<?php
//////////////////////////////////////////////////////////////////////
// MAILER CONTACT FORM PAGE
//////////////////////////////////////////////////////////////////////

// Prepare data fields
$from = $name = $subject = $msg = null;

// Error set 440 : user screw up
define("ERROR_440_BASE_CODE",        440); // base code = no error
define("ERROR_440_ADDRESS_MISSING",    1); // bit 0 = sender address missing
define("ERROR_440_NAME_MISSING",       2); // bit 1 = sender name missing
define("ERROR_440_SUBJECT_MISSING",    4); // bit 2 = e-mail subject missing
define("ERROR_440_BODY_MISSING",       8); // bit 3 = e-mail body missing
define("ERROR_440_ADDRESS_INCORRECT", 16); // bit 4 = e-mail address is incorrect format

// Error set 550 : server screw up
define("ERROR_550_BASE_CODE",     550); // base code = no error
define("ERROR_550_SENDING_FAILURE", 1); // bit 0 = e-mail sending failed
define("ERROR_550_MEMORY_FAILURE",  2); // bit 1 = memory failed
define("ERROR_550_SPAM_DETECTED",   4); // bit 2 = spam was detected, e-mail was dropped

// Explanation: I decided to add spam detection as a server error for a simple reason:
// it may be false positive, so the user may know that something went wrong.
// Spambots won't actually perceive the returned page with additional informations,
// so they won't ever notice their spam went dropped.

// Set basic error codes -> no bits = no error
$user_error   = ERROR_440_BASE_CODE;
$server_error = ERROR_550_BASE_CODE;

// Testing errors preparation
$test_error_440_address_missing   = false;
$test_error_440_name_missing      = false;
$test_error_440_subject_missing   = false;
$test_error_440_body_missing      = false;
$test_error_440_address_incorrect = false;
//----------------------------------------
$test_error_550_sending_failure   = false;
$test_error_550_memory_failure    = false;
$test_error_550_spam_detected     = false;
//----------------------------------------
$test_error_no_error_success      = false;

// Get the informations: testing errors (method get)
if(isset($_GET['test_address_missing'])) {
	$test_error_440_address_missing   = true;
}
if(isset($_GET['test_name_missing'])) {
	$test_error_440_name_missing      = true;
}
if(isset($_GET['test_subject_missing'])) {
	$test_error_440_subject_missing   = true;
}
if(isset($_GET['test_body_missing'])) {
	$test_error_440_body_missing      = true;
}
if(isset($_GET['test_address_incorrect'])) {
	$test_error_440_address_incorrect = true;
}
if(isset($_GET['test_sending_failure'])) {
	$test_error_550_sending_failure   = true;
}
if(isset($_GET['test_memory_failure'])) {
	$test_error_550_memory_failure    = true;
}
if(isset($_GET['test_spam_detected'])) {
	$test_error_550_spam_detected     = true;
}
if(isset($_GET['test_success'])) {
	$test_error_no_error_success      = true;
}

// Set general test
$test_general = $test_error_440_address_missing || $test_error_440_name_missing || $test_error_440_subject_missing || $test_error_440_body_missing || $test_error_440_address_incorrect || $test_error_550_sending_failure || $test_error_550_memory_failure || $test_error_550_spam_detected || $test_error_no_error_success;

// Get the informations: data fields (method post)
if(isset($_POST['from'])) {
	$from = $_POST['from'];
}
if(isset($_POST['name'])) {
	$name = $_POST['name'];
}
if(isset($_POST['subject'])) {
	$subject = $_POST['subject'];
}
if(isset($_POST['msg'])) {
	$msg = $_POST['msg'];
}

// Set default values
$default = is_null($from) && is_null($name) && is_null($subject) && is_null($msg);

if(!$default) {
	// Errors: user screw up (440 set)
	if(empty($from)) {
		$user_error += ERROR_440_ADDRESS_MISSING;
	}
	if(empty($name)) {
		$user_error += ERROR_440_NAME_MISSING;
	}
	if(empty($subject)) {
		$user_error += ERROR_440_SUBJECT_MISSING;
	}
	if(empty($msg)) {
		$user_error += ERROR_440_BODY_MISSING;
	}
	if(!empty($from)) {
		preg_match("/^([a-zA-Z0-9\.\-]*)\@([a-zA-Z0-9\-]*)\.([a-zA-Z0-9]*)$/", $from, $from_array);

		if(is_null($from_array)) {
			$server_error += ERROR_550_MEMORY_FAILURE;
		} elseif(empty($from_array)) {
			$user_error += ERROR_440_ADDRESS_INCORRECT;
		}
	}

	// Check user or server error
	if($user_error != ERROR_440_BASE_CODE || $server_error != ERROR_550_BASE_CODE) {
		goto error;
	}

	// Setup spam prevention
	$regex = "/(from\:|to\:|bcc\:|cc\:|content\-type\:|mime\-version\:|subject\:|x\-mailer\:|reply\-to\:|\%0a|\%0b)/i";

	if(preg_match($regex, $from) || preg_match($regex, $name) || preg_match($regex, $subject) || preg_match($regex, $msg)) {
		$server_error += ERROR_550_SPAM_DETECTED; // if something in all four fields matches some of the headers,
		goto error;                               // it detects spam and drops the e-mail. Spambots won't ever notice.
	}

	// Prepare mail send
	$send_to        = 'Marek Poláček <marpolda@gmail.com>'; // e-mail address of receipt - change to yours!
	$send_from      = filter_var($from, FILTER_SANITIZE_EMAIL); // Remove all
	$full_subject   = '[TESTING FORM] ' . trim($subject); // Compose your own subject format to help YOU organise
                                                          // messages from your websites.
	$final_subject  = str_replace(array("\r","\n"),array(""," "),$full_subject);
	$final_message  = wordwrap(trim($msg), 70, '\r\n');
	$final_name     = trim($name);

	$success = mail($send_to, $final_subject, $final_message, "From: $final_name <$send_from>");

	if(!$success) {
		$server_error += ERROR_550_SENDING_FAILURE; // If the e-mail failed to send, show the message.
                                                    // This may be because of SMTP server missing or malfunctioning,
                                                    // or function mail() is forbidden to use at the server.
	}
}

// All errors passed
error:
$dir_errors  = '';
$dir_success = '';

// Get error bits
$user_error_bits   = $user_error   - ERROR_440_BASE_CODE;
$server_error_bits = $server_error - ERROR_550_BASE_CODE;

$e440_address_missing   = $user_error_bits & ERROR_440_ADDRESS_MISSING;
$e440_name_missing      = $user_error_bits & ERROR_440_NAME_MISSING;
$e440_subject_missing   = $user_error_bits & ERROR_440_SUBJECT_MISSING;
$e440_body_missing      = $user_error_bits & ERROR_440_BODY_MISSING;
$e440_address_incorrect = $user_error_bits & ERROR_440_ADDRESS_INCORRECT;

$e550_sending_failure = $server_error_bits & ERROR_550_SENDING_FAILURE;
$e550_memory_failure  = $server_error_bits & ERROR_550_MEMORY_FAILURE;
$e550_spam_detected   = $server_error_bits & ERROR_550_SPAM_DETECTED;

$successfully_sent = ($user_error == ERROR_440_BASE_CODE) && ($server_error == ERROR_550_BASE_CODE) && !$default;

if($e440_address_missing || $test_error_440_address_missing) {
	$dir_errors .= '<p>Please enter your <srong>e-mail address</strong> ';
	$dir_errors .= 'like that: \'<strong>john.cena@gmail.com</strong>\'. ';
	$dir_errors .= 'You can\'t send an e-mail <strong>without sender address</strong>.</p>';
}
if($e440_name_missing || $test_error_440_name_missing) {
	$dir_errors .= '<p>Please enter your <strong>name</strong> (or nickname at least). ';
	$dir_errors .= 'You have to <strong>identify</strong> somewhat.</p>';
}
if($e440_subject_missing || $test_error_440_subject_missing) {
	$dir_errors .= '<p>Please enter <strong>message subject</strong>. ';
	$dir_errors .= 'It helps to <strong>distinguish</strong> single mails.</p>';
}
if($e440_body_missing || $test_error_440_body_missing) {
	$dir_errors .= '<p>Please enter at least a single letter to <strong>message body</strong>. ';
	$dir_errors .= 'However, something <strong>meaningful</strong> would be better, ';
	$dir_errors .= 'to make sure the message won\'t end up <strong>in trash</strong>.</p>';
}
if($e440_address_incorrect || $test_error_440_address_incorrect) {
	$dir_errors .= '<p>Entered <strong>e-mail address</strong> is ';
	$dir_errors .= '<strong>incorrect format</strong>. ';
	$dir_errors .= 'E-mail address <strong>has to be</strong> in format ';
	$dir_errors .= '\'<strong>john.cena@gmail.com</strong>\'.</p>';
}
if($e550_sending_failure || $test_error_550_sending_failure) {
	$dir_errors .= '<p>Message failed to send. Please try again later.</p>';
}
if($e550_memory_failure || $test_error_550_memory_failure) {
	$dir_errors .= '<p>Memory failure has occured. Please try again later.</p>';
}
if($e550_spam_detected || $test_error_550_spam_detected) {
	$dir_errors .= '<p>Your message was detected by a spam filter. If you think ';
	$dir_errors .= 'it\'s a mistake, please write an e-mail to websites admin.</p>';
}
if($successfully_sent || $test_error_no_error_success) {
	$dir_success .= '<p>Your message was successfully sent.</p>';
}
?><!DOCTYPE HTML>
<html type="text/html" lang="en-US">
	<head>
		<meta charset="utf-8" />
		<title>Contact form</title>
		<style type="text/css">
			body {
				font-family: "Arial CE", Arial, Helvetica, sans-serif;
				font-size: 12pt;
			}

			p {
				margin: 0px;
				margin-bottom: 0.3em;
				margin-top: 0.3em;
			}

			table {
				border: 0px;
				margin: 0px;
				margin-top: 10px;
				margin-bottom: 10px;
				padding: 0px;
				table-collapse: separated;
				table-align: center;
			}

			.info, input, textarea {
				border: 1px solid;
				border-radius: 5px;
				padding: 5px;
			}

			.info {
				font-size: 10pt;
				margin-top: 20px;
				margin-bottom: 20px;
			}

			input {
				font-size: 15pt;
			}

			label {
				font-size: 15pt;
				font-weight: bold;
			}

			.error {
				/* ERROR background */
				background-color: #ef9669;
				border-color: maroon;
			}

			.success {
				/* SUCCESS background */
				background-color: #69ef69;
				border-color: green;
			}

			input[type="text"], textarea {
				background-color: #fceded;
				border-color: gray;
				width: 600px;
			}

			input[type="submit"], input[type="reset"] {
				background-color: #fedcab;
				border-color: gray;
			}

			input:hover, textarea:hover {
				border-color: silver;
			}
		</style>
	</head>
	<body>
		<h1><center>Contact form</center></h1>
		<?php if(!empty($dir_errors)) {
			echo '<div class="info error"';
			if($test_general) {
				echo ' title="Testing dump"'; // when you enter ?test_* after the contact-form.php in your address bar,
                                              // it will perform a testing dump of the errors. Combine multiple errors
                                              // by adding next &test_* statements. That applies also to test_success
                                              // statement, which tests the success message.
                                              // This should be removed in final tweaks on real website, don't forget!
			}
			echo '>';
			echo $dir_errors;
			echo '</div>';
		}
		if(!empty($dir_success)) {
			echo '<div class="info success"';
			if($test_general) {
				echo ' title="Testing dump"';
			}
			echo '>';
			echo $dir_success;
			echo '</div>';
		} ?>
		<form method="post" action="<?php echo $_SERVER['PHP_SELF']; // points to self page ?>">
			<center><strong>Every single field is required!</strong></center>
			<label for="from"><table>
				<tr><td width="200">Sender e-mail address:</td>
				<td width="650"><input type="text" name="from"<?php if(!$default) {
					if(!empty($from) && !$successfully_sent) {
						echo " value=\"$from\"";
					}
				} ?> placeholder="john.cena@gmail.com" /></td></tr>
			</table></label>
			<label for="name"><table>
				<tr><td width="200">Name:</td>
				<td width="650"><input type="text" name="name"<?php if(!$default) {
					if(!empty($name) && !$successfully_sent) {
						echo " value=\"$name\"";
					}
				} ?> placeholder="John Cena" /></td></tr>
			</table></label>
			<label for="subject"><table>
				<tr><td width="200">Subject:</td>
				<td width="650"><input type="text" name="subject"<?php if(!$default) {
					if(!empty($subject) && !$successfully_sent) {
						echo " value=\"$subject\"";
					}
				} ?> placeholder="Important notice!" /></td></tr>
			</table></label>
			<label for="msg"><table>
				<tr><td width="200">Message body:</td>
				<td width="650"><textarea name="msg" cols="70" rows="20"><?php if(!$default) {
					if(!empty($msg) && !$successfully_sent) {
						echo "$msg";
					}
				} ?></textarea></td></tr>
			</table></label>
			<center><input type="submit" value="Submit" />&nbsp;<input type="reset" value="Cancel" /></center>
		</form>
	</body>
</html>