Quick Shell

local programArgs = {
    ['rom/programs/cd'] = {'path'},
    ['rom/programs/copy'] = {'source', 'destination'},
    ['rom/programs/delete'] = {'path'},
    ['rom/programs/edit'] = {'path'},
    ['rom/programs/eject'] = {'side'},
    ['rom/programs/gps'] = {'locate'},
    ['rom/programs/help'] = {'topic'},
    ['rom/programs/label'] = {'set', 'text'},
    ['rom/programs/mkdir'] = {'path'},
    ['rom/programs/monitor'] = {'side', 'program', 'arguments'},
    ['rom/programs/move'] = {'source', 'destination'},
    ['rom/programs/color/paint'] = {'path'},
    ['rom/programs/http/pastebin'] = {'get', 'code', 'filename'},
    ['rom/programs/redpulse'] = {'side', 'count', 'period'},
    ['rom/programs/redset'] = {'side', 'true/false'},
    ['rom/programs/redstone'] = {'side', 'true/false'},
    ['rom/programs/rename'] = {'source', 'destination'},
    ['rom/programs/type'] = {'path'},
    ['rom/programs/bg'] = {'program'},
    ['rom/programs/fg'] = {'program'},
    ['rom/programs/rednet/chat'] = {'join', 'hostname', 'username'},
    ['rom/programs/turtle/craft'] = {'amount'},
    ['rom/programs/turtle/equip'] = {'slot', 'side'},
    ['rom/programs/turtle/excavate'] = {'diameter'},
    ['rom/programs/turtle/go'] = {'direction', 'distance'},
    ['rom/programs/turtle/refuel'] = {'amount'},
    ['rom/programs/turtle/tunnel'] = {'length'},
    ['rom/programs/turtle/turn'] = {'direction', 'turns'},
    ['rom/programs/turtle/unequip'] = {'side'},
}
-- Colours
local promptColour, textColour, bgColour, suggestionColour
if term.isColour() then
    promptColour = colours.yellow
    textColour = colours.white
    suggestionColour = colours.grey
    suggestionBackgroundColour = colours.black
    bgColour = colours.black
else
    promptColour = colours.white
    textColour = colours.white
    suggestionColour = colours.black
    suggestionBackgroundColour = colours.white
    bgColour = colours.black
end
term.setCursorPos(1,1)
term.setBackgroundColor( bgColour )
term.setTextColour( promptColour )
term.write( os.version())
term.setTextColour(textColour)
term.write(' Quick Shell')
print()
term.setTextColour( textColour )


local function removeFileName(str)
    local pos = 0
    local current = 0

    repeat
      current = string.find(str, "/", pos)
      if current ~= nil then pos = current + 1 end
    until (current == nil)

    return string.gsub (str, string.sub (str, pos), "")
end

local function match(str, arg)
    if #str == 0 then
        return ''
    end
    local items = {}
    local function insertTable(tbl)
        if tbl and type(tbl) == 'table' then
            for i, v in ipairs(tbl) do
                local add = true
                for i2, v2 in ipairs(items) do
                    if v2 == v then
                        add = false
                        break
                    end
                end
                if add then
                    table.insert(items, v)
                end
            end
        elseif tbl then
            table.insert(items, tbl)
        end
    end

    if arg == 'program' then
        insertTable(shell.resolveProgram(str))
        for k, v in pairs(shell.aliases()) do
            insertTable(k)
        end
        insertTable(shell.programs())
    elseif arg == 'side' then
        insertTable({'left', 'right', 'top', 'bottom', 'front', 'back'})
        insertTable(peripheral.getNames())
    elseif arg == 'direction' then
        insertTable({'left', 'right', 'forward', 'back', 'down', 'up'})
    elseif arg == 'true/false' then
        insertTable({'true', 'false'})
    elseif arg == 'set' then
        insertTable({'get', 'set', 'clear'})
    elseif arg == 'locate' then
        insertTable({'locate', 'host'})
    elseif arg == 'set' then
        insertTable({'get', 'set', 'clear'})
    elseif arg == 'get' then
        insertTable({'get', 'put', 'run'})
    elseif arg == 'topic' then
        insertTable(help.topics())
        insertTable('index')
    elseif arg == 'path' or arg == 'source' then
        local path = removeFileName(str)
        local p, _ = removeFileName(path)
        if not fs.isDir(p) then
            return ''
        end
        local items = fs.list(p)
        for i, item in ipairs(items) do
            if string.lower(fs.getName(string.sub(fs.getName(item), 1, string.len(fs.getName(str))))) == string.lower(fs.getName(str)) then
                return p .. item
            end
        end
        return ''
    end

    for i, item in ipairs(items) do
        if string.lower(string.sub(item, 1, string.len(str))) == string.lower(str) then
            return item
        end
    end
    return ''
end
local function tabRead( _sReplaceChar, _tHistory )
    term.setCursorBlink( true )

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

    local w, h = term.getSize()
    local sx, sy = term.getCursorPos()
    local previousMatch = ''
    local hasMatched = false
    local function redraw( _sCustomReplaceChar, ignoreMatch )
        local nScroll = 0
        if sx + nPos >= w then
            nScroll = (sx + nPos) - w
        end

        term.setCursorPos( 1, sy )
        term.clearLine()
        term.setBackgroundColor( bgColour )
        term.setTextColour( promptColour )
        term.write( shell.dir() .. "> " )
        if not hasMatched and not ignoreMatch then
            term.setCursorPos( sx, sy )
            term.setTextColour(suggestionColour)
            term.setBackgroundColour(suggestionBackgroundColour)
            previousMatch = match(sLine, 'program')
            term.write(previousMatch)
            term.setBackgroundColour(bgColour)
        elseif not ignoreMatch and hasMatched and nPos >= #previousMatch + 1 then
            local args = programArgs[shell.resolveProgram(previousMatch)]
            previousArgs = ''
            if args then
                term.setCursorPos( sx + #sLine, sy )
                if sLine:sub(-1) ~= ' ' then
                    term.write(' ')
                    term.setCursorPos( sx + #sLine + 1, sy )
                end
                term.setTextColour(suggestionColour)
                term.setBackgroundColour(suggestionBackgroundColour)
                local tWords = {}
                for _match in string.gmatch( sLine, "[^ \t]+" ) do
                    table.insert(tWords, _match)
                end
                table.remove(tWords,1)

                for i, arg in ipairs(args) do
                    if #tWords < i then
                        term.write(arg..' ')
                    elseif i == #tWords and sLine:sub(-1) ~= ' ' then
                        term.setCursorPos( sx + #sLine - #tWords[i], sy)
                        local m = match(tWords[i], arg)
                        if #m ~= 0 then
                            term.write(m..' ')
                        else
                            term.write(tWords[i]..' ')
                        end
                    end
                end
                term.setBackgroundColour(bgColour)
            end
        end
        term.setTextColour(textColour)
        term.setCursorPos( sx, sy )
        local sReplace = _sCustomReplaceChar or _sReplaceChar
        if sReplace then
            term.write( string.rep( sReplace, string.len(sLine) - nScroll ) )
        else
            term.write( string.sub( sLine, nScroll + 1 ) )
        end
        term.setCursorPos( sx + nPos - nScroll, sy )
    end

    while true do
        local sEvent, param = os.pullEvent()
        if sEvent == "char" then
            sLine = string.sub( sLine, 1, nPos ) .. param .. string.sub( sLine, nPos + 1 )
            if (hasMatched and nPos <= #previousMatch) or (not hasMatched and param == ' ') then
                local pos, len = sLine:find("[^ \t]+")
                if pos and len then
                    previousMatch = sLine:sub(pos, len)
                    hasMatched = true
                end
            end
            term.setCursorPos(1, 2)
            nPos = nPos + 1
            redraw()

        elseif sEvent == "key" then
            if param == keys.enter then
                -- Enter
                redraw(nil, true)
                break

            elseif param == keys.tab and nPos == #sLine then
                if nPos >= #previousMatch + 1 and nPos == #sLine then
                    local args = programArgs[shell.resolveProgram(previousMatch)]
                    local sMatch = ''

                    local tWords = {}
                    for match in string.gmatch( sLine, "[^ \t]+" ) do
                        table.insert(tWords, match)
                    end

                    sMatch = match(tWords[#tWords], args[#tWords-1])
                    if #sMatch ~= 0 then
                        sLine = ''
                        tWords[#tWords] = sMatch
                        for i, v in ipairs(tWords) do
                            sLine = sLine .. v .. ' '
                        end
                        nPos = #sLine
                        redraw()
                    else
                        sLine = sLine .. ' '
                        nPos = #sLine
                        redraw()
                    end
                else
                    local sMatch = match(sLine, 'program')
                    if #sMatch ~= 0 then
                        nPos = #sMatch + 1
                        sLine = sMatch .. ' '
                        hasMatched = true
                        previousMatch = sMatch
                        redraw()
                    end
                end
            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 == #sLine and string.sub( sLine, nPos, nPos) == ' ' then
                --if hasMatched and nPos == #previousMatch + 1 then
                    local tWords = {}
                    for match in string.gmatch( sLine, "[^ \t]+" ) do
                        table.insert(tWords, match)
                    end
                    table.remove(tWords, #tWords)
                    sLine = ''
                    for i, v in ipairs(tWords) do
                        sLine = sLine .. v .. ' '
                    end
                    nPos = #sLine
                    if #tWords == 0 then
                        previousMatch = ''
                        hasMatched = false
                    end

                    redraw()
                elseif nPos > 0 then
                    redraw(" ")
                    sLine = string.sub( sLine, 1, nPos - 1 ) .. string.sub( sLine, nPos + 1 )
                    if hasMatched and nPos <= #previousMatch then
                        local pos, len = sLine:find("[^ \t]+")
                        if pos and len then
                            previousMatch = sLine:sub(pos, len)
                        end
                    end
                    nPos = nPos - 1
                    redraw()
                end
            elseif param == keys.home then
                -- Home
                redraw(" ")
                nPos = 0
                redraw()
            elseif param == keys.delete then
                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
        end
    end

    term.setCursorBlink( false )
    term.setCursorPos( w + 1, sy )
    print()

    return sLine
end


-- Read commands and execute them
local tCommandHistory = {}
while not bExit do
    term.setBackgroundColor( bgColour )
    term.setTextColour( promptColour )
    term.write( shell.dir() .. "> " )
    term.setTextColour( textColour )

    local sLine = tabRead( nil, tCommandHistory )
    table.insert( tCommandHistory, sLine )
    shell.run(sLine)
end