Mezzaluna/runtime/share/mezzaluna/layout_manager.lua

--- This is a wrapper around mez's hooks and keybinds to allow users to create
--- layouts without multiple different layouts conflicting.
---
--- TODO: this may be overridden by the user by setting mez.layout prior to the
--- runtime loading

---@class layout a singular layout
---@field name string the name of the layout
---@field callback function this is the function which is run when changes to current state have been made
---@field events string[]? this is a list of the events that callback will be run on

---@class layout_manager manage all your layouts
---@field layouts layout[] all the layouts that are registered
---@field current_layout layout the currently active layout
local layout_manager = {
  layouts = {},
  --- the baseline events for a new layout
  events = {
    "ViewMapPre",
    "ViewUnmapPost",
    -- "ViewPointerMotion",
  }
}

--- create a new layout
---@param options layout
---@return layout your_layout returns your new layout
function layout_manager.new_layout(options)
  local layout = {}

  layout.name = options.name
  layout.callback = options.callback
  layout.events = layout_manager.events

  -- store the new layout in the layout list
  layout_manager.layouts[#layout_manager.layouts + 1] = layout
  return layout
end

--- set the current layout
---@param layout_name string the name of the layout already created in the layout_manager
function layout_manager.set_layout(layout_name)
  local layout = nil
  for _, l in ipairs(layout_manager.layouts) do
    if l.name == layout_name then
      layout = l
    end
  end
  assert(layout, "layout '"..layout_name.."' does not exist")

  if layout_manager.current_layout then
    local current_layout = layout_manager.current_layout
    -- TODO: this actually doesn't exist in mez just yet
    -- mez.hook.del(current_layout)
  end
  mez.hook.add(layout.events, {
    callback = function ()
      print("layouting")
      for _, output in ipairs(mez.output.get_all_ids()) do
        layout.callback(output)
      end
      print("layouting done")
    end,
  })
  layout.callback()
end

return layout_manager