<?php

require_once ('dbutils.php');


class CommonUtils {
	var $dbutils;
	
	function __construct() {
		$this->dbutils = new DbUtils();
		// $this->products = new Products(); --> endless loop!
		// $this->lastSettingOfDisplayMode = "all";
		//error_reporting(E_ALL);
	}
	
	function verifyLastBillId($pdo,$nextIdToUse) {
		if ($nextIdToUse == 1) {
			return true;
		}
		if (is_null($pdo)) {
			$pdo = $this->dbutils->openDbAndReturnPdo();
		}
		$nextIdToUse = intval($nextIdToUse);
		$sql = "SELECT value,signature FROM %work% WHERE item=?";
		$stmt = $pdo->prepare($this->dbutils->resolveTablenamesInSqlString($sql));
		$stmt->execute(array("lastbillid"));
		$row =$stmt->fetchObject();
		$lastBillid = intval($row->value);
		$lastBillInc = $lastBillid+1;
		$signature = base64_decode($row->signature);
		
		if ($lastBillInc != $nextIdToUse) {
			return false;
		} else {
			// test for correct signature
			$pubkeyid = $this->getCert($pdo);
			$ok = openssl_verify("B($lastBillid)", $signature, $pubkeyid);
			openssl_free_key($pubkeyid);
			
			if ($ok == 0) {
				return false;
			} else {
				// is id already used in bill table?
				$sql = "SELECT id FROM %bill% WHERE id=?";
				$stmt = $pdo->prepare($this->dbutils->resolveTablenamesInSqlString($sql));
				$stmt->execute(array($nextIdToUse));
				if ($stmt->rowCount() > 0) {
					return false;
				} else {
					// is there a gap or does the previous id exist?
					$sql = "SELECT id FROM %bill% WHERE id=?";
					$stmt = $pdo->prepare($this->dbutils->resolveTablenamesInSqlString($sql));
					$stmt->execute(array($nextIdToUse - 1));
					if ($stmt->rowCount() != 1) {
						return false;
					} else {
						return true;
					}
				}
			}
		}
	}
	
	function getPrivkey($pdo) {
		$privkey = $this->getKeyFromWorkTable($pdo, "privkey");
		return(openssl_get_privatekey($privkey)); // private key
	}
	
	function getCert($pdo) {
		$pubKey = $this->getKeyFromWorkTable($pdo, "cert");
		return(openssl_get_publickey($pubKey));
	}
	
	function getKeyFromWorkTable($pdo,$key) {
		$sql = "SELECT signature FROM %work% WHERE item=?";
		$stmt = $pdo->prepare($this->dbutils->resolveTablenamesInSqlString($sql));
		$stmt->execute(array($key));
		$row =$stmt->fetchObject();
		return($row->signature);
	}
	
	function setLastBillIdInWorkTable($pdo,$lastBillId) {
		if (is_null($pdo)) {
			$pdo = $this->dbutils->openDbAndReturnPdo();
		}
		$pkeyid = $this->getPrivkey($pdo);
		openssl_sign("B($lastBillId)", $signature, $pkeyid);
		openssl_free_key($pkeyid);
		$sql = "UPDATE %work% SET value=?, signature=? WHERE item=?";
		$stmt = $pdo->prepare($this->dbutils->resolveTablenamesInSqlString($sql));
		$signature = base64_encode($signature);
		$stmt->execute(array($lastBillId,$signature,"lastbillid"));
	}
	
	function verifyBill($pdo,$id) {
		if (is_null($pdo)) {
			$pdo = $this->dbutils->openDbAndReturnPdo();
		}

		$sql = "SELECT billdate,brutto,netto,userid,IF(tax is not null, tax, '0.00') as tax,signature FROM %bill% WHERE id=?";
		$stmt = $pdo->prepare($this->dbutils->resolveTablenamesInSqlString($sql));
		$stmt->execute(array($id));
		$row = $stmt->fetchObject();
		
		$billdate =  $row->billdate;
		$brutto = $row->brutto;
		$netto = $row->netto;
		$tax = $row->tax;
		$userid = $row->userid;
		$signature = $row->signature;
		
		return($this->verifyBillByValues($pdo,$billdate, $brutto, $netto, $tax, $userid, $signature));
	}
	
	function verifyBillByValues($pdo,$billdate,$brutto,$netto,$tax,$userid,$signature) {
		if (is_null($signature)) {
			return false;
		}
		if (is_null($pdo)) {
			$pdo = $this->dbutils->openDbAndReturnPdo();
		}

		$brutto = number_format($brutto, 2, ".", '');
		$netto = number_format($netto, 2, ".", '');
		$tax = number_format($tax, 2, ".", '');
		
		$data = "D($billdate)B($brutto)N($netto)T($tax)U($userid)";
		$pubkeyid = $this->getCert($pdo);
		$ok = openssl_verify($data, $signature, $pubkeyid);
		openssl_free_key($pubkeyid);

		if ($ok == 0) {
			return false;
		} else {
			return true;
		}
	}
		
	function calcSignatureForBill($pdo,$theTime,$brutto,$netto,$tax,$userid) {
		// now calculate the signature for the bill entry
		$bruttostr = number_format($brutto, 2, ".", '');
		$nettostr = number_format($netto, 2, ".", '');
		if (is_null($tax)) {
			$taxstr = "0.00";
		} else {
			$taxstr = number_format($tax, 2, ".", '');
		}
		$data = "D($theTime)B($bruttostr)N($nettostr)T($taxstr)U($userid)";
		$pkeyid = $this->getPrivkey($pdo);
		openssl_sign($data, $signature, $pkeyid);
		openssl_free_key($pkeyid);
		return $signature;
	}
	
	function createGridTableWithSqrtSizeOfButtons ($inputArray) {
		// create a table that is optimal (sqrt-like size)
		$numberOfIcons = count($inputArray); 
		if ($numberOfIcons == 0) {
			// no items to display
			return;
		}
		$numberOfCols = ceil(sqrt($numberOfIcons));
		$porcentageWidth = floor(100/$numberOfCols);
		
		echo '<table class=gridtable>';
		$colcounter = 0;
		for ($index=0;$index<$numberOfIcons;$index++) {
			if ($colcounter == 0) {
				echo "<tr><td>";
			}
			$anEntry = $inputArray[$index];
			$textOfButton = $anEntry["textOfButton"]; #
			$onClickMethod = $anEntry["onClickMethod"]; // With parameters!
			
			$button = '<input type="button" value="' . $textOfButton . '"';			
			$button = $button . ' onclick="' . $onClickMethod . '"';
			$button = $button . ' style="height: 50px; width:' . $porcentageWidth . '%; font-size:20px; background-color:#b3b3c9" />';
			echo $button;
			$colcounter++;
			if ($colcounter == $numberOfCols) {
				$colcounter = 0;
				echo "</tr>";
			}
		}
		echo "</tr>";
		echo "</table>";
	}
	
	
	function createGridTableWithSqrtSizeOfStyleButtons($inputArray) {
		$this->createGridTableWithSqrtSizeOfStyleButtonsAndHeader($inputArray,'','dummy');
	}
	
	function getTableNameFromId($tableid) {
		if (is_null($tableid) || ($tableid == 0)) {
			return "-"; // togo
		}
		$sql = "SELECT tableno FROM " . DB_RESTTABLES_TABLE . " WHERE id=". $tableid;
		$dbresult = $this->dbutils->performSqlCommand($sql);
		$zeile = mysqli_fetch_array( $dbresult, MYSQL_ASSOC);
		$tablename = $zeile['tableno'];
		mysqli_free_result( $dbresult );
		return $tablename;
	}
	
	function getCurrentPriceLevel() {
		$sql = "SELECT setting FROM %config% WHERE name='pricelevel'";
		$dbresult = $this->dbutils->performSqlCommand($sql);
		$zeile = mysqli_fetch_array( $dbresult, MYSQL_ASSOC);
		$pricelevelid = $zeile['setting'];
		mysqli_free_result( $dbresult );
		
		$sql = "SELECT id,name FROM %pricelevel% WHERE id=$pricelevelid";
		$dbresult = $this->dbutils->performSqlCommand($sql);
		$zeile = mysqli_fetch_array( $dbresult, MYSQL_ASSOC);
		$pricelevelname = $zeile['name'];
		mysqli_free_result( $dbresult );
		
		return (array("id" => $pricelevelid, "name" => $pricelevelname));
	}
	
	function createGridTableWithSqrtSizeOfStyleButtonsAndHeader ($inputArray,$headline,$headercolor) {
		// create a table that is optimal (sqrt-like size)
		$numberOfIcons = count($inputArray);
		if ($numberOfIcons == 0) {
			// no items to display
			return;
		}
		$numberOfCols = ceil(sqrt($numberOfIcons));
		$porcentageWidth = floor(100.0/$numberOfCols);
	
		echo '<table class=gridtable>';
		
		// Headline
		if ($headline <> '') {
			echo '<tr><th style="background-color:#' . $headercolor . '">' . $headline . '</th>';
		}
		
		$colcounter = 0;
		for ($index=0;$index<$numberOfIcons;$index++) {
			if ($colcounter == 0) {
				echo "<tr><td>";
			}
			$anEntry = $inputArray[$index];
			$textOfButton = $anEntry["textOfButton"]; #
			$onClickMethod = $anEntry["onClickMethod"]; // With parameters!
			$style = $anEntry["style"];
				
			$button = '<input type="button" value="' . $textOfButton . '"';
			$button = $button . ' onclick="' . $onClickMethod . '"';
			$button = $button . ' style="' . $style . '; width:' . $porcentageWidth . '%;" />';
			echo $button;
			$colcounter++;
			if ($colcounter == $numberOfCols) {
				$colcounter = 0;
				echo "</tr>";
			}
		}
		echo "</tr>";
		echo "</table>";
	}
	
	function getCurrency() {
		$pdo = $this->dbutils->openDbAndReturnPdo();
		
		$sql = "SELECT setting from %config% where name='currency'";
		$stmt = $pdo->prepare($this->dbutils->resolveTablenamesInSqlString($sql));
		$stmt->execute();
		$row =$stmt->fetchObject();
		if ($row != null) {
			return $row->setting;
		} else {
			return "Euro";
		}
	}
}
?>