How to Integrate Fitbit API with V0

1// app/api/fitbit/auth/route.ts
2import { NextResponse } from 'next/server';
3
4export async function GET() {
5  const clientId = process.env.FITBIT_CLIENT_ID!;
6  const redirectUri = `${process.env.NEXT_PUBLIC_APP_URL}/api/fitbit/callback`;
7  const scope = 'activity sleep heartrate profile';
8
9  const params = new URLSearchParams({
10    response_type: 'code',
11    client_id: clientId,
12    redirect_uri: redirectUri,
13    scope,
14    expires_in: '604800', // 7 days
15  });
16
17  return NextResponse.redirect(
18    `https://www.fitbit.com/oauth2/authorize?${params.toString()}`
19  );
20}
21
22// app/api/fitbit/callback/route.ts
23import { NextRequest, NextResponse } from 'next/server';
24import { cookies } from 'next/headers';
25
26export async function GET(request: NextRequest) {
27  const { searchParams } = new URL(request.url);
28  const code = searchParams.get('code');
29  const error = searchParams.get('error');
30
31  if (error || !code) {
32    return NextResponse.redirect(
33      `${process.env.NEXT_PUBLIC_APP_URL}/?error=fitbit_auth_failed`
34    );
35  }
36
37  const clientId = process.env.FITBIT_CLIENT_ID!;
38  const clientSecret = process.env.FITBIT_CLIENT_SECRET!;
39  const redirectUri = `${process.env.NEXT_PUBLIC_APP_URL}/api/fitbit/callback`;
40
41  const credentials = Buffer.from(`${clientId}:${clientSecret}`).toString('base64');
42
43  try {
44    const tokenRes = await fetch('https://api.fitbit.com/oauth2/token', {
45      method: 'POST',
46      headers: {
47        'Authorization': `Basic ${credentials}`,
48        'Content-Type': 'application/x-www-form-urlencoded',
49      },
50      body: new URLSearchParams({
51        code,
52        grant_type: 'authorization_code',
53        redirect_uri: redirectUri,
54      }).toString(),
55    });
56
57    if (!tokenRes.ok) {
58      throw new Error(`Token exchange failed: ${tokenRes.status}`);
59    }
60
61    const tokens = await tokenRes.json();
62
63    // Store tokens in cookies (for single-user app)
64    // For multi-user: store in database keyed by authenticated user ID
65    const cookieStore = await cookies();
66    cookieStore.set('fitbit_access_token', tokens.access_token, {
67      httpOnly: true,
68      secure: true,
69      maxAge: tokens.expires_in,
70      sameSite: 'lax',
71    });
72    cookieStore.set('fitbit_refresh_token', tokens.refresh_token, {
73      httpOnly: true,
74      secure: true,
75      maxAge: 60 * 60 * 24 * 30, // 30 days
76      sameSite: 'lax',
77    });
78
79    return NextResponse.redirect(`${process.env.NEXT_PUBLIC_APP_URL}/dashboard`);
80  } catch (err) {
81    console.error('Fitbit OAuth error:', err);
82    return NextResponse.redirect(
83      `${process.env.NEXT_PUBLIC_APP_URL}/?error=token_exchange_failed`
84    );
85  }
86}

1// app/api/fitbit/today/route.ts
2import { NextRequest, NextResponse } from 'next/server';
3import { cookies } from 'next/headers';
4
5async function refreshFitbitToken(refreshToken: string): Promise<string | null> {
6  const credentials = Buffer.from(
7    `${process.env.FITBIT_CLIENT_ID}:${process.env.FITBIT_CLIENT_SECRET}`
8  ).toString('base64');
9
10  const res = await fetch('https://api.fitbit.com/oauth2/token', {
11    method: 'POST',
12    headers: {
13      Authorization: `Basic ${credentials}`,
14      'Content-Type': 'application/x-www-form-urlencoded',
15    },
16    body: new URLSearchParams({
17      grant_type: 'refresh_token',
18      refresh_token: refreshToken,
19    }).toString(),
20  });
21
22  if (!res.ok) return null;
23
24  const data = await res.json();
25  const cookieStore = await cookies();
26  cookieStore.set('fitbit_access_token', data.access_token, {
27    httpOnly: true, secure: true, maxAge: data.expires_in, sameSite: 'lax',
28  });
29  cookieStore.set('fitbit_refresh_token', data.refresh_token, {
30    httpOnly: true, secure: true, maxAge: 60 * 60 * 24 * 30, sameSite: 'lax',
31  });
32  return data.access_token;
33}
34
35async function fitbitGet(path: string, accessToken: string): Promise<Response> {
36  return fetch(`https://api.fitbit.com${path}`, {
37    headers: { Authorization: `Bearer ${accessToken}` },
38    cache: 'no-store',
39  });
40}
41
42export async function GET(request: NextRequest) {
43  const cookieStore = await cookies();
44  let accessToken = cookieStore.get('fitbit_access_token')?.value;
45  const refreshToken = cookieStore.get('fitbit_refresh_token')?.value;
46
47  if (!accessToken && !refreshToken) {
48    return NextResponse.json({ error: 'Not authenticated', needsAuth: true }, { status: 401 });
49  }
50
51  const today = new Date().toISOString().split('T')[0];
52
53  // Try fetching with current token; refresh if expired
54  let activityRes = accessToken
55    ? await fitbitGet(`/1/user/-/activities/date/${today}.json`, accessToken)
56    : null;
57
58  if ((!activityRes || activityRes.status === 401) && refreshToken) {
59    accessToken = await refreshFitbitToken(refreshToken);
60    if (!accessToken) {
61      return NextResponse.json({ error: 'Session expired, please reconnect Fitbit', needsAuth: true }, { status: 401 });
62    }
63    activityRes = await fitbitGet(`/1/user/-/activities/date/${today}.json`, accessToken);
64  }
65
66  if (!activityRes || !activityRes.ok) {
67    return NextResponse.json({ error: 'Failed to fetch Fitbit data' }, { status: 500 });
68  }
69
70  const [activityData, sleepRes, heartRes] = await Promise.all([
71    activityRes.json(),
72    fitbitGet(`/1.2/user/-/sleep/date/${today}.json`, accessToken),
73    fitbitGet(`/1/user/-/activities/heart/date/${today}/1d.json`, accessToken),
74  ]);
75
76  const sleepData = sleepRes.ok ? await sleepRes.json() : null;
77  const heartData = heartRes.ok ? await heartRes.json() : null;
78
79  const summary = activityData.summary || {};
80  const mainSleep = sleepData?.sleep?.[0];
81
82  return NextResponse.json({
83    date: today,
84    activity: {
85      steps: summary.steps || 0,
86      caloriesOut: summary.caloriesOut || 0,
87      activeMinutes: (summary.veryActiveMinutes || 0) + (summary.fairlyActiveMinutes || 0),
88      distance: summary.distances?.find((d: { activity: string }) => d.activity === 'total')?.distance || 0,
89    },
90    sleep: mainSleep ? {
91      totalMinutes: mainSleep.minutesAsleep,
92      efficiency: mainSleep.efficiency,
93      deepMinutes: mainSleep.levels?.summary?.deep?.minutes || 0,
94      remMinutes: mainSleep.levels?.summary?.rem?.minutes || 0,
95      lightMinutes: mainSleep.levels?.summary?.light?.minutes || 0,
96    } : null,
97    heartRate: {
98      restingHeartRate: heartData?.['activities-heart']?.[0]?.value?.restingHeartRate || null,
99    },
100  });
101}