nebula.lua

local application = {}
local currentFrameUUID = ""

local themes = {
  ["nebula.theme.light"] = {
    background = 1,
    text = 128,
    button = {
      background = 256,
      text = 128,
      selectionBackground = 256,
      selectionText = 1
    }
  }
}

local random = math.random
local function uuid()
  local template ='xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'
  return string.gsub(template, '[xy]', function (c)
    local v = (c == 'x') and random(0, 0xf) or random(8, 0xb)
    return string.format('%x', v)
  end)
end

local function createElement(parent, type, x, y, ...)
  extra = { ... }
  if not parent.children then
    error("Could not add type " .. type .. " to element")
    return nil
  end
  if type == "label" then
    local text = extra[1]
    local data = {
      type = "nebula.objectType.label",
      text = text,
      uuid = uuid(),
      x = x,
      y = y,
      visible = true
    }
    table.insert(parent.children, data)
    return parent.children[#parent.children]
  elseif type == "button" then
    local text = extra[1]
    local clickEvent = extra[2]
    local paddingX = extra[3] or 1
    local data = {
      type = "nebula.objectType.button",
      text = text,
      uuid = uuid(),
      padding = {
        x = paddingX
      },
      onClick = clickEvent,
      x = x,
      y = y,
      endX = x + string.len(string.rep(" ", paddingX) .. text .. string.rep(" ", paddingX)),
      endY = y,
      visible = true
    }
    table.insert(parent.children, data)
    return parent.children[#parent.children]
  elseif type == "frame" then
    local data = {
      type = "nebula.objectType.frame",
      uuid = uuid(),
      children = {},
      visible = true
    }
    data.addChild = function( ... )
      return createElement(data, ...)
    end
    table.insert(parent.children, data)
    return parent.children[#parent.children]
  end
end

local function createApplication(type, theme)
  if theme == nil then theme = "light" end
  application = {}
  if type == "default" then
    application.type = "nebula.applicationType.default"
  end
  if theme == "light" then
    application.theme = "nebula.theme.light"
  end
  application.children = {}
  application.uuid = uuid()
  application.addChild = function( ... )
    return createElement(application, ...)
  end
  return application
end

local function redraw()
  if application ~= {} then
    local theme = themes[application.theme]
    term.setBackgroundColor(theme.background)
    term.clear()
    local function loadItems(list)
      currentFrameUUID = list.uuid
      for i, v in pairs(list.children) do
        if v.type == "nebula.objectType.label" and v.visible == true then
          term.setCursorPos(v.x, v.y)
          term.setBackgroundColor(theme.background)
          term.setTextColor(theme.text)
          term.write(v.text)
        elseif v.type == "nebula.objectType.button" and v.visible == true then
          term.setCursorPos(v.x, v.y)
          term.setBackgroundColor(theme.button.background)
          term.setTextColor(theme.button.text)
          term.write(string.rep(" ", v.padding.x) .. v.text .. string.rep(" ", v.padding.x))
        elseif v.type == "nebula.objectType.frame" and v.visible == true then
          term.setBackgroundColor(theme.background)
          term.clear()
          loadItems(v.children)
        end
      end
    end
    loadItems(application)
  else
    error("No application")
  end
end

local function init()
  while true do
    local e = {os.pullEvent()}
    if e[1] == "mouse_click" then
      local m, x, y = e[2], e[3], e[4]
      local function checkButtons(frame)
        for i, v in pairs(frame.children) do
          if v.type == "nebula.objectType.button" then
            if x >= v.x and x <= v.endX and y >= v.y and y <= v.endY and v.visible == true then
              local theme = themes[application.theme]
              term.setCursorPos(v.x, v.y)
              term.setBackgroundColor(theme.button.selectionBackground)
              term.setTextColor(theme.button.selectionText)
              term.write(string.rep(" ", v.padding.x) .. v.text .. string.rep(" ", v.padding.x))
              sleep(0.1)
              redraw()

              v.onClick()
              break
            end
          end
        end
      end
      if currentSelectedFrameUUID == application.uuid then
        checkButtons(application)
      else
        local function checkChildren(object)
          for i, v in pairs(object.children) do
            if v.type == "nebula.objectType.frame" then
              if v.uuid == currentSelectedFrameUUID then
                checkButtons(v)
                break
              end
            end
          end
        end
      end
    end
  end
end

return {
  draw = redraw,
  createApplication = createApplication,
  elements = application,
  init = init
}