/**
 * EncryptID Database Layer — PostgreSQL
 *
 * Replaces in-memory Maps with persistent PostgreSQL storage.
 * Uses the 'postgres' npm package (lightweight, no native deps with Bun).
 */

import postgres from 'postgres';
import { readFileSync } from 'fs';
import { join } from 'path';

// ============================================================================
// CONNECTION
// ============================================================================

const DATABASE_URL = process.env.DATABASE_URL;
if (!DATABASE_URL) {
  throw new Error('DATABASE_URL environment variable is required');
}

const sql = postgres(DATABASE_URL, {
  max: 10,
  idle_timeout: 20,
  connect_timeout: 10,
});

// ============================================================================
// TYPES
// ============================================================================

export interface StoredCredential {
  credentialId: string;
  publicKey: string;
  userId: string;
  username: string;
  counter: number;
  createdAt: number;
  lastUsed?: number;
  transports?: string[];
}

export interface StoredChallenge {
  challenge: string;
  userId?: string;
  type: 'registration' | 'authentication';
  createdAt: number;
  expiresAt: number;
}

// ============================================================================
// INITIALIZATION
// ============================================================================

export async function initDatabase(): Promise<void> {
  const schema = readFileSync(join(import.meta.dir, 'schema.sql'), 'utf-8');
  await sql.unsafe(schema);
  console.log('EncryptID: Database initialized');

  // Clean expired challenges on startup
  await cleanExpiredChallenges();
}

// ============================================================================
// USER OPERATIONS
// ============================================================================

export async function createUser(id: string, username: string, displayName?: string, did?: string): Promise<void> {
  await sql`
    INSERT INTO users (id, username, display_name, did)
    VALUES (${id}, ${username}, ${displayName || username}, ${did || null})
    ON CONFLICT (id) DO NOTHING
  `;
}

export async function getUserByUsername(username: string) {
  const [user] = await sql`SELECT * FROM users WHERE username = ${username}`;
  return user || null;
}

// ============================================================================
// CREDENTIAL OPERATIONS
// ============================================================================

export async function storeCredential(cred: StoredCredential): Promise<void> {
  // Ensure user exists first
  await createUser(cred.userId, cred.username);

  await sql`
    INSERT INTO credentials (credential_id, user_id, public_key, counter, transports, created_at)
    VALUES (
      ${cred.credentialId},
      ${cred.userId},
      ${cred.publicKey},
      ${cred.counter},
      ${cred.transports || null},
      ${new Date(cred.createdAt)}
    )
  `;
}

export async function getCredential(credentialId: string): Promise<StoredCredential | null> {
  const rows = await sql`
    SELECT c.credential_id, c.public_key, c.user_id, c.counter,
           c.transports, c.created_at, c.last_used, u.username
    FROM credentials c
    JOIN users u ON c.user_id = u.id
    WHERE c.credential_id = ${credentialId}
  `;
  if (rows.length === 0) return null;

  const row = rows[0];
  return {
    credentialId: row.credential_id,
    publicKey: row.public_key,
    userId: row.user_id,
    username: row.username,
    counter: row.counter,
    createdAt: new Date(row.created_at).getTime(),
    lastUsed: row.last_used ? new Date(row.last_used).getTime() : undefined,
    transports: row.transports,
  };
}

export async function updateCredentialUsage(credentialId: string, newCounter: number): Promise<void> {
  await sql`
    UPDATE credentials
    SET counter = ${newCounter}, last_used = NOW()
    WHERE credential_id = ${credentialId}
  `;
}

export async function getUserCredentials(userId: string): Promise<StoredCredential[]> {
  const rows = await sql`
    SELECT c.credential_id, c.public_key, c.user_id, c.counter,
           c.transports, c.created_at, c.last_used, u.username
    FROM credentials c
    JOIN users u ON c.user_id = u.id
    WHERE c.user_id = ${userId}
  `;

  return rows.map(row => ({
    credentialId: row.credential_id,
    publicKey: row.public_key,
    userId: row.user_id,
    username: row.username,
    counter: row.counter,
    createdAt: new Date(row.created_at).getTime(),
    lastUsed: row.last_used ? new Date(row.last_used).getTime() : undefined,
    transports: row.transports,
  }));
}

// ============================================================================
// CHALLENGE OPERATIONS
// ============================================================================

export async function storeChallenge(ch: StoredChallenge): Promise<void> {
  await sql`
    INSERT INTO challenges (challenge, user_id, type, created_at, expires_at)
    VALUES (
      ${ch.challenge},
      ${ch.userId || null},
      ${ch.type},
      ${new Date(ch.createdAt)},
      ${new Date(ch.expiresAt)}
    )
  `;
}

export async function getChallenge(challenge: string): Promise<StoredChallenge | null> {
  const rows = await sql`
    SELECT * FROM challenges WHERE challenge = ${challenge}
  `;
  if (rows.length === 0) return null;

  const row = rows[0];
  return {
    challenge: row.challenge,
    userId: row.user_id || undefined,
    type: row.type as 'registration' | 'authentication',
    createdAt: new Date(row.created_at).getTime(),
    expiresAt: new Date(row.expires_at).getTime(),
  };
}

export async function deleteChallenge(challenge: string): Promise<void> {
  await sql`DELETE FROM challenges WHERE challenge = ${challenge}`;
}

export async function cleanExpiredChallenges(): Promise<number> {
  const result = await sql`DELETE FROM challenges WHERE expires_at < NOW()`;
  return result.count;
}

// ============================================================================
// USER EMAIL OPERATIONS
// ============================================================================

export async function setUserEmail(userId: string, email: string): Promise<void> {
  await sql`UPDATE users SET email = ${email} WHERE id = ${userId}`;
}

export async function getUserByEmail(email: string) {
  const [user] = await sql`SELECT * FROM users WHERE email = ${email}`;
  return user || null;
}

export async function getUserById(userId: string) {
  const [user] = await sql`SELECT * FROM users WHERE id = ${userId}`;
  return user || null;
}

// ============================================================================
// RECOVERY TOKEN OPERATIONS
// ============================================================================

export interface StoredRecoveryToken {
  token: string;
  userId: string;
  type: 'email_verify' | 'account_recovery';
  createdAt: number;
  expiresAt: number;
  used: boolean;
}

export async function storeRecoveryToken(rt: StoredRecoveryToken): Promise<void> {
  await sql`
    INSERT INTO recovery_tokens (token, user_id, type, created_at, expires_at, used)
    VALUES (
      ${rt.token},
      ${rt.userId},
      ${rt.type},
      ${new Date(rt.createdAt)},
      ${new Date(rt.expiresAt)},
      ${rt.used}
    )
  `;
}

export async function getRecoveryToken(token: string): Promise<StoredRecoveryToken | null> {
  const rows = await sql`SELECT * FROM recovery_tokens WHERE token = ${token}`;
  if (rows.length === 0) return null;
  const row = rows[0];
  return {
    token: row.token,
    userId: row.user_id,
    type: row.type as 'email_verify' | 'account_recovery',
    createdAt: new Date(row.created_at).getTime(),
    expiresAt: new Date(row.expires_at).getTime(),
    used: row.used,
  };
}

export async function markRecoveryTokenUsed(token: string): Promise<void> {
  await sql`UPDATE recovery_tokens SET used = TRUE WHERE token = ${token}`;
}

export async function cleanExpiredRecoveryTokens(): Promise<number> {
  const result = await sql`DELETE FROM recovery_tokens WHERE expires_at < NOW()`;
  return result.count;
}

// ============================================================================
// SPACE MEMBERSHIP
// ============================================================================

export interface StoredSpaceMember {
  spaceSlug: string;
  userDID: string;
  role: string;
  joinedAt: number;
  grantedBy?: string;
}

export async function getSpaceMember(
  spaceSlug: string,
  userDID: string,
): Promise<StoredSpaceMember | null> {
  const rows = await sql`
    SELECT * FROM space_members
    WHERE space_slug = ${spaceSlug} AND user_did = ${userDID}
  `;
  if (rows.length === 0) return null;
  const row = rows[0];
  return {
    spaceSlug: row.space_slug,
    userDID: row.user_did,
    role: row.role,
    joinedAt: new Date(row.joined_at).getTime(),
    grantedBy: row.granted_by || undefined,
  };
}

export async function listSpaceMembers(
  spaceSlug: string,
): Promise<StoredSpaceMember[]> {
  const rows = await sql`
    SELECT * FROM space_members
    WHERE space_slug = ${spaceSlug}
    ORDER BY joined_at ASC
  `;
  return rows.map((row) => ({
    spaceSlug: row.space_slug,
    userDID: row.user_did,
    role: row.role,
    joinedAt: new Date(row.joined_at).getTime(),
    grantedBy: row.granted_by || undefined,
  }));
}

export async function upsertSpaceMember(
  spaceSlug: string,
  userDID: string,
  role: string,
  grantedBy?: string,
): Promise<StoredSpaceMember> {
  const rows = await sql`
    INSERT INTO space_members (space_slug, user_did, role, granted_by)
    VALUES (${spaceSlug}, ${userDID}, ${role}, ${grantedBy ?? null})
    ON CONFLICT (space_slug, user_did)
    DO UPDATE SET role = ${role}, granted_by = ${grantedBy ?? null}
    RETURNING *
  `;
  const row = rows[0];
  return {
    spaceSlug: row.space_slug,
    userDID: row.user_did,
    role: row.role,
    joinedAt: new Date(row.joined_at).getTime(),
    grantedBy: row.granted_by || undefined,
  };
}

export async function removeSpaceMember(
  spaceSlug: string,
  userDID: string,
): Promise<boolean> {
  const result = await sql`
    DELETE FROM space_members
    WHERE space_slug = ${spaceSlug} AND user_did = ${userDID}
  `;
  return result.count > 0;
}

// ============================================================================
// HEALTH CHECK
// ============================================================================

export async function checkDatabaseHealth(): Promise<boolean> {
  try {
    await sql`SELECT 1`;
    return true;
  } catch {
    return false;
  }
}

export { sql };