CC - DoubleClick

local expect = require "cc.expect".expect

local click_out = 0
local timeout = 250

local dc = {}

--- Check if the filter is valid to return the event.
---@param got string? The actual event.
---@param filter string? The filter given.
---@retutn boolean valid The validity of the event.
local function check_filter(got, filter)
  return not filter or filter == got
end

--- Pull an event, listening gor double-clicks.
---@param filter string? The event name, or any event.
---@return string event_name The event name.
---@return any ... Event arguments.
function dc.pull(filter)
  expect(1, filter, "string", "nil")
  while true do
    local event = table.pack(os.pullEvent())

    if event[1] == "mouse_click" then
      local current = os.epoch "utc"

      -- if we passed the timeout time (single click)
      if current > click_out then
        -- calculate the next timeout time
        click_out = current + timeout
      else
        -- Double click! Change the event type
        event[1] = "mouse_double_click"

        -- Also reset the double-click timer.
        -- Next click will start the timer, click after that will be double again.
        click_out = 0
      end
    end

    if check_filter(event[1], filter) then
      return table.unpack(event, 1, event.n)
    end
  end
end

--- Sets the length of the interval for a doubleclick
---@param n number The timeout, in milliseconds.
function dc.setTimeout(n)
  expect(1, n, "number")

  timeout = n
end

return dc