R/resource_manager.R

In villager: A Framework for Designing and Running Agent Based Models

#' @export
#' @title Resource Manager
#' @docType class
#' @description This object manages all of the resources in a village.
#' @section Methods:
#' \describe{
#'   \item{\code{initialize()}}{Creates a new manager}
#'   \item{\code{get_resources()}}{Gets all of the resources that the manager has}
#'   \item{\code{get_resource()}}{Retrieves a resource from the manager}
#'   \item{\code{add_resource()}}{Adds a resource to the manager}
#'   \item{\code{remove_resource()}}{Removes a resource from the manager}
#'   \item{\code{get_resource_index()}}{Retrieves the index of the resource}
#'   \item{\code{get_states()}}{Returns a list of states}
#'   \item{\code{load()}}{Loads a csv file of resources and adds them to the manager.}
#'   }
resource_manager <- R6::R6Class(
  "resource_manager",
  public = list(
    #' @field resources A list of resource objects
    #' @field resource_class The class used to represent resources
    resources = NA,
    resource_class = NULL,
    #' Creates a new , empty, resource manager for a village.
    #' @description Get a new instance of a resource_manager
    #' @param resource_class The class being used to describe the resources being managed
    initialize = function(resource_class =
                            villager::resource) {
      self$resources <- vector()
      self$resource_class <-
        resource_class
    },

    #' Gets all of the managed resources
    #'
    #' @return A list of resources
    get_resources = function() {
      return(self$resources)
    },

    #' Gets a resource given a resource name
    #'
    #' @param name The name of the requested resource
    #' @return A resource object
    get_resource = function(name) {
      for (res in self$resources) {
        if (res$name == name) {
          return(res)
        }
      }
    },

    #' Adds a resource to the manager.
    #'
    #' @param ... The resources to add
    #' @return None
    add_resource = function(...) {
      for (new_resource in list(...))
      self$resources <- append(self$resources, new_resource)
    },

    #' Removes a resource from the manager
    #'
    #' @param name The name of the resource being removed
    #' @return None
    remove_resource = function(name) {
      resource_index <- self$get_resource_index(name)
      self$resources <-
        self$resources[-resource_index]
    },

    #' Returns the index of a resource in the internal resource list
    #'
    #' @param name The name of the resource being located
    #' @return The index in the list, or R's default return value
    get_resource_index = function(name) {
      for (i in seq_len(length(self$resources))) {
        if (self$resources[[i]]$name == name) {
          return(i)
        }
      }
    },

    #' Returns a data.frame where each row is a resource.
    #'
    #' @details Subclasses should not have to override this method because it takes all member variables into account
    #' @return A single data.frame
    get_states = function() {
      # Allocate the appropriate sized table so that the row can be emplaced instead of appended
      resource_count <-
        length(self$resources)
      resource_fields <-
        names(self$resource_class$public_fields)
      state_table <-
        data.frame(matrix(nrow = resource_count, ncol = length(resource_fields)))
      if (resource_count > 0) {
        colnames(state_table) <- resource_fields
        for (i in 1:resource_count) {
          state_table[i,] <-  self$resources[[i]]$as_table()
        }
      }
      return(state_table)
    },

    #' Loads a csv file of resources into the manager
    #'
    #' @param file_name The path to the csv file
    #' @return None
    load = function(file_name) {
      resources <- read.csv(file_name)
      for (i in seq_len(nrow(resources))) {
        resource_row <- resources[i,]
        self$add_resource(resource$new(name = resource_row$name, quantity = resource_row$quantity))
      }
    }
  )
)