prisme-flow/nodes/bridge/bot/lib/message-template.js

prisme platform flow engine

/**
 * Created by prisme.io on 09/06/2017.
 */

var _ = require('underscore')

module.exports = function (msg, node) {
  // extract subtokens from a object value
  var extractObjectKeys = function (value, subtokens) {
    var result = value
    var currentValue = value

    if (_.isArray(subtokens) && !_.isEmpty(subtokens)) {
      _(subtokens).each(function (subtoken) {
        if (_.isObject(currentValue) && currentValue[subtoken] != null) {
          currentValue = currentValue[subtoken]
        }
      })
      result = currentValue
    }

    return result
  }

  var getTokenValue = function (token, msg) {
    var value = null
    var context = node.context()
    var subtokens = token.split('.')
    var variable = subtokens[0]
    var chatContext = msg.chat()

    if (token === 'payload') {
      value = String(msg.payload)
    } else if (chatContext != null && chatContext.get(variable) != null) {
      value = chatContext.get(variable)
    } else if (!_.isEmpty(context.flow.get(variable))) {
      value = context.flow.get(variable)
    } else if (!_.isEmpty(context.get(variable))) {
      value = context.get(variable)
    } else if (!_.isEmpty(context.global.get(variable))) {
      value = context.global.get(variable)
    } else if (!_.isEmpty(msg[variable])) {
      value = msg[variable]
    }

    // access sub tokens
    if (subtokens.length > 0) {
      value = extractObjectKeys(value, subtokens.slice(1))
    }

    return value != null ? value : ''
  }

  var replaceTokens = function (message, tokens, msg) {
    if (tokens != null && tokens.length !== 0) {
      // replace all tokens
      _(tokens).each(function (token) {
        var value = getTokenValue(token, msg)
        message = message.replace(new RegExp('{{' + token + '}}', 'g'), value)
      })
    }

    return message
  }

  return function (message) {
    if (_.isEmpty(message)) {
      return message
    }
    // extract tokens
    var tokens = message.match(/\{\{([A-Za-z0-9\-\.]*?)\}\}/g)
    if (tokens != null && tokens.length != 0) {
      tokens = _(tokens).map(function (token) {
        return token.replace('{{', '').replace('}}', '')
      })
    }
    // replace them
    return replaceTokens(message, tokens, msg)
  }
}