From b9c4f1dcf1333c14e2d1b67561ec7a5f955baa6e Mon Sep 17 00:00:00 2001
From: "David T. Sadler" <davidtsadler@googlemail.com>
Date: Sun, 9 Aug 2026 20:04:39 +0100
Subject: Initial commit

---
 src/TokenManager.php | 179 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 179 insertions(+)
 create mode 100644 src/TokenManager.php

(limited to 'src/TokenManager.php')

diff --git a/src/TokenManager.php b/src/TokenManager.php
new file mode 100644
index 0000000..96b3969
--- /dev/null
+++ b/src/TokenManager.php
@@ -0,0 +1,179 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TCB;
+
+use TCB\Credentials;
+use TCB\HttpServer;
+use TCB\Request;
+use TCB\Response;
+use TCB\TokenStorage;
+
+final class TokenManager
+{
+    private string $authorisationCode;
+
+    public function __construct(
+        private readonly Credentials $credentials,
+        private readonly HttpServer $httpServer,
+        private readonly TokenStorage $storage,
+    ) {}
+
+    public function getAccessToken(): string
+    {
+        if ($this->storage->accessToken === '' || $this->storage->refreshToken === '') {
+            $this->authorise();
+            $this->requestAccessToken();
+        }
+
+        if ($this->storage->expiresOn < time()) {
+            $this->refreshAccessToken();
+        }
+
+        return $this->storage->accessToken;
+    }
+
+    private function authorise(): void
+    {
+        $this->authorisationCode = '';
+
+        $this->httpServer->get(
+            '/callback',
+            function (Request $request, HttpServer $server): Response {
+                $server->closeAfterResponse();
+
+                if (
+                    !array_key_exists('state', $request->params)
+                    || $request->params['state'] !== $this->credentials->state
+                ) {
+                    $body = 'State mismatch.';
+                } elseif (array_key_exists('error', $request->params)) {
+                    $body = "Error from Spotify: {$request->params['error']}";
+                } elseif (!array_key_exists('code', $request->params)) {
+                    $body = "Missing authorisation code from Spotify.";
+                } else {
+                    $this->authorisationCode = $request->params['code'];
+                    $body = 'Authorisation code received from Spotify. You can close this page and go back to the terminal.';
+                }
+
+                return new Response(
+                    statusCode: 200,
+                    contentType: 'text/plain; charset=UTF-8',
+                    body: htmlspecialchars($body, ENT_QUOTES),
+                );
+            },
+        );
+
+        $query = http_build_query([
+            'response_type' => 'code',
+            'client_id' => $this->credentials->clientID,
+            'redirect_uri' => $this->credentials->redirectURI,
+            'state' => $this->credentials->state,
+            'scope' => 'playlist-read-private',
+            'show_dialog' => false,
+        ]);
+
+        echo "Visit the below URL in your browser to authorise access to Spotify.\n";
+        echo "https://accounts.spotify.com/authorize?$query\n";
+        echo "Waiting for authorisation from Spotify...\n";
+
+        $this->httpServer->run();
+
+        if ($this->authorisationCode === '') {
+            echo "Failed to get authorisation code from Spotify.\n";
+            exit(1);
+        }
+    }
+
+    private function requestAccessToken(): void
+    {
+        echo "Requesting an access token from Spotify.\n";
+
+        $ch = curl_init();
+
+        curl_setopt_array($ch, [
+            CURLOPT_URL => 'https://accounts.spotify.com/api/token',
+            CURLOPT_POST => true,
+            CURLOPT_HTTPHEADER => [
+                'Authorization: Basic ' . base64_encode($this->credentials->clientID . ':' . $this->credentials->clientSecret),
+                'Content-Type: application/x-www-form-urlencoded',
+            ],
+            CURLOPT_POSTFIELDS => http_build_query([
+                'grant_type'  => 'authorization_code',
+                'code' => $this->authorisationCode,
+                'redirect_uri' => $this->credentials->redirectURI,
+            ]),
+            CURLOPT_RETURNTRANSFER => true,
+        ]);
+
+        $response = curl_exec($ch);
+        $statusCode = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
+
+        if ($statusCode !== 200) {
+            echo "Non 200 response from Spotify: $statusCode $response\n";
+            exit(1);
+        }
+
+        $data = json_decode($response, true) ?? [];
+
+        $accessToken = $data['access_token'] ?? '';
+        $refreshToken = $data['refresh_token'] ?? '';
+        $expiresIn = $data['expires_in'] ?? 0;
+
+        if ($accessToken === '' || $refreshToken === '') {
+            echo "Failed to get access token from Spotify.\n";
+            exit(1);
+        }
+
+        $this->storage->accessToken = $accessToken;
+        $this->storage->refreshToken = $refreshToken;
+        $this->storage->expiresOn = time() + $expiresIn;
+        $this->storage->save();
+    }
+
+    private function refreshAccessToken(): void
+    {
+        echo "Refreshing the Spotify access token.\n";
+
+        $ch = curl_init();
+
+        curl_setopt_array($ch, [
+            CURLOPT_URL => 'https://accounts.spotify.com/api/token',
+            CURLOPT_POST => true,
+            CURLOPT_HTTPHEADER => [
+                'Authorization: Basic ' . base64_encode($this->credentials->clientID . ':' . $this->credentials->clientSecret),
+                'Content-Type: application/x-www-form-urlencoded',
+            ],
+            CURLOPT_POSTFIELDS => http_build_query([
+                'grant_type'  => 'refresh_token',
+                'refresh_token' => $this->storage->refreshToken,
+            ]),
+            CURLOPT_RETURNTRANSFER => true,
+        ]);
+
+        $response = curl_exec($ch);
+        $statusCode = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
+
+        if ($statusCode !== 200) {
+            echo "Non 200 response from Spotify: $statusCode $response\n";
+            exit(1);
+        }
+
+        $data = json_decode($response, true) ?? [];
+
+        $accessToken = $data['access_token'] ?? '';
+        $refreshToken = $data['refresh_token'] ?? $this->storage->refreshToken;
+        $expiresIn = $data['expires_in'] ?? 0;
+
+        if ($accessToken === '' || $refreshToken === '') {
+            echo "Failed to refresh the Spotify access token.\n";
+            exit(1);
+        }
+
+        $this->storage->accessToken = $accessToken;
+        $this->storage->refreshToken = $refreshToken;
+        $this->storage->expiresOn = time() + $expiresIn;
+        $this->storage->save();
+    }
+}
-- 
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