<?php
namespace Szurubooru;

class Validator
{
	private $config;

	public function __construct(\Szurubooru\Config $config)
	{
		$this->config = $config;
	}

	public function validate(\Szurubooru\IValidatable $validatable)
	{
		$validatable->validate($this);
	}

	public function validateNumber($subject)
	{
		if (!preg_match('/^-?[0-9]+$/', $subject))
			throw new \DomainException($subject . ' does not look like a number.');
	}

	public function validateNonEmpty($subject, $subjectName = 'Object')
	{
		if (!$subject)
			throw new \DomainException($subjectName . ' cannot be empty.');
	}

	public function validateLength($subject, $minLength, $maxLength, $subjectName = 'Object')
	{
		$this->validateMinLength($subject, $minLength, $subjectName);
		$this->validateMaxLength($subject, $maxLength, $subjectName);
	}

	public function validateMinLength($subject, $minLength, $subjectName = 'Object')
	{
		if (strlen($subject) < $minLength)
			throw new \DomainException($subjectName . ' must have at least ' . $minLength . ' character(s).');
	}

	public function validateMaxLength($subject, $maxLength, $subjectName = 'Object')
	{
		if (strlen($subject) > $maxLength)
			throw new \DomainException($subjectName . ' must have at most ' . $maxLength . ' character(s).');
	}

	public function validateUserName($userName)
	{
		$minUserNameLength = intval($this->config->users->minUserNameLength);
		$maxUserNameLength = intval($this->config->users->maxUserNameLength);
		$this->validateNonEmpty($userName, 'User name');
		$this->validateLength($userName, $minUserNameLength, $maxUserNameLength, 'User name');

		if (preg_match('/[^a-zA-Z0-9_-]/', $userName))
		{
			throw new \DomainException('User name may contain only characters, numbers, underscore (_) and dash (-).');
		}
	}

	public function validateEmail($email)
	{
		if (!$email)
			return;

		if (!preg_match('/^[^@]+@[^@]+\.\w+$/', $email))
			throw new \DomainException('Specified e-mail appears to be invalid.');
	}

	public function validatePassword($password)
	{
		$minPasswordLength = intval($this->config->security->minPasswordLength);
		$this->validateNonEmpty($password, 'Password');
		$this->validateMinLength($password, $minPasswordLength, 'Password');

		if (preg_match('/[^\x20-\x7f]/', $password))
		{
			throw new \DomainException(
				'Password may contain only characters from ASCII range to avoid potential problems with encoding.');
		}
	}

	public function validatePostTags($tags)
	{
		if (empty($tags))
			throw new \DomainException('Tags cannot be empty.');

		//<> causes HTML injection and problems with Markdown.
		//\/ causes problems with URLs.
		//; causes problems with search argument parsing in JS frontend.
		//whitespace causes problems with search.
		$illegalCharacters = str_split("<>;\\/\r\n\t " . chr(160));
		foreach ($tags as $tag)
		{
			if (empty($tag))
				throw new \DomainException('Tags cannot be empty.');

			//: causes problems with complex search (e.g. id:5).
			if (strpos($tag, ':') > 0)
				throw new \DomainException('Colon in tag may appear only at the beginning.');

			$this->validateMaxLength($tag, 64, 'Tag');

			foreach ($illegalCharacters as $char)
			{
				if (strpos($tag, $char) !== false)
				{
					throw new \DomainException(
						sprintf('Tags cannot contain any of following characters: %s.',
						implode(', ', array_map(function($char)
							{
								if ($char === "\n") return "new line";
								if ($char === "\r") return "carriage return";
								if ($char === "\t") return "tab";
								if ($char === " ") return "space";
								if ($char === chr(160)) return "hard space";
								return $char;
							}, $illegalCharacters))));
				}
			}
		}
	}

	public function validatePostSource($source)
	{
		$this->validateMaxLength($source, 200, 'Source');
	}

	public function validateToken($token)
	{
		$this->validateNonEmpty($token, 'Token');
	}
}