PixelToast BIOS

-- Written for PixelToast's BIOS

-- Settings:
local header = "Tabs system"
local footer = "By JTK =)"

-- Center print/write function
local function cwrite(t)
    t = tostring(t)
    local x, y = term.getCursorPos()
    term.setCursorPos((51-#t)/2, y)
    write(t)
end

local function cprint(t)
    cwrite(t)
    write("\n") -- So we don't count \n in string length
end

-- Display table:
local disp = {
    -- Tabs
    {
        ['name'] = "Tab 1",
        -- Rows
        ['rows'] = {
            -- Row
            {
                ['name'] = "Row 1",
                -- function to be called when row selected and user hits enter
                -- Don't define if function unwanted
                ['func'] = function() term.setCursorPos(1, 19); write("Row 1 clicked!"); sleep(1) end,
            },

            {
                ['name'] = "Row 2",
            },

            {
                ['name'] = "Row 3",
            },
        },
    },

    {
        ['name'] = "Tab 2",
        ['rows'] = {
            {
                ['name'] = "1st Row",
            },

            {
                ['name'] = "2nd Row",
            },

            {
                ['name'] = "3rd Row",
            },
        },
    },

    {
        ['name'] = "Tab 3",
        ['rows'] = {
            {
                ['name'] = "Row a",
            },

            {
                ['name'] = "Row b",
            },

            {
                ['name'] = "Row c",
            },
        },
    },

    {
        ['name'] = "Time",
        -- This tab does not have any rows to be selected
        ['rows'] = false,
        -- It also calls this function when this tab is selected
        ['func'] = function()
            term.setTextColor(colors.black)
            term.setBackgroundColor(colors.white)

            parallel.waitForAny(
                function()
                    while true do
                        local e, k = os.pullEvent("key")
                        if k == keys.left or k == keys.right then
                            os.queueEvent("key", k)
                            return
                        end
                    end
                end,

                function()
                    while true do
                        term.setCursorPos(1, 4)
                        term.clearLine()
                        cprint("Time: "..textutils.formatTime(os.time(), true))
                        sleep(0.3)
                    end
                end
            )
        end,
    },

    {
        ['name'] = "Exit",
        ['rows'] = {
            {
                ['name'] = "Exit",
                ['func'] = function() return "EXIT" end, -- Return "EXIT" (Special return code that exits program)
            },
        },
    },
}

-- Function to be called on quit (Press F12)
local function onquit()
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.white)
    term.clear()
    term.setCursorPos(1, 1)
    print("Bye bye!")
end

-- Screen write func
local function screen(tab, row)

    -- Clear
    term.setBackgroundColor(colors.white)
    term.clear()

    -- Write header
    term.setCursorPos(1, 1) -- First line
    term.setBackgroundColor(colors.cyan)
    term.setTextColor(colors.black)
    term.clearLine()

    cwrite(header)

    -- Write tabs
    term.setCursorPos(1, 2)
    term.setBackgroundColor(colors.blue)
    term.clearLine()

    for i = 1, #disp do
        write((i == 1) and "" or " ") -- Write begging space

        term.setBackgroundColor((i == tab) and colors.white or colors.blue) -- Set colors for text
        term.setTextColor((i == tab) and colors.black or colors.white)

        write(disp[i].name) -- Write text

        term.setBackgroundColor(colors.blue)

        write((i == #disp) and "" or " ") -- Write ending space
    end

    -- Write line
    term.setTextColor(colors.blue)
    term.setBackgroundColor(colors.white)
    term.setCursorPos(1, 3)

    for i = 1, 51 do -- Write line
        write("-")
    end

    local spos = 0
    local length = #disp[tab].name + 2 -- Calculate length

    for i = 1, tab - 1 do -- Calculate hole's start position
        spos = spos + #disp[i].name + 2
    end

    term.setCursorPos(spos, 3)

    for i = 1, length do -- Write 'hole'
        write(" ")
    end

    -- Write rows
    term.setTextColor(colors.black)
    term.setCursorPos(1, 4)

    local rows = disp[tab].rows

    if rows then -- Check for no rows
        for i = 1, #rows do
            local cursor = (i == row) and "> " or "  "
            print(cursor..rows[i].name)
        end
    end

    -- Write footer
    term.setCursorPos(term.getSize()) -- Last line
    term.setBackgroundColor(colors.cyan)
    term.setTextColor(colors.black)
    term.clearLine()

    cwrite(footer)
end

-- Initialize:
local tab = 1
local row = 1

-- Initial screen draw
screen(tab, row)

while true do

    -- Wait for key
    local e, k = os.pullEvent("key")

    -- Change tabs
    if k == keys.right and tab < #disp then
        tab = tab + 1
        row = 1

        -- Redraw screen
        screen(tab, row)

        -- Call tab's function
        if type(disp[tab].func) == "function" then
            disp[tab].func ()
        end
    end

    if k == keys.left and tab > 1 then
        tab = tab - 1
        row = 1

        -- Redraw screen
        screen(tab, row)

        -- Call tab's function
        if type(disp[tab].func) == "function" then
            disp[tab].func ()
        end
    end

    -- Change rows
    if disp[tab].rows then -- Check for no rows
        if k == keys.down and row < #disp[tab].rows then
            row = row + 1

            -- Redraw screen
            screen(tab, row)
        end

        if k == keys.up and row > 1 then
            row = row - 1

            -- Redraw screen
            screen(tab, row)
        end
    end

    -- Quit on F12
    if k == keys.f12 then
        onquit()
        return
    end

    -- Call function if enter
    if k == keys.enter then
        if type(disp[tab]['rows'][row]['func']) == "function" then
            local ret = disp[tab]['rows'][row]['func'] () -- Call function

            if ret == "EXIT" then -- If EXIT then die
                onquit()
                return
            end
        end
    end
end