<?php
	interface ImpDBO {
		function changeUser($Username, $Password);
		function execute($sql);
		function getAffectedRowCount();
		function getLastInsertId();
		function getPerformanceCounters();
		function getUniqueIdentifier($Table, $ID);
		function query($sql);
		function queryValue($sql);
		function queryValues($sql);
		function escape($s); 	// Legacy-style, returns without enclosing quotes
		function quote($s); 	// PDO-style, returns strings including enclosing quotes if needed
		function setCharacterSet($charset = 'utf8');
	}

	abstract class ImpDB implements ImpDBO {
		# Performance monitoring:
		protected $cummulativeQueryTime = 0;
		protected $extendedProfiling    = false;
		protected $logQueries           = false;
		protected $profileQueries       = false;
		protected $queryCount           = 0;
		protected $queryLog             = array();

		# If non-empty, this->log() calls will call $Log->Log() instead of error_log
		protected $Log;

		protected $lastRowCount;

		function __destruct() {
			if ($this->profileQueries) $this->printQueryLog();
		}

		function logQueries($b = true) {
			$this->logQueries = $b;
		}

		function profileQueries($b = true) {
			$this->profileQueries = $b;
		}

		function setLog(Log $Log) {
			$this->Log = $Log;
		}

		function log($Message, $Priority = false) {
			if (isset($this->Log)) {
				$this->Log->Log($Message, $Priority);
			} else {
				error_log(get_class($this) . ": " . $Message);
			}
		}

		function startTimer() {
			if (!$this->profileQueries) return;
			$this->queryStartTime = microtime(true);

			if ($this->extendedProfiling) {
				$this->initialSessionStatus = $this->getSessionStatus();
			}
		}

		function stopTimer($sql) {
			if (!$this->profileQueries) {
				if ($this->logQueries) $this->log($sql);
				return false;
			}

			$elapsed = microtime(true) - $this->queryStartTime;
			$this->cummulativeQueryTime += $elapsed;

			if ($this->logQueries) {
				$this->log("$sql (Elapsed time: " . number_format($elapsed, 6) . " seconds. Total: {$this->queryCount} queries in " . number_format($this->cummulativeQueryTime, 6) . " seconds)", PEAR_LOG_DEBUG);
			}

			$this->queryCount++;

			if (!isset($this->queryLog[$sql])) {
				$this->queryLog[$sql] = array(
					"Count" => 1,
					"Time" => $elapsed
				);
			} else {
				$this->queryLog[$sql]['Count']++;
				$this->queryLog[$sql]['Time'] += $elapsed;
			}

			if ($this->extendedProfiling) {
				$deltas = array_diff($this->initialSessionStatus, $this->getSessionStatus());
				$tmp = new ImpTable($deltas);
				$tmp->Caption = $sql;
				$tmp->generate();
			}
		}

		function escape($v) {
			 if (is_array($v)) {
					foreach ($v as $k => $i) {
						$v[$k] = $this->quote($i);
					}
					return $v;
			 } else {
				 return $this->quote($v, $this);
			 }
		}

		function escapeString($v) {
			return $this->escape($v);
		}

		function getAffectedRowCount() {
			return $this->lastRowCount;
		}

		function queryValue($sql) {
			$args = func_get_args();
			$rs = call_user_func_array(array($this, 'query'), $args);
			return $rs ? array_first(array_first($rs)) : false;
		}

		function queryValues($sql) {
			$args = func_get_args();
			$ret = array();
			$rs = call_user_func_array(array($this, 'query'), $args);

			foreach ($rs as $r) {
				$ret[] = reset($r);
			}
			return $ret;
		}


		/* Diagnostic code */
		function printQueryLog() {
			include_once('ImpUtils/ImpTable.php');

			uasort($this->queryLog, create_function('$a,$b', 'return strcmp($b["Count"], $a["Count"]);'));

			$d = array();

			$TotalQueries = 0;
			foreach ($this->queryLog as $k => $v) {
				$d[] = array("Query" => $k, 'Count' => $v['Count'], 'Time' => round($v['Time'] * 1000000), 'Cost' => round($v['Time'] * 1000000 / $v['Count']));
				$TotalQueries += $v['Count'];
			}

			assert($TotalQueries == $this->queryCount);

			$className                       = get_class($this);

			$QueryTable                      = new ImpTable($d);
			$QueryTable->JSRenderQueue       = $className . '_Table_Generators';

			$QueryTable->DefaultSortKey      = 'Time';
			$QueryTable->DefaultSortOrder    = 'Descending';
			$QueryTable->AutoSort();

			$QueryTable->Attributes['id']    = $className . '_Queries';
			$QueryTable->Attributes['class'] = 'ImpUtils Debug';
			$QueryTable->Caption             = $className . ': ' . number_format($TotalQueries) . ' queries in ' . number_format($this->cummulativeQueryTime, 3) . ' seconds';

			$QueryTable->ColumnHeaders       = array(
				'Query' => array('label' => 'SQL Statement'),
				'Count' => array('label' => 'Count',           'formatter' => 'YAHOO.widget.DataTable.formatNumber'),
				'Time'  => array('label' => 'Time (&micro;s)', 'formatter' => 'YAHOO.widget.DataTable.formatNumber'),
				'Cost'  => array('label' => 'Cost',            'formatter' => 'YAHOO.widget.DataTable.formatNumber')
			);
			?>
			<script type="text/javascript" charset="utf-8">
				<?=$QueryTable->JSRenderQueue?> = new Array();
			</script>
			<a href="#" class="<?=$QueryTable->Attributes['class']?>" style="position: fixed; bottom: 0; text-align: center; width: 100%; padding: 1em 0; background-color: lightgrey; color: black;" onclick="this.style.display='none';document.getElementById('<?=$className?>_Queries').style.display='block';while(f = <?=$QueryTable->JSRenderQueue?>.shift()){ f(); }; return false"><?=$QueryTable->Caption?> (Show)</a>
			<style>
				#<?=$className?>_Queries {
					text-align: left;
					padding: 2pt;
					background-color: white;
					color: black;
					margin-top: 4em;
					display:none;
				}

				#<?=$className?>_Queries caption {
					font-weight: bold;
					text-align: center;
					background-color: #666699;
					margin: 0;
				}

				#<?=$className?>_Queries thead {
					background-color: lightgray;
				}

				#<?=$className?>_Queries a {
					color: inherit ! important;
					font-weight: inherit ! important;
				}

				#<?=$className?>_Queries th {
					padding: 2pt;
					padding-right: 1em;
					font-weight: bold;
					white-space: nowrap;
					border: none;
				}

				#<?=$className?>_Queries td {
					font-family: monospace;
					font-size: 9px;
					border: none;
				}

				#<?=$className?>_Queries tr:nth-child(odd) {
					background-color: lightgreen;
				}
			</style>
			<?
				$QueryTable->generate();
		}
	}
?>