Tetrahedron BIOS

function loadstring(code, env)
    local e = _G
    local name = "@code"
    if type(env) == "table" then e = env
    elseif type(env) == "string" then name = env end
    return load(code, name, "t", e)
end

-- Load in expect from the module path.
--
-- Ideally we'd use require, but that is part of the shell, and so is not
-- available to the BIOS or any APIs. All APIs load this using dofile, but that
-- has not been defined at this point.
local expect

do
    local h = fs.open("rom/modules/main/cc/expect.lua", "r")
    local f, err = loadstring(h.readAll(), "@expect.lua")
    h.close()

    if not f then error(err) end
    expect = f().expect
end

if _VERSION == "Lua 5.1" then
    -- If we're on Lua 5.1, install parts of the Lua 5.2/5.3 API so that programs can be written against it
    local type = type
    local nativeload = load
    local nativeloadstring = loadstring
    local nativesetfenv = setfenv

    --- Historically load/loadstring would handle the chunk name as if it has
    -- been prefixed with "=". We emulate that behaviour here.
    local function prefix(chunkname)
        if type(chunkname) ~= "string" then return chunkname end
        local head = chunkname:sub(1, 1)
        if head == "=" or head == "@" then
            return chunkname
        else
            return "=" .. chunkname
        end
    end

    function load( x, name, mode, env )
        expect(1, x, "function", "string")
        expect(2, name, "string", "nil")
        expect(3, mode, "string", "nil")
        expect(4, env, "table", "nil")

        local ok, p1, p2 = pcall( function()
            if type(x) == "string" then
                local result, err = nativeloadstring( x, name )
                if result then
                    if env then
                        env._ENV = env
                        nativesetfenv( result, env )
                    end
                    return result
                else
                    return nil, err
                end
            else
                local result, err = nativeload( x, name )
                if result then
                    if env then
                        env._ENV = env
                        nativesetfenv( result, env )
                    end
                    return result
                else
                    return nil, err
                end
            end
        end )
        if ok then
            return p1, p2
        else
            error( p1, 2 )
        end
    end
    table.unpack = unpack
    table.pack = function( ... ) return { n = select( "#", ... ), ... } end

    if _CC_DISABLE_LUA51_FEATURES then
        -- Remove the Lua 5.1 features that will be removed when we update to Lua 5.2, for compatibility testing.
        -- See "disable_lua51_functions" in ComputerCraft.cfg
        setfenv = nil
        getfenv = nil
        loadstring = nil
        unpack = nil
        math.log10 = nil
        table.maxn = nil
    else
        loadstring = function(string, chunkname) return nativeloadstring(string, prefix( chunkname )) end

        -- Inject a stub for the old bit library
        _G.bit = {
            bnot = bit32.bnot,
            band = bit32.band,
            bor = bit32.bor,
            bxor = bit32.bxor,
            brshift = bit32.arshift,
            blshift = bit32.lshift,
            blogic_rshift = bit32.rshift,
        }
    end
end

if _VERSION == "Lua 5.3" and not bit32 then
    -- If we're on Lua 5.3, install the bit32 api from Lua 5.2
    -- (Loaded from a string so this file will still parse on <5.3 lua)
    load( [[
        bit32 = {}

        function bit32.arshift( n, bits )
            if type(n) ~= "number" or type(bits) ~= "number" then
                error( "Expected number, number", 2 )
            end
            return n >> bits
        end

        function bit32.band( m, n )
            if type(m) ~= "number" or type(n) ~= "number" then
                error( "Expected number, number", 2 )
            end
            return m & n
        end

        function bit32.bnot( n )
            if type(n) ~= "number" then
                error( "Expected number", 2 )
            end
            return ~n
        end

        function bit32.bor( m, n )
            if type(m) ~= "number" or type(n) ~= "number" then
                error( "Expected number, number", 2 )
            end
            return m | n
        end

        function bit32.btest( m, n )
            if type(m) ~= "number" or type(n) ~= "number" then
                error( "Expected number, number", 2 )
            end
            return (m & n) ~= 0
        end

        function bit32.bxor( m, n )
            if type(m) ~= "number" or type(n) ~= "number" then
                error( "Expected number, number", 2 )
            end
            return m ~ n
        end

        function bit32.lshift( n, bits )
            if type(n) ~= "number" or type(bits) ~= "number" then
                error( "Expected number, number", 2 )
            end
            return n << bits
        end

        function bit32.rshift( n, bits )
            if type(n) ~= "number" or type(bits) ~= "number" then
                error( "Expected number, number", 2 )
            end
            return n >> bits
        end
    ]] )()
end

-- Install lua parts of the os api
function os.version()
    return "CraftOS 1.8"
end

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

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

-- Install globals
function sleep( nTime )
    expect(1, nTime, "number", "nil")
    local timer = os.startTimer( nTime or 0 )
    repeat
        local _, param = os.pullEvent( "timer" )
    until param == timer
end

function write( sText )
    expect(1, sText, "string", "number")

    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 #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, #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, #text + 1 )
            if #text > w then
                -- Print a multiline word
                while #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 + #text - 1 > w then
                    newLine()
                end
                term.write( text )
                x, y = term.getCursorPos()
            end
        end
    end

    return nLinesPrinted
end

function print( ... )
    local nLinesPrinted = 0
    local nLimit = select("#", ... )
    for n = 1, nLimit do
        local s = tostring( select( n, ... ) )
        if n < nLimit then
            s = s .. "\t"
        end
        nLinesPrinted = nLinesPrinted + write( s )
    end
    nLinesPrinted = nLinesPrinted + write( "\n" )
    return nLinesPrinted
end

function printError( ... )
    local oldColour
    if term.isColour() then
        oldColour = term.getTextColour()
        term.setTextColour( colors.red )
    end
    print( ... )
    if term.isColour() then
        term.setTextColour( oldColour )
    end
end

function read( _sReplaceChar, _tHistory, _fnComplete, _sDefault )
    expect(1, _sReplaceChar, "string", "nil")
    expect(2, _tHistory, "table", "nil")
    expect(3, _fnComplete, "function", "nil")
    expect(4, _sDefault, "string", "nil")

    term.setCursorBlink( true )

    local sLine
    if type( _sDefault ) == "string" then
        sLine = _sDefault
    else
        sLine = ""
    end
    local nHistoryPos
    local nPos, nScroll = #sLine, 0
    if _sReplaceChar then
        _sReplaceChar = string.sub( _sReplaceChar, 1, 1 )
    end

    local tCompletions
    local nCompletion
    local function recomplete()
        if _fnComplete and nPos == #sLine then
            tCompletions = _fnComplete( sLine )
            if tCompletions and #tCompletions > 0 then
                nCompletion = 1
            else
                nCompletion = nil
            end
        else
            tCompletions = nil
            nCompletion = nil
        end
    end

    local function uncomplete()
        tCompletions = nil
        nCompletion = nil
    end

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

    local function redraw( _bClear )
        local cursor_pos = nPos - nScroll
        if sx + cursor_pos >= w then
            -- We've moved beyond the RHS, ensure we're on the edge.
            nScroll = sx + nPos - w
        elseif cursor_pos < 0 then
            -- We've moved beyond the LHS, ensure we're on the edge.
            nScroll = nPos
        end

        local _, cy = term.getCursorPos()
        term.setCursorPos( sx, cy )
        local sReplace = _bClear and " " or _sReplaceChar
        if sReplace then
            term.write( string.rep( sReplace, math.max( #sLine - nScroll, 0 ) ) )
        else
            term.write( string.sub( sLine, nScroll + 1 ) )
        end

        if nCompletion then
            local sCompletion = tCompletions[ nCompletion ]
            local oldText, oldBg
            if not _bClear then
                oldText = term.getTextColor()
                oldBg = term.getBackgroundColor()
                term.setTextColor( colors.white )
                term.setBackgroundColor( colors.gray )
            end
            if sReplace then
                term.write( string.rep( sReplace, #sCompletion ) )
            else
                term.write( sCompletion )
            end
            if not _bClear then
                term.setTextColor( oldText )
                term.setBackgroundColor( oldBg )
            end
        end

        term.setCursorPos( sx + nPos - nScroll, cy )
    end

    local function clear()
        redraw( true )
    end

    recomplete()
    redraw()

    local function acceptCompletion()
        if nCompletion then
            -- Clear
            clear()

            -- Find the common prefix of all the other suggestions which start with the same letter as the current one
            local sCompletion = tCompletions[ nCompletion ]
            sLine = sLine .. sCompletion
            nPos = #sLine

            -- Redraw
            recomplete()
            redraw()
        end
    end
    while true do
        local sEvent, param, param1, param2 = os.pullEvent()
        if sEvent == "char" then
            -- Typed key
            clear()
            sLine = string.sub( sLine, 1, nPos ) .. param .. string.sub( sLine, nPos + 1 )
            nPos = nPos + 1
            recomplete()
            redraw()

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

        elseif sEvent == "key" then
            if param == keys.enter then
                -- Enter
                if nCompletion then
                    clear()
                    uncomplete()
                    redraw()
                end
                break

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

            elseif param == keys.right then
                -- Right
                if nPos < #sLine then
                    -- Move right
                    clear()
                    nPos = nPos + 1
                    recomplete()
                    redraw()
                else
                    -- Accept autocomplete
                    acceptCompletion()
                end

            elseif param == keys.up or param == keys.down then
                -- Up or down
                if nCompletion then
                    -- Cycle completions
                    clear()
                    if param == keys.up then
                        nCompletion = nCompletion - 1
                        if nCompletion < 1 then
                            nCompletion = #tCompletions
                        end
                    elseif param == keys.down then
                        nCompletion = nCompletion + 1
                        if nCompletion > #tCompletions then
                            nCompletion = 1
                        end
                    end
                    redraw()

                elseif _tHistory then
                    -- Cycle history
                    clear()
                    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, nScroll = #sLine, 0
                    else
                        sLine = ""
                        nPos, nScroll = 0, 0
                    end
                    uncomplete()
                    redraw()

                end

            elseif param == keys.backspace then
                -- Backspace
                if nPos > 0 then
                    clear()
                    sLine = string.sub( sLine, 1, nPos - 1 ) .. string.sub( sLine, nPos + 1 )
                    nPos = nPos - 1
                    if nScroll > 0 then nScroll = nScroll - 1 end
                    recomplete()
                    redraw()
                end

            elseif param == keys.home then
                -- Home
                if nPos > 0 then
                    clear()
                    nPos = 0
                    recomplete()
                    redraw()
                end

            elseif param == keys.delete then
                -- Delete
                if nPos < #sLine then
                    clear()
                    sLine = string.sub( sLine, 1, nPos ) .. string.sub( sLine, nPos + 2 )
                    recomplete()
                    redraw()
                end

            elseif param == keys["end"] then
                -- End
                if nPos < #sLine then
                    clear()
                    nPos = #sLine
                    recomplete()
                    redraw()
                end

            elseif param == keys.tab then
                -- Tab (accept autocomplete)
                acceptCompletion()

            end

        elseif sEvent == "mouse_click" or sEvent == "mouse_drag" and param == 1 then
            local _, cy = term.getCursorPos()
            if param1 >= sx and param1 <= w and param2 == cy then
                -- Ensure we don't scroll beyond the current line
                nPos = math.min(math.max(nScroll + param1 - sx, 0), #sLine)
                redraw()
            end

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

        end
    end

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

    return sLine
end

function loadfile( filename, mode, env )
    -- Support the previous `loadfile(filename, env)` form instead.
    if type(mode) == "table" and env == nil then
        mode, env = nil, mode
    end

    expect(1, filename, "string")
    expect(2, mode, "string", "nil")
    expect(3, env, "table", "nil")

    local file = fs.open( filename, "r" )
    if not file then return nil, "File not found" end

    local func, err = load( file.readAll(), "@" .. fs.getName( filename ), mode, env )
    file.close()
    return func, err
end

function dofile( _sFile )
    expect(1, _sFile, "string")

    local fnFile, e = loadfile( _sFile, nil, _G )
    if fnFile then
        return fnFile()
    else
        error( e, 2 )
    end
end

-- Install the rest of the OS api
function os.run( _tEnv, _sPath, ... )
    expect(1, _tEnv, "table")
    expect(2, _sPath, "string")

    local tArgs = table.pack( ... )
    local tEnv = _tEnv
    setmetatable( tEnv, { __index = _G } )
    local fnFile, err = loadfile( _sPath, nil, tEnv )
    if fnFile then
        local ok, err = pcall( function()
            fnFile( table.unpack( tArgs, 1, tArgs.n ) )
        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

local tAPIsLoading = {}
function os.loadAPI( _sPath )
    expect(1, _sPath, "string")
    local sName = fs.getName( _sPath )
    if sName:sub(-4) == ".lua" then
        sName = sName:sub(1, -5)
    end
    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, nil, tEnv )
    if fnAPI then
        local ok, err = pcall( fnAPI )
        if not ok then
            tAPIsLoading[sName] = nil
            return error( "Failed to load API " .. sName .. " due to " .. err, 1 )
        end
    else
        tAPIsLoading[sName] = nil
        return error( "Failed to load API " .. sName .. " due to " .. err, 1 )
    end

    local tAPI = {}
    for k, v in pairs( tEnv ) do
        if k ~= "_ENV" then
            tAPI[k] =  v
        end
    end

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

function os.unloadAPI( _sName )
    expect(1, _sName, "string")
    if _sName ~= "_G" and type(_G[_sName]) == "table" then
        _G[_sName] = nil
    end
end

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

-- Install the lua part of the FS api
local tEmpty = {}
function fs.complete( sPath, sLocation, bIncludeFiles, bIncludeDirs )
    expect(1, sPath, "string")
    expect(2, sLocation, "string")
    expect(3, bIncludeFiles, "boolean", "nil")
    expect(4, bIncludeDirs, "boolean", "nil")

    bIncludeFiles = bIncludeFiles ~= false
    bIncludeDirs = bIncludeDirs ~= false
    local sDir = sLocation
    local nStart = 1
    local nSlash = string.find( sPath, "[/\\]", nStart )
    if nSlash == 1 then
        sDir = ""
        nStart = 2
    end
    local sName
    while not sName do
        local nSlash = string.find( sPath, "[/\\]", nStart )
        if nSlash then
            local sPart = string.sub( sPath, nStart, nSlash - 1 )
            sDir = fs.combine( sDir, sPart )
            nStart = nSlash + 1
        else
            sName = string.sub( sPath, nStart )
        end
    end

    if fs.isDir( sDir ) then
        local tResults = {}
        if bIncludeDirs and sPath == "" then
            table.insert( tResults, "." )
        end
        if sDir ~= "" then
            if sPath == "" then
                table.insert( tResults, bIncludeDirs and ".." or "../" )
            elseif sPath == "." then
                table.insert( tResults, bIncludeDirs and "." or "./" )
            end
        end
        local tFiles = fs.list( sDir )
        for n = 1, #tFiles do
            local sFile = tFiles[n]
            if #sFile >= #sName and string.sub( sFile, 1, #sName ) == sName then
                local bIsDir = fs.isDir( fs.combine( sDir, sFile ) )
                local sResult = string.sub( sFile, #sName + 1 )
                if bIsDir then
                    table.insert( tResults, sResult .. "/" )
                    if bIncludeDirs and #sResult > 0 then
                        table.insert( tResults, sResult )
                    end
                else
                    if bIncludeFiles and #sResult > 0 then
                        table.insert( tResults, sResult )
                    end
                end
            end
        end
        return tResults
    end
    return tEmpty
end

-- Load APIs
local bAPIError = false
local tApis = fs.list( "rom/apis" )
for _, 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 and fs.isDir( "rom/apis/turtle" ) then
    -- Load turtle APIs
    local tApis = fs.list( "rom/apis/turtle" )
    for _, 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 _, 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.lua" ) 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

-- Set default settings
settings.set( "shell.allow_startup", true )
settings.set( "shell.allow_disk_startup", commands == nil )
settings.set( "shell.autocomplete", true )
settings.set( "edit.autocomplete", true )
settings.set( "edit.default_extension", "lua" )
settings.set( "paint.default_extension", "nfp" )
settings.set( "lua.autocomplete", true )
settings.set( "list.show_hidden", false )
settings.set( "motd.enable", false )
settings.set( "motd.path", "/rom/motd.txt:/motd.txt" )
if term.isColour() then
    settings.set( "bios.use_multishell", true )
end
if _CC_DEFAULT_SETTINGS then
    for sPair in string.gmatch( _CC_DEFAULT_SETTINGS, "[^,]+" ) do
        local sName, sValue = string.match( sPair, "([^=]*)=(.*)" )
        if sName and sValue then
            local value
            if sValue == "true" then
                value = true
            elseif sValue == "false" then
                value = false
            elseif sValue == "nil" then
                value = nil
            elseif tonumber(sValue) then
                value = tonumber(sValue)
            else
                value = sValue
            end
            if value ~= nil then
                settings.set( sName, value )
            else
                settings.unset( sName )
            end
        end
    end
end

-- Load user settings
if fs.exists( ".settings" ) then
    settings.load( ".settings" )
end

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

-- End
os.shutdown()