<?
class Artists {
	/**
	 * Given an array of GroupIDs, return their associated artists.
	 *
	 * @param array $GroupIDs
	 * @return an array of the following form:
	 * 	GroupID => {
	 *		[ArtistType] => {
	 *			id, name, aliasid
	 *		}
	 *	}
	 * ArtistType is an int. It can be:
	 * 1 => Main artist
	 * 2 => Guest artist
	 * 4 => Composer
	 * 5 => Conductor
	 * 6 => DJ
	 */
	public static function get_artists($GroupIDs) {
		global $Cache, $DB;
		$Results = array();
		$DBs = array();
		foreach($GroupIDs as $GroupID) {
			if(!is_number($GroupID)) {
				continue;
			}
			$Artists = $Cache->get_value('groups_artists_'.$GroupID);
			if(is_array($Artists)) {
				$Results[$GroupID] = $Artists;
			} else {
				$DBs[] = $GroupID;
			}
		}
		if(count($DBs) > 0) {
			$IDs = implode(',', $DBs);
			if(empty($IDs)) {
				$IDs = "null";
			}
			$DB->query("SELECT ta.GroupID,
					ta.ArtistID,
					aa.Name,
					ta.Importance,
					ta.AliasID
				FROM torrents_artists AS ta
					JOIN artists_alias AS aa ON ta.AliasID = aa.AliasID
				WHERE ta.GroupID IN ($IDs)
				ORDER BY ta.GroupID ASC,
					ta.Importance ASC,
					aa.Name ASC;");
			while(list($GroupID,$ArtistID,$ArtistName,$ArtistImportance,$AliasID) = $DB->next_record(MYSQLI_BOTH, false)) {
				$Results[$GroupID][$ArtistImportance][] = array('id' => $ArtistID, 'name' => $ArtistName, 'aliasid' => $AliasID);
				$New[$GroupID][$ArtistImportance][] = array('id' => $ArtistID, 'name' => $ArtistName, 'aliasid' => $AliasID);
			}
			foreach($DBs as $GroupID) {
				if(isset($New[$GroupID])) {
					$Cache->cache_value('groups_artists_'.$GroupID, $New[$GroupID]);
				}
				else {
					$Cache->cache_value('groups_artists_'.$GroupID, array());
				}
			}
			$Missing = array_diff($GroupIDs, array_keys($Results));
			if(!empty($Missing)) {
				$Results += array_fill_keys($Missing, array());
			}
		}
		return $Results;
	}


	/**
	 * Convenience function for get_artists, when you just need one group.
	 *
	 * @param int $GroupID
	 * @return array - see get_artists
	 */
	public static function get_artist($GroupID) {
		$Results = Artists::get_artists(array($GroupID));
		return $Results[$GroupID];
	}


	/**
	 * Format an array of artists for display.
	 * TODO: Revisit the logic of this, see if we can helper-function the copypasta.
	 *
	 * @param array Artists an array of the form output by get_artists
	 * @param boolean $MakeLink if true, the artists will be links, if false, they will be text.
	 * @param boolean $IncludeHyphen if true, appends " - " to the end.
	 * @param $Escape if true, output will be escaped. Think carefully before setting it false.
	 */
	public static function display_artists($Artists, $MakeLink = true, $IncludeHyphen = true, $Escape = true) {
		if(!empty($Artists)) {
			$ampersand = ($Escape) ? ' &amp; ' : ' & ';
			$link = '';

			$MainArtists = isset($Artists[1]) ? $Artists[1] : null;
			$Guests      = isset($Artists[2]) ? $Artists[2] : null;
			$Composers   = isset($Artists[4]) ? $Artists[4] : null;
			$Conductors  = isset($Artists[5]) ? $Artists[5] : null;
			$DJs         = isset($Artists[6]) ? $Artists[6] : null;

			if ((count($MainArtists) + count($Conductors) + count($DJs) == 0) && (count($Composers) == 0)) {
				return '';
			}
			// Various Composers is not needed and is ugly and should die
			switch(count($Composers)) {
				case 0:
					break;
				case 1:
					$link .= Artists::display_artist($Composers[0], $MakeLink, $Escape);
					break;
				case 2:
					$link .= Artists::display_artist($Composers[0], $MakeLink, $Escape).$ampersand.Artists::display_artist($Composers[1], $MakeLink, $Escape);
					break;
			}

			if ((count($Composers) > 0) && (count($Composers) < 3) && (count($MainArtists) > 0)) {
				$link .= ' performed by ';
			}

			$ComposerStr = $link;

			switch(count($MainArtists)) {
				case 0:
					break;
				case 1:
					$link .= Artists::display_artist($MainArtists[0], $MakeLink, $Escape);
					break;
				case 2:
					$link .= Artists::display_artist($MainArtists[0], $MakeLink, $Escape).$ampersand.Artists::display_artist($MainArtists[1], $MakeLink, $Escape);
					break;
				default:
					$link .= 'Various Artists';
			}

			/*if(!empty($Guests) &&  (count($MainArtists) + count($Composers) > 0) && (count($MainArtists) + count($Composers) + count($Conductors) < 3)) {
				switch(count($Guests)) {
					case 1:
						$link .= ' with '.Artists::display_artist($Guests[0], $MakeLink, $Escape);
						break;
					case 2:
						$link .= ' with '.Artists::display_artist($Guests[0], $MakeLink, $Escape).$ampersand.Artists::display_artist($Guests[1], $MakeLink, $Escape);
						break;
				}
			}*/

			if ((count($Conductors) > 0) && (count($MainArtists) + count($Composers) > 0) && (count($Composers) < 3 || count($MainArtists) > 0)) {
				$link .= ' under ';
			}
			switch(count($Conductors)) {
				case 0:
					break;
				case 1:
					$link .= Artists::display_artist($Conductors[0], $MakeLink, $Escape);
					break;
				case 2:
					$link .= Artists::display_artist($Conductors[0], $MakeLink, $Escape).$ampersand.Artists::display_artist($Conductors[1], $MakeLink, $Escape);
					break;
				default:
					$link .= ' Various Conductors';
			}

			if ((count($Composers) > 0) && (count($MainArtists) + count($Conductors) > 3) && (count($MainArtists) > 1) && (count($Conductors) > 1)) {
				$link = $ComposerStr . 'Various Artists';
			} elseif ((count($Composers) > 2) && (count($MainArtists) + count($Conductors) == 0)) {
				$link = 'Various Composers';
			}

			// DJs override everything else
			switch(count($DJs)) {
				case 0:
					break;
				case 1:
					$link = Artists::display_artist($DJs[0], $MakeLink, $Escape);
					break;
				case 2:
					$link = Artists::display_artist($DJs[0], $MakeLink, $Escape).$ampersand.Artists::display_artist($DJs[1], $MakeLink, $Escape);
					break;
				default :
					$link = 'Various DJs';
			}
			return $link.($IncludeHyphen?' - ':'');
		} else {
			return '';
		}
	}


	/**
	 * Formats a single artist name.
	 *
	 * @param array $Artist an array of the form ('id'=>ID, 'name'=>Name)
	 * @param boolean $MakeLink If true, links to the artist page.
	 * @param boolean $Escape If false and $MakeLink is false, returns the unescaped, unadorned artist name.
	 * @return string Formatted artist name.
	 */
	public static function display_artist($Artist, $MakeLink = true, $Escape = true) {
		if ($MakeLink && !$Escape) {
			error('Invalid parameters to Artists::display_artist()');
		} elseif ($MakeLink) {
			return '<a href="artist.php?id='.$Artist['id'].'">'.display_str($Artist['name']).'</a>';
		} elseif ($Escape) {
			return display_str($Artist['name']);
		} else {
			return $Artist['name'];
		}
	}

	/**
	 * Deletes an artist and their requests, wiki, and tags.
	 * Does NOT delete their torrents.
	 *
	 * @param int $ArtistID
	 */
	public static function delete_artist($ArtistID) {
		global $DB, $LoggedUser, $Cache;

		$DB->query("SELECT Name FROM artists_group WHERE ArtistID = ".$ArtistID);
		list($Name) = $DB->next_record(MYSQLI_NUM, false);

		// Delete requests
		$DB->query("SELECT RequestID FROM requests_artists WHERE ArtistID=".$ArtistID." AND ArtistID != 0");
		$Requests = $DB->to_array();
		foreach($Requests AS $Request) {
			list($RequestID) = $Request;
			$DB->query('DELETE FROM requests WHERE ID='.$RequestID);
			$DB->query('DELETE FROM requests_votes WHERE RequestID='.$RequestID);
			$DB->query('DELETE FROM requests_tags WHERE RequestID='.$RequestID);
			$DB->query('DELETE FROM requests_artists WHERE RequestID='.$RequestID);
		}

		// Delete artist
		$DB->query('DELETE FROM artists_group WHERE ArtistID='.$ArtistID);
		$DB->query('DELETE FROM artists_alias WHERE ArtistID='.$ArtistID);
		$Cache->decrement('stats_artist_count');

		// Delete wiki revisions
		$DB->query('DELETE FROM wiki_artists WHERE PageID='.$ArtistID);

		// Delete tags
		$DB->query('DELETE FROM artists_tags WHERE ArtistID='.$ArtistID);

		$Cache->delete_value('artist_'.$ArtistID);
		// Record in log

		if(!empty($LoggedUser['Username'])) {
			$Username = $LoggedUser['Username'];
		} else {
			$Username = 'System';
		}
		Misc::write_log('Artist '.$ArtistID.' ('.$Name.') was deleted by '.$Username);
	}


	/**
	 * Remove LRM (left-right-marker) and trims, because people copypaste carelessly.
	 * If we don't do this, we get seemingly duplicate artist names.
	 * TODO: make stricter, e.g. on all whitespace characters or Unicode normalisation
	 *
	 * @param string $ArtistName
	 */
	public static function normalise_artist_name($ArtistName) {
		// \u200e is &lrm;
		$ArtistName = trim($ArtistName);
		$ArtistName = preg_replace('/^(\xE2\x80\x8E)+/', '', $ArtistName);
		$ArtistName = preg_replace('/(\xE2\x80\x8E)+$/', '', $ArtistName);
		return trim(preg_replace('/ +/', ' ', $ArtistName));
	}
}
?>