import hashlib
import base64
import secrets

# Generate code verifier (43-128 characters)
code_verifier = secrets.token_urlsafe(32)

# Generate code challenge (SHA-256 hash of verifier)
digest = hashlib.sha256(code_verifier.encode("utf-8")).digest()
code_challenge = base64.urlsafe_b64encode(digest).rstrip(b"=").decode("utf-8")

# Store code_verifier in your session: you need it for token exchange
print(f"Verifier: {code_verifier}")
print(f"Challenge: {code_challenge}")

import crypto from "crypto";

// Generate code verifier (43-128 characters)
const codeVerifier = crypto.randomBytes(32).toString("base64url");

// Generate code challenge (SHA-256 hash of verifier)
const codeChallenge = crypto
  .createHash("sha256")
  .update(codeVerifier)
  .digest("base64url");

// Store codeVerifier in your session: you need it for token exchange
console.log(`Verifier: ${codeVerifier}`);
console.log(`Challenge: ${codeChallenge}`);

import requests

response = requests.post(
    "https://api.saturday.fit/v1/oauth/token",
    data={
        "grant_type": "authorization_code",
        "code": auth_code,
        "redirect_uri": "https://your-app.com/callback",
        "client_id": "your_partner_id",
        "client_secret": "your_client_secret",
        "code_verifier": code_verifier,
    },
)

tokens = response.json()
access_token = tokens["access_token"]      # JWT, 1-hour expiry
refresh_token = tokens["refresh_token"]    # Opaque, 90-day expiry
expires_in = tokens["expires_in"]          # Seconds until access token expires

const response = await fetch("https://api.saturday.fit/v1/oauth/token", {
  method: "POST",
  headers: { "Content-Type": "application/x-www-form-urlencoded" },
  body: new URLSearchParams({
    grant_type: "authorization_code",
    code: authCode,
    redirect_uri: "https://your-app.com/callback",
    client_id: "your_partner_id",
    client_secret: "your_client_secret",
    code_verifier: codeVerifier,
  }),
});

const tokens = await response.json();
const accessToken = tokens.access_token;   // JWT, 1-hour expiry
const refreshToken = tokens.refresh_token; // Opaque, 90-day expiry

import requests

response = requests.post(
    "https://api.saturday.fit/v1/oauth/token",
    data={
        "grant_type": "refresh_token",
        "refresh_token": refresh_token,
        "client_id": "your_partner_id",
    },
)

new_tokens = response.json()
# Rotation: save the new refresh token, the old one stops working shortly
access_token = new_tokens["access_token"]
refresh_token = new_tokens["refresh_token"]

const response = await fetch("https://api.saturday.fit/v1/oauth/token", {
  method: "POST",
  headers: { "Content-Type": "application/x-www-form-urlencoded" },
  body: new URLSearchParams({
    grant_type: "refresh_token",
    refresh_token: refreshToken,
    client_id: "your_partner_id",
  }),
});

const newTokens = await response.json();
// Rotation: save the new refresh token, the old one stops working shortly