local M = {}

local global_handlers = {}

local Event = {
  Ready = "Ready",
  NodeRenamed = "NodeRenamed",
  TreeOpen = "TreeOpen",
  TreeClose = "TreeClose",
  FileCreated = "FileCreated",
  FileRemoved = "FileRemoved",
  FolderCreated = "FolderCreated",
  FolderRemoved = "FolderRemoved",
}

local function get_handlers(event_name)
  return global_handlers[event_name] or {}
end

local function register_handler(event_name, handler)
  local handlers = get_handlers(event_name)
  table.insert(handlers, handler)
  global_handlers[event_name] = handlers
end

local function dispatch(event_name, payload)
  for _, handler in pairs(get_handlers(event_name)) do
    local success, error = pcall(handler, payload)
    if not success then
      vim.api.nvim_err_writeln("Handler for event " .. event_name .. " errored. " .. vim.inspect(error))
    end
  end
end

--@private
function M._dispatch_ready()
  dispatch(Event.Ready)
end

--@private
function M._dispatch_node_renamed(old_name, new_name)
  dispatch(Event.NodeRenamed, { old_name = old_name, new_name = new_name })
end

--@private
function M._dispatch_file_removed(fname)
  dispatch(Event.FileRemoved, { fname = fname })
end

--@private
function M._dispatch_file_created(fname)
  dispatch(Event.FileCreated, { fname = fname })
end

--@private
function M._dispatch_folder_created(folder_name)
  dispatch(Event.FolderCreated, { folder_name = folder_name })
end

--@private
function M._dispatch_folder_removed(folder_name)
  dispatch(Event.FolderRemoved, { folder_name = folder_name })
end

--@private
function M._dispatch_on_tree_open()
  dispatch(Event.TreeOpen, nil)
end

--@private
function M._dispatch_on_tree_close()
  dispatch(Event.TreeClose, nil)
end

--Registers a handler for the Ready event.
--@param handler (function) Handler with the signature `function()`
function M.on_nvim_tree_ready(handler)
  register_handler(Event.Ready, handler)
end

--Registers a handler for the NodeRenamed event.
--@param handler (function) Handler with the signature function(payload), where payload is a table containing:
--  - old_name (string) Absolute path to the old node location.
--  - new_name (string) Absolute path to the new node location.
function M.on_node_renamed(handler)
  register_handler(Event.NodeRenamed, handler)
end

--Registers a handler for the FileCreated event.
--@param handler (function) Handler with the signature function(payload), where payload is a table containing:
--  - fname (string) Absolute path to the created file.
function M.on_file_created(handler)
  register_handler(Event.FileCreated, handler)
end

--Registers a handler for the FileRemoved event.
--@param handler (function) Handler with the signature function(payload), where payload is a table containing:
--  - fname (string) Absolute path to the removed file.
function M.on_file_removed(handler)
  register_handler(Event.FileRemoved, handler)
end

--Registers a handler for the FolderCreated event.
--@param handler (function) Handler with the signature function(payload), where payload is a table containing:
--  - folder_name (string) Absolute path to the created folder.
function M.on_folder_created(handler)
  register_handler(Event.FolderCreated, handler)
end

--Registers a handler for the FolderRemoved event.
--@param handler (function) Handler with the signature function(payload), where payload is a table containing:
--  - folder_name (string) Absolute path to the removed folder.
function M.on_folder_removed(handler)
  register_handler(Event.FolderRemoved, handler)
end

--Registers a handler for the TreeOpen event.
--@param handler (function) Handler with the signature function(payload)
function M.on_tree_open(handler)
  register_handler(Event.TreeOpen, handler)
end

--Registers a handler for the TreeClose event.
--@param handler (function) Handler with the signature function(payload)
function M.on_tree_close(handler)
  register_handler(Event.TreeClose, handler)
end

return M