How to fix auth/invalid-hash-algorithm: Hash algorithm doesn't match supported options in Firebase

// WRONG - lowercase algorithm name
const users = [
  {
    uid: "user123",
    email: "[email protected]",
    passwordHash: Buffer.from("hashedpassword"),
    passwordSalt: Buffer.from("salt"),
    customClaims: {},
  }
];

await admin.auth().importUsers(users, {
  hash: {
    algorithm: "sha256", // WRONG: should be uppercase SHA256
    rounds: 1000
  }
});

// CORRECT
await admin.auth().importUsers(users, {
  hash: {
    algorithm: "SHA256", // Correct casing
    rounds: 1000
  }
});

import * as admin from "firebase-admin";

const users = [
  {
    uid: "user123",
    email: "[email protected]",
    passwordHash: Buffer.from("hashedpassword"),
    passwordSalt: Buffer.from("salt")
  }
];

// PBKDF2_SHA256 with valid rounds (0-120000)
await admin.auth().importUsers(users, {
  hash: {
    algorithm: "PBKDF2_SHA256",
    rounds: 25000 // Valid: within 0-120000 range
  }
});

// SHA256 with valid rounds (1-8192)
await admin.auth().importUsers(users, {
  hash: {
    algorithm: "SHA256",
    rounds: 1000 // Valid: within 1-8192 range
  }
});

const users = [
  {
    uid: "user123",
    email: "[email protected]",
    passwordHash: Buffer.from("hmachashedpassword"),
    // No password salt for HMAC
  }
];

// Provide the HMAC key
await admin.auth().importUsers(users, {
  hash: {
    algorithm: "HMAC_SHA256",
    key: Buffer.from("your-secret-key-used-in-original-system") // Required for HMAC
  }
});

await admin.auth().importUsers(users, {
  hash: {
    algorithm: "SCRYPT",
    memoryCost: 15,
    parallelization: 8,
    blockSize: 128,
    saltSeparator: Buffer.from("Bw==", "base64"),
    signerKey: Buffer.from("your-signer-key", "base64")
  }
});

const testUsers = users.slice(0, 10); // Test with first 10 users

try {
  const result = await admin.auth().importUsers(testUsers, {
    hash: {
      algorithm: "PBKDF2_SHA256",
      rounds: 25000
    }
  });
  
  console.log("Imported:", result.successCount, "Failed:", result.failureCount);
  
  // Check individual error messages
  result.errors.forEach((err, idx) => {
    if (err) {
      console.error(`User ${idx}: ${err.message}`);
    }
  });
} catch (err) {
  console.error("Import batch failed:", err.message);
  // Fix the algorithm or parameters before importing remaining users
}