<?php
$data = array();
$message = '';

//
// INITIALIZE AND CHECK SANITY
//

// task must be set
if (!isset($_REQUEST['task'])) {
  $message = 'This request requires a task to be set';
} else if ($_REQUEST['task'] == 'query') {
  if (!canView('System')) {
    $message = 'Insufficient permissions to view log entries for user '.validHtmlStr($user->Username());
  } else {
    $data = queryRequest();
  }
} else if ($_REQUEST['task'] == 'create' ) {
  global $user;
  if (!$user or (!canEdit('System') and !ZM_LOG_INJECT)) {
    $message = 'Insufficient permissions to create log entries for user '.validHtmlStr($user->Username());
  } else {
    createRequest();
  }
} else if ($_REQUEST['task'] == 'delete') {
  global $user;
  if (!canEdit('System')) {
    $message = 'Insufficient permissions to delete log entries for user '.validHtmlStr($user->Username());
  } else {
    if (!empty($_REQUEST['ids'])) {
      $ids = array_map('intval', (array)$_REQUEST['ids']);
      $placeholders = implode(',', array_fill(0, count($ids), '?'));
      dbQuery('DELETE FROM Logs WHERE Id IN (' . $placeholders . ')', $ids);
    }
  }
} else {
  // Only the query and create tasks are supported at the moment
  $message = 'Unrecognised task '.validHtmlStr($_REQUEST['task']);
}

if ($message) {
  ajaxError($message);
  return;
}
ajaxResponse($data);

//
// FUNCTION DEFINITIONS
//

function createRequest() {
  // Every field here is attacker-controlled. Coerce each to a scalar and strip
  // control characters (newlines, carriage returns, tabs, etc.) so nothing can
  // forge additional lines in the text log file, and so non-scalar input (e.g.
  // message[]=x) cannot trip a TypeError in logPrint(). A log message is a
  // single line; the Log view stores it as one Message column regardless.
  $sanitize = function($value) {
    return is_scalar($value) ? preg_replace('/[\x00-\x1F\x7F]+/', ' ', (string)$value) : '';
  };

  $level = $sanitize($_POST['level'] ?? '');
  $message = $sanitize($_POST['message'] ?? '');
  // Strip the URL scheme/host from file, then the control characters.
  $file = (isset($_POST['file']) && is_scalar($_POST['file']))
    ? $sanitize(preg_replace('/\w+:\/\/[\w.:]+\//', '', (string)$_POST['file']))
    : '';

  if ($level === '' || $message === '') {
    ZM\Error('Invalid log create: level and message are required');
    return;
  }

  ZM\logInit(array('id'=>'web_js'));
  // Firefox reports the location as "line:column" (e.g. 1500:28).  validInt()
  // only strips non-digit characters, so it splices the two together into
  // 150028, which overflows the smallint Logs.Line column and makes this
  // endpoint die with a 500 -- the log request fails on the very error it was
  // sent to report.  Take the leading line number and clamp it to the column.
  $line = NULL;
  if (!empty($_POST['line']) and is_scalar($_POST['line'])
      and preg_match('/\d+/', (string)$_POST['line'], $line_matches)) {
    $line = min((int)$line_matches[0], 65535);
  }

  $levels = array_flip(ZM\Logger::$codes);
  if (!isset($levels[$level])) {
    ZM\Error('Unexpected logger level '.$level); // already sanitized above
    $level = 'ERR';
  }
  ZM\Logger::fetch()->logPrint($levels[$level], $message, $file, $line);
}

function queryRequest() {
  // Offset specifies the starting row to return, used for pagination
  $offset = 0;
  if (isset($_REQUEST['offset'])) {
    if ((!is_int($_REQUEST['offset']) and !ctype_digit($_REQUEST['offset']))) {
      ZM\Error('Invalid value for offset: ' . $_REQUEST['offset']);
    } else {
      $offset = $_REQUEST['offset'];
    }
  }

  // Limit specifies the number of rows to return
  $limit = 100;
  if (isset($_REQUEST['limit'])) {
    if ((!is_int($_REQUEST['limit']) and !ctype_digit($_REQUEST['limit']))) {
      ZM\Error('Invalid value for limit: ' . $_REQUEST['limit']);
    } else {
      $limit = $_REQUEST['limit'];
    }
  }
  // The table we want our data from
  $table = 'Logs';

  $nameMainQuery = 't1'; # To optimize queries using a subquery
  $nameSubQuery = 't2';

  // The names of the dB columns in the log table we are interested in
  $columns = array('Id', 'TimeKey', 'Component', 'ServerId', 'Pid', 'Code', 'Message', 'File', 'Line');
  $columnsContext = $columns;
  // The names of columns shown in the log view that are NOT dB columns in the database
  $col_alt = array('DateTime', 'Server');

  $sort = 'TimeKey';
  if (isset($_REQUEST['sort'])) {
    $sort = $_REQUEST['sort'];
    if ($sort == 'DateTime') $sort = 'TimeKey';
    if ($sort == 'Server') $sort = 'ServerId';
  }
  if (!in_array($sort, array_merge($columns, $col_alt))) {
    ZM\Error('Invalid sort field: ' . $sort);
    return;
  }

  // Order specifies the sort direction, either asc or desc
  $order = (isset($_REQUEST['order']) and (strtolower($_REQUEST['order']) == 'asc')) ? 'ASC' : 'DESC';

  if ($nameMainQuery !== '' && $nameSubQuery !== '') {
    array_walk($columnsContext, function(&$value, $key, $nameMainQuery) {
      $value = $nameMainQuery . '.' . $value;
    }, $nameMainQuery);
  }

  $col_str = implode(', ', $columns);
  $col_str_context = implode(', ', $columnsContext);
  $data = array();
  $query = array();
  $query['values'] = array();
  $likes = array();
  $where = '';
   // There are two search bars in the log view, normal and advanced
  // Making an exuctive decision to ignore the normal search, when advanced search is in use
  // Alternatively we could try to do both
  //
  // Advanced search contains an array of "column name" => "search text" pairs
  // Bootstrap table sends json_ecoded array, which we must decode
  $advsearch = isset($_REQUEST['filter']) ? json_decode($_REQUEST['filter'], JSON_OBJECT_AS_ARRAY) : array();
  // Search contains a user entered string to search on
  $search = isset($_REQUEST['search']) ? $_REQUEST['search'] : '';
  if (count($advsearch)) {
    foreach ($advsearch as $col=>$text) {
      if (!in_array($col, array_merge($columns, $col_alt))) {
        ZM\Error("'$col' is not a searchable column name");
        continue;
      }
      // Don't use wildcards on advanced search
      //$text = '%' .$text. '%';
      array_push($likes, $col.' LIKE ?');
      array_push($query['values'], $text);
    }
    $where = '(' .implode(' OR ', $likes). ')';

  } else if ($search != '') {
    $search = '%' .$search. '%';
    foreach ( $columns as $col ) {
      array_push($likes, $col.' LIKE ?');
      array_push($query['values'], $search);
    }
    $where = '(' .implode(' OR ', $likes). ')';
  }

  // Component is a multi-select: accept a scalar (legacy) or an array of
  // component names and match any of them.
  $requestComponents = array();
  if (isset($_REQUEST['Component'])) {
    foreach ((array)$_REQUEST['Component'] as $component) {
      if (is_scalar($component) && (string)$component !== '') $requestComponents[] = (string)$component;
    }
  }
  if (count($requestComponents)) {
    if ($where) $where .= ' AND ';
    $placeholders = implode(', ', array_fill(0, count($requestComponents), '?'));
    $where .= 'Component IN (' . $placeholders . ')';
    foreach ($requestComponents as $component) $query['values'][] = $component;
  }

  if (!empty($_REQUEST['ServerId'])) {
    if ($where) $where .= ' AND ';
    $where .= 'ServerId = ?';
    $query['values'][] = $_REQUEST['ServerId'];
  }
/* We have an indexed 'Level', not 'Code'.
  if (!empty($_REQUEST['level'])) {
    if ($where) $where .= ' AND ';
    $where .= 'Code = ?';
    $query['values'][] = $_REQUEST['level'];
  }
*/
  // Level is a multi-select: accept a scalar (legacy) or an array of level codes
  // ('DBG', 'INF', ...). Keep only recognized codes and match any of them.
  $level_codes = array_flip(ZM\Logger::$codes);
  $requestLevels = array();
  if (isset($_REQUEST['level'])) {
    foreach ((array)$_REQUEST['level'] as $level) {
      if (is_scalar($level) && isset($level_codes[(string)$level])) {
        $requestLevels[(string)$level] = $level_codes[(string)$level];
      }
    }
  }
  if (count($requestLevels)) {
    if ($where) $where .= ' AND ';
    $placeholders = implode(', ', array_fill(0, count($requestLevels), '?'));
    $where .= ' Level IN (' . $placeholders . ')';
    foreach ($requestLevels as $code) $query['values'][] = $code;
  }

  if (!empty($_REQUEST['StartDateTime'])) {
    $start_time = strtotime($_REQUEST['StartDateTime']);
    if ($start_time) {
      if ($where) $where .= ' AND ';
      $where .= 'TimeKey >= ?';
      $query['values'][] = $start_time;
    } else {
      ZM\Warning("Unable to parse StartDateTime ".$_REQUEST['StartDateTime']. " into a timestamp");
    }
  }
  if (!empty($_REQUEST['EndDateTime'])) {
    $end_time = strtotime($_REQUEST['EndDateTime']);
    if ($end_time) {
      if ($where) $where .= ' AND ';
      $where .= 'TimeKey <= ?';
      $query['values'][] = $end_time;
    } else {
      ZM\Warning("Unable to parse EndDateTime ".$_REQUEST['EndDateTime']. " into a timestamp");
    }
  }

  # An embedded panel queries a component of its own choosing, so remembering
  # what it asked for would overwrite the Log view's selection.
  if (empty($_REQUEST['embedded'])) {
    zm_session_start();
    $_SESSION['zmLogComponent'] = $requestComponents;
    $_SESSION['zmLogFilterLevel'] = array_keys($requestLevels);
    session_write_close();
  }

  if ($where) $where = ' WHERE '.$where;

  $data['totalNotFiltered'] = dbFetchOne('SELECT count(*) AS Total FROM `' .$table.'`', 'Total');
  if ($where) {
    $data['total'] = dbFetchOne('SELECT count(*) AS Total FROM `' .$table.'` '.$where, 'Total', $query['values']);
  } else {
    $data['total'] = $data['totalNotFiltered'];
  }

  if ($nameMainQuery !== '' && $nameSubQuery !== '') { # Optimized query
    $query['sql'] = '
      SELECT ' .$col_str_context. ' 
      FROM `' .$table. '` ' .$nameMainQuery. ' 
      JOIN (
        SELECT Id 
        FROM `'.$table.'` '.$where. ' 
        ORDER BY ' .$sort. ' ' .$order. ' 
        LIMIT ?, ?
      ) AS ' .$nameSubQuery. ' 
      ON ' .$nameMainQuery. '.Id=' .$nameSubQuery. '.Id 
      ORDER BY ' .$nameMainQuery. '.' .$sort. ' ' .$order;
  } else {
    $query['sql'] = 'SELECT ' .$col_str. ' FROM `' .$table. '` ' .$where. ' ORDER BY ' .$sort. ' ' .$order. ' LIMIT ?, ?';
  }

  array_push($query['values'], $offset, $limit);

  $rows = array();
  $results = dbFetchAll($query['sql'], NULL, $query['values']);

  global $dateTimeFormatter;
  foreach ($results as $row) {
    $row['DateTime'] = empty($row['TimeKey']) ? '' : $dateTimeFormatter->format(intval($row['TimeKey']));
    $Server = $row['ServerId'] ? ZM\Server::find_one(array('Id'=>$row['ServerId'])) : null;

    $row['Server'] = $Server ? $Server->Name() : '';
    // Strip out all characters that are not ASCII 32-126 (yes, 126)
    $row['Message'] = preg_replace('/[^\x20-\x7E]/', '', htmlspecialchars($row['Message']));
    $row['File'] = preg_replace('/[^\x20-\x7E]/', '', strip_tags($row['File']));
    $rows[] = $row;
  }
  $data['rows'] = $rows;
  $data['logstate'] = logState();
  $data['updated'] = $dateTimeFormatter->format(time());

  return $data;
}