<?php namespace Illuminate\Auth\Passwords;

use Closure;
use UnexpectedValueException;
use Illuminate\Contracts\Auth\UserProvider;
use Illuminate\Contracts\Mail\Mailer as MailerContract;
use Illuminate\Contracts\Auth\PasswordBroker as PasswordBrokerContract;
use Illuminate\Contracts\Auth\CanResetPassword as CanResetPasswordContract;

class PasswordBroker implements PasswordBrokerContract {

	/**
	 * The password token repository.
	 *
	 * @var \Illuminate\Auth\Passwords\TokenRepositoryInterface
	 */
	protected $tokens;

	/**
	 * The user provider implementation.
	 *
	 * @var \Illuminate\Contracts\Auth\UserProvider
	 */
	protected $users;

	/**
	 * The mailer instance.
	 *
	 * @var \Illuminate\Contracts\Mail\Mailer
	 */
	protected $mailer;

	/**
	 * The view of the password reset link e-mail.
	 *
	 * @var string
	 */
	protected $emailView;

	/**
	 * The custom password validator callback.
	 *
	 * @var \Closure
	 */
	protected $passwordValidator;

	/**
	 * Create a new password broker instance.
	 *
	 * @param  \Illuminate\Auth\Passwords\TokenRepositoryInterface  $tokens
	 * @param  \Illuminate\Contracts\Auth\UserProvider  $users
	 * @param  \Illuminate\Contracts\Mail\Mailer  $mailer
	 * @param  string  $emailView
	 * @return void
	 */
	public function __construct(TokenRepositoryInterface $tokens,
                                UserProvider $users,
                                MailerContract $mailer,
                                $emailView)
	{
		$this->users = $users;
		$this->mailer = $mailer;
		$this->tokens = $tokens;
		$this->emailView = $emailView;
	}

	/**
	 * Send a password reset link to a user.
	 *
	 * @param  array  $credentials
	 * @param  \Closure|null  $callback
	 * @return string
	 */
	public function sendResetLink(array $credentials, Closure $callback = null)
	{
		// First we will check to see if we found a user at the given credentials and
		// if we did not we will redirect back to this current URI with a piece of
		// "flash" data in the session to indicate to the developers the errors.
		$user = $this->getUser($credentials);

		if (is_null($user))
		{
			return PasswordBrokerContract::INVALID_USER;
		}

		// Once we have the reset token, we are ready to send the message out to this
		// user with a link to reset their password. We will then redirect back to
		// the current URI having nothing set in the session to indicate errors.
		$token = $this->tokens->create($user);

		$this->emailResetLink($user, $token, $callback);

		return PasswordBrokerContract::RESET_LINK_SENT;
	}

	/**
	 * Send the password reset link via e-mail.
	 *
	 * @param  \Illuminate\Contracts\Auth\CanResetPassword  $user
	 * @param  string  $token
	 * @param  \Closure|null  $callback
	 * @return int
	 */
	public function emailResetLink(CanResetPasswordContract $user, $token, Closure $callback = null)
	{
		// We will use the reminder view that was given to the broker to display the
		// password reminder e-mail. We'll pass a "token" variable into the views
		// so that it may be displayed for an user to click for password reset.
		$view = $this->emailView;

		return $this->mailer->send($view, compact('token', 'user'), function($m) use ($user, $token, $callback)
		{
			$m->to($user->getEmailForPasswordReset());

			if ( ! is_null($callback)) call_user_func($callback, $m, $user, $token);
		});
	}

	/**
	 * Reset the password for the given token.
	 *
	 * @param  array     $credentials
	 * @param  \Closure  $callback
	 * @return mixed
	 */
	public function reset(array $credentials, Closure $callback)
	{
		// If the responses from the validate method is not a user instance, we will
		// assume that it is a redirect and simply return it from this method and
		// the user is properly redirected having an error message on the post.
		$user = $this->validateReset($credentials);

		if ( ! $user instanceof CanResetPasswordContract)
		{
			return $user;
		}

		$pass = $credentials['password'];

		// Once we have called this callback, we will remove this token row from the
		// table and return the response from this callback so the user gets sent
		// to the destination given by the developers from the callback return.
		call_user_func($callback, $user, $pass);

		$this->tokens->delete($credentials['token']);

		return PasswordBrokerContract::PASSWORD_RESET;
	}

	/**
	 * Validate a password reset for the given credentials.
	 *
	 * @param  array  $credentials
	 * @return \Illuminate\Contracts\Auth\CanResetPassword
	 */
	protected function validateReset(array $credentials)
	{
		if (is_null($user = $this->getUser($credentials)))
		{
			return PasswordBrokerContract::INVALID_USER;
		}

		if ( ! $this->validateNewPassword($credentials))
		{
			return PasswordBrokerContract::INVALID_PASSWORD;
		}

		if ( ! $this->tokens->exists($user, $credentials['token']))
		{
			return PasswordBrokerContract::INVALID_TOKEN;
		}

		return $user;
	}

	/**
	 * Set a custom password validator.
	 *
	 * @param  \Closure  $callback
	 * @return void
	 */
	public function validator(Closure $callback)
	{
		$this->passwordValidator = $callback;
	}

	/**
	 * Determine if the passwords match for the request.
	 *
	 * @param  array  $credentials
	 * @return bool
	 */
	public function validateNewPassword(array $credentials)
	{
		list($password, $confirm) = [
			$credentials['password'], $credentials['password_confirmation'],
		];

		if (isset($this->passwordValidator))
		{
			return call_user_func(
				$this->passwordValidator, $credentials) && $password === $confirm;
		}

		return $this->validatePasswordWithDefaults($credentials);
	}

	/**
	 * Determine if the passwords are valid for the request.
	 *
	 * @param  array  $credentials
	 * @return bool
	 */
	protected function validatePasswordWithDefaults(array $credentials)
	{
		list($password, $confirm) = [
			$credentials['password'], $credentials['password_confirmation'],
		];

		return $password === $confirm && mb_strlen($password) >= 6;
	}

	/**
	 * Get the user for the given credentials.
	 *
	 * @param  array  $credentials
	 * @return \Illuminate\Contracts\Auth\CanResetPassword
	 *
	 * @throws \UnexpectedValueException
	 */
	public function getUser(array $credentials)
	{
		$credentials = array_except($credentials, ['token']);

		$user = $this->users->retrieveByCredentials($credentials);

		if ($user && ! $user instanceof CanResetPasswordContract)
		{
			throw new UnexpectedValueException("User must implement CanResetPassword interface.");
		}

		return $user;
	}

	/**
	 * Get the password reset token repository implementation.
	 *
	 * @return \Illuminate\Auth\Passwords\TokenRepositoryInterface
	 */
	protected function getRepository()
	{
		return $this->tokens;
	}

}
