Gazelle/classes/torrentsearch.class.php

<?php
#declare(strict_types=1);

class TorrentSearch
{
    const TAGS_ANY = 0;
    const TAGS_ALL = 1;
    const SPH_BOOL_AND = ' ';
    const SPH_BOOL_OR = ' | ';

    // Map of sort mode => attribute name for ungrouped torrent page
    public static $SortOrders = [
        'year' => 'year',
        'time' => 'id',
        'size' => 'size',
        'seeders' => 'seeders',
        'leechers' => 'leechers',
        'snatched' => 'snatched',
        'cataloguenumber' => 'cataloguenumber',
        'random' => 1
    ];

    // Map of sort mode => attribute name for grouped torrent page
    private static $SortOrdersGrouped = [
        'year' => 'year',
        'time' => 'id',
        'size' => 'maxsize',
        'seeders' => 'sumseeders',
        'leechers' => 'sumleechers',
        'snatched' => 'sumsnatched',
        'cataloguenumber' => 'cataloguenumber',
        'random' => 1
    ];

    // Map of sort mode => aggregate expression required for some grouped sort orders
    private static $AggregateExp = [
        'size' => 'MAX(size) AS maxsize',
        'seeders' => 'SUM(seeders) AS sumseeders',
        'leechers' => 'SUM(leechers) AS sumleechers',
        'snatched' => 'SUM(snatched) AS sumsnatched'
    ];

    // Map of attribute name => global variable name with list of values that can be used for filtering
    private static $Attributes = [
        'filter_cat' => false,
        'releasetype' => 'ReleaseTypes',
        'freetorrent' => false,
        'censored' => false,
        'size_unit' => false,
        'year' => false
    ];

    // List of fields that can be used for fulltext searches
    private static $Fields = [
        'artistname' => 1, # Author
        'audioformat' => 1, # Version
        'cataloguenumber' => 1, # Accession Number
        'numbers' => 1, # Combined &uarr;
        'codec' => 1, # License
        'container' => 1, # Format
        'archive' => 0, # todo
        'description' => 1, # Not group desc
        'filelist' => 1,
        'groupname' => 1, # Title
        'GroupTitle2' => 1, # Organism
        'Groupnamejp' => 1, # Strain
        'advgroupname' => 1,
        'media' => 1, # Platform
        'resolution' => 1, # Scope
        'searchstr' => 1,
        'series' => 1, # Location
        'studio' => 1, # Department/Lab
        'location' => 1, # Combined &uarr;
        'taglist' => 1
  ];

    // List of torrent-specific fields that can be used for filtering
    private static $TorrentFields = [
        'description' => 1,
        'encoding' => 1,
        'censored' => 1,
        'filelist' => 1,
        'format' => 1,
        'media' => 1
  ];

    // Some form field names don't match the ones in the index
    private static $FormsToFields = [
        # todo: Keep testing the granularity of filter combos
        'searchstr' => '*',
        'advgroupname' => '*', # todo: Fix this ;)
        'numbers' => '(cataloguenumber,audioformat)',
        'location' => '(studio,series)',
        #'searchstr' => '(groupname,GroupTitle2,groupnamejp,artistname,studio,series,cataloguenumber,yearfulltext)',
        #'advgroupname' => '(groupname,GroupTitle2,groupnamejp)',
  ];

    // Specify the operator type to use for fields. Empty key sets the default
    private static $FieldOperators = [
        '' => self::SPH_BOOL_AND,
        'encoding' => self::SPH_BOOL_OR,
        'format' => self::SPH_BOOL_OR,
        'media' => self::SPH_BOOL_OR
    ];

    // Specify the separator character to use for fields. Empty key sets the default
    private static $FieldSeparators = [
        '' => ' ',
        'encoding' => '|',
        'format' => '|',
        'media' => '|',
        'taglist' => ','
    ];

    // Primary SphinxqlQuery object used to get group IDs or torrent IDs for ungrouped searches
    private $SphQL;
    // Second SphinxqlQuery object used to get torrent IDs if torrent-specific fulltext filters are used
    private $SphQLTor;
    // Ordered result array or false if query resulted in an error
    private $SphResults;
    // Requested page
    private $Page;
    // Number of results per page
    private $PageSize;
    // Number of results
    private $NumResults = 0;
    // Array with info from all matching torrent groups
    private $Groups = [];
    // Whether any filters were used
    private $Filtered = false;
    // Whether the random sort order is selected
    private $Random = false;

    /*
     * Storage for fulltext search terms
     * ['Field name' => [
     *     'include' => [],
     *     'exclude' => [],
     *     'operator' => self::SPH_BOOL_AND | self::SPH_BOOL_OR
     * ]], ...
     */
    private $Terms = [];
    // Unprocessed search terms for retrieval
    private $RawTerms = [];
    // Storage for used torrent-specific attribute filters
    // ['Field name' => 'Search expression', ...]
    private $UsedTorrentAttrs = [];
    // Storage for used torrent-specific fulltext fields
    // ['Field name' => 'Search expression', ...]
    private $UsedTorrentFields = [];

    /**
     * Initialize and configure a TorrentSearch object
     *
     * @param bool $GroupResults whether results should be grouped by group id
     * @param string $OrderBy attribute to use for sorting the results
     * @param string $OrderWay Whether to use ascending or descending order
     * @param int $Page Page number to display
     * @param int $PageSize Number of results per page
     */
    public function __construct($GroupResults, $OrderBy, $OrderWay, $Page, $PageSize)
    {
        if ($GroupResults && !isset(self::$SortOrdersGrouped[$OrderBy])
        || !$GroupResults && !isset(self::$SortOrders[$OrderBy])
        || !in_array($OrderWay, ['asc', 'desc'])
    ) {
            global $Debug;
            $ErrMsg = "TorrentSearch constructor arguments:\n" . print_r(func_get_args(), true);
            $Debug->analysis('Bad arguments in TorrentSearch constructor', $ErrMsg, 3600*24);
            error(-1);
        }

        if (!is_number($Page) || $Page < 1) {
            $Page = 1;
        }

        if (check_perms('site_search_many')) {
            $this->Page = $Page;
        } else {
            $this->Page = min($Page, SPHINX_MAX_MATCHES / $PageSize);
        }

        $ResultLimit = $PageSize;
        $this->PageSize = $PageSize;
        $this->GroupResults = $GroupResults;
        $this->SphQL = new SphinxqlQuery();
        $this->SphQL->where_match('_all', 'fake', false);

        if ($OrderBy === 'random') {
            $this->SphQL->select('id, groupid')
        ->order_by('RAND()', '');
            $this->Random = true;
            $this->Page = 1;
            if ($GroupResults) {
                // Get more results because ORDER BY RAND() can't be used in GROUP BY queries
                $ResultLimit *= 5;
            }
        } elseif ($GroupResults) {
            $Select = 'groupid';
            if (isset(self::$AggregateExp[$OrderBy])) {
                $Select .= ', ' . self::$AggregateExp[$OrderBy];
            }
            $this->SphQL->select($Select)
        ->group_by('groupid')
        ->order_group_by(self::$SortOrdersGrouped[$OrderBy], $OrderWay)
        ->order_by(self::$SortOrdersGrouped[$OrderBy], $OrderWay);
        } else {
            $this->SphQL->select('id, groupid')
        ->order_by(self::$SortOrders[$OrderBy], $OrderWay);
        }

        $Offset = ($this->Page - 1) * $ResultLimit;
        $MinMax = G::$Cache->get_value('sphinx_min_max_matches');
        $MaxMatches = max($Offset + $ResultLimit, $MinMax ? $MinMax : 1000); # todo: Keep an eye on this
        $this->SphQL->from('torrents, delta')
      ->limit($Offset, $ResultLimit, $MaxMatches);
    }

    /**
     * Process search terms and run the main query
     *
     * @param array $Terms Array containing all search terms (e.g. $_GET)
     * @return array List of matching group IDs with torrent ID as key for ungrouped results
     */
    public function query($Terms = [])
    {
        $this->process_search_terms($Terms);
        $this->build_query();
        $this->run_query();
        $this->process_results();
        return $this->SphResults;
    }

    public function insert_hidden_tags($tags)
    {
        $this->SphQL->where_match($tags, 'taglist', false);
    }

    /**
     * Internal function that runs the queries needed to get the desired results
     */
    private function run_query()
    {
        $SphQLResult = $this->SphQL->query();
        if ($SphQLResult->Errno > 0) {
            $this->SphResults = false;
            return;
        }

        if ($this->Random && $this->GroupResults) {
            $TotalCount = $SphQLResult->get_meta('total_found');
            $this->SphResults = $SphQLResult->collect('groupid');
            $GroupIDs = array_keys($this->SphResults);
            $GroupCount = count($GroupIDs);
            while ($SphQLResult->get_meta('total') < $TotalCount && $GroupCount < $this->PageSize) {
                // Make sure we get $PageSize results, or all of them if there are less than $PageSize hits
                $this->SphQL->where('groupid', $GroupIDs, true);
                $SphQLResult = $this->SphQL->query();

                if (!$SphQLResult->has_results()) {
                    break;
                }

                $this->SphResults += $SphQLResult->collect('groupid');
                $GroupIDs = array_keys($this->SphResults);
                $GroupCount = count($GroupIDs);
            }

            if ($GroupCount > $this->PageSize) {
                $this->SphResults = array_slice($this->SphResults, 0, $this->PageSize, true);
            }
            $this->NumResults = count($this->SphResults);
        } else {
            $this->NumResults = (int)$SphQLResult->get_meta('total_found');
            if ($this->GroupResults) {
                $this->SphResults = $SphQLResult->collect('groupid');
            } else {
                $this->SphResults = $SphQLResult->to_pair('id', 'groupid');
            }
        }
    }

    /**
     * Process search terms and store the parts in appropriate arrays until we know if
     * the NOT operator can be used
     */
    private function build_query()
    {
        foreach ($this->Terms as $Field => $Words) {
            $SearchString = '';

            if (isset(self::$FormsToFields[$Field])) {
                $Field = self::$FormsToFields[$Field];
            }

            $QueryParts = ['include' => [], 'exclude' => []];
            if (!empty($Words['include'])) {
                foreach ($Words['include'] as $Word) {
                    $QueryParts['include'][] = Sphinxql::sph_escape_string($Word);
                }
            }

            if (!empty($Words['exclude'])) {
                foreach ($Words['exclude'] as $Word) {
                    $QueryParts['exclude'][] = '!' . Sphinxql::sph_escape_string(substr($Word, 1));
                }
            }

            if (!empty($QueryParts)) {
                if (isset($Words['operator'])) {
                    // Is the operator already specified?
                    $Operator = $Words['operator'];
                } elseif (isset(self::$FieldOperators[$Field])) {
                    // Does this field have a non-standard operator?
                    $Operator = self::$FieldOperators[$Field];
                } else {
                    // Go for the default operator
                    $Operator = self::$FieldOperators[''];
                }

                if (!empty($QueryParts['include'])) {
                    if ($Field === 'taglist') {
                        foreach ($QueryParts['include'] as $key => $Tag) {
                            $QueryParts['include'][$key] = '( '.$Tag.' | '.$Tag.':* )';
                        }
                    }
                    $SearchString .= '( ' . implode($Operator, $QueryParts['include']) . ' ) ';
                }

                if (!empty($QueryParts['exclude'])) {
                    $SearchString .= implode(' ', $QueryParts['exclude']);
                }

                $this->SphQL->where_match($SearchString, $Field, false);
                if (isset(self::$TorrentFields[$Field])) {
                    $this->UsedTorrentFields[$Field] = $SearchString;
                }
                $this->Filtered = true;
            }
        }
    }

    /**
     * Look at each search term and figure out what to do with it
     *
     * @param array $Terms Array with search terms from query()
     */
    private function process_search_terms($Terms)
    {
        foreach ($Terms as $Key => $Term) {
            if (isset(self::$Fields[$Key])) {
                $this->process_field($Key, $Term);
            } elseif (isset(self::$Attributes[$Key])) {
                $this->process_attribute($Key, $Term);
            }
            $this->RawTerms[$Key] = $Term;
        }
        $this->post_process();
    }

    /**
     * Process attribute filters and store them in case we need to post-process grouped results
     *
     * @param string $Attribute Name of the attribute to filter against
     * @param mixed $Value The filter's condition for a match
     */
    private function process_attribute($Attribute, $Value)
    {
        if ($Value === '') {
            return;
        }

        if ($Attribute === 'year') {
            $this->search_year($Value);
        } elseif ($Attribute === 'size_unit') {
            // For the record, size_unit must appear in the GET parameters after size_min and size_max for this to work. Sorry.
            if (is_numeric($this->RawTerms['size_min']) || is_numeric($this->RawTerms['size_max'])) {
                $this->SphQL->where_between('size', [intval(($this->RawTerms['size_min'] ?? 0)*(1024**$Value)), intval(min(PHP_INT_MAX, ($this->RawTerms['size_max'] ?? INF)*(1024**$Value)))]);
            }
        } elseif ($Attribute === 'freetorrent') {
            if ($Value === 3) {
                $this->SphQL->where('freetorrent', 0, true);
                $this->UsedTorrentAttrs['freetorrent'] = 3;
            } elseif ($Value >= 0 && $Value < 3) {
                $this->SphQL->where('freetorrent', $Value);
                $this->UsedTorrentAttrs[$Attribute] = $Value;
            }
        } elseif ($Attribute === 'filter_cat') {
            if (!is_array($Value)) {
                $Value = array_fill_keys(explode('|', $Value), 1);
            }
            $CategoryFilter = [];
            foreach (array_keys($Value) as $Category) {
                if (is_number($Category)) {
                    $CategoryFilter[] = $Category;
                } else {
                    global $Categories;
                    $ValidValues = array_map('strtolower', $Categories);
                    if (($CategoryID = array_search(strtolower($Category), $ValidValues)) !== false) {
                        $CategoryFilter[] = $CategoryID + 1;
                    }
                }
            }
            $this->SphQL->where('categoryid', ($CategoryFilter ?? 0));
        } else {
            if (!is_number($Value) && self::$Attributes[$Attribute] !== false) {
                // Check if the submitted value can be converted to a valid one
                $ValidValuesVarname = self::$Attributes[$Attribute];
                global $$ValidValuesVarname;
                $ValidValues = array_map('strtolower', $$ValidValuesVarname);
                if (($Value = array_search(strtolower($Value), $ValidValues)) === false) {
                    // Force the query to return 0 results if value is still invalid
                    $Value = max(array_keys($ValidValues)) + 1;
                }
            }
            $this->SphQL->where($Attribute, $Value);
            $this->UsedTorrentAttrs[$Attribute] = $Value;
        }

        $this->Filtered = true;
    }

    /**
     * Look at a fulltext search term and figure out if it needs special treatment
     *
     * @param string $Field Name of the search field
     * @param string $Term Search expression for the field
     */
    private function process_field($Field, $Term)
    {
        $Term = trim($Term);
        if ($Term === '') {
            return;
        }

        if ($Field === 'searchstr') {
            $this->search_basic($Term);
        } elseif ($Field === 'filelist') {
            $this->search_filelist($Term);
        } elseif ($Field === 'taglist') {
            $this->search_taglist($Term);
        } else {
            $this->add_field($Field, $Term);
        }
    }

    /**
     * Some fields may require post-processing
     */
    private function post_process()
    {
        if (isset($this->Terms['taglist'])) {
            // Replace bad tags with tag aliases
            $this->Terms['taglist'] = Tags::remove_aliases($this->Terms['taglist']);
            if (isset($this->RawTerms['tags_type']) && (int)$this->RawTerms['tags_type'] === self::TAGS_ANY) {
                $this->Terms['taglist']['operator'] = self::SPH_BOOL_OR;
            }

            // Update the RawTerms array so get_terms() can return the corrected search terms
            if (isset($this->Terms['taglist']['include'])) {
                $AllTags = $this->Terms['taglist']['include'];
            } else {
                $AllTags = [];
            }

            if (isset($this->Terms['taglist']['exclude'])) {
                $AllTags = array_merge($AllTags, $this->Terms['taglist']['exclude']);
            }
            $this->RawTerms['taglist'] = str_replace('_', '.', implode(', ', $AllTags));
        }
    }

    /**
     * Handle magic keywords in the basic torrent search
     *
     * @param string $Term Given search expression
     */
    private function search_basic($Term)
    {
        global $Bitrates, $Formats, $Media;
        #$SearchBitrates = array_map('strtolower', $Bitrates);
        #array_push($SearchBitrates, 'v0', 'v1', 'v2', '24bit');
        #$SearchFormats = array_map('strtolower', $Formats);
        $SearchMedia = array_map('strtolower', $Media);

        foreach (explode(' ', $Term) as $Word) {
            /*
            if (in_array($Word, $SearchBitrates)) {
              $this->add_word('encoding', $Word);
            } elseif (in_array($Word, $SearchFormats)) {
              $this->add_word('format', $Word);
            }
            */

            if (in_array($Word, $SearchMedia)) {
                $this->add_word('media', $Word);
            } else {
                $this->add_word('searchstr', $Word);
            }
        }
    }

    /**
     * Use phrase boundary for file searches to make sure we don't count
     * partial hits from multiple files
     *
     * @param string $Term Given search expression
     */
    private function search_filelist($Term)
    {
        $SearchString = '"' . Sphinxql::sph_escape_string($Term) . '"~20';
        $this->SphQL->where_match($SearchString, 'filelist', false);
        $this->UsedTorrentFields['filelist'] = $SearchString;
        $this->Filtered = true;
    }

    /**
     * Prepare tag searches before sending them to the normal treatment
     *
     * @param string $Term Given search expression
     */
    private function search_taglist($Term)
    {
        $Term = strtr($Term, '.', '_');
        $this->add_field('taglist', $Term);
    }

    /**
     * The year filter accepts a range. Figure out how to handle the filter value
     *
     * @param string $Term Filter condition. Can be an integer or a range with the format X-Y
     * @return bool True if parameters are valid
     */
    private function search_year($Term)
    {
        $Years = explode('-', $Term);
        if (count($Years) === 1 && is_number($Years[0])) {
            // Exact year
            $this->SphQL->where('year', $Years[0]);
        } elseif (count($Years) === 2) {
            if (empty($Years[0]) && is_number($Years[1])) {
                // Range: 0 - 2005
                $this->SphQL->where_lt('year', $Years[1], true);
            } elseif (empty($Years[1]) && is_number($Years[0])) {
                // Range: 2005 - 2^32-1
                $this->SphQL->where_gt('year', $Years[0], true);
            } elseif (is_number($Years[0]) && is_number($Years[1])) {
                // Range: 2005 - 2009
                $this->SphQL->where_between('year', [min($Years), max($Years)]);
            } else {
                // Invalid input
                return false;
            }
        } else {
            // Invalid input
            return false;
        }
        return true;
    }

    /**
     * Add a field filter that doesn't need special treatment
     *
     * @param string $Field Name of the search field
     * @param string $Term Search expression for the field
     */
    private function add_field($Field, $Term)
    {
        if (isset(self::$FieldSeparators[$Field])) {
            $Separator = self::$FieldSeparators[$Field];
        } else {
            $Separator = self::$FieldSeparators[''];
        }

        $Words = explode($Separator, $Term);
        foreach ($Words as $Word) {
            $this->add_word($Field, $Word);
        }
    }

    /**
     * Add a keyword to the array of search terms
     *
     * @param string $Field Name of the search field
     * @param string $Word Keyword
     */
    private function add_word($Field, $Word)
    {
        $Word = trim($Word);
        // Skip isolated hyphens to enable "Artist - Title" searches
        if ($Word === '' || $Word === '-') {
            return;
        }

        if ($Word[0] === '!' && strlen($Word) >= 2 && strpos($Word, '!', 1) === false) {
            $this->Terms[$Field]['exclude'][] = $Word;
        } else {
            $this->Terms[$Field]['include'][] = $Word;
        }
    }

    /**
     * @return array Torrent group information for the matches from Torrents::get_groups
     */
    public function get_groups()
    {
        return $this->Groups;
    }

    /**
     * @param string $Type Field or attribute name
     * @return string Unprocessed search terms
     */
    public function get_terms($Type)
    {
        return $this->RawTerms[$Type] ?? '';
    }

    /**
     * @return int Result count
     */
    public function record_count()
    {
        return $this->NumResults;
    }

    /**
     * @return bool Whether any filters were used
     */
    public function has_filters()
    {
        return $this->Filtered;
    }

    /**
     * @return bool Whether any torrent-specific fulltext filters were used
     */
    public function need_torrent_ft()
    {
        return $this->GroupResults && $this->NumResults > 0 && !empty($this->UsedTorrentFields);
    }

    /**
     * Get torrent group info and remove any torrents that don't match
     */
    private function process_results()
    {
        if (count($this->SphResults) === 0) {
            return;
        }

        $this->Groups = Torrents::get_groups($this->SphResults);
        if ($this->need_torrent_ft()) {
            // Query Sphinx for torrent IDs if torrent-specific fulltext filters were used
            $this->filter_torrents_sph();
        } elseif ($this->GroupResults) {
            // Otherwise, let PHP discard unmatching torrents
            $this->filter_torrents_internal();
        }
        // Ungrouped searches don't need any additional filtering
    }

    /**
     * Build and run a query that gets torrent IDs from Sphinx when fulltext filters
     * were used to get primary results and they are grouped
     */
    private function filter_torrents_sph()
    {
        $AllTorrents = [];
        foreach ($this->Groups as $GroupID => $Group) {
            if (!empty($Group['Torrents'])) {
                $AllTorrents += array_fill_keys(array_keys($Group['Torrents']), $GroupID);
            }
        }

        $TorrentCount = count($AllTorrents);
        $this->SphQLTor = new SphinxqlQuery();
        $this->SphQLTor->where_match('_all', 'fake', false);
        $this->SphQLTor->select('id')->from('torrents, delta');

        foreach ($this->UsedTorrentFields as $Field => $Term) {
            $this->SphQLTor->where_match($Term, $Field, false);
        }

        $this->SphQLTor->copy_attributes_from($this->SphQL);
        $this->SphQLTor->where('id', array_keys($AllTorrents))->limit(0, $TorrentCount, $TorrentCount);
        $SphQLResultTor = $this->SphQLTor->query();
        $MatchingTorrentIDs = $SphQLResultTor->to_pair('id', 'id');

        foreach ($AllTorrents as $TorrentID => $GroupID) {
            if (!isset($MatchingTorrentIDs[$TorrentID])) {
                unset($this->Groups[$GroupID]['Torrents'][$TorrentID]);
            }
        }
    }

    /**
     * Non-Sphinx method of collecting IDs of torrents that match any
     * torrent-specific attribute filters that were used in the search query
     */
    private function filter_torrents_internal()
    {
        foreach ($this->Groups as $GroupID => $Group) {
            if (empty($Group['Torrents'])) {
                continue;
            }
            
            foreach ($Group['Torrents'] as $TorrentID => $Torrent) {
                if (!$this->filter_torrent_internal($Torrent)) {
                    unset($this->Groups[$GroupID]['Torrents'][$TorrentID]);
                }
            }
        }
    }

    /**
     * Post-processing to determine if a torrent is a real hit or if it was
     * returned because another torrent in the group matched. Only used if
     * there are no torrent-specific fulltext conditions
     *
     * @param array $Torrent Torrent array, probably from Torrents::get_groups()
     * @return bool True if it's a real hit
     */
    private function filter_torrent_internal($Torrent)
    {
        if (isset($this->UsedTorrentAttrs['freetorrent'])) {
            $FilterValue = $this->UsedTorrentAttrs['freetorrent'];
            if ($FilterValue === '3' && $Torrent['FreeTorrent'] === '0') {
                // Either FL or NL is ok
                return false;
            } elseif ($FilterValue !== '3' && $FilterValue !== (int)$Torrent['FreeTorrent']) {
                return false;
            }
        }
        return true;
    }
}