feat: custom captcha

3 files changed, 154 insertions, 7 deletions

diff --git a/src/accounts.php b/src/accounts.php
index 99d1a9c..72c766f 100644
--- a/src/accounts.php
+++ b/src/accounts.php
@@ -5,11 +5,6 @@ function authorize_user(bool $required = false): bool
 {
     session_start();
 
-    if (!isset($_SESSION["captcha_solved"]) && !CLIENT_REQUIRES_JSON) {
-        header("Location: /captcha.php");
-        exit;
-    }
-
     if (!isset($_COOKIE["secret_key"]) && !isset($_SERVER["HTTP_AUTHORIZATION"])) {
         if (isset($_SESSION["user_id"])) {
             session_unset();
diff --git a/src/captcha.php b/src/captcha.php
new file mode 100644
index 0000000..d6d2547
--- /dev/null
+++ b/src/captcha.php
@@ -0,0 +1,151 @@
+<?php
+function generate_image_captcha(int $width, int $height, int $difficulty, string $file_name, string $file_folder): string
+{
+    $image = imagecreatetruecolor($width, $height);
+
+    $background = imagecolorallocate($image, 0xDD, 0xDD, 0xDD);
+    imagefilledrectangle($image, 0, 0, $width, $height, $background);
+
+    $files = scandir($file_folder);
+    array_splice($files, 0, 2);
+
+    for ($i = 0; $i < 50 * $difficulty; $i++) {
+        $unprocessed = imagecreatefrompng("$file_folder/" . $files[random_int(0, count($files) - 1)]);
+
+        $oldw = imagesx($unprocessed);
+        $oldh = imagesy($unprocessed);
+
+        $w = random_int(round($oldw / 4), round($oldw / 2));
+        $h = random_int(round($oldh / 4), round($oldh / 2));
+
+        $file = imagecreatetruecolor($w, $h);
+        imagealphablending($file, false);
+        $transparent = imagecolorallocatealpha($file, 0, 0, 0, 127);
+        imagefill($file, 0, 0, $transparent);
+        imagesavealpha($file, true);
+
+        imagecopyresampled($file, $unprocessed, 0, 0, 0, 0, $w, $h, $oldw, $oldh);
+
+        $angle = random_int(0, 360);
+
+        $file = imagerotate($file, $angle, $transparent);
+
+        for ($j = 0; $j < random_int(2, 5 * $difficulty); $j++) {
+            imagefilter($file, IMG_FILTER_GAUSSIAN_BLUR);
+        }
+
+        if (random_int(0, 15) % 3 == 0) {
+            imagefilter($file, IMG_FILTER_NEGATE);
+        }
+
+        if (random_int(0, 20) % 4 == 0) {
+            imagefilter($file, IMG_FILTER_PIXELATE, 4);
+        }
+
+        $w = imagesx($file);
+        $h = imagesy($file);
+
+        imagecopy(
+            $image,
+            $file,
+            random_int(0, $width - $w),
+            random_int(0, $height - $h),
+            0,
+            0,
+            $w,
+            $h
+        );
+    }
+
+    $foreground = imagecreatefrompng("$file_folder/$file_name.png");
+    $transparent = imagecolorallocatealpha($foreground, 0, 0, 0, 127);
+    $angle = random_int(0, max: 180);
+    $foreground = imagerotate($foreground, $angle, $transparent);
+    $w = imagesx($foreground);
+    $h = imagesy($foreground);
+    imagecopy(
+        $image,
+        $foreground,
+        random_int(0, $width - $w),
+        random_int(0, $height - $h),
+        0,
+        0,
+        $w,
+        $h
+    );
+
+    ob_start();
+    imagepng($image);
+    $source = ob_get_contents();
+    ob_clean();
+
+    return "data:image/png;base64," . base64_encode($source);
+}
+
+function html_captcha_form()
+{
+    echo '' ?>
+    <div class="box" id="form-captcha-wrapper" style="display: none;">
+        <div class="box navtab">
+            Solve captcha
+        </div>
+        <div class="box content">
+            <noscript>JavaScript is required for captcha!</noscript>
+            <form id="form-captcha">
+                <img src="" alt="Generating captcha..." id="form-captcha-img" width="256">
+                <div class="column small-gap">
+                    <div class="row small-gap">
+                        <input type="text" name="answer" placeholder="Enter emote name..." class="grow"
+                            id="form-captcha-answer">
+                        <button type="submit" class="green" id="form-captcha-solve">Solve</button>
+                    </div>
+                </div>
+            </form>
+        </div>
+    </div>
+    <script>
+        const formElement = document.getElementById("form-captcha");
+        const formWrapper = document.getElementById("form-captcha-wrapper");
+
+        function get_captcha() {
+            fetch("/captcha.php")
+                .then((response) => response.json())
+                .then((json) => {
+                    if (json.data == null) {
+                        formWrapper.style.display = "none";
+                        return;
+                    }
+
+                    document.getElementById("form-captcha-answer").value = null;
+
+                    formWrapper.style.display = "flex";
+
+                    document.getElementById("form-captcha-img").setAttribute("src", json.data);
+                });
+        }
+
+        get_captcha();
+
+        formElement.addEventListener("submit", (e) => {
+            e.preventDefault();
+
+            const answer = document.getElementById("form-captcha-answer");
+            const body = new FormData(formElement);
+
+            fetch("/captcha.php", {
+                "method": "POST",
+                "body": body
+            })
+                .then((response) => response.json())
+                .then((json) => {
+                    if (json.status_code == 200 && json.data == null) {
+                        formWrapper.style.display = "none";
+                        return;
+                    }
+
+                    get_captcha();
+                });
+        });
+    </script>
+    <?php ;
+}
\ No newline at end of file
diff --git a/src/config.sample.php b/src/config.sample.php
index ed206f6..3d30044 100644
--- a/src/config.sample.php
+++ b/src/config.sample.php
@@ -65,9 +65,10 @@ define("TWITCH_CLIENT_ID", "AAAAAAAAA"); // Client ID of your Twitch application
 define("TWITCH_SECRET_KEY", "BBBBBBBBB"); // Secret key of your Twitch application.
 define("TWITCH_REDIRECT_URI", ((isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off') ? "https" : "http") . "://$_SERVER[HTTP_HOST]/account/login/twitch.php"); // Redirect URI of your Twitch application.
 
-// HCAPTCHA
+// CAPTCHA
 define("CAPTCHA_ENABLE", true); // Enable built-in captcha.
-define("CAPTCHA_WORDS", ["hello", "apple", "cat"]); // Captcha words.
+define("CAPTCHA_SIZE", [580, 220]); // Captcha size.
+define("CAPTCHA_FORCE_USERS", false); // Force authorized users to solve captcha.
 
 // FOR DEVELOPERS
 define("CLIENT_REQUIRES_JSON", isset($_SERVER["HTTP_ACCEPT"]) && $_SERVER["HTTP_ACCEPT"] == "application/json");
\ No newline at end of file