SiteEditor.php

<?php

class SiteEditor {
    private $userPasswordHash;
    private $contentPath;
    private $post = array();

    public function __construct($userPasswordHash, $contentPath) {
        $this->userPasswordHash = strtolower($userPasswordHash);
        $this->contentPath = $contentPath;
        session_start();
    }

    public function handleRequest(array $post) {
        $this->post = $post;
        $this->assertLoggedIn();
        if($this->isRequestChangeContent()) {
            $this->changeContent();
        } elseif ($this->isRequestTypeChanges()) {
            $this->typeChanges();
        }
        $this->echoChooseSite();
    }

    private function getTxtFilesAsOptions() {
        $sites = '';
        foreach (glob($this->contentPath . '*.txt') as $site) {
            $site = substr($site, strrpos($site, '/') + 1);
            $sites.= '<option value="' . $site . '">' . $site . '</option>';
        }
        return $sites;
    }

    private function typeChanges() {
        $file = $this->contentPath . $this->form('file');
        $this->assertValidTxtFile($file);
        $content = $this->decodeContent($this->readFile($file));
        $this->echoTypeChangesPage($file, $content);
    }

    private function readFile($file) {
        if (($result = file_get_contents($file)) === false) {
            throw new RuntimeException('Error while reading file: ' . $file);
        }
        return $result;
    }

    private function decodeContent($content) {
        return str_replace('<br>', "\n", $content);
    }

    private function isRequestTypeChanges() {
        return $this->form('chooseSite') && $this->form('file');
    }

    private function changeContent() {
        $file = $this->contentPath . $this->form('file');
        $this->assertValidTxtFile($file);
        $content = $this->encodeContent($this->form('content'));
        $this->writeToFile($file, $content);
    }

    private function writeToFile($file, $content) {
        if (@file_put_contents($file, $content) === false) {
            throw new RuntimeException('Error while writing file: ' . $file);
        }
    }

    private function encodeContent($content) {
        $content = html_entity_decode($content, ENT_QUOTES);
        return str_replace(array("\r\n", "\n", "\r"), '<br>', $content);
    }

    private function assertValidTxtFile($file) {
        $file = str_replace('/', '_', $file);
        if ($this->isInvalidFile($file)) {
            throw new RuntimeException('Invalid file:' . $file);
        }
    }

    private function isInvalidFile($file) {
        return substr($file, -4) == '.txt' && is_file($file) && is_writable($file) && is_readable($file);
    }

    private function isRequestChangeContent() {
        return $this->form('changeContent') && $this->form('file') && $this->form('content');
    }

    private function assertLoggedIn() {
        if ($this->isLoggedIn()) {
            return;
        }
        if ($this->form('login')) {
            if ($this->validateLoginForm()) {
                $this->login();
                $this->post = array();
            } else {
                throw new Exception('Invalid login data provided');
            }
        }
        $this->echoLoginPage();
    }

    private function login() {
        $_SESSION['login'] = true;
    }

    private function isLoggedIn() {
        return isset($_SESSION['login']);
    }

    private function validateLoginForm() {
        return
            $this->form('user') && $this->form('password') &&
            $this->validateHash($this->form('user'), $this->form('password'))
            ;
    }

    private function validateHash($user, $password) {
        return hash('sha512', $user . 'XX' . $password) == $this->userPasswordHash;
    }

    private function form($index) {
        return isset($this->post[$index]) ? $this->post[$index] : null;
    }

    private function echoLoginPage() {
        ?>
            <!-- I am a login page-->
            <form action="fsb.php" method="post"><input type="text" name="user"> <input type="password" name="password"><input type="submit" name="login" value="login"></form>
        <?php
        exit(0);
    }

    private function echoTypeChangesPage($file, $content) {
        ?>
            <!-- I am a site-editing page-->
            <form action="fsb.php" method="post">site: <?php echo $file ?> <input type="hidden" name="file" value="<?php echo $_POST['file'] ?>"><textarea name="content"><?php echo $content ?></textarea><input type="submit" name="changeContent" value="edit"></form>
        <?php
        exit(0);
    }

    private function echoChooseSite() {
        $sites = $this->getTxtFilesAsOptions();
        ?>
            <!-- I am a site-choosing page-->
            <form action="fsb.php" method="post"><select name="file"><?php echo $sites ?></select><input type="submit" name="chooseSite" value="next"></form>
        <?php
        exit(0);
    }
}