targetType == objectType then
            return true
        end
        objectType = objectType:getSuper()
    end
    return false
  end

  function Object:toString()
    return self:getClass():getName().." ("..tostring(self):sub(8, -1)..")"
  end

  function Object:extend(obj)
    self.__index = self -- This is a metatable

    local obj = obj or {}
    obj.__super = self
    local obj = setmetatable(obj, self)
    return obj
  end

  Class = Object:extend({__name = "Class"})
  function Class:new(...)
    local instance = { __class = self }
    self:extend(instance)
    instance:init(...)
    return instance
  end

  function Class:getName(name)
    return self.__name
  end
  function Class:subClass(name)
    local instance = { }
    instance.__name = name

    return self:extend(instance)
  end
end
do
  local log = fs.open("BobCat.log", "w")


  function Debug(Message, ...)
    Log("DEBUG", Message, ...)
  end
  function Print(Message, ...)
    print(Log("PRINT", Message, ...))
  end
  function PrintError(Message, ...)
    printError(Log("WARNING", Message, ...))
  end
  function Error(Message, ...)
    error(Log("ERROR", Message, ...))
  end

  function Log(Type, Message, ...)
    local str = string.format(tostring(Message), unpack({...}))
    log.writeLine("["..Type.."] "..str)
    log.flush()

    return str
  end
end
do
  --[=====================================================================[
  v0.6 Copyright © 2013-2014 Gavin Kistner <[email protected]>; MIT Licensed
  See http://github.com/Phrogz/SLAXML for details.
  --]=====================================================================]
  SLAXML = {
    VERSION = "0.6",
    _call = {
        pi = function(target,content)
            print(string.format("<?%s %s?>",target,content))
        end,
        comment = function(content)
            print(string.format("<!-- %s -->",content))
        end,
        startElement = function(name,nsURI,nsPrefix)
                             io.write("<")
            if nsPrefix then io.write(nsPrefix,":") end
                             io.write(name)
            if nsURI    then io.write(" (ns='",nsURI,"')") end
                             print(">")
        end,
        attribute = function(name,value,nsURI,nsPrefix)
            io.write('  ')
            if nsPrefix then io.write(nsPrefix,":") end
                             io.write(name,'=',string.format('%q',value))
            if nsURI    then io.write(" (ns='",nsURI,"')") end
            io.write("\n")
        end,
        text = function(text)
            print(string.format("  text: %q",text))
        end,
        closeElement = function(name,nsURI,nsPrefix)
            print(string.format("</%s>",name))
        end,
    }
  }

  function SLAXML:parser(callbacks)
    return { _call=callbacks or self._call, parse=SLAXML.parse }
  end

  function SLAXML:parse(xml,options)
    if not options then options = { stripWhitespace=false } end

    -- Cache references for maximum speed
    local find, sub, gsub, char, push, pop = string.find, string.sub, string.gsub, string.char, table.insert, table.remove
    local first, last, match1, match2, match3, pos2, nsURI
    local unpack = unpack or table.unpack
    local pos = 1
    local state = "text"
    local textStart = 1
    local currentElement={}
    local currentAttributes={}
    local currentAttributeCt -- manually track length since the table is re-used
    local nsStack = {}

    local entityMap  = { ["lt"]="<", ["gt"]=">", ["amp"]="&", ["quot"]='"', ["apos"]="'" }
    local entitySwap = function(orig,n,s) return entityMap[s] or n=="#" and char(s) or orig end
    local function unescape(str) return gsub( str, '(&(#?)([%d%a]+);)', entitySwap ) end
    local anyElement = false

    local function finishText()
        if first>textStart and self._call.text then
            local text = sub(xml,textStart,first-1)
            if options.stripWhitespace then
                text = gsub(text,'^%s+','')
                text = gsub(text,'%s+$','')
                if #text==0 then text=nil end
            end
            if text then self._call.text(unescape(text)) end
        end
    end

    local function findPI()
        first, last, match1, match2 = find( xml, '^<%?([:%a_][:%w_.-]*) ?(.-)%?>', pos )
        if first then
            finishText()
            if self._call.pi then self._call.pi(match1,match2) end
            pos = last+1
            textStart = pos
            return true
        end
    end

    local function findComment()
        first, last, match1 = find( xml, '^<!%-%-(.-)%-%->', pos )
        if first then
            finishText()
            if self._call.comment then self._call.comment(match1) end
            pos = last+1
            textStart = pos
            return true
        end
    end

    local function nsForPrefix(prefix)
        if prefix=='xml' then return 'http://www.w3.org/XML/1998/namespace' end -- http://www.w3.org/TR/xml-names/#ns-decl
        for i=#nsStack,1,-1 do if nsStack[i][prefix] then return nsStack[i][prefix] end end
        error(("Cannot find namespace for prefix %s"):format(prefix))
    end

    local function startElement()
        anyElement = true
        first, last, match1 = find( xml, '^<([%a_][%w_.-]*)', pos )
        if first then
            currentElement[2] = nil -- reset the nsURI, since this table is re-used
            currentElement[3] = nil -- reset the nsPrefix, since this table is re-used
            finishText()
            pos = last+1
            first,last,match2 = find(xml, '^:([%a_][%w_.-]*)', pos )
            if first then
                currentElement[1] = match2
                currentElement[3] = match1 -- Save the prefix for later resolution
                match1 = match2
                pos = last+1
            else
                currentElement[1] = match1
                for i=#nsStack,1,-1 do if nsStack[i]['!'] then currentElement[2] = nsStack[i]['!']; break end end
            end
            currentAttributeCt = 0
            push(nsStack,{})
            return true
        end
    end

    local function findAttribute()
        first, last, match1 = find( xml, '^%s+([:%a_][:%w_.-]*)%s*=%s*', pos )
        if first then
            pos2 = last+1
            first, last, match2 = find( xml, '^"([^<"]*)"', pos2 ) -- FIXME: disallow non-entity ampersands
            if first then
                pos = last+1
                match2 = unescape(match2)
            else
                first, last, match2 = find( xml, "^'([^<']*)'", pos2 ) -- FIXME: disallow non-entity ampersands
                if first then
                    pos = last+1
                    match2 = unescape(match2)
                end
            end
        end
        if match1 and match2 then
            local currentAttribute = {match1,match2}
            local prefix,name = string.match(match1,'^([^:]+):([^:]+)$')
            if prefix then
                if prefix=='xmlns' then
                    nsStack[#nsStack][name] = match2
                else
                    currentAttribute[1] = name
                    currentAttribute[4] = prefix
                end
            else
                if match1=='xmlns' then
                    nsStack[#nsStack]['!'] = match2
                    currentElement[2]      = match2
                end
            end
            currentAttributeCt = currentAttributeCt + 1
            currentAttributes[currentAttributeCt] = currentAttribute
            return true
        end
    end

    local function findCDATA()
        first, last, match1 = find( xml, '^<!%[CDATA%[(.-)%]%]>', pos )
        if first then
            finishText()
            if self._call.text then self._call.text(match1) end
            pos = last+1
            textStart = pos
            return true
        end
    end

    local function closeElement()
        first, last, match1 = find( xml, '^%s*(/?)>', pos )
        if first then
            state = "text"
            pos = last+1
            textStart = pos

            -- Resolve namespace prefixes AFTER all new/redefined prefixes have been parsed
            if currentElement[3] then currentElement[2] = nsForPrefix(currentElement[3])    end
            if self._call.startElement then self._call.startElement(unpack(currentElement)) end
            if self._call.attribute then
                for i=1,currentAttributeCt do
                    if currentAttributes[i][4] then currentAttributes[i][3] = nsForPrefix(currentAttributes[i][4]) end
                    self._call.attribute(unpack(currentAttributes[i]))
                end
            end

            if match1=="/" then
                pop(nsStack)
                if self._call.closeElement then self._call.closeElement(unpack(currentElement)) end
            end
            return true
        end
    end

    local function findElementClose()
        first, last, match1, match2 = find( xml, '^</([%a_][%w_.-]*)%s*>', pos )
        if first then
            nsURI = nil
            for i=#nsStack,1,-1 do if nsStack[i]['!'] then nsURI = nsStack[i]['!']; break end end
        else
            first, last, match2, match1 = find( xml, '^</([%a_][%w_.-]*):([%a_][%w_.-]*)%s*>', pos )
            if first then nsURI = nsForPrefix(match2) end
        end
        if first then
            finishText()
            if self._call.closeElement then self._call.closeElement(match1,nsURI) end
            pos = last+1
            textStart = pos
            pop(nsStack)
            return true
        end
    end

    while pos<#xml do
        if state=="text" then
            if not (findPI() or findComment() or findCDATA() or findElementClose()) then
                if startElement() then
                    state = "attributes"
                else
                    first, last = find( xml, '^[^<]+', pos )
                    pos = (first and last or pos) + 1
                end
            end
        elseif state=="attributes" then
            if not findAttribute() then
                if not closeElement() then
                    print(state)
                    error("Was in an element and couldn't find attributes or the close.")
                end
            end
        end
    end

    if not anyElement then error("Parsing did not discover any elements") end
    if #nsStack > 0 then error("Parsing ended with unclosed elements") end
  end
end
do
  --@require Class.lua

  --Base class for pages
  Page = Class:subClass("Page")
  function Page:init(Url)
    self.Url = Url
    self.Title = Url

    self.Ids = { }
    self.Clicks = { }
  end
end
do
  --@require ../../Class.lua

  --Base class for elements inside the DOM tree
  Element = Class:subClass("Element")
  function Element:init(Data, Page)
    self.Type = Data.Type
    self.Tag = Data.Tag

    self.Page = Page

    self.Parent = nil
  end

  function Element:setParent(Parent)
    self.Parent = Parent
  end

  function Element:draw(Gui) end
  function Element:stripWhitespace() end

  function Element:previousElement()
    local previous = nil
    for _, Child in pairs(self.Parent.Children) do
        if Child == self then
            break
        end

        previous = Child
    end
    return previous
  end

  function Element:nextElement()
    local nextElement = nil
    for _, Child in pairs(self.Parent.Children) do
        if nextElement then
            break
        end

        if Child == self then
            nextElement = true
        end
    end
    return nextElement
  end


  --Text elements
  TextElement = Element:subClass("TextElement")
  function TextElement:init(Data, Page)
    self:super(Element).init(Data, Page)

    self.Contents = Data.Value or ""
  end
  function TextElement:toString()
    return self.Contents
  end

  function TextElement:draw(Buffer)
    --Buffer:print(self.Contents)
    write(self.Contents)
  end

  function TextElement:stripWhitespace()
    self.Contents = self.Contents:gsub("%s+", " ")
  end
end
do
  --@require ../Class.lua
  --@require ../Logger.lua

  local Tags = { }
  local DefaultClass = nil

  TagRegister = Class:subClass("TagRegister")
  function TagRegister.Register(tag, class)
    Debug("Registering %s for tag %s", class:getName(), tag)
    Tags[tag] = class
  end

  function TagRegister.SetDefaultClass(class)
    DefaultClass = class
  end

  function TagRegister.CreateElement(Data, ThisPage)
    local EClass = Tags[Data.Tag]
    if EClass == nil then
        EClass = DefaultClass
    end
    return EClass:new(Data, ThisPage)
  end
end
do
  --@require ../Class.lua
  --From Lyqyd's FrameBuffer API (http://pastebin.com/Aaza6h5v)

  FrameBuffer = Class:subClass("FrameBuffer")
  function FrameBuffer:init(sizeX, sizeY, colour)
    self.text = {}
    self.textColor = {}
    self.backColor = {}
    self.cursorX = 1
    self.cursorY = 1
    self.curTextColor = "0"
    self.curBackColor = "f"
    self.sizeX = sizeX or 51
    self.sizeY = sizeY or -1
    self.endY = sizeY or 0
    if colour == nil then colour = true end
    self.color = colour

    self:createLine()
  end

  function FrameBuffer:write(text)
    text = tostring(text)

    --Debug("Writing %s (%s, %s)", text, self.curTextColor, self.curBackColor)
    local pos = self.cursorX
    if (self.cursorY > self.sizeY and self.sizeY ~= -1) or self.cursorY < 1 then
        self.cursorX = pos + #text
        return

    end

    if pos + #text <= 1 then
        --skip entirely.
        self.cursorX = pos + #text
        return
    elseif pos < 1 then
        --adjust text to fit on screen starting at one.
        writeText = string.sub(text, math.abs(self.cursorX) + 2)
        self.cursorX = 1
    elseif pos > self.sizeX then
        --if we're off the edge to the right, skip entirely.
        self.cursorX = pos + #text
        return
    else
        writeText = text
    end

    local lineText = self.text[self.cursorY]
    local lineColor = self.textColor[self.cursorY]
    local lineBack = self.backColor[self.cursorY]
    local preStop = self.cursorX - 1
    local preStart = math.min(1, preStop)
    local postStart = self.cursorX + string.len(writeText)
    local postStop = self.sizeX
    self.text[self.cursorY] = string.sub(lineText, preStart, preStop)..writeText..string.sub(lineText, postStart, postStop)
    self.textColor[self.cursorY] = string.sub(lineColor, preStart, preStop)..string.rep(self.curTextColor, #writeText)..string.sub(lineColor, postStart, postStop)
    self.backColor[self.cursorY] = string.sub(lineBack, preStart, preStop)..string.rep(self.curBackColor, #writeText)..string.sub(lineBack, postStart, postStop)
    self.cursorX = pos + string.len(text)
  end

  function FrameBuffer:createLine(line)
    if line==nil then
        self.endY = self.endY + 1
        line = self.endY
    elseif line > self.endY then
        self.endY = line
    end

    --Debug("Creating line at: %s", line)

    self.text[line] = string.rep(" ", self.sizeX)
    self.textColor[line] = string.rep(self.curTextColor, self.sizeX)
    self.backColor[line] = string.rep(self.curBackColor, self.sizeX)
  end

  function FrameBuffer:clearLine()
    self:createLine(self.cursorY)
  end

  function FrameBuffer:clear()
    self.text = {}
    self.textColor = {}
    self.backColor = {}
    self.cursorX = 1
    self.cursorY = 1
    self.curTextColor = "0"
    self.curBackColor = "f"
    self.endY = self.sizeY or 0
  end

  function FrameBuffer:getCursorPos()
    return self.cursorX, self.cursorY
  end
  function FrameBuffer:setCursorPos(x, y)
    self.cursorX = math.floor(tonumber(x)) or self.cursorX
    self.cursorY = math.floor(tonumber(y)) or self.cursorY


    --Debug("Cursor to %s, %s", x,y)

    if not self.text[y] then
        local last = nil
        for i = self.endY+1, y,1 do
            if last ~= i then
                self:createLine(i)
                last = i
            end
        end
    end
  end
  function FrameBuffer:setCursorBlink(b) end
  function FrameBuffer:scroll(n)
    self.cursorX = self.cursorX + n
  end

  function FrameBuffer:getSize()
    local y = self.sizeY
    if y == -1 then
        y = self.endY + 1000
    end
    return self.sizeX, y
  end

  function FrameBuffer:setTextColor(clr)
    if clr and clr <= 32768 and clr >= 1 then
        if self.color then
            self.curTextColor = string.format("%x", math.floor(math.log(clr) / math.log(2)))
        elseif clr == 1 or clr == 32768 then
            self.curTextColor = string.format("%x", math.floor(math.log(clr) / math.log(2)))
        else
            return nil, "Colour not supported"
        end
    end
  end
  FrameBuffer.setTextColour = FrameBuffer.setTextColor
  function FrameBuffer:setBackgroundColor(clr)
    if clr and clr <= 32768 and clr >= 1 then
        if self.color then
            self.curBackColor = string.format("%x", math.floor(math.log(clr) / math.log(2)))
        elseif clr == 32768 or clr == 1 then
            self.curBackColor = string.format("%x", math.floor(math.log(clr) / math.log(2)))
        else
            return nil, "Colour not supported"
        end
    end
  end
  FrameBuffer.setBackgroundColour = FrameBuffer.setBackgroundColor
  function FrameBuffer:isColor()
    return self.color == true
  end
  FrameBuffer.isColour = FrameBuffer.isColor

  function FrameBuffer:draw(redirect)
    local x, y = redirect.getCursorPos()

    for p=1, self.endY do
        self:drawLine(redirect, p)
    end
    redirect.setCursorPos(x + self.cursorX, y + self.cursorY)
    redirect.setTextColor(2 ^ tonumber(self.curTextColor, 16))
    redirect.setBackgroundColor(2 ^ tonumber(self.curBackColor, 16))
  end

  function FrameBuffer:drawLine(redirect, line)
    local x, y = redirect.getCursorPos()
    local w, h = redirect.getSize()

    local thisY = line + y
    --redirect.setCursorPos(x, thisY)

    --If off the edge
    if not self.text[line] then
        return
    end

    local lineEnd = false
    local offset = x
    while not lineEnd do
        local textColorString = string.match(string.sub(self.textColor[line], offset), string.sub(self.textColor[line], offset, offset).."*")
        local backColorString = string.match(string.sub(self.backColor[line], offset), string.sub(self.backColor[line], offset, offset).."*")

        redirect.setTextColor(2 ^ tonumber(string.sub(textColorString, 1, 1), 16))
        redirect.setBackgroundColor(2 ^ tonumber(string.sub(backColorString, 1, 1), 16))
        redirect.write(string.sub(self.text[line], offset, offset + math.min(#textColorString, #backColorString) - 1))
        offset = offset + math.min(#textColorString, #backColorString)

        if offset > self.sizeX then lineEnd = true end
    end
  end

  function FrameBuffer:getColours()
    return {2 ^ tonumber(string.sub(self.curTextColor, 1, 1), 16), 2 ^ tonumber(string.sub(self.curBackColor, 1, 1), 16)}
  end

  function FrameBuffer:restoreColours(colours)
    self:setTextColour(colours[1])
    self:setBackgroundColour(colours[2])
  end

  function FrameBuffer:resetColours()
    self:setBackgroundColour(colours.black)
    self:setTextColour(colours.white)
  end
end
do
  --@require ../Class.lua
  --@require ../Logger.lua
  --@require FrameBuffer.lua

  GuiHost = Class:subClass("GuiHost")

  function GuiHost:init(Page, Document)
    self.Page = Page
    self.Document = Document

    self.Navigation = nil

    local w, h = term.getSize()
    self.Buffer = FrameBuffer:new(w - 1, nil, true)

    self.y=0
  end

  function GuiHost:prepareDraw()
    local current = term.current()
    Debug("Loading")
    self.Buffer:clear()
    term.redirect(self.Buffer:createTable())

    self.Document:draw(self.Buffer)
    term.redirect(current)
    Debug("Loaded")
  end

  --Drawing
  function GuiHost:setY(y)
    local w, h = term.getSize()
    if y >= 0 and y < (self.Buffer.endY - h + 2) then
        self.y = y
    end
  end

  function GuiHost:draw()
    term.setBackgroundColour(colours.black)
    term.clear()
    self:DrawHeader()
    Debug("Drawing start")

    local w, h = term.getSize()

    for i=1, h, 1 do
        term.setCursorPos(1, i+2)
        self.Buffer:drawLine(term, i+self.y)
    end
    Debug("Drawing end")
  end

  function GuiHost:DrawHeader()
    term.setCursorPos(1,1)

    term.setBackgroundColour(colours.red)
    term.setTextColour(colours.white)
    term.write("<")

    term.setBackgroundColour(colours.orange)
    term.write(">")

    term.setBackgroundColour(colours.lightGrey)

    term.write(" " .. self.Page.Url .. string.rep(" ", term.getSize() - #self.Page.Url))

    term.setTextColour(colours.blue)

    term.setCursorPos(1,2)
    term.clearLine()
    term.write(self.Page.Title)

    term.setCursorPos(1, 3)
    term.setBackgroundColour(colours.black)
    term.setTextColour(colours.white)
  end

  function GuiHost:click(x, y)
    if y <= 2 then
        --Can't respond to navigation
        if not self.Navigation then
            return
        end
        --Action in headerbar
        if y == 1 then
            if x == 1 then
                self.Navigation:back()
            elseif x == 2 then
                self.Navigation:forward()
            else
                self:startEdit()
            end
        end
    end
  end

  function GuiHost:startEdit()

    term.setBackgroundColour(colours.lightGrey)
    term.setTextColour(colours.white)
    term.setCursorBlink(true)

    local line = self.Page.Url

    local w = term.getSize()
    local sx = 4
    local pos = #line

    term.setCursorPos(sx + pos, 1)

    local function redraw( customReplaceChar )
        local scroll = 0
        if sx + pos >= w then
            scroll = (sx + pos) - w
        end

        local cx,cy = term.getCursorPos()
        term.setCursorPos( sx, cy )
        local replace = customReplaceChar
        if replace then
            term.write( string.rep( replace, math.max( string.len(line) - scroll, 0 ) ) )
        else
            term.write( string.sub( line, scroll + 1 ) )
        end
        term.setCursorPos( sx + pos - scroll, cy )
    end

    while true do
        local event, param = os.pullEvent()
        if event == "char" then
            -- Typed key
            line = string.sub( line, 1, pos ) .. param .. string.sub( line, pos + 1 )
            pos = pos + 1
            redraw()

        elseif event == "paste" then
            -- Pasted text
            line = string.sub( line, 1, pos ) .. param .. string.sub( line, pos + 1 )
            pos = pos + string.len( param )
            redraw()

        elseif event == "key" then
            if param == keys.enter then
                -- Enter
                break
            elseif param == 1 then
                --Escape
                term.setCursorBlink(false)
                return

            elseif param == keys.left then
                -- Left
                if pos > 0 then
                    pos = pos - 1
                    redraw()
                end

            elseif param == keys.right then
                -- Right
                if pos < string.len(line) then
                    redraw(" ")
                    pos = pos + 1
                    redraw()
                end
            elseif param == keys.backspace then
                -- Backspace
                if pos > 0 then
                    redraw(" ")
                    line = string.sub( line, 1, pos - 1 ) .. string.sub( line, pos + 1 )
                    pos = pos - 1
                    redraw()
                end
            elseif param == keys.home then
                -- Home
                redraw(" ")
                pos = 0
                redraw()
            elseif param == keys.delete then
                -- Delete
                if pos < string.len(line) then
                    redraw(" ")
                    line = string.sub( line, 1, pos ) .. string.sub( line, pos + 2 )
                    redraw()
                end
            elseif param == keys["end"] then
                -- End
                redraw(" ")
                pos = string.len(line)
                redraw()
            end

        elseif event == "term_resize" then
            -- Terminal resized
            w = term.getSize()
            redraw()

        end
    end

    term.setCursorBlink(false)

    self.Navigation:load(line)
  end
end
do
  --@require ../Class.lua
  --@require ../Logger.lua
  --@require Elements/Element.lua
  --@require SlaXml.lua
  --@require TagRegister.lua

  DomTreeParser = Class:subClass("DomTreeParser")

  local Push, Pop = table.insert, table.remove

  function DomTreeParser.Parse(Xml, ThisPage)
    local Document = {
        ['Type'] = 'document',
        ['Tag'] = '#document',
        ['Attributes'] = {}, --Should have none but prevents breaking it
        ['Children'] = {},
    }

    local Current = Document
    local Children = Current.Children
    local Stack = { Document }

    local Parser = SLAXML:parser({

        -- When "<foo" or <x:foo is seen
        startElement = function(Tag, nsURI, nsPrefix)
            Tag = Tag:lower()
            local El = {
                ['Type'] = "element",
                ['Tag'] = Tag,
                ['Children'] = {},
                --['El'] = {}, -- (Only tags)
                ['Attributes'] = {},
                ['NsURI'] = nsURI,
            }
            if Current==Document then
                if Document.Root then
                    Error(("Encountered element '%s' when the document already has a root '%s' element"):format(Tag, Document.Root.Name))
                end
                Document.Root = El
            end

            Current = El
            Push(Stack,El)
        end,
        -- attribute found on current element
        attribute = function(Name, Value, nsURI, nsPrefix)
            Name = Name:lower()
            if not Current or Current.Type~="element" then
                Error(("Encountered an attribute %s=%s but it wasn't inside an element"):format(Name,Value))
            end

            if nsURI ~= nil then
                Current.Attributes[nsURI .. ':' .. Name] = Value
            else
                Current.Attributes[Name] = Value
            end
        end,
        -- When "</foo>" or </x:foo> or "/>" is seen
        closeElement = function(Tag, nsURI)
            Tag = Tag:lower()

            if Current.Tag~=Tag or Current.Type~="element" then
                Error(("Received a close element notification for '%s' but was inside a '%s' %s"):format(Tag, Current.Tag, Current.Type))
            end

            local El = Current

            Pop(Stack)
            Current = Stack[#Stack]
            Push(Current.Children, TagRegister.CreateElement(El, ThisPage))
        end,
        -- text and CDATA nodes
        text = function(Text)
            if Current.Type~='document' then
                if Current.Type~="element" then
                    Error(("Received a text notification '%s' but was inside a %s"):format(Text, Current.Type))
                end
                Push(Current.Children, TextElement:new({
                    ['Type']='text',
                    ['Tag']='#text',
                    ['Value']=Text,
                }, ThisPage))
            end
        end,
    })

    -- Ignore whitespace-only text nodes and strip leading/trailing whitespace from text
    -- (does not strip leading/trailing whitespace from CDATA)
    Parser:parse(Xml, {stripWhitespace=true})

    return DocumentElement:new(Document)
  end
end
do
  --@require ../TagRegister.lua
  --@require Element.lua

  --Base class for HTML elements inside the dom tree
  HtmlElement = Element:subClass("HtmlElement")
  TagRegister.SetDefaultClass(HtmlElement)

  function HtmlElement:init(Data, Page)
    self:super(Element).init(Data, Page)

    self.Children = Data.Children
    self.Attributes = Data.Attributes

    local Id = self.Attributes["id"]
    if Id ~= nil and Id ~= "" then
        Page.Ids[Id] = self
    end

    for _, Child in ipairs(self.Children) do
        Child:setParent(self)
    end
  end
  function HtmlElement:innerHTML()
    local Out = ''
    for _, Child in ipairs(self.Children) do
        Out = Out .. Child:toString()
    end

    return Out
  end
  function HtmlElement:toString()
    local Out = '<'..self.Tag
    for Key,Value in pairs(self.Attributes) do
        Out = Out .. ' ' .. Key ..'="'..Value..'"'
    end

    Out = Out .. '>'
    Out = Out .. self:innerHTML()

    return Out.. '</'..self.Tag..'>'
  end
  function HtmlElement:subClass(name, tag)
    local instance = self:super(Element).subClass(name)
    if tag then
        TagRegister.Register(tag, instance)
    end

    return instance
  end

  function HtmlElement:height()
    local Height = 0
    for _, Child in pairs(self.Children) do
        Height = Height + Child.height()
    end
    return Height
  end

  function HtmlElement:draw(Gui)
    for _, Child in ipairs(self.Children) do
        Child:draw(Gui)
    end
  end

  function HtmlElement:stripWhitespace()
    for _,Child in ipairs(self.Children) do
        Child:stripWhitespace()
        if Child.Type == "text" and (Child.Contents == "" or Child.Contents == nil) then
            table.remove(self.Children, _)
        end
    end
  end


  --Root document
  DocumentElement = Element:subClass("DocumentElement")
  function DocumentElement:init(Data, Page)
    self:super(Element).init(Data, Page)

    self.Children = Data.Children

    self.Html = nil
    self.Head = nil
    self.Body = nil
    for _, Child in pairs(self.Children) do
        if Child.Tag == "html" then
            self.Html = Child
            self.Head = Child.Head
            self.Body = Child.Body
        end
    end
  end

  function DocumentElement:draw(Buffer)
    self.Body:draw(Buffer)
  end

  function DocumentElement:stripWhitespace()
    self.Body:stripWhitespace()
  end
end
do
  --@require HtmlElement.lua

  --The <html> tag
  HtmlTagElement = HtmlElement:subClass("HtmlTagElement", "html")
  function HtmlTagElement:init(Data, Page)
    self:super(HtmlElement).init(Data, Page)

    self.Head = nil
    self.Body = nil
    for _, Child in pairs(self.Children) do
        if Child.Tag == "head" then
            self.Head = Child
        elseif Child.Tag == "body" then
            self.Body = Child
        end
    end
  end

  --The <head> tag
  HeadElement = HtmlElement:subClass("HeadElement", "head")
  function HeadElement:width()
    return 0
  end
  function HeadElement:height()
    return 0
  end

  --The <title tag
  TitleElement = HtmlElement:subClass("TitleElement", "title")
  function TitleElement:init(Data, Page)
    self:super(HtmlElement).init(Data, Page)
    Page.Title = self:innerHTML()
  end
end
do
  --@require Class.lua
  --@require Html/DomTree.lua
  --@require Gui/GuiHelper.lua
  --@require Page.lua

  local ErrorPage = [[
  <html>
    <head>
        <title>Error</title>
    </head>
    <body>
        <h1>Sorry, could not access that page</h1>
    </body>
  </html>
  ]]

  local StartPage = [[
  <html>
    <head>
        <title>About BobCat</title>
    </head>
    <body>
        <h1>Hai!</h1>
    </body>
  </html>
  ]]

  Navigation = Class:subClass("Navigation")
  function Navigation:init()
    self.History = { "about:new"}
    self.HistoryIndex = 1

    self.Page = Page:new("about:new")
    self.Document = DomTreeParser.Parse(StartPage, self.Page)

    self.Gui = GuiHost:new(self.Page, self.Document)
    self.Gui.Navigation = self
    self.Gui:prepareDraw()
  end

  function Navigation:load(Url, ...)
    Debug("Going to page %s", Url)

    if Url:sub(0, 7) == "file://" then
        self:loadLocal(Url:sub(8), ...)
    elseif Url == "about:new" then
        self:_loadAbout()
    else
        self:loadRemote(Url, ...)
    end
  end

  function Navigation:loadRemote(Url, PostData, Headers, AddToNav)
    self.Page = Page:new(Url)

    local Result = http.post(Url, PostData, Headers)
    if not Result then
        self:_loadDocument(ErrorPage)
    else
        self:_loadDocument(Result:readAll())
        if AddToNav ~= false then
            self:_addNavigation(Url)
        end
    end
  end

  function Navigation:loadLocal(File, AddToNav)
    local Url = "file://"..tostring(File)
    self.Page = Page:new(Url)

    local Result = fs.open(File, "r")
    if not Result then
        self:_loadDocument(ErrorPage)
    else
        self:_loadDocument(Result.readAll())

        if AddToNav ~= false then
            self:_addNavigation(Url)
        end
    end
  end

  function Navigation:_loadAbout()
    self.Page = Page:new("about:new")
    self:_loadDocument(StartPage)
  end

  function Navigation:_addNavigation(Url)
    self.HistoryIndex = self.HistoryIndex + 1

    local length = #self.History
    if length > self.HistoryIndex then
        for i = self.HistoryIndex, length, 1 do
            table.remove(self.History, i)
        end
    end

    table.insert(self.History, Url)
  end

  function Navigation:_loadDocument(Contents)
    self.Document=DomTreeParser.Parse(Contents, self.Page)

    if not self.Document then
        Error("Could not load document")
    end

    self.Document:stripWhitespace()

    self.Gui.Page = self.Page
    self.Gui.Document = self.Document

    Debug("Gui Draw from Navigation")
    self.Gui:prepareDraw()
  end

  function Navigation:back()
    if self.HistoryIndex > 1 then
        self.HistoryIndex = self.HistoryIndex - 1

        self:refresh()
    end
  end

  function Navigation:forward()
    if self.HistoryIndex < #self.History then
        self.HistoryIndex = self.HistoryIndex + 1

        self:refresh()
    end
  end

  function Navigation:refresh()
    local Url = self.History[self.HistoryIndex]

    if Url:sub(0, 7) == "file://" then
        self:loadLocal(Url:sub(8), false)
    elseif Url == "about:new" then
        self:_loadAbout()
    else
        self:loadRemote(Url, nil, nil, false)
    end
  end
end
do
  --@require HtmlElement.lua
  --@require ../../Logger.lua


  --The <body> tag
  BodyElement = HtmlElement:subClass("BodyElement", "body")

  BlockElement = HtmlElement:subClass("BlockElement")
  function BlockElement:init(...)
    self:super(HtmlElement).init(...)

    self.PaddingTop = 1
    self.PaddingBottom = 1
  end
  function BlockElement:draw(Buffer)
    local x, y = Buffer:getCursorPos()

    if x ~= 1 then
        Buffer:setCursorPos(1, y + self.PaddingTop)
    else
        Buffer:setCursorPos(1, y + self.PaddingTop - 1)
    end

    self:blockDraw(Buffer)

    local x, y = Buffer:getCursorPos()
    Buffer:setCursorPos(1, y+self.PaddingBottom)
  end
  function BlockElement:blockDraw(buffer) self:super(HtmlElement).draw(Buffer) end

  HeaderOne = BlockElement:subClass("HeaderOne", "h1")
  function HeaderOne:init(...)
    self:super(BlockElement).init(...)

    self.PaddingTop = 2
  end
  function HeaderOne:blockDraw(Buffer)
    local col = Buffer:getColours()

    Buffer:setBackgroundColour(colours.blue)
    Buffer:setTextColour(colours.yellow)

    self:super(BlockElement).blockDraw(Buffer)

    Buffer:restoreColours(col)
  end

  HeaderTwo = BlockElement:subClass("HeaderTwo", "h2")
  function HeaderTwo:blockDraw(Buffer)
    local col = Buffer:getColours()

    Buffer:setBackgroundColour(colours.cyan)
    Buffer:setTextColour(colours.orange)

    self:super(BlockElement).blockDraw(Buffer)

    Buffer:restoreColours(col)
  end


  Link = HtmlElement:subClass("Link", "a")
  function Link:init(Data, Page)
    self:super(HtmlElement).init(Data, Page)

    self.Link = self.Attributes.href
  end

  function Link:draw(Buffer)
    local col = Buffer:getColours()

    Buffer:setTextColour(colours.lime)

    self:super(HtmlElement).draw(Buffer)

    Buffer:restoreColours(col)
  end

  Script = HtmlElement:subClass("Script", "script")
  function Script:draw(Buffer) end

  Paragraph = BlockElement:subClass("Paragraph", "p")
end
--@require Html/Elements/Element.lua
--@require Html/Elements/HtmlElement.lua
--@require Html/Elements/HeadElements.lua
--@require Html/Elements/BodyElements.lua

--@require Html/DomTree.lua
--@require Page.lua

--@require Navigation.lua