/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/**
 * LogShake is a module which listens for log requests sent by Gaia. In
 * response to a sufficiently large acceleration (a shake), it will save log
 * files to an arbitrary directory which it will then return on a
 * 'capture-logs-success' event with detail.logFilenames representing each log
 * file's filename in the directory. If an error occurs it will instead produce
 * a 'capture-logs-error' event.
 */

/* enable Mozilla javascript extensions and global strictness declaration,
 * disable valid this checking */
/* jshint moz: true */
/* jshint -W097 */
/* jshint -W040 */
/* global Services, Components, dump, LogCapture, LogParser,
   OS, Promise, volumeService, XPCOMUtils, SystemAppProxy */

'use strict';

const Cu = Components.utils;
const Ci = Components.interfaces;

Cu.import('resource://gre/modules/XPCOMUtils.jsm');

XPCOMUtils.defineLazyModuleGetter(this, 'LogCapture', 'resource://gre/modules/LogCapture.jsm');
XPCOMUtils.defineLazyModuleGetter(this, 'LogParser', 'resource://gre/modules/LogParser.jsm');
XPCOMUtils.defineLazyModuleGetter(this, 'OS', 'resource://gre/modules/osfile.jsm');
XPCOMUtils.defineLazyModuleGetter(this, 'Promise', 'resource://gre/modules/Promise.jsm');
XPCOMUtils.defineLazyModuleGetter(this, 'Services', 'resource://gre/modules/Services.jsm');
XPCOMUtils.defineLazyModuleGetter(this, 'SystemAppProxy', 'resource://gre/modules/SystemAppProxy.jsm');

XPCOMUtils.defineLazyServiceGetter(this, 'powerManagerService',
                                   '@mozilla.org/power/powermanagerservice;1',
                                   'nsIPowerManagerService');

XPCOMUtils.defineLazyServiceGetter(this, 'volumeService',
                                   '@mozilla.org/telephony/volume-service;1',
                                   'nsIVolumeService');

this.EXPORTED_SYMBOLS = ['LogShake'];

function debug(msg) {
  dump('LogShake.jsm: '+msg+'\n');
}

/**
 * An empirically determined amount of acceleration corresponding to a
 * shake
 */
const EXCITEMENT_THRESHOLD = 500;
const DEVICE_MOTION_EVENT = 'devicemotion';
const SCREEN_CHANGE_EVENT = 'screenchange';
const CAPTURE_LOGS_ERROR_EVENT = 'capture-logs-error';
const CAPTURE_LOGS_SUCCESS_EVENT = 'capture-logs-success';

// Map of files which have log-type information to their parsers
const LOGS_WITH_PARSERS = {
  '/dev/__properties__': LogParser.prettyPrintPropertiesArray,
  '/dev/log/main': LogParser.prettyPrintLogArray,
  '/dev/log/system': LogParser.prettyPrintLogArray,
  '/dev/log/radio': LogParser.prettyPrintLogArray,
  '/dev/log/events': LogParser.prettyPrintLogArray,
  '/proc/cmdline': LogParser.prettyPrintArray,
  '/proc/kmsg': LogParser.prettyPrintArray,
  '/proc/meminfo': LogParser.prettyPrintArray,
  '/proc/uptime': LogParser.prettyPrintArray,
  '/proc/version': LogParser.prettyPrintArray,
  '/proc/vmallocinfo': LogParser.prettyPrintArray,
  '/proc/vmstat': LogParser.prettyPrintArray
};

let LogShake = {
  QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver]),
  /**
   * If LogShake is listening for device motion events. Required due to lag
   * between HAL layer of device motion events and listening for device motion
   * events.
   */
  deviceMotionEnabled: false,

  /**
   * If a capture has been requested and is waiting for reads/parsing. Used for
   * debouncing.
   */
  captureRequested: false,

  /**
   * Start existing, observing motion events if the screen is turned on.
   */
  init: function() {
    // TODO: no way of querying screen state from power manager
    // this.handleScreenChangeEvent({ detail: {
    //   screenEnabled: powerManagerService.screenEnabled
    // }});

    // However, the screen is always on when we are being enabled because it is
    // either due to the phone starting up or a user enabling us directly.
    this.handleScreenChangeEvent({ detail: {
      screenEnabled: true
    }});

    SystemAppProxy.addEventListener(SCREEN_CHANGE_EVENT, this, false);

    Services.obs.addObserver(this, 'xpcom-shutdown', false);
  },

  /**
   * Handle an arbitrary event, passing it along to the proper function
   */
  handleEvent: function(event) {
    switch (event.type) {
    case DEVICE_MOTION_EVENT:
      if (!this.deviceMotionEnabled) {
        return;
      }
      this.handleDeviceMotionEvent(event);
      break;

    case SCREEN_CHANGE_EVENT:
      this.handleScreenChangeEvent(event);
      break;
    }
  },

  /**
   * Handle an observation from Services.obs
   */
  observe: function(subject, topic) {
    if (topic === 'xpcom-shutdown') {
      this.uninit();
    }
  },

  startDeviceMotionListener: function() {
    if (!this.deviceMotionEnabled) {
      SystemAppProxy.addEventListener(DEVICE_MOTION_EVENT, this, false);
      this.deviceMotionEnabled = true;
    }
  },

  stopDeviceMotionListener: function() {
    SystemAppProxy.removeEventListener(DEVICE_MOTION_EVENT, this, false);
    this.deviceMotionEnabled = false;
  },

  /**
   * Handle a motion event, keeping track of 'excitement', the magnitude
   * of the device's acceleration.
   */
  handleDeviceMotionEvent: function(event) {
    // There is a lag between disabling the event listener and event arrival
    // ceasing.
    if (!this.deviceMotionEnabled) {
      return;
    }

    var acc = event.accelerationIncludingGravity;

    var excitement = acc.x * acc.x + acc.y * acc.y + acc.z * acc.z;

    if (excitement > EXCITEMENT_THRESHOLD) {
      if (!this.captureRequested) {
        this.captureRequested = true;
        captureLogs().then(logResults => {
          // On resolution send the success event to the requester
          SystemAppProxy._sendCustomEvent(CAPTURE_LOGS_SUCCESS_EVENT, {
            logFilenames: logResults.logFilenames,
            logPrefix: logResults.logPrefix
          });
          this.captureRequested = false;
        },
        error => {
          // On an error send the error event
          SystemAppProxy._sendCustomEvent(CAPTURE_LOGS_ERROR_EVENT, {error: error});
          this.captureRequested = false;
        });
      }
    }
  },

  handleScreenChangeEvent: function(event) {
    if (event.detail.screenEnabled) {
      this.startDeviceMotionListener();
    } else {
      this.stopDeviceMotionListener();
    }
  },

  /**
   * Stop logshake, removing all listeners
   */
  uninit: function() {
    this.stopDeviceMotionListener();
    SystemAppProxy.removeEventListener(SCREEN_CHANGE_EVENT, this, false);
    Services.obs.removeObserver(this, 'xpcom-shutdown');
  }
};

function getLogFilename(logLocation) {
  // sanitize the log location
  let logName = logLocation.replace(/\//g, '-');
  if (logName[0] === '-') {
    logName = logName.substring(1);
  }
  return logName + '.log';
}

function getSdcardPrefix() {
  return volumeService.getVolumeByName('sdcard').mountPoint;
}

function getLogDirectory() {
  let d = new Date();
  d = new Date(d.getTime() - d.getTimezoneOffset() * 60000);
  let timestamp = d.toISOString().slice(0, -5).replace(/[:T]/g, '-');
  // return directory name of format 'logs/timestamp/'
  return OS.Path.join('logs', timestamp, '');
}

/**
 * Captures and saves the current device logs, returning a promise that will
 * resolve to an array of log filenames.
 */
function captureLogs() {
  let logArrays = readLogs();
  return saveLogs(logArrays);
}

/**
 * Read in all log files, returning their formatted contents
 */
function readLogs() {
  let logArrays = {};
  for (let loc in LOGS_WITH_PARSERS) {
    let logArray = LogCapture.readLogFile(loc);
    if (!logArray) {
      continue;
    }
    let prettyLogArray = LOGS_WITH_PARSERS[loc](logArray);

    logArrays[loc] = prettyLogArray;
  }
  return logArrays;
}

/**
 * Save the formatted arrays of log files to an sdcard if available
 */
function saveLogs(logArrays) {
  if (!logArrays || Object.keys(logArrays).length === 0) {
    return Promise.resolve({
      logFilenames: [],
      logPrefix: ''
    });
  }

  let sdcardPrefix, dirName;
  try {
    sdcardPrefix = getSdcardPrefix();
    dirName = getLogDirectory();
  } catch(e) {
    // Return promise failed with exception e
    // Handles missing sdcard
    return Promise.reject(e);
  }

  debug('making a directory all the way from '+sdcardPrefix+' to '+(sdcardPrefix + '/' + dirName));
  return OS.File.makeDir(OS.Path.join(sdcardPrefix, dirName), {from: sdcardPrefix})
    .then(function() {
    // Now the directory is guaranteed to exist, save the logs
    let logFilenames = [];
    let saveRequests = [];

    for (let logLocation in logArrays) {
      debug('requesting save of ' + logLocation);
      let logArray = logArrays[logLocation];
      // The filename represents the relative path within the SD card, not the
      // absolute path because Gaia will refer to it using the DeviceStorage
      // API
      let filename = dirName + getLogFilename(logLocation);
      logFilenames.push(filename);
      let saveRequest = OS.File.writeAtomic(OS.Path.join(sdcardPrefix, filename), logArray);
      saveRequests.push(saveRequest);
    }

    return Promise.all(saveRequests).then(function() {
      debug('returning logfilenames: '+logFilenames.toSource());
      return {
        logFilenames: logFilenames,
        logPrefix: dirName
      };
    });
  });
}

LogShake.init();
this.LogShake = LogShake;