Setup initial skeleton for Spotify Auth

frontend/app/(tabs)/explore.tsx

@@ -1,17 +1,10 @@
 import React from 'react';
-import { Text, SafeAreaView, Button } from 'react-native';
-import { TEST } from 'react-native-dotenv';
+import { Text, SafeAreaView } from 'react-native';
 
 export default function TabTwoScreen() {
   return (
     <SafeAreaView>
       <Text>Tab Two</Text>
-      <Button
-        title="asdf"
-        onPress={() => {
-          console.log(TEST);
-        }}
-      />
     </SafeAreaView>
   );
 }

frontend/package.json

@@ -19,6 +19,7 @@
     "@react-navigation/bottom-tabs": "^7.2.0",
     "@react-navigation/native": "^7.0.14",
     "expo": "~52.0.25",
+    "expo-auth-session": "^6.0.2",
     "expo-blur": "~14.0.2",
     "expo-constants": "~17.0.4",
     "expo-font": "~13.0.3",

frontend/tsconfig.json

@@ -0,0 +1,10 @@
+{
+  "compilerOptions": {},
+  "extends": "expo/tsconfig.base",
+  "include": [
+    "**/*.ts",
+    "**/*.tsx",
+    ".expo/types/**/*.ts",
+    "expo-env.d.ts"
+  ]
+}

frontend/types.d.ts

@@ -0,0 +1,5 @@
+export interface AccessTokenResponse {
+  access_token: string;
+  refresh_token: string;
+  expires_in: number;
+}

frontend/utils/spotify.ts

@@ -0,0 +1,42 @@
+import { AccessTokenResponse } from '../types';
+import { makeRedirectUri } from 'expo-auth-session';
+import { SPOTIFY_CLIENT_ID, SPOTIFY_CLIENT_SECRET } from 'react-native-dotenv';
+
+export const getClientId = () => {
+  return SPOTIFY_CLIENT_ID;
+};
+
+const getClientSecret = () => {
+  return SPOTIFY_CLIENT_SECRET;
+};
+
+const generateAccessTokenParams = (code: string) => {
+  const params = new URLSearchParams();
+
+  params.append('grant_type', 'authorization_code');
+  params.append('code', code);
+  params.append('redirect_uri', makeRedirectUri());
+
+  return params.toString();
+};
+
+export const fetchAccessToken = async (code: string) => {
+  const response = await fetch('https://accounts.spotify.com/api/token', {
+    method: 'POST',
+    body: generateAccessTokenParams(code),
+    headers: {
+      'content-type': 'application/x-www-form-urlencoded',
+      Authorization: 'Basic ' + btoa(getClientId() + ':' + getClientSecret()),
+    },
+  });
+
+  const json = (await response.json()) as AccessTokenResponse;
+
+  console.log(json);
+
+  return {
+    accessToken: json.access_token,
+    expiration: json.expires_in,
+    refreshToken: json.refresh_token,
+  };
+};