Buttons API - ComputerCraft

--Button API (c) Jeremiah Lowe 2017
--Created in ZeroBrane studio and tested on the 1.7.10 pack
--Revised on 12/2023 for use on Devil's Anarchy 1.12.2 pack
--Can be adapted to work with other libraries
--=====================
--= Library functions =
--=====================
--The default style for all non-toggle buttons
defaultStyle = {
  procedural = false,
  backCol = colors.lightGray,
  foreCol = colors.white,
  dispTxt = "Button",
  padd = 1,
  size = 1
}
--Returns a style that is used when drawing the button to the screen
--displayText: The text to display on the button
--backgroundColor: The background color of the button
--foregroundColor: The foreground/text color of the button
--textSize: The text size
--padding: The padding size of the button
function createStyle(displayText, backgroundColor, foregroundColor, textSize, padding)
  if displayText == nil then displayText = defaultStyle.dispTxt end
  if textSize == nil then textSize = defaultStyle.size end
  if padding == nil then padding = defaultStyle.padd end
  if backgroundColor == nil then backgroundColor = defaultStyle.backCol end
  if foregroundColor == nil then foregroundColor = defaultStyle.foreCol end
  return {procedural = false, backCol = backgroundColor, foreCol = foregroundColor, dispTxt = displayText, size = textSize, padd = padding}
end
--Creates a style that changes when you press the button
--pressedStyle: The style to use when the button is pressed
--unpressedStyle: The style to use when the button is not pressed
function createProceduralStyle(pressedStyle, unpressedStyle, unusableStyle)
  if pressedStyle == nil then pressedStyle = defaultStyle end
  if unpressedStyle == nil then unpressedStyle = defaultStyle end
  if unusableStyle == nil then unusableStyle = defaultStyle end
  return {procedural = true, pStyle = pressedStyle, uStyle = unpressedStyle, dStyle = unusableStyle}
end
--The default style for all toggle buttons
defaultStyleT = createProceduralStyle(
  createStyle("Enabled", colors.lightGray, colors.green, 1, 1),
  createStyle("Disabled", colors.lightGray, colors.red, 1, 1),
  createStyle("Unusable", colors.lightGray, colors.black, 1, 1))
--Returns a button with the specified values, can be added with addButton
--xPosition: X position of the button
--yPosition: Y position of the button
--isToggleButton (default false): Is the button a toggle button?
--style (defaults to default style): Style of the button
--onClickFunction: Called when the button is clicked params:[monitor, button, style]
--onDrawFunction (default nil): Called when the button is drawn params:[button, style]
function createButton(xPosition, yPosition, style, isToggleButton, onClickFunction, onDrawFunction)
  local btn = {
    x = xPosition, y = yPosition, s = style,
    isToggle = isToggleButton,
    onClick = onClickFunction,
    onDraw = onDrawFunction,
    enabled = false, drawn = false, unusable = false
  }
  --Gets the correct style for the button, depends on if it is enabled or not
  function btn.getStyle()
    if btn.s.procedural then
      if btn.unusable then
        return btn.s.dStyle
      elseif btn.enabled then
        return btn.s.pStyle
      else
        return btn.s.uStyle
      end
    else
      return btn.s
    end
  end
  return btn
end
--Array of curent buttons
local buttons = {}
--Counts the length of a table
--NOTE: This is an internal method, only use it if you know what you're doing
--tbl: The table
function len(tbl)
  local count = 0
  for k, v in pairs(tbl) do count = count + 1 end
  return count
end
--Returns a "Button ID" that used for removing the button
--btn: The button to add
function addButton(btn)
  local l = len(buttons)
  for i=0, l do
    if buttons[i] == nil then
      buttons[i] = btn
      return i
    end
  end
  i[l] = btn
  return l
end
--Returns the removed button
--id: The ID of the button to remove, retrieved from addButton(btn)
function removeButton(id)
  local btn = buttons[id]
  if btn ~= nil then
    buttons[id] = nil
  end
  return btn
end
--====================
--=     Graphics     =
--====================
--Applies a style onto a monitor
--NOTE: This is an internal method, only use it if you know what you're doing
--mon: The monitor
--btn: The button the style is from
--s: The style
function initMonitor(mon, btn, s)
  assert(mon ~= nil)
  assert(btn ~= nil)
  assert(s ~= nil)
  assert(not s.procedural)
  if mon.isColor() then
    mon.setTextColor(s.foreCol)
    mon.setBackgroundColor(s.backCol)
  end
  mon.setTextScale(s.size)
  mon.setCursorPos(btn.x, btn.y)
  mon.setCursorBlink(false)
end
--Writes a line to the monitor, similar to println(msg) from other languages
--mon: The monitor to write to
--txt: The text to write
function monWriteLine(mon, txt)
  cx, cy = mon.getCursorPos()
  mon.write(txt)
  mon.setCursorPos(cx, cy + 1)
end
--Draws over the button's area
--mon: The monitor to draw on
--btn: The button to edit
function monitorClearButtonArea(mon, btn)

end
--Draws a button to the specified monitor
--mon: The monitor to draw on
--btn: The button to draw
function monitorDrawButton(mon, btn)
  assert(mon ~= nil)
  assert(btn ~= nil)
  monitorClearButtonArea(mon, btn)
  local s = btn.getStyle()
  if s == nil then s = defaultStyle end
  initMonitor(mon, btn, s)
  local dtxt = s.dispTxt
  for i=1, s.padd do dtxt = " " .. dtxt .. " " end
  local w, ln = string.len(dtxt), ""
  for i=1, w do ln = ln .. " " end
  for i=1, s.padd do monWriteLine(mon, ln) end
  monWriteLine(mon, dtxt)
  for i=1, s.padd do monWriteLine(mon, ln) end
  btn.drawn = true
  btn.x2, btn.y2 = mon.getCursorPos()
  btn.x2 = btn.x2 + w
  if btn.onDraw ~= nil then btn.onDraw(mon, btn, s) end
end
--Draws all the buttons to the monitor
--mon: The monitor to draw it on
function monitorDraw(mon)
  assert(mon ~= nil and buttons ~= nil)
  for k, b in pairs(buttons) do
    if b ~= nil then
      monitorDrawButton(mon, b)
    end
  end
end
--====================
--= Event management =
--====================
--Detects if a coordinate intersects with a rectangle
--x, y: The coordinate to check
--x1, y1: The minimum coordinates of the rectangle
--x2, y2: The maximum coordinates of the rectangle
function intersects(x, y, x1, y1, x2, y2)
  local xInt = x >= x1 and x <= x2
  local yInt = y >= y1 and y <= y2
  return xInt and yInt
end
--Sends a touch event to the rest of the API and redraws any updated buttons
--mon: The monitor to re-draw the buttons onto
--x, y: The x and y coordinates of the touch event
function onTouch(mon, x, y)
  for k, b in pairs(buttons) do
    if b ~= nil and b.drawn then
      local int = intersects(x, y, b.x, b.y, b.x2, b.y2)
      if int and b.onClick ~= nil and not b.unusable then
        if b.isToggle then
          b.enabled = not b.enabled
          b.onClick(b, b.enabled)
        else
          b.onClick(b, true)
          b.enabled = false
        end
        monitorDrawButton(mon, b)
      end
    end
  end
end
--An input loop that constantly checks for events, This is an INFINITE loop!
function inputLoop()
  while true do
    local e, s, x, y = os.pullEvent("monitor_touch")
    onTouch(peripheral.wrap(s), x, y)
  end
end