module HelixSync
  # Provides a mechanism for managing client workspaces for projects.
  class ClientService

    # Rack environment
    attr_accessor :env

    def initialize(env: nil)
      @env = env
    end

    @@handle_create_client = []

    # Callback methods that can implement client workspace creation based on
    # projects.
    #
    # Each callback should take 4 parameters:
    #
    # - `project` [String] The project ID.
    #
    # - `device` [String] A device ID (like a hostname or MAC address) that
    #                     we'll associate with the client.
    #
    # - `root` [String] The Root field of the client, the base directory for
    #                   the new setting.
    #
    # - `env` [Hash] The rack environment
    #
    # Your callback should return the new client name if it's been handled.
    #
    # It's assumed that your implementation will handle other defaults
    # responsibly.
    #
    # Example:
    #
    #     HelixSync::ClientService.handle_create_client << lambda do |project, device, root, env|
    #       client_name = go_make_client()
    #       return client_name if client_name # Just return nil if you can't handle it
    #     end
    def self.handle_create_client
      @@handle_create_client
    end

    # Create a client for the project.
    #
    # Returns the new client name if successful, nil otherwise.
    def create_client(project, device, root)
      client_id = nil
      @@handle_create_client.find do |handler|
        id = handler.call(project, device, root, env)
        client_id = id if id
        id
      end
      client_id
    end

    def p4
      env['p4']
    end
  end
end