/**
  Copyright 2012, Mozilla Foundation

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
 */

'use strict';

/**
 * To log state transferring in a proper way, rather dump raw console
 * messages and then overwhelm it.
 */

(function(exports) {
  var LockScreenStateLogger = function() {};

  LockScreenStateLogger.prototype.start =
  function lss_start(configs) {
    this.stateStack = [];
    this.configs = {
      verbose: false || configs.verbose,
      warning: false || configs.warning,
      error: true && configs.error,
      graph: false || configs.graph,
      debug: true && configs.debug,
      reporter: configs.reporter || this.consoleReporter.bind(this)
    };
    return this;
  };

  LockScreenStateLogger.prototype.debug =
  function lss_debug() {
    if (this.configs.debug) {
      this.log.apply(this, ['[I] '].concat(Array.from(arguments)));
    }
    return this;
  };

  LockScreenStateLogger.prototype.verbose =
  function lss_verbose() {
    if (this.configs.verbose) {
      this.log.apply(this, ['[V] '].concat(Array.from(arguments)));
    }
    return this;
  };

  LockScreenStateLogger.prototype.warning = function lss_warning() {
    if (this.configs.warning || this.configs.verbose) {
      this.log.apply(this, ['[!] '].concat(Array.from(arguments)));
    }
    return this;
  };

  LockScreenStateLogger.prototype.error =
  function lss_error() {
    if (this.configs.error || this.configs.warning ||
        this.configs.verbose) {
      this.log.apply(this, ['[E] '].concat(Array.from(arguments)));
    }
    return this;
  };

  /**
   * Print the stack. For example:
   *
   *  logger.debug('the thing at stack: ').stack()
   *
   * would print out the message and the stack.
   */
  LockScreenStateLogger.prototype.stack = function lss_stack() {
    this.log((new Error()).stack);
    return this;
  };

  /**
   * Log the transferring manipulation.
   *
   * To log the conditions, this function would stringify the conditions
   * and then parse it to do the deep copy. So please turn off the
   * `config.debug` in production mode.
   *
   * @param from {string} - from state type
   * @param to {string} - to state type
   * @param conditions {object} - under what conditions we do the transferring
   */
  LockScreenStateLogger.prototype.transfer =
  function lss_transfer(from, to, conditions = {}) {
    if (!this.configs.debug) {
      return;
    }
    var transferDetails = {
      from: from,
      to: to,
      conditions: JSON.parse(JSON.stringify(conditions))
    };
    if (this.configs.graph) {
      this.stateStack.push(transferDetails);
    }
    this.debug(`State transfer: from ${from} to ${to} because of:`,
      transferDetails.conditions);
    return this;
  };

  /**
   * To get the graph. The array it return would be:
   *
   *     [ 'foo', {conditions}, 'bar', {conditions}, 'gamma'...]
   *
   * which can be rendered as a real graph.
   */
  LockScreenStateLogger.prototype.graph =
  function lss_graph() {
    return this.stateStack.reduce((prev, info) => {
      return prev.concat([info.from, info.conditions, info.to]);
    }, []);
  };

  LockScreenStateLogger.prototype.log =
  function lss_log() {
    var reporter = this.configs.reporter;
    reporter.apply(this, arguments);
    return this;
  };

  LockScreenStateLogger.prototype.stop =
  function lss_stop() {
    this.stateStack.length = 0;
    return this;
  };

  LockScreenStateLogger.prototype.consoleReporter =
  function lss_consoleReporter() {
    console.log.apply(console, arguments);
    return this;
  };
  exports.LockScreenStateLogger = LockScreenStateLogger;
})(window);