SimplePHPForm.php

<?php
/**
* Simple Forms for PHP
*
* Automatic form handling with validation, helpers, warnings and more.
* Form fields: text fields, text areas, dropdowns, checkboxes, radio buttons and hidden fields.
* Validation flags: required, email, phone, number, lengthmax *, lengthmin *, sizemax *, sizemin *
*
* See ./examples/basic.php and ./examples/advanced.php and ./examples/centered.php for usage.
*/
class SimplePHPForm
{
	const STATE_NEW = 0;
	const STATE_SUCCESS = 1;
	const STATE_VALIDATE = 2;
	const STATE_FAIL = 3;
	const STATE_ERROR = 4;
	const STATE_DUPLICATE = 5;

	function __construct(
			public $url_action='',
			public $message_new='Registration Form',
			public $message_success='Form submitted successfully! You should receive a confirmation email shortly!',
			public $message_fail='Oops! We had trouble accepting your form. Details below.',
			public $message_error='You have discovered an internal error. Please contact us!',
			public $message_duplicate='You are already registered. If there is an issue, please contact us.',
			public $state=self::STATE_NEW,
			public $input_list=[]
		)
	{
		// Using PHP 8 constructor promotion.
	}

	/**
	* Add new field to form.
	* @param string $name Field name which can be refernced internally.
	* @param string $type Field type.
	* @param string $data Default data displayed in field.
	* @param string $data_validation_flags Data entered will be sanitized against this list of tests.
	* @param string $text_title Title of field.
	* @param string $text_help Helper text which is displayed to the User at fill-out time.
	* @param string $text_error Error text which is displayed to the User when validation fails.
	*/
	function add($name, $type, $data, $data_validation_flags, $text_title, $text_help, $text_error)
	{
		// Set default data.
		$data_default = $data;

		// Get form submission data from $_POST if it exists.
		if(isset($_POST['simplephpform_'.$name]))
		{
			$data = $_POST['simplephpform_'.$name];
			$this->state = self::STATE_VALIDATE; // We've got data during this pass. Form should be validated.
		}

		$this->input_list[$name] = new SimplePHPFormInput($name, $type, $data, $data_validation_flags, $data_default, $text_title, $text_help, $text_error);

		// Special logic for checkbox types because browsers simply do not $_POST them if they are unchecked.
		if($type == 'checkbox' && $this->state != self::STATE_NEW)
		{
			if(isset($_POST['simplephpform_'.$name]))
				$this->input_list[$name]->data = true;
			else
				$this->input_list[$name]->data = false;
		}
	}

	/**
	* Add new dropdown field to form.
	* @param string $name Field name which can be refernced internally.
	* @param string $data Default data for the field.
	* @param string $value Default display value for the field.
	*/
	function addDropdownEntry($name, $data, $value)
	{
		$this->input_list[$name]->dropdown_entries[$value] = $data;
	}

	/**
	* Add new radio button field to form.
	* @param string $name Field name which can be refernced internally.
	* @param string $value Default display value for the field.
	* @param string $data Default data for the field.
	*/
	function addRadioButton($name, $value, $data)
	{
		$this->input_list[$name]->radio_entries[$value] = $data;
	}

	// Display form state to User.
	function displayState()
	{
		$output = '';

		if($this->state == self::STATE_NEW) {
			$output = '<div class="simplephpform_state_untouched">'.$this->message_new.'</div>';
		} if($this->state == self::STATE_SUCCESS) {
			$output = '<div class="simplephpform_state_success">'.$this->message_success.'</div> <br />';
		} if($this->state == self::STATE_FAIL) {
			$output = '<div class="simplephpform_state_fail">'.$this->message_fail.'</div>';
		} if($this->state == self::STATE_ERROR) {
			$output = '<div class="simplephpform_state_fail">'.$this->message_error.'</div>';
		} if($this->state == self::STATE_DUPLICATE) {
			$output = '<div class="simplephpform_state_success">'.$this->message_duplicate.'</div>';
		}

		return $output."\n";
	}

	/**
	* Display the form.
	* @param string|bool $name If string: Display individual field. True: All fields with full form. False: All fields.
	*/
	function display($name=false)
	{
		// No name specified? Return them all in the order they were defined.
		if(!is_string($name))
		{
			$output = '';
			$output .= $this->displayState();
			$output .= '<form method="post" action="'.$this->url_action.'" class="simplephpform">';

			foreach($this->input_list as $input)
				$output .= $this->display($input->name)."\n";

			$output .= '<input type="submit" value="Submit Form" class="simplephpform_submit" />';
			$output .= '</form>';

			return $output;
		}

		// Generate output if the specified Form Input exists.
		if(array_key_exists($name, $this->input_list))
		{
			$output = '';
			$target = $this->input_list[$name];
			$type = strtolower(trim($target->type));

			if($type == 'textarea') // Text area.
			{
				$output .= '<div class="simplephpform_title">'.$target->text_title.'</div>'."\n";
				$output .= '<textarea name="simplephpform_'.$target->name.'" rows="'.$target->rows.'" cols="'.$target->columns.'">'.$target->data.'</textarea>'."\n";

				// Helper or error message?
				if($target->state != self::STATE_FAIL && $target->text_error != NULL)
					$output .= '<div class="simplephpform_error">'.$target->text_error.'</div>'."\n";
				else if($target->text_help != NULL)
					$output .= '<div class="simplephpform_help">'.$target->text_help.'</div>'."\n";
			}
			else if($type == 'dropdown') // Drop down menu.
			{
				$output .= '<div class="simplephpform_title">'.$target->text_title.'</div>'."\n";
				$output .= '<select name="simplephpform_'.$target->name.'">'."\n";

				foreach($target->dropdown_entries as $drop_down_value => $drop_down_name)
				{
					if($target->data == $drop_down_value)
						$output .= '<option value="'.$drop_down_value.'" selected="selected">'.$drop_down_name.'</option>'."\n";
					else
						$output .= '<option value="'.$drop_down_value.'">'.$drop_down_name.'</option>'."\n";
				}

				$output .= '</select>'."\n";

				// Helper or error message?
				if($target->state == self::STATE_FAIL)
					$output .= '<div class="simplephpform_error">'.$target->text_error.'</div>'."\n";
				else if($target->text_help != NULL)
					$output .= '<div class="simplephpform_help">'.$target->text_help.'</div>'."\n";
			}
			else if($type == 'radio') // Radio button.
			{
				$output .= '<div class="simplephpform_title">'.$target->text_title.'</div><div class="simplephpform_radiobox">'."\n";

				foreach($target->radio_entries as $radio_name => $radio_value)
				{
					if($target->data == $radio_value)
						$output .= '<label><input type="radio" name="simplephpform_'.$target->name.'" value="'.$radio_value.'" checked="checked" > '.$radio_name."</label></input>\n";
					else
						$output .= '<label><input type="radio" name="simplephpform_'.$target->name.'" value="'.$radio_value.'" > '.$radio_name."</label></input>\n";
				}

				$output .= '</div>';

				// Helper or error message?
				if($target->state == self::STATE_FAIL)
					$output .= '<div class="simplephpform_error">'.$target->text_error.'</div>'."\n";
				else if($target->text_help != NULL)
					$output .= '<div class="simplephpform_help">'.$target->text_help.'</div>'."\n";
			}
			else if($type == 'checkbox') // Check box. Never needs an error message. Will never need an error or info message.
			{
				$output .= '<div class="simplephpform_title"></div><div style="float: left; margin-bottom: 2px;">'."\n";

				if(boolval($target->data))
					$output .= '<label><input type="'.$target->type.'" name="simplephpform_'.$target->name.'" checked="checked" />'.$target->text_title."</label>\n";
				else
					$output .= '<label><input type="'.$target->type.'" name="simplephpform_'.$target->name.'" />'.$target->text_title."</label>\n";

				$output .= '</div>';
			}
			else if($type == 'hidden') // Hidden type, for metadata, etc.
			{
				$output .= '<input type="'.$target->type.'" name="simplephpform_'.$target->name.'" value="'.$target->data.'" />'."\n";
			}
			else // Default. Textbox, password, etc.
			{
				$output .= '<div class="simplephpform_title">'.$target->text_title.'</div>'."\n";

				$output .= '<label><input type="'.$target->type.'" name="simplephpform_'.$target->name.'" value="'.$target->data.'" />'."\n";

				if($target->state == self::STATE_FAIL)
					$output .= '<div class="simplephpform_error">'.$target->text_error.'</div>'."\n";
				else if($target->text_help != NULL)
					$output .= '<div class="simplephpform_help">'.$target->text_help.'</div>'."\n";

				$output .= '</label>';
			}

			$output .= '<div class="simplephpform_clear"></div>';
			return $output;
		}
	}

	// Reset all form data to defaults.
	function reset()
	{
		foreach($this->input_list as $input)
			$input->data = $input->data_default;
	}

	// Get data from the form.
	function get($name)
	{
		if(isset($this->input_list[$name]->data))
			return $this->input_list[$name]->data;
		return null;
	}

	// Validate form data.
	function validate()
	{
		// Was this form submitted? Or is this page new?
		if($this->state == self::STATE_NEW)
			return false; // Invalid by default.

		// Set state as successfull first, then run validation test gauntlet ...
		$this->state = self::STATE_SUCCESS;

		foreach($this->input_list as $input)
		{
			// Set individual input entry state successful at first, then run validation test gauntlet ...
			$input->state = self::STATE_SUCCESS;

			// What validation tests need to be run?
			for($i = 0; $i < count($input->data_validation_flags); $i += 1)
				if(!empty($input->data_validation_flags[$i]))
				{
					// Sanitize flag by stripping whitespace, and making lowercase.
					$flag = strtolower(trim($input->data_validation_flags[$i]));
					// Always trim data.
					$input->data = trim($input->data);

					// *** If we have a test for this flag, run it! ***

					// Test: Is the entry required?
					if($flag == 'required')
						if(!$this->validateExists($input->data))
							$input->state = self::STATE_FAIL;

					// Test: Is the entry an email?
					if($flag == 'email')
						if(!$this->validateEmail($input->data))
							$input->state = self::STATE_FAIL;

					// Test: Is the entry a phone number?
					if($flag == 'phone')
						if(!$this->validatePhone($input->data))
							$input->state = self::STATE_FAIL;

					// Test: Is the entry a number?
					if($flag == 'number')
						if(!$this->validateNumber($input->data))
							$input->state = self::STATE_FAIL;

					// Process multi-part flags.
					$flag_parts = explode(' ', $flag);

					// Test: Is there a max string length?
					if($flag_parts[0] == 'lengthmax')
						if(isset($flag_parts[1]))
							if(!$this->validateLengthMax($input->data, $flag_parts[1]))
								$input->state = self::STATE_FAIL;

					// Test: Is there a min string length?
					if($flag_parts[0] == 'lengthmin')
						if(isset($flag_parts[1]))
							if(!$this->validateLengthMin($input->data, $flag_parts[1]))
								$input->state = self::STATE_FAIL;

					// Test: Is there a max number size?
					if($flag_parts[0] == 'sizemax')
						if(isset($flag_parts[1]))
							if(!$this->validateSizeMax($input->data, $flag_parts[1]))
								$input->state = self::STATE_FAIL;

					// Test: Is there a min number size?
					if($flag_parts[0] == 'sizemin')
						if(isset($flag_parts[1]))
							if(!$this->validateSizeMin($input->data, $flag_parts[1]))
								$input->state = self::STATE_FAIL;

				}
		}

		// Did ALL individual input entries validate successfully? If no, set form state to fail.
		foreach($this->input_list as $input)
			if($input->state == self::STATE_FAIL)
				$this->state = self::STATE_FAIL;

		// No input entries? Also fail.
		if(count($this->input_list) < 1)
			$this->state = self::STATE_FAIL;

		if($this->state == self::STATE_SUCCESS)
			return true;
		else
			return false;
	}

	// Does data exist?
	function validateExists($data)
	{
		if($data != '')
			return true;
		return false;
	}

	// Valid email?
	function validateEmail($data)
	{
		if(strlen($data) > 5 && strstr($data, '@') && strstr($data, '.') && strstr($data, ' ') == false && $data[0] != '@')
			return true;
		return false;
	}

	// Valid phone number?
	function validatePhone($data)
	{
		$data = strval($data);
		for ($i = 0; $i < strlen($data); $i++)
			if(strpos('1234567890()- ', $data[$i]) === false)
				return false; // Invalid character.
		if(strlen($data) > 10 && strlen($data) < 26)
			return true;
		return false;
	}

	// Valid number?
	function validateNumber($data)
	{
		if(is_numeric($data))
			return true;
		return false;
	}

	// Valid maximum string length?
	function validateLengthMax($data, $size)
	{
		if(strlen($data) <= $size)
			return true;
		return false;
	}

	// Valid minimum string length?
	function validateLengthMin($data, $size)
	{
		if(strlen($data) >= $size)
			return true;
		return false;
	}

	// Valid maximum number size?
	function validateSizeMax($data, $size)
	{
		if(is_numeric($data))
			if($data <= $size)
				return true;
		return false;
	}

	// Valid minimum number size?
	function validateSizeMin($data, $size)
	{
		if(is_numeric($data))
			if($data >= $size)
				return true;
		return false;
	}
}

// Used internally by SimplePHPForm to hold field data.
class SimplePHPFormInput
{
	function __construct(
			public $name=NULL,
			public $type='text',
			public $data='',
			public $data_validation_flags=[],
			public $data_default='',
			public $text_title='',
			public $text_help='',
			public $text_error='',
			// Internal state.
			public $state=SimplePHPForm::STATE_NEW,
			// Special variables used for specific input types.
			public $rows=3,
			public $columns=30,
			public $dropdown_entries=[],
			public $radio_entries=[]
		)
	{
		// Using PHP 8 constructor promotion.
		// If checkbox, $data needs to be true or false.
		if($type == 'checkbox')
		{
			$this->data = boolval($data);
			$this->data_default = boolval($data_default);
		}
	}
}