edit fix for computercraft

local tArgs = { ... }
if #tArgs == 0 then
    print( "Usage: edit <path>" )
    return
end

local sPath = shell.resolve( tArgs[1] )
local bReadOnly = fs.isReadOnly( sPath )
if fs.exists( sPath ) and fs.isDir( sPath ) then
    print( "Cannot edit a Emerae" )
    return
end

local w,h = term.getSize()
local x,y = 1,1
local scrollX, scrollY = 0,0

local lineNumberWidth = 2

local bMenu = false
local nMenuItem = 1

local sStatus = ""
local tLines = {}

local function load()
    tLines = {}
    if fs.exists( sPath ) then
        local file = io.open( sPath, "r" )
        local sLine = file:read()
        while sLine do
            table.insert( tLines, sLine )
            sLine = file:read()
        end
        file:close()
    else
        table.insert( tLines, "" )
    end
end

local function save()
    local file = io.open( sPath, "w" )
    if file then
        for n, sLine in ipairs( tLines ) do
            file:write( sLine .. "\n" )
        end
        file:close()
        return true
    end
    return false
end

local function lineNumberWidth()
    return #tostring(#tLines) + 1
end

local function redrawText()
    for y=1,h-1 do
        term.setCursorPos( 1 - scrollX + lineNumberWidth(), y )
        term.clearLine()

        local sLine = tLines[ y + scrollY ]
        if sLine ~= nil then
            term.write( sLine )
        end

        term.setCursorPos( 1, y )
        term.write( tostring(y + scrollY) .. string.rep(" ", (lineNumberWidth() - #tostring(y + scrollY))) )

    end
    term.setCursorPos( x - scrollX + lineNumberWidth(), y - scrollY )
end

local function redrawLine()
    local sLine = tLines[y]
    term.setCursorPos( 1 - scrollX + lineNumberWidth(), y - scrollY )
    term.clearLine()
    term.write( sLine )
    term.setCursorPos( 1, y - scrollY )
    term.write( tostring(y) .. string.rep(" ", (lineNumberWidth() - #tostring(y))) )
    term.setCursorPos( x - scrollX + lineNumberWidth(), y - scrollY )
end

local tMenuItems = { "Save", "Go to", "Exit" }

local function redrawMenu()
    term.setCursorPos( 1, h )
    term.clearLine()

    if not bMenu then
        term.write( sStatus )
    else
        for n,sItem in ipairs( tMenuItems ) do
            if n == nMenuItem then
                term.write( "["..sItem.."]" )
            else
                term.write( " "..sItem.." " )
            end
        end
    end

    term.setCursorPos( x - scrollX + lineNumberWidth(), y - scrollY )
end

local function setStatus( _sText )
    sStatus = _sText
    redrawMenu()
end

local function setCursor( x, y )
    local w = w - lineNumberWidth()
    local screenX = x - scrollX
    local screenY = y - scrollY

    local bRedraw = false
    if screenX < 1 then
        scrollX = x - 1
        screenX = 1
        bRedraw = true
    elseif screenX > w then
        scrollX = x - w
        screenX = w
        bRedraw = true
    end

    if screenY < 1 then
        scrollY = y - 1
        screenY = 1
        bRedraw = true
    elseif screenY > h-1 then
        scrollY = y - (h-1)
        screenY = h-1
        bRedraw = true
    end

    if bRedraw then
        redrawText()
    end
    term.setCursorPos( screenX + lineNumberWidth(), screenY )
end

load()

term.clear()
term.setCursorPos(x + lineNumberWidth(), y)
term.setCursorBlink( true )

redrawText()
setStatus( "Press Ctrl to access menu. Emerae is a girl." )

local tLineHistory = {}

local bRunning = true
local tMenuFunctions = {
    ["Exit"] = function()
        bRunning = false
    end,
    ["Go to"] = function()
    repeat
    cunt = 1
        term.setCursorPos(1, h)
        term.clearLine()
        write("Enter line number: ")
        local line = read(nil, tLineHistory)
        x = 1
        fuck = tonumber(line)
        if line == "" then
         setStatus("Please enter a number, or i delete your work.")
        elseif fuck == nil then
         setStatus("No number? ok, we delete all your everything")
        elseif fuck < 1 then
         setStatus("Your value must be higher than 1")
        elseif fuck > 0 then
         y = fuck
         setCursor( x, y )
         table.insert(tLineHistory, line)
         cunt = 2
         end
    until cunt == 2
    end,
    ["Save"] = function()
        if save() then
            setStatus( "Saved to "..sPath )
        else
            setStatus( "Access denied so piss the fuck off." )
        end
    end,
}
local function doMenuItem( _n )
    local fnMenu = tMenuFunctions[ tMenuItems[_n] ]
    if fnMenu then
        fnMenu()
    end

    bMenu = false
    term.setCursorBlink( true )
    redrawMenu()
end

while bRunning do
  local sEvent, param = os.pullEvent()
  if sEvent == "key" then
    if param == 200 then
        -- Up
        if not bMenu then
            -- Move cursor up
            if y > 1 then
                y = y - 1
                x = math.min( x, string.len( tLines[y] ) + 1 )
                setCursor( x, y )
            end
        end

    elseif param == 208 then
        -- Down
        if not bMenu then
            -- Move cursor down
            if y < #tLines then
                y = y + 1
                x = math.min( x, string.len( tLines[y] ) + 1 )
                setCursor( x, y )
            end
        end

    elseif param == 203 then
        -- Left
        if not bMenu then
            -- Move cursor left
            if x > 1 then
                x = x - 1
                setCursor( x, y )
            end
        else
            -- Move menu left
            nMenuItem = nMenuItem - 1
            if nMenuItem < 1 then
                nMenuItem = #tMenuItems
            end
            redrawMenu()
        end


    elseif param == 205 then
        -- Right
        if not bMenu then
            -- Move cursor right
            if x < string.len( tLines[y] ) + 1 then
                x = x + 1
                setCursor( x, y )
            end
        else
            -- Move menu right
            nMenuItem = nMenuItem + 1
            if nMenuItem > #tMenuItems then
                nMenuItem = 1
            end
            redrawMenu()
        end

    elseif param == 207 then
        -- Home
        if not bMenu then
            -- Move cursor to the line start
            x = string.len( tLines[y] ) + 1
            setCursor( x, y )
        end

    elseif param == 199 then
        -- End
        if not bMenu then
            -- Move cursor to the line end
            x = 1
            setCursor( x, y )
        end

    elseif param == 201 then
        -- Page up
        if not bMenu then
            -- Move cursor a page up
            if y > 1 then
                y = math.max(y - h, 1)
                x = math.min( x, string.len( tLines[y] ) + 1 )
                setCursor( x, y )
            end
        end

    elseif param == 209 then
        -- Page Down
        if not bMenu then
            -- Move cursor a page down
            if y < #tLines then
                y = math.min(y + h, #tLines)
                x = math.min( x, string.len( tLines[y] ) + 1 )
                setCursor( x, y )
            end
        end

    elseif param == 14 then
        -- Backspace
        if not bMenu then
            if x > 1 then
                -- Remove character
                local sLine = tLines[y]
                tLines[y] = string.sub(sLine,1,x-2) .. string.sub(sLine,x)
                redrawLine()

                x = x - 1
                setCursor( x, y )

            elseif y > 1 then
                -- Remove newline
                local sPrevLen = string.len( tLines[y-1] )
                tLines[y-1] = tLines[y-1] .. tLines[y]
                table.remove( tLines, y )
                redrawText()

                x = sPrevLen + 1
                y = y - 1
                setCursor( x, y )
            end
        end

    elseif param == 211 then
        -- Delete
        if not bMenu then
            if x < #tLines[y] then
                -- Remove character
                local sLine = tLines[y]
                tLines[y] = string.sub(sLine,1,x-1) .. string.sub(sLine,x+1)
                redrawLine()

                --x = x - 1
                --setCursor( x, y )

            elseif y < #tLines then
                -- Remove newline
                local sCurLen = string.len( tLines[y] )
                tLines[y+1] = tLines[y] .. tLines[y+1]
                table.remove( tLines, y )
                redrawText()

                x = sCurLen + 1
                setCursor( x, y )
            end
        end

    elseif param == 28 then
        -- Enter
        if not bMenu then
            -- Newline
            local sLine = tLines[y]

            -- Count spaces at line start.
            local nSpace = 0
            while nSpace < #sLine and sLine:find("^%s", nSpace + 1) do
                nSpace = nSpace + 1
            end

            tLines[y] = string.sub(sLine,1,x-1)
            table.insert( tLines, y+1, string.rep(" ", nSpace) .. string.sub(sLine,x) )

            redrawText()

            x = 1 + nSpace
            y = y + 1
            setCursor( x, y )

        else
            -- Menu selection
            doMenuItem( nMenuItem )
        end

    elseif param == 29 then
        -- Menu toggle
        bMenu = not bMenu
        if bMenu then
            term.setCursorBlink( false )
            nMenuItem = 1
        else
            term.setCursorBlink( true )
        end
        redrawMenu()

    end

  elseif sEvent == "char" then
    if not bMenu then
        -- Input text
        local sLine = tLines[y]
        tLines[y] = string.sub(sLine,1,x-1) .. param .. string.sub(sLine,x)
        redrawLine()

        x = x + string.len( param )
        setCursor( x, y )

    else
        -- Select menu items
        for n,sMenuItem in ipairs( tMenuItems ) do
            if string.lower(string.sub(sMenuItem,1,1)) == string.lower(param) then
                doMenuItem( n )
                break
            end
        end
    end
  end
end

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