document = {}

function document.new(w,h,data)
    document.w,document.h = w,h
    if data == nil then
        document.data = {}
        for i=1,h*w,1 do
            document.data[i] = {col=colors.white,bgCol=colors.black,char=32}
        end
    else
        document.data = data
    end
    document.cPos = {x=1,y=1}
    document.lRender={x=1,y=1}
    document.isDirty=true
    document.active=false
    document.col = colors.white
    document.bgCol = colors.black
end

function document.activate()
    document.active=true
end

function document.deactivate()
    document.active=false
end

function document.key(key)
    if document.active then
        if key == keys.left then
            document.moveCursor(-1,nil)
        elseif key == keys.right then
            document.moveCursor(1,nil)
        elseif key == keys.up then
            document.moveCursor(0,-1)
        elseif key == keys.down then
            document.moveCursor(0,1)
        elseif key == keys.backspace and (document.cPos.x+((document.cPos.y-1)*document.h))>1 then
            print(document.cPos.x+((document.cPos.y-1)*document.h)) read()
            print(textutils.serialize(table.remove(document.data,document.cPos.x+((document.cPos.y-1)*document.h)))) read()
            print(textutils.serialize(document.data[1]))read()
       --     table.insert(document.data,#document.data,{col=colors.white,bgCol=colors.black,char=32})
            document.moveCursor(-1,nil)
            document.isDirty=true
        end
    end
end

function document.char(char)
    if document.insertMode then
        document.data[document.cPos.y][document.cPos.x].char = string.byte(char,1)
        document.moveCursor(1,nil)
        document.isDirty=true
    else
        table.insert(document.data,document.cPos.x+(document.cPos.y*document.h),{col=document.col,bgCol=document.bgCol,char=string.byte(char,1)})
        table.remove(document.data,#document.data)
        document.moveCursor(1,nil)
        document.isDirty=true
    end
end

function document.moveCursor(x,y)
    local nX,nY = document.cPos.x,document.cPos.y
    if x ~= 0 and x ~= nil then
        nX = nX+x
        if nX < 1 and y == nil and nY > 1 then
            nX = document.w
            nY = math.max(1,nY - 1)
        elseif nX > document.w and y == nil and nY < document.h then
            nY = nY + 1
            nX = 1
        end
    end
    if y ~= 0 and y ~= nil then
        nY = nY + y
    end
    document.setCursor(nX,nY)
end

function document.setCursor(x,y)
    document.cPos={x=math.max(1,math.min(document.w,x)),y=math.max(1,math.min(document.h,y))}
    document.updateCursorPos()
end

function document.updateCursorPos()
    term.setCursorPos(document.cPos.x+document.lRender.x-1,document.cPos.y+document.lRender.y-1)
end

function document.render(x,y)
    if x == nil then x = document.lRender.x end
    if y == nil then y = document.lRender.y end
    document.lRender={x=x,y=y}
    local l = 1
    local s = ""
    local cols = {bg=document.data[1].bgCol,fg=document.data[1].col}
    term.setCursorPos(x,y)
    for i=1,#document.data,1 do
        local cL = math.ceil(i/document.w)

        if l ~= cL or cols.bg ~= document.data[i].bgCol or cols.fg ~= document.data[i].col then
            term.setBackgroundColor(cols.bg)
            term.setTextColor(cols.fg)
            term.write(s)
            if l ~= cL then
                term.setCursorPos(x,y+l-1)
            end
            l=cL

            s = ""
            cols.bg = document.data[i].bgCol
            cols.fg = document.data[i].col
        end
        s= s..string.char(document.data[i].char)
    end
    if s ~= "" then
        term.setBackgroundColor(cols.bg)
        term.setTextColor(cols.fg)
        term.write(s)
    end

    term.setCursorPos(document.cPos.x-1+x,document.cPos.y-1+y)
    term.setCursorBlink(true)
    document.isDirty=false

end

function document.checkCoords(x,y)
    return (x >= document.lRender.x and x < document.lRender.x+document.w and y >= document.lRender.y and y < document.lRender.y+document.h)
end