service.js

/** service.js
 *  Encapsulates a teletext service object
 *  Environment: node.js server side script
 *  @brief A service is a service name and a set of pages.
 */
'use strict'
// import logger
const LOG = require('./log.js')

/** Constructor
 * @param serviceName - a Service name such as BBCONE_2007_06_19
 */
global.Service = function (serviceName) {
  // member variables
  this.name = serviceName
  this.pages = []

  // What do we want to do with a service?
  // 1) Keep pages in numerical order
  // 2) Load pages and save pages
  // 3) Expire pages and remove them
  /** Give a teletext page, inserts it into the local page list
   * @todo What do we do about a duplicate page?
   * We don't intend to cache pages forever so there won't ever be many pages to search through
   */
  this.addPage = function (page) {
    if (this.findPage(page.pageNumber) === false) {
      this.pages.push(page)
    }
  }

  /** Seek the three digit page number that we are looking for
   * This is a part of a cacheing scheme so a missing page is not an errot
   *  @return false if the page does not exist
   */
  this.findPage = function (mpp) {
    LOG.fn(
      ['service', 'findPage'],
      `Looking for page=${mpp}`,
      LOG.LOG_LEVEL_VERBOSE
    )

    // Page out of range?
    if (mpp < 0x100 || mpp > 0x7ff) {
      return false
    }

    // For each page in the service...
    for (let p = 0; p < this.pages.length; p++) {
      if (this.pages[p].pageNumber === mpp) {
        return this.pages[p]
      }
    }

    return false
  }

  /** Switcher.
   *  If the message is for this service, send it to the pages
   */
  this.keyMessage = function (key) {
    LOG.fn(
      ['service', 'keyMessage'],
      `Got a keymessage, name=${this.name}, data=${key.s}`,
      LOG.LOG_LEVEL_INFO
    )

    LOG.fn(
      ['service', 'keyMessage'],
      `key data=${JSON.stringify(key, null, 4)}`,
      LOG.LOG_LEVEL_VERBOSE
    )
  }

  /** Match the given name with the service name
   * @return true if the service name matches
   */
  this.matchName = function (name) {
    return this.name === name
  }
}