<?php

// Make sure we are called from index.php
if (!defined('SECURITY'))
  die('Hacking attempt');


/*
 * We give access to plenty of statistics through this class
 * Statistics should be non-intrusive and not change any
 * rows in our database to ensure data integrity for the backend
 **/
class Statistics {
  private $sError = '';
  private $table = 'statistics_shares';

  public function __construct($debug, $mysqli, $config, $share, $user, $block, $memcache) {
    $this->debug = $debug;
    $this->mysqli = $mysqli;
    $this->share = $share;
    $this->config = $config;
    $this->user = $user;
    $this->block = $block;
    $this->memcache = $memcache;
    $this->debug->append("Instantiated Share class", 2);
  }

  /* Some basic get and set methods
   **/
  private function setErrorMessage($msg) {
    $this->sError = $msg;
  }
  public function getError() {
    return $this->sError;
  }

  private function checkStmt($bState) {
    if ($bState ===! true) {
      $this->debug->append("Failed to prepare statement: " . $this->mysqli->error);
      $this->setErrorMessage('Failed to prepare statement');
      return false;
    }
    return true;
  }

  /**
   * Another wrapper, we want to store data in memcache and return the actual data
   * for further processing
   * @param key string Our memcache key
   * @param data mixed Our data to store in Memcache
   * @param expiration time Our expiration time, see Memcached documentation
   * @return data mixed Return our stored data unchanged
   **/
  public function setCache($key, $data, $expiration=NULL) {
    if ($this->config['memcache']['enabled']) $this->memcache->set($key, $data, $expiration);
    return $data;
  }

  /**
   * Get our last $limit blocks found
   * @param limit int Last limit blocks
   * @return array
   **/
  public function getBlocksFound($limit=10) {
    $this->debug->append("STA " . __METHOD__, 4);
    if ($data = $this->memcache->get(__FUNCTION__ . $limit)) return $data;
    $stmt = $this->mysqli->prepare("
      SELECT b.*, a.username as finder
      FROM " . $this->block->getTableName() . " AS b
      LEFT JOIN accounts AS a
      ON b.account_id = a.id
      ORDER BY height DESC LIMIT ?");
    if ($this->checkStmt($stmt) && $stmt->bind_param("i", $limit) && $stmt->execute() && $result = $stmt->get_result())
      return $this->setCache(__FUNCTION__ . $limit, $result->fetch_all(MYSQLI_ASSOC), 5);
    // Catchall
    $this->debug->append("Failed to find blocks:" . $this->mysqli->error);
    return false;
  }

  /**
   * Currently the only function writing to the database
   * Stored per block user statistics of valid and invalid shares
   * @param aStats array Array with user id, valid and invalid shares
   * @param iBlockId int Block ID as store in the Block table
   * @return bool
   **/
  public function updateShareStatistics($aStats, $iBlockId) {
    $this->debug->append("STA " . __METHOD__, 4);
    $stmt = $this->mysqli->prepare("INSERT INTO $this->table (account_id, valid, invalid, block_id) VALUES (?, ?, ?, ?)");
    if ($this->checkStmt($stmt) && $stmt->bind_param('iiii', $aStats['id'], $aStats['valid'], $aStats['invalid'], $iBlockId) && $stmt->execute()) return true;
    // Catchall
    $this->debug->append("Failed to update share stats: " . $this->mysqli->error);
    return false;
  }

  /**
   * Get our current pool hashrate for the past 10 minutes across both
   * shares and shares_archive table
   * @param none
   * @return data object Return our hashrateas an object
   **/
  public function getCurrentHashrate() {
    $this->debug->append("STA " . __METHOD__, 4);
    if ($data = $this->memcache->get(__FUNCTION__)) return $data;
    $stmt = $this->mysqli->prepare("
      SELECT SUM(hashrate) AS hashrate FROM
      (
        SELECT ROUND(COUNT(id) * POW(2, " . $this->config['difficulty'] . ")/600/1000) AS hashrate FROM " . $this->share->getTableName() . " WHERE time > DATE_SUB(now(), INTERVAL 10 MINUTE)
        UNION
        SELECT ROUND(COUNT(id) * POW(2, " . $this->config['difficulty'] . ")/600/1000) AS hashrate FROM " . $this->share->getArchiveTableName() . " WHERE time > DATE_SUB(now(), INTERVAL 10 MINUTE)
      ) AS sum");
    // Catchall
    if ($this->checkStmt($stmt) && $stmt->execute() && $result = $stmt->get_result() ) return $this->setCache(__FUNCTION__, $result->fetch_object()->hashrate);
    $this->debug->append("Failed to get hashrate: " . $this->mysqli->error);
    return false;
  }

  /**
   * Same as getCurrentHashrate but for Shares
   * @param none
   * @return data object Our share rate in shares per second
   **/
  public function getCurrentShareRate() {
    $this->debug->append("STA " . __METHOD__, 4);
    if ($data = $this->memcache->get(__FUNCTION__)) return $data;
    $stmt = $this->mysqli->prepare("
      SELECT ROUND(SUM(sharerate) / 600, 2) AS sharerate FROM
      (
        SELECT COUNT(id) AS sharerate FROM " . $this->share->getTableName() . " WHERE time > DATE_SUB(now(), INTERVAL 10 MINUTE)
        UNION ALL
        SELECT COUNT(id) AS sharerate FROM " . $this->share->getArchiveTableName() . " WHERE time > DATE_SUB(now(), INTERVAL 10 MINUTE)
      ) AS sum");
    if ($this->checkStmt($stmt) && $stmt->execute() && $result = $stmt->get_result() ) return $this->setCache(__FUNCTION__, $result->fetch_object()->sharerate);
    // Catchall
    $this->debug->append("Failed to fetch share rate: " . $this->mysqli->error);
    return false;
  }

  /**
   * Get total shares for this round, since last block found
   * @param none
   * @return data array invalid and valid shares
   **/
  public function getRoundShares() {
    $this->debug->append("STA " . __METHOD__, 4);
    if ($data = $this->memcache->get(__FUNCTION__)) return $data;
    $stmt = $this->mysqli->prepare("
      SELECT
      ( SELECT IFNULL(count(id), 0)
      FROM " . $this->share->getTableName() . "
      WHERE UNIX_TIMESTAMP(time) >IFNULL((SELECT MAX(time) FROM blocks),0)
        AND our_result = 'Y' ) as valid,
      ( SELECT IFNULL(count(id), 0)
      FROM " . $this->share->getTableName() . "
      WHERE UNIX_TIMESTAMP(time) >IFNULL((SELECT MAX(time) FROM blocks),0)
        AND our_result = 'N' ) as invalid");
    if ( $this->checkStmt($stmt) && $stmt->execute() && $result = $stmt->get_result() )
      return $this->setCache(__FUNCTION__, $result->fetch_assoc());
    // Catchall
    $this->debug->append("Failed to fetch round shares: " . $this->mysqli->error);
    return false;
  }

  /**
   * Get amount of shares for a specific user
   * @param account_id int User ID
   * @return data array invalid and valid share counts
   **/
  public function getUserShares($account_id) {
    $this->debug->append("STA " . __METHOD__, 4);
    if ($data = $this->memcache->get(__FUNCTION__ . $account_id)) return $data;
    $stmt = $this->mysqli->prepare("
      SELECT
      (
        SELECT COUNT(s.id)
        FROM " . $this->share->getTableName() . " AS s,
             " . $this->user->getTableName() . " AS u
        WHERE u.username = SUBSTRING_INDEX( s.username, '.', 1 )
          AND UNIX_TIMESTAMP(s.time) >IFNULL((SELECT MAX(b.time) FROM " . $this->block->getTableName() . " AS b),0)
          AND our_result = 'Y'
          AND u.id = ?
      ) AS valid,
      (
        SELECT COUNT(s.id)
        FROM " . $this->share->getTableName() . " AS s,
             " . $this->user->getTableName() . " AS u
        WHERE u.username = SUBSTRING_INDEX( s.username, '.', 1 )
          AND UNIX_TIMESTAMP(s.time) >IFNULL((SELECT MAX(b.time) FROM " . $this->block->getTableName() . " AS b),0)
          AND our_result = 'N'
          AND u.id = ?
      ) AS invalid"); 
    if ($stmt && $stmt->bind_param("ii", $account_id, $account_id) && $stmt->execute() && $result = $stmt->get_result())
      return $this->setCache(__FUNCTION__ . $account_id, $result->fetch_assoc());
    // Catchall
    $this->debug->append("Unable to fetch user round shares: " . $this->mysqli->error);
    return false;
  }

  /**
   * Same as getUserShares for Hashrate
   * @param account_id integer User ID
   * @return data integer Current Hashrate in khash/s
   **/
  public function getUserHashrate($account_id) {
    if ($data = $this->memcache->get(__FUNCTION__ . $account_id)) return $data;
    $stmt = $this->mysqli->prepare("
      SELECT ROUND(COUNT(s.id) * POW(2, " . $this->config['difficulty'] . ")/600/1000) AS hashrate
      FROM " . $this->share->getTableName() . " AS s,
           " . $this->user->getTableName() . " AS u
      WHERE u.username = SUBSTRING_INDEX( s.username, '.', 1 )
        AND s.time > DATE_SUB(now(), INTERVAL 10 MINUTE)
        AND u.id = ?");
    if ($this->checkStmt($stmt) && $stmt->bind_param("i", $account_id) && $stmt->execute() && $result = $stmt->get_result() )
      return $this->setCache(__FUNCTION__ . $account_id, $result->fetch_object()->hashrate);
    // Catchall
    $this->debug->append("Failed to fetch hashrate: " . $this->mysqli->error);
    return false;
  }

  /**
   * Get hashrate for a specific worker
   * @param worker_id int Worker ID to fetch hashrate for
   * @return data int Current hashrate in khash/s
   **/
  public function getWorkerHashrate($worker_id) {
    $this->debug->append("STA " . __METHOD__, 4);
    if ($data = $this->memcache->get(__FUNCTION__ . $worker_id)) return $data;
    $stmt = $this->mysqli->prepare("
      SELECT ROUND(COUNT(s.id) * POW(2,21)/600/1000) AS hashrate
      FROM " . $this->share->getTableName() . " AS s,
           " . $this->user->getTableName() . " AS u
      WHERE u.username = SUBSTRING_INDEX( s.username, '.', 1 )
        AND s.time > DATE_SUB(now(), INTERVAL 10 MINUTE)
        AND u.id = ?");
    if ($this->checkStmt($stmt) && $stmt->bind_param("i", $account_id) && $stmt->execute() && $result = $stmt->get_result() )
      return $this->setCache(__FUNCTION__ . $worker_id, $result->fetch_object()->hashrate);
    // Catchall
    $this->debug->append("Failed to fetch hashrate: " . $this->mysqli->error);
    return false;
  }

  /**
   * get our top contributors for either shares or hashrate
   * @param type string shares or hashes
   * @param limit int Limit result to $limit
   * @return data array Users with shares, account or hashrate, account
   **/
  public function getTopContributors($type='shares', $limit=15) {
    $this->debug->append("STA " . __METHOD__, 4);
    if ($data = $this->memcache->get(__FUNCTION__ . $type . $limit)) return $data;
    switch ($type) {
    case 'shares':
      $stmt = $this->mysqli->prepare("
        SELECT
            COUNT(id) AS shares,
            SUBSTRING_INDEX( username, '.', 1 ) AS account
        FROM " . $this->share->getTableName() . "
        GROUP BY account
        ORDER BY shares DESC
        LIMIT ?");
      if ($this->checkStmt($stmt) && $stmt->bind_param("i", $limit) && $stmt->execute() && $result = $stmt->get_result())
        return $this->setCache(__FUNCTION__ . $type . $limit, $result->fetch_all(MYSQLI_ASSOC));
      $this->debug->append("Fetching shares failed: ");
      return false;
      break;

    case 'hashes':
      $stmt = $this->mysqli->prepare("
        SELECT
          ROUND(COUNT(id) * POW(2," . $this->config['difficulty'] . ")/600/1000,2) AS hashrate,
          SUBSTRING_INDEX( username, '.', 1 ) AS account
        FROM " . $this->share->getTableName() . "
        WHERE time > DATE_SUB(now(), INTERVAL 10 MINUTE)
        GROUP BY account
        ORDER BY hashrate DESC LIMIT ?");
      if ($this->checkStmt($stmt) && $stmt->bind_param("i", $limit) && $stmt->execute() && $result = $stmt->get_result())
        return $this->setCache(__FUNCTION__ . $type . $limit, $result->fetch_all(MYSQLI_ASSOC));
      $this->debug->append("Fetching shares failed: ");
      return false;
      break;
    }
  }

  /**
   * get Hourly hashrate for a user
   * Not working yet since I was not able to solve this via SQL queries
   * @param account_id int User ID
   * @return data array NOT FINISHED YET
   **/
  public function getHourlyHashrateByAccount($account_id) {
    $this->debug->append("STA " . __METHOD__, 4);
    if ($data = $this->memcache->get(__FUNCTION__ . $account_id)) return $data;
    $stmt = $this->mysqli->prepare("
      SELECT
      ROUND(COUNT(s.id) * POW(2, 12)/600/1000) AS hashrate,
        HOUR(s.time) AS hour
        FROM " . $this->share->getTableName() . " AS s, accounts AS a
        WHERE time < NOW() - INTERVAL 1 HOUR AND time > NOW() - INTERVAL 25 HOUR
        AND a.username = SUBSTRING_INDEX( s.username, '.', 1 )
        AND a.id = ?
        GROUP BY HOUR(time)
        UNION ALL
        SELECT
        ROUND(COUNT(s.id) * POW(2, 12)/600/1000) AS hashrate,
          HOUR(s.time) AS hour
          FROM " . $this->share->getArchiveTableName() . " AS s, accounts AS a
          WHERE time < NOW() - INTERVAL 1 HOUR AND time > NOW() - INTERVAL 25 HOUR
          AND a.username = SUBSTRING_INDEX( s.username, '.', 1 )
          AND a.id = ?
          GROUP BY HOUR(time)");
    if ($this->checkStmt($stmt) && $stmt->bind_param("ii", $account_id, $account_id) && $stmt->execute() && $result = $stmt->get_result())
      return $this->setCache(__FUNCTION__ . $account_id, $result->fetch_all(MYSQLI_ASSOC), 3600);
    // Catchall
    $this->debug->append("Failed to fetch hourly hashrate: " . $this->mysqli->error);
    return false;
  }
}

$statistics = new Statistics($debug, $mysqli, $config, $share, $user, $block, $memcache);