and again...

-- Install safe versions of various library functions
-- These will not put cfunctions on the stack, so don't break serialisation
xpcall = function( _fn, _fnErrorHandler )
    local typeT = type( _fn )
    assert( typeT == "function", "bad argument #1 to xpcall (function expected, got "..typeT..")" )
    local co = coroutine.create( _fn )
    local tResults = { coroutine.resume( co ) }
    while coroutine.status( co ) ~= "dead" do
        tResults = { coroutine.resume( co, coroutine.yield() ) }
    end
    if tResults[1] == true then
        return true, unpack( tResults, 2 )
    else
        return false, _fnErrorHandler( tResults[2] )
    end
end

pcall = function( _fn, ... )
    local typeT = type( _fn )
    assert( typeT == "function", "bad argument #1 to pcall (function expected, got "..typeT..")" )
    local tArgs = { ... }
    return xpcall(
        function()
            return _fn( unpack( tArgs ) )
        end,
        function( _error )
            return _error
        end
    )
end

function pairs( _t )
    local typeT = type( _t )
    if typeT ~= "table" then
        error( "bad argument #1 to pairs (table expected, got "..typeT..")", 2 )
    end
    return next, _t, nil
end

function ipairs( _t )
    local typeT = type( _t )
    if typeT ~= "table" then
        error( "bad argument #1 to ipairs (table expected, got "..typeT..")", 2 )
    end
    return function( t, var )
        var = var + 1
        local value = t[var]
        if value == nil then
            return
        end
        return var, value
    end, _t, 0
end

function coroutine.wrap( _fn )
    local typeT = type( _fn )
    if typeT ~= "function" then
        error( "bad argument #1 to coroutine.wrap (function expected, got "..typeT..")", 2 )
    end
    local co = coroutine.create( _fn )
    return function( ... )
        local tResults = { coroutine.resume( co, ... ) }
        if tResults[1] then
            return unpack( tResults, 2 )
        else
            error( tResults[2], 2 )
        end
    end
end

function string.gmatch( _s, _pattern )
    local type1 = type( _s )
    if type1 ~= "string" then
        error( "bad argument #1 to string.gmatch (string expected, got "..type1..")", 2 )
    end
    local type2 = type( _pattern )
    if type2 ~= "string" then
        error( "bad argument #2 to string.gmatch (string expected, got "..type2..")", 2 )
    end

    local nPos = 1
    return function()
        local nFirst, nLast = string.find( _s, _pattern, nPos )
        if nFirst == nil then
            return
        end
        nPos = nLast + 1
        return string.match( _s, _pattern, nFirst )
    end
end

local nativesetmetatable = setmetatable
function setmetatable( _o, _t )
    if _t and type(_t) == "table" then
        local idx = rawget( _t, "__index" )
        if idx and type( idx ) == "table" then
            rawset( _t, "__index", function( t, k ) return idx[k] end )
        end
        local newidx = rawget( _t, "__newindex" )
        if newidx and type( newidx ) == "table" then
            rawset( _t, "__newindex", function( t, k, v ) newidx[k] = v end )
        end
    end
    return nativesetmetatable( _o, _t )
end

-- Install fix for luaj's broken string.sub/string.find
local nativestringfind = string.find
local nativestringsub = string.sub
function string.sub( ... )
    local r = nativestringsub( ... )
    if r then
        return r .. ""
    end
    return nil
end
function string.find( s, ... )
    return nativestringfind( s .. "", ... );
end

-- Install lua parts of the os api
function os.version()
    return "CraftOS 1.7"
end

function os.pullEventRaw( sFilter )
    return coroutine.yield( sFilter )
end

function os.pullEvent( sFilter )
    local eventData = { os.pullEventRaw( sFilter ) }
    if eventData[1] == "terminate" then
        error( "Terminated", 0 )
    end
    return unpack( eventData )
end

-- Install globals
function sleep( nTime )
    local timer = os.startTimer( nTime or 0 )
    repeat
        local sEvent, param = os.pullEvent( "timer" )
    until param == timer
end

function write( sText )
    local w,h = term.getSize()
    local x,y = term.getCursorPos()

    local nLinesPrinted = 0
    local function newLine()
        if y + 1 <= h then
            term.setCursorPos(1, y + 1)
        else
            term.setCursorPos(1, h)
            term.scroll(1)
        end
        x, y = term.getCursorPos()
        nLinesPrinted = nLinesPrinted + 1
    end

    -- Print the line with proper word wrapping
    while string.len(sText) > 0 do
        local whitespace = string.match( sText, "^[ \t]+" )
        if whitespace then
            -- Print whitespace
            term.write( whitespace )
            x,y = term.getCursorPos()
            sText = string.sub( sText, string.len(whitespace) + 1 )
        end

        local newline = string.match( sText, "^\n" )
        if newline then
            -- Print newlines
            newLine()
            sText = string.sub( sText, 2 )
        end

        local text = string.match( sText, "^[^ \t\n]+" )
        if text then
            sText = string.sub( sText, string.len(text) + 1 )
            if string.len(text) > w then
                -- Print a multiline word
                while string.len( text ) > 0 do
                    if x > w then
                        newLine()
                    end
                    term.write( text )
                    text = string.sub( text, (w-x) + 2 )
                    x,y = term.getCursorPos()
                end
            else
                -- Print a word normally
                if x + string.len(text) - 1 > w then
                    newLine()
                end
                term.write( text )
                x,y = term.getCursorPos()
            end
        end
    end

    return nLinesPrinted
end

function print( ... )
    local nLinesPrinted = 0
    for n,v in ipairs( { ... } ) do
        nLinesPrinted = nLinesPrinted + write( tostring( v ) )
    end
    nLinesPrinted = nLinesPrinted + write( "\n" )
    return nLinesPrinted
end

function printError( ... )
    if term.isColour() then
        term.setTextColour( colours.red )
    end
    local x,y = term.getCursorPos()
    print( ... )
    term.setTextColour( colours.white )
end

function read( _sReplaceChar, _tHistory )
    term.setCursorBlink( true )

    local sLine = ""
    local nHistoryPos
    local nPos = 0
    if _sReplaceChar then
        _sReplaceChar = string.sub( _sReplaceChar, 1, 1 )
    end

    local w = term.getSize()
    local sx = term.getCursorPos()

    local function redraw( _sCustomReplaceChar )
        local nScroll = 0
        if sx + nPos >= w then
            nScroll = (sx + nPos) - w
        end

        local cx,cy = term.getCursorPos()
        term.setCursorPos( sx, cy )
        local sReplace = _sCustomReplaceChar or _sReplaceChar
        if sReplace then
            term.write( string.rep( sReplace, math.max( string.len(sLine) - nScroll, 0 ) ) )
        else
            term.write( string.sub( sLine, nScroll + 1 ) )
        end
        term.setCursorPos( sx + nPos - nScroll, cy )
    end

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

        elseif sEvent == "paste" then
            -- Pasted text
            sLine = string.sub( sLine, 1, nPos ) .. param .. string.sub( sLine, nPos + 1 )
            nPos = nPos + string.len( param )
            redraw()

        elseif sEvent == "key" then
            if param == keys.enter then
                -- Enter
                break

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

            elseif param == keys.right then
                -- Right
                if nPos < string.len(sLine) then
                    redraw(" ")
                    nPos = nPos + 1
                    redraw()
                end

            elseif param == keys.up or param == keys.down then
                -- Up or down
                if _tHistory then
                    redraw(" ")
                    if param == keys.up then
                        -- Up
                        if nHistoryPos == nil then
                            if #_tHistory > 0 then
                                nHistoryPos = #_tHistory
                            end
                        elseif nHistoryPos > 1 then
                            nHistoryPos = nHistoryPos - 1
                        end
                    else
                        -- Down
                        if nHistoryPos == #_tHistory then
                            nHistoryPos = nil
                        elseif nHistoryPos ~= nil then
                            nHistoryPos = nHistoryPos + 1
                        end
                    end
                    if nHistoryPos then
                        sLine = _tHistory[nHistoryPos]
                        nPos = string.len( sLine )
                    else
                        sLine = ""
                        nPos = 0
                    end
                    redraw()
                end
            elseif param == keys.backspace then
                -- Backspace
                if nPos > 0 then
                    redraw(" ")
                    sLine = string.sub( sLine, 1, nPos - 1 ) .. string.sub( sLine, nPos + 1 )
                    nPos = nPos - 1
                    redraw()
                end
            elseif param == keys.home then
                -- Home
                redraw(" ")
                nPos = 0
                redraw()
            elseif param == keys.delete then
                -- Delete
                if nPos < string.len(sLine) then
                    redraw(" ")
                    sLine = string.sub( sLine, 1, nPos ) .. string.sub( sLine, nPos + 2 )
                    redraw()
                end
            elseif param == keys["end"] then
                -- End
                redraw(" ")
                nPos = string.len(sLine)
                redraw()
            end

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

        end
    end

    local cx, cy = term.getCursorPos()
    term.setCursorBlink( false )
    term.setCursorPos( w + 1, cy )
    print()

    return sLine
end

loadfile = function( _sFile )
    local file = fs.open( _sFile, "r" )
    if file then
        local func, err = loadstring( file.readAll(), fs.getName( _sFile ) )
        file.close()
        return func, err
    end
    return nil, "File not found"
end

dofile = function( _sFile )
    local fnFile, e = loadfile( _sFile )
    if fnFile then
        setfenv( fnFile, getfenv(2) )
        return fnFile()
    else
        error( e, 2 )
    end
end

-- Install the rest of the OS api
function os.run( _tEnv, _sPath, ... )
    local tArgs = { ... }
    local fnFile, err = loadfile( _sPath )
    if fnFile then
        local tEnv = _tEnv
        --setmetatable( tEnv, { __index = function(t,k) return _G[k] end } )
        setmetatable( tEnv, { __index = _G } )
        setfenv( fnFile, tEnv )
        local ok, err = pcall( function()
            fnFile( unpack( tArgs ) )
        end )
        if not ok then
            if err and err ~= "" then
                printError( err )
            end
            return false
        end
        return true
    end
    if err and err ~= "" then
        printError( err )
    end
    return false
end

-- Prevent access to metatables or environments of strings, as these are global between all computers
do
    local getfenv = getfenv
    local nativegetmetatable = getmetatable
    local nativeerror = error
    local nativetype = type
    local string_metatable = nativegetmetatable("")
    local string_env = getfenv(("").gsub)
    function getmetatable( t )
        local mt = nativegetmetatable( t )
        if mt == string_metatable or mt == string_env then
            nativeerror( "Attempt to access string metatable", 2 )
        else
            return mt
        end
    end
    function getfenv( env )
        if env == nil then
            env = 2
        elseif nativetype( env ) == "number" and env > 0 then
            env = env + 1
        end
        local fenv = getfenv(env)
        if fenv == string_metatable or fenv == string_env then
            --nativeerror( "Attempt to access string metatable", 2 )
            return getfenv( 0 )
        else
            return fenv
        end
    end
end

local tAPIsLoading = {}
function os.loadAPI( _sPath )
    local sName = fs.getName( _sPath )
    if tAPIsLoading[sName] == true then
        printError( "API "..sName.." is already being loaded" )
        return false
    end
    tAPIsLoading[sName] = true

    local tEnv = {}
    setmetatable( tEnv, { __index = _G } )
    local fnAPI, err = loadfile( _sPath )
    if fnAPI then
        setfenv( fnAPI, tEnv )
        local ok, err = pcall( fnAPI )
        if not ok then
            printError( err )
            tAPIsLoading[sName] = nil
            return false
        end
    else
        printError( err )
        tAPIsLoading[sName] = nil
        return false
    end

    local tAPI = {}
    for k,v in pairs( tEnv ) do
        tAPI[k] =  v
    end

    _G[sName] = tAPI
    tAPIsLoading[sName] = nil
    return true
end

function os.unloadAPI( _sName )
    if _sName ~= "_G" and type(_G[_sName]) == "table" then
        _G[_sName] = nil
    end
end

function os.sleep( nTime )
    sleep( nTime )
end

local nativeShutdown = os.shutdown
function os.shutdown()
    nativeShutdown()
    while true do
        coroutine.yield()
    end
end

local nativeReboot = os.reboot
function os.reboot()
    nativeReboot()
    while true do
        coroutine.yield()
    end
end

-- Install the lua part of the HTTP api (if enabled)
if http then
    local nativeHTTPRequest = http.request

    local function wrapRequest( _url, _post, _headers )
        local ok, err = nativeHTTPRequest( _url, _post, _headers )
        if ok then
            while true do
                local event, param1, param2 = os.pullEvent()
                if event == "http_success" and param1 == _url then
                    return param2
                elseif event == "http_failure" and param1 == _url then
                    return nil, param2
                end
            end
        end
        return nil, err
    end

    http.get = function( _url, _headers )
        return wrapRequest( _url, nil, _headers )
    end

    http.post = function( _url, _post, _headers )
        return wrapRequest( _url, _post or "", _headers )
    end

    http.request = function( _url, _post, _headers )
        local ok, err = nativeHTTPRequest( _url, _post, _headers )
        if not ok then
            os.queueEvent( "http_failure", _url, err )
        end
        return ok, err
    end
end

-- Load APIs
local bAPIError = false
local tApis = fs.list( "rom/apis" )
for n,sFile in ipairs( tApis ) do
    if string.sub( sFile, 1, 1 ) ~= "." then
        local sPath = fs.combine( "rom/apis", sFile )
        if not fs.isDir( sPath ) then
            if not os.loadAPI( sPath ) then
                bAPIError = true
            end
        end
    end
end

if turtle then
    -- Load turtle APIs
    local tApis = fs.list( "rom/apis/turtle" )
    for n,sFile in ipairs( tApis ) do
        if string.sub( sFile, 1, 1 ) ~= "." then
            local sPath = fs.combine( "rom/apis/turtle", sFile )
            if not fs.isDir( sPath ) then
                if not os.loadAPI( sPath ) then
                    bAPIError = true
                end
            end
        end
    end
end

if pocket and fs.isDir( "rom/apis/pocket" ) then
    -- Load pocket APIs
    local tApis = fs.list( "rom/apis/pocket" )
    for n,sFile in ipairs( tApis ) do
        if string.sub( sFile, 1, 1 ) ~= "." then
            local sPath = fs.combine( "rom/apis/pocket", sFile )
            if not fs.isDir( sPath ) then
                if not os.loadAPI( sPath ) then
                    bAPIError = true
                end
            end
        end
    end
end

if commands and fs.isDir( "rom/apis/command" ) then
    -- Load command APIs
    if os.loadAPI( "rom/apis/command/commands" ) then
        -- Add a special case-insensitive metatable to the commands api
        local tCaseInsensitiveMetatable = {
            __index = function( table, key )
                local value = rawget( table, key )
                if value ~= nil then
                    return value
                end
                if type(key) == "string" then
                    local value = rawget( table, string.lower(key) )
                    if value ~= nil then
                        return value
                    end
                end
                return nil
            end
        }
        setmetatable( commands, tCaseInsensitiveMetatable )
        setmetatable( commands.async, tCaseInsensitiveMetatable )

        -- Add global "exec" function
        exec = commands.exec
    else
        bAPIError = true
    end
end

if bAPIError then
    print( "Press any key to continue" )
    os.pullEvent( "key" )
    term.clear()
    term.setCursorPos( 1,1 )
end

-- Run the shell
local ok, err = pcall( function()
    parallel.waitForAny(
        function()
            if term.isColour() then
                os.run( {}, "rom/programs/advanced/multishell" )
            else
                os.run( {}, "rom/programs/shell" )
            end
            os.run( {}, "rom/programs/shutdown" )
        end,
        function()
            rednet.run()
        end )
end )

-- If the shell errored, let the user read it.
term.redirect( term.native() )
if not ok then
    printError( err )
    pcall( function()
        term.setCursorBlink( false )
        print( "Press any key to continue" )
        os.pullEvent( "key" )
    end )
end


-- Setup paths
local sPath = ".:/rom/programs"
if term.isColor() then
    sPath = sPath..":/rom/programs/advanced"
end
if turtle then
    sPath = sPath..":/rom/programs/turtle"
else
    sPath = sPath..":/rom/programs/rednet:/rom/programs/fun"
    if term.isColor() then
        sPath = sPath..":/rom/programs/fun/advanced"
    end
end
if pocket then
    sPath = sPath..":/rom/programs/pocket"
end
if commands then
    sPath = sPath..":/rom/programs/command"
end
if http then
    sPath = sPath..":/rom/programs/http"
end
shell.setPath( sPath )
help.setPath( "/rom/help" )

-- Setup aliases
shell.setAlias( "ls", "list" )
shell.setAlias( "dir", "list" )
shell.setAlias( "cp", "copy" )
shell.setAlias( "mv", "move" )
shell.setAlias( "rm", "delete" )
shell.setAlias( "clr", "clear" )
shell.setAlias( "rs", "redstone" )
shell.setAlias( "sh", "shell" )
if term.isColor() then
    shell.setAlias( "background", "bg" )
    shell.setAlias( "foreground", "fg" )
end

-- Run autorun files
if fs.exists( "/rom/autorun" ) and fs.isDir( "/rom/autorun" ) then
    local tFiles = fs.list( "/rom/autorun" )
    table.sort( tFiles )
    for n, sFile in ipairs( tFiles ) do
        if string.sub( sFile, 1, 1 ) ~= "." then
            local sPath = "/rom/autorun/"..sFile
            if not fs.isDir( sPath ) then
                shell.run( sPath )
            end
        end
    end
end

-- Run the user created startup, either from disk drives or the root
local sUserStartup = shell.resolveProgram( "/startup" )
local bEnableDiskStartup = (commands == nil)
if bEnableDiskStartup then
    for n,sName in pairs( peripheral.getNames() ) do
        if disk.isPresent( sName ) and disk.hasData( sName ) then
            local sDiskStartup = shell.resolveProgram( "/" .. disk.getMountPath( sName ) .. "/startup" )
            if sDiskStartup then
                sUserStartup = sDiskStartup
                break
            end
        end
    end
end
if sUserStartup then
    shell.run( sUserStartup )
end


-- End
os.shutdown()