local arg={...}--command line arguments
quit = false
local oldPull = os.pullEvent;
os.pullEvent = os.pullEventRaw;

function quitProgram()
  local event, param1 = os.pullEvent("char")
  if param1 == "q" then
    quit = true
  end
end

term.setBackgroundColor(colours.white)
term.setTextColor(colours.black)
term.clear()
term.setCursorPos(1,1)
term.setCursorBlink(false)
version="TMNET Browser 1.2"
siteName=""
currentSite=""
siteID=-1
pageName=""
currentX=1
currentY=1
menuMode=false
ddns=true
ddnsID=-1
webType=0--0=no site, 1=normal site, 2=menu
-------------------------
--web related functions--
-------------------------

function whois(name)--returns ID if found, -1 if not on dns, and nil if no dns
    --prevent unnecessary communication
    if name~=currentSite then
        if ddns==true then rednet.send(ddnsID,"@whois "..name)
        else rednet.broadcast("@whois "..name) end
        _,webID=rednet.receive(1)
        siteID=tonumber(webID)--convert it to a number
        currentSite=name
    end
    return siteID
end
function getColour(value)
    --TODO prevent crashing on invalid number
    number=tonumber(value)
    if number==nil then--convert hexadecimal
        if value=="A" then
            number=10
        elseif value=="B" then
            number=11
        elseif value=="C" then
            number=12
        elseif value=="D" then
            number=13
        elseif value=="E" then
            number=14
        elseif value=="F" then
            number=15
        else
            return colours.black
        end
    end
    return bit.blshift(1,number)
end
function loadPage(webID,page)
    rednet.send(webID,page or "/home")
    pagetext=""
    for i=1,17 do
        from,text=rednet.receive(0.5)
        if text==nil then break end
        pagetext=pagetext..text.."\n"
    end

    --term.write(pagetext)--doesn't support newline apparently
    --print(pagetext)
    line=1
    term.setCursorPos(2,line)
    colourmode=0--1=^ detected 2=nextchar text 3=nextchar backround
    term.setBackgroundColor(colours.white)
    term.setTextColor(colours.black)
    --my slow and tedious method of rendering the page
    for current=1,string.len(pagetext) do
        letter=string.sub(pagetext,current,current)--TODO surely an easier way?
        if letter==nil then letter=" " end
        if colourmode==0 then --normal
            if letter=="^" then
                colourmode=1
            elseif letter=="\n" then
                line=line+1--next line
                if line==17 then break end--too much! TODO tweak this value
                term.setCursorPos(2,line)
                term.setBackgroundColor(colours.white)
                term.setTextColor(colours.black)--reset colours for next line
            else
                term.write(letter)--nothing special
            end
        elseif colourmode==1 then --might be a colour
            if letter=="f" then--foreground colour
                colourmode=2--next char will set foreground
            elseif letter=="b" then--background colour
                colourmode=3--next char will set background
            else--not correct, probably not intended as a colour
                term.write("^"..letter)--put ^ back as well
            end
        elseif colourmode==2 then--set text colour
            --print(letter)--debug
            term.setTextColor(getColour(letter))
            colourmode=0--back to normal
        elseif colourmode==3 then--set background colour
            term.setBackgroundColor(getColour(letter))
            colourmode=0--back to normal
        end
    end
end

-----------------
--GUI functions--
-----------------
function drawError(text)
    term.setBackgroundColor(colours.white)
    term.setTextColor(colours.red)
    term.setCursorPos(2,1)
    term.write("ERROR:")
    term.setCursorPos(2,2)
    term.write(text)
    webType=0
end
function drawButton(x,y,text,conditionA,conditionB,active)
    term.setCursorPos(x,y)
    if conditionA==conditionB and active then
        term.setBackgroundColor(colours.grey)
        term.write("[")
    else
        term.setBackgroundColor(colours.lightGrey)
        term.write(" ")
    end

    term.write(text)

    if conditionA==conditionB and active then
        term.write("]")
    else
        --term.write(" ")
    end
end

function renderGUI()
    --draw left bar
    term.setTextColor(colours.white)
    term.setBackgroundColor(colours.lightGrey)
    for line=1,18 do
        term.setCursorPos(1,line)
        term.write(" ")
    end
    --draw right cursor
    if menuMode==false then
        term.setCursorPos(1,currentY)
        term.setBackgroundColor(colours.grey)
        term.write(">")
    end
    --draw bottom bar
    term.setBackgroundColor(colours.lightGrey)
    term.setCursorPos(1,19)
    for line=1,51 do
        term.write(" ")
    end
    --term.setCursorPos(1,19)
    --term.write(siteName..pageName)
    --draw menu bar items
    drawButton(42,19,"Refresh",currentX,3,menuMode)
    drawButton(36,19,"Menu",currentX,2,menuMode)
    drawButton(1,19,siteName..pageName,currentX,1,menuMode)
end

function popup(text)--a nice GUI popup asking for text
    term.setTextColor(colours.white)
    term.setCursorPos(7,5)
    term.setBackgroundColor(colours.blue)
    for y=5,13 do
        term.setCursorPos(7,y)
        for x=7,47 do
            if y==8 then--user input row
                if x==7 or x== 47 then
                    term.setBackgroundColor(colours.lightGrey)
                else
                    term.setBackgroundColor(colours.grey)
                end
            end
            term.write(" ")
        end
        term.setBackgroundColor(colours.lightGrey)
    end
    --finished drawing window. add text
    term.setBackgroundColor(colours.blue)
    term.setCursorPos(7,5)--TODO: center text
    term.write(text)
    term.setBackgroundColor(colours.grey)
    term.setCursorPos(8,8)
    return io.read()
end

function refresh()
    webType=1--website
    term.setTextColor(colours.black)
    term.setBackgroundColor(colours.white)

    term.clear()
    term.setCursorPos(1,1)

    renderGUI()

    webID=whois(siteName)
    if webID==nil or webID==-1 then--find what went wrong
            if webID==nil and ddns==false then drawError("Server Not Found (Spelling?)")
        elseif webID==nil and ddns==true then drawError("No Response from DDNS")
        elseif webID==-1 and ddns==true then drawError("Site Not Found on DDNS (Spelling?)")
        else drawError("Unknown Error, Contact TMNET Support") end

    else loadPage(webID,pageName) end

    renderGUI()
end
-------------------
--other functions--
-------------------
function getDeviceSide(deviceType)
  -- List of all sides
  local lstSides = {"left","right","top","bottom","front","back"};
  -- Now loop through all the sides
  for i, side in pairs(lstSides) do
    if (peripheral.isPresent(side)) then
      -- Yup, there is something on this side
      if (peripheral.getType(side) == string.lower(deviceType)) then
        -- Yes, this is the device type we need, so return the side
        return side;
      end
    end
  end
  --nothing found, return nill
  return nil;
end
function split(text,splitAt)
    state=false
    outA=""
    outB=""
    for i=1,string.len(text) do
        if string.sub(text,i,i)==splitAt then
            state=true
        end
        if state==false then
            outA=outA..string.sub(text,i,i)
        else
            outB=outB..string.sub(text,i,i)
        end
    end
    return outA,outB
end
--like split, but removes extra char
function split2(text,splitAt)
    outA,outB=split(text,splitAt)
    outB=string.sub(outB,2,-1)--remove first char (= to splitAt)
    return outA,outB
end

function interpret(text)
    command,args=split2(text,":")
    if command=="glob" then
        siteName,pageName=split2(args,"/")
        pageName="/"..pageName
        refresh()
    end
    if command=="loc" then
        pageName="/"..args
        refresh()
    end
    if command=="ref" then
        refresh()
    end
    if command=="ask" then
        arg1,arg2=split2(args,":")--expected format: ask:cookie:question
        rednet.send(siteID,"ans:"..arg1..":"..popup(arg2))
        print("please wait...")--TODO place this nicely in the text entry field
        --note: server should send refresh as soon as it is done
    end
    --TODO add input command
end
function enterPage()
    siteName,pageName=split(popup("web address"),"/")
    if pageName==nil or pageName=="" then
        pageName="/home"
    end
    refresh()
end
function renderMenu()
    term.setTextColor(colours.black)
    term.setBackgroundColor(colours.white)

    term.clear()
    term.setCursorPos(1,1)
    --add one space before every line due to side bar
    print(" "..version)
    print(" Designed by Train Master Network Systems, Inc.")
    print("")
    if ddnsID~=nil then print(" ID of Dedicated DNS: "..ddnsID) end
    if siteID~=nil then print(" ID of Current Website: "..siteID) end
    print(" Using Modem on Side: "..portSide)
    renderGUI()
end
function handleSelect()
    if menuMode==true then
        --edit web adress
        if currentX==1 then
            enterPage()
        end
        if currentX==2 then
            renderMenu()
        end
        --refresh
        if currentX==3 then
            refresh()
        end
    else--clicked on site
        if webType==1 then
            rednet.send(siteID,"exec:"..pageName..":"..currentY)
        end
        --TODO add interactive menu
    end
end
-----------------------
--program begins here--
-----------------------
portSide=getDeviceSide("modem")
if portSide==nil then
    print("No Modems Found!")
end
rednet.open(portSide)
rednet.broadcast("@ddns")--search for dedicated dns
ddnsID,result=rednet.receive(1)
if result==nil then
ddns=false
print(" Warning: No DDNS Found")
end
renderGUI()
enterPage()
renderGUI()
while true do
    parallel.waitForAny(quitProgram, otherStuff)
    if quit then
      print("Quitting....")
      break
    end
    event, p1, p2, p3 = os.pullEventRaw()
    if event=="key" or event=="char" then
        --up
        if p1==200 then
            if currentY~=1 then currentY=currentY-1 end
            menuMode=false
        end
        --down
        if p1==208  then
            if currentY~=18 then currentY=currentY+1 end
            menuMode=false
        end

        --left
        if p1==203 then
            if currentX~=1 then currentX=currentX-1 end
            menuMode=true
        end
        --right
        if p1==205 then
            if currentX~=3 then currentX=currentX+1 end
            menuMode=true
        end
        --enter or space (select)
        if p1==28 or p1==" "  then --removed 57
            handleSelect()
        end
        renderGUI()
    elseif event=="mouse_click" then
        if p3==19 then
            menuMode=true
            currentX=1--default if below is false
            if p2>36 then currentX=2 end
            if p2>42 then currentX=3 end
        else
            menuMode=false
            currentY=p3
        end
        handleSelect()
        renderGUI()
    --only receive messages from current website
    elseif event=="rednet_message" and p1==siteID then
        interpret(p2)
    elseif event=="terminate" then
        term.setBackgroundColor(colours.black)
        term.setTextColor(colours.white)
        term.clear()
        term.setCursorPos(1,1)
    break
    end
    --TODO make an options menu
    --TODO add error handling
end
os.pullEvent = oldPull;