/**
 * setup.ts — /api/setup/* route surface (Phase 12 initial-setup wizard).
 *
 * Mounted in index.ts: app.route('/api/setup', setupRouter)
 * Mount position: BEFORE app.use('/api/*', devAuthBypass()) so the wizard
 * is reachable pre-authentication — same pre-auth surface as /health (T-01-03).
 *
 * Security contract (Pitfall 8, T-12-04, T-12-05, T-12-06):
 *   - Every handler calls isSetupLocked() as its FIRST statement; returns 423 if locked.
 *   - noEchoHook: Zod validation errors for the credential step NEVER return received values.
 *   - App password is NEVER logged or echoed (T-12-05).
 *   - VAPID_PRIVATE_KEY is read ONLY from process.env — never from app_config or returned (T-12-06).
 *   - validateEncryptAndStoreCredential is the ONLY credential-handling path (D-09 / no new crypto).
 *   - Shared helper called directly — no admin route invocation (pre-auth endpoint cannot reach it).
 *
 * Routes:
 *   GET  /api/setup/status           → { setupComplete: boolean }
 *   POST /api/setup/config           → upsert oidc_issuer, oidc_client_id, vapid_public_key, app_external_url
 *   POST /api/setup/validate/db      → SELECT 1 connectivity check
 *   POST /api/setup/validate/oidc    → fetch {issuer}/.well-known/openid-configuration
 *   POST /api/setup/validate/vapid   → setVapidDetails structural check (env keys only)
 *   POST /api/setup/credential       → insert local user + validateEncryptAndStoreCredential
 *   POST /api/setup/complete         → set app_config.setup_complete='true'
 */

import { Hono } from 'hono';
import type { Context } from 'hono';
import { zValidator } from '@hono/zod-validator';
import { z } from 'zod';
import { eq, sql, and, isNull } from 'drizzle-orm';
import { db } from '../db/client.js';
import { users, appConfig, memberCredentials } from '../db/schema.js';
import { isSetupLocked } from '../lib/setupGuard.js';
import { COLOR_PALETTE } from '../auth/user.js';
import {
  validateEncryptAndStoreCredential,
  CredentialValidationError,
} from '../broker/credentialSync.js';
import webpush from 'web-push';

export const setupRouter = new Hono();

// ---------------------------------------------------------------------------
// noEchoHook — NEVER return Zod error details for credential endpoints (T-12-05 / Pitfall 7).
// Zod's error object contains issues[].received which echoes the submitted value.
// Always return { error: 'Invalid request' } 400, no other fields.
// ---------------------------------------------------------------------------

const noEchoHook = (result: { success: boolean }, c: Context) => {
  if (!result.success) {
    return c.json({ error: 'Invalid request' }, 400);
  }
};

// ---------------------------------------------------------------------------
// Zod schemas
// ---------------------------------------------------------------------------

const configSchema = z.object({
  oidcIssuer: z
    .string()
    .url()
    .refine((v) => v.startsWith('https://'), { message: 'oidcIssuer must be an https URL' }),
  oidcClientId: z.string().min(1).max(256),
  vapidPublicKey: z.string().min(1).max(512),
  appExternalUrl: z
    .string()
    .url()
    .max(512)
    .refine((v) => v.startsWith('https://'), { message: 'appExternalUrl must be an https URL' }),
});

const credentialSchema = z.object({
  fastmailEmail: z.string().email().max(256),
  appPassword: z.string().min(1).max(500),
});

// ---------------------------------------------------------------------------
// GET /api/setup/status
//
// Returns { setupComplete: boolean } derived from app_config.setup_complete.
// Reachable pre-auth (no OIDC guard). Does NOT check the 423 guard — status
// is always readable so the PWA can decide whether to show the wizard.
// ---------------------------------------------------------------------------

setupRouter.get('/status', async (c) => {
  // isSetupLocked() is the authoritative check for both explicit and effective-config
  // completion (D-10). Using it here keeps the status response in sync with the guard
  // without a second DB read pattern (covers setup_complete AND effective-config).
  const locked = await isSetupLocked();
  // Gap 3 (backend): surface the NON-SECRET DB name so the PWA can render a read-only
  // field giving the "database connection verified" row an on-screen referent. Only the
  // database NAME is exposed — never DB_HOST/DB_USER/DB_PASSWORD (connection secrets/topology).
  return c.json({ setupComplete: locked, dbName: process.env.DB_NAME ?? null });
});

// ---------------------------------------------------------------------------
// POST /api/setup/config
//
// Collects non-secret operator config and upserts into app_config:
//   oidc_issuer, oidc_client_id, vapid_public_key, app_external_url
//
// Validates: oidcIssuer must be an https URL (T-12-08 SSRF mitigation).
// All other fields are non-secret (D-01 / D-02).
// ---------------------------------------------------------------------------

setupRouter.post('/config', zValidator('json', configSchema), async (c) => {
  const locked = await isSetupLocked();
  if (locked) return c.json({ error: 'Setup already complete' }, 423);

  const { oidcIssuer, oidcClientId, vapidPublicKey, appExternalUrl } = c.req.valid('json');

  await db
    .insert(appConfig)
    .values({ key: 'oidc_issuer', value: oidcIssuer })
    .onDuplicateKeyUpdate({ set: { value: oidcIssuer } });

  await db
    .insert(appConfig)
    .values({ key: 'oidc_client_id', value: oidcClientId })
    .onDuplicateKeyUpdate({ set: { value: oidcClientId } });

  await db
    .insert(appConfig)
    .values({ key: 'vapid_public_key', value: vapidPublicKey })
    .onDuplicateKeyUpdate({ set: { value: vapidPublicKey } });

  await db
    .insert(appConfig)
    .values({ key: 'app_external_url', value: appExternalUrl })
    .onDuplicateKeyUpdate({ set: { value: appExternalUrl } });

  return c.json({ ok: true }, 200);
});

// ---------------------------------------------------------------------------
// POST /api/setup/validate/db
//
// Proves DB connectivity via SELECT 1.
// Returns 200 { ok: true } on success, 503 on failure.
// ---------------------------------------------------------------------------

setupRouter.post('/validate/db', async (c) => {
  const locked = await isSetupLocked();
  if (locked) return c.json({ error: 'Setup already complete' }, 423);

  try {
    await db.execute(sql`SELECT 1`);
    return c.json({ ok: true }, 200);
  } catch (err) {
    console.error('[setup/validate/db] DB round-trip failed:', err instanceof Error ? err.message : String(err));
    return c.json({ ok: false, error: 'DB unavailable' }, 503);
  }
});

// ---------------------------------------------------------------------------
// POST /api/setup/validate/oidc
//
// Validates OIDC issuer by fetching {issuer}/.well-known/openid-configuration.
// Reads oidc_issuer from app_config (written by /config step).
// 5-second timeout via AbortSignal.timeout (Node.js 18+).
// Returns 200 { ok: true } on success, 400 { ok: false } on failure.
// ---------------------------------------------------------------------------

setupRouter.post('/validate/oidc', async (c) => {
  const locked = await isSetupLocked();
  if (locked) return c.json({ error: 'Setup already complete' }, 423);

  const [row] = await db
    .select({ value: appConfig.value })
    .from(appConfig)
    .where(eq(appConfig.key, 'oidc_issuer'))
    .limit(1);

  const issuer = row?.value;
  if (!issuer) {
    return c.json({ ok: false, error: 'OIDC issuer not configured' }, 400);
  }

  try {
    const res = await fetch(`${issuer}/.well-known/openid-configuration`, {
      signal: AbortSignal.timeout(5000),
    });
    if (!res.ok) {
      throw new Error(`HTTP ${res.status}`);
    }
    return c.json({ ok: true }, 200);
  } catch (err) {
    // IN-01: Log raw error server-side only — do not echo internal network detail
    // (e.g. "connect ECONNREFUSED 192.168.1.50:9091") to the pre-auth caller.
    console.error('[setup/validate/oidc]', err instanceof Error ? err.message : String(err));
    return c.json({ ok: false, error: 'OIDC discovery failed. Check the issuer URL.' }, 400);
  }
});

// ---------------------------------------------------------------------------
// POST /api/setup/validate/vapid
//
// Validates the operator-entered VAPID public key (app_config.vapid_public_key)
// against the configured key pair:
//   1. Equality (gap 2): the submitted public key MUST equal process.env.VAPID_PUBLIC_KEY.
//      A wrong/typoed key (e.g. "BH123") now fails the row and gates Continue — push
//      would silently break in production otherwise (SETUP-02).
//   2. Structural: webpush.setVapidDetails() validates the env pair's byte structure.
//
// VAPID_PRIVATE_KEY is read ONLY from process.env — NEVER from app_config or returned
// (T-12-06 / D-01 / SC-3). The equality check compares the submitted PUBLIC key to the
// env PUBLIC key only — the private key is never compared or echoed.
// Returns 200 { ok: true } on success, 400 { ok: false } on any failure.
// ---------------------------------------------------------------------------

setupRouter.post('/validate/vapid', async (c) => {
  const locked = await isSetupLocked();
  if (locked) return c.json({ error: 'Setup already complete' }, 423);

  const privateKey = process.env.VAPID_PRIVATE_KEY ?? '';
  const publicKey = process.env.VAPID_PUBLIC_KEY ?? '';

  if (!privateKey || !publicKey) {
    return c.json({ ok: false, error: 'VAPID_PRIVATE_KEY and VAPID_PUBLIC_KEY env vars must be set' }, 400);
  }

  // Gap 2: assert the operator-submitted public key matches the env public key BEFORE
  // the structural check. Read the submitted key from app_config (same idiom as validate/oidc).
  const [submittedRow] = await db
    .select({ value: appConfig.value })
    .from(appConfig)
    .where(eq(appConfig.key, 'vapid_public_key'))
    .limit(1);

  const submittedPublicKey = submittedRow?.value;
  if (!submittedPublicKey || submittedPublicKey !== publicKey) {
    return c.json({
      ok: false,
      error:
        'VAPID public key does not match the configured key pair. Paste the exact VAPID_PUBLIC_KEY printed by `npm run generate-secrets`.',
    }, 400);
  }

  try {
    // setVapidDetails runs validatePrivateKey (32-byte check) and validatePublicKey (65-byte check)
    // internally — this is the library's own structural validation (Pattern 7).
    // Using a placeholder subject for validation only (actual subject used at startup in index.ts).
    webpush.setVapidDetails(
      process.env.VAPID_SUBJECT || 'mailto:validate@familysync.local',
      publicKey,
      privateKey,
    );
    return c.json({ ok: true }, 200);
  } catch (err) {
    return c.json({
      ok: false,
      error: err instanceof Error ? err.message : 'VAPID validation failed',
    }, 400);
  }
});

// ---------------------------------------------------------------------------
// POST /api/setup/credential
//
// Creates the pre-OIDC local user (oidcIss=null, oidcSub=null, claimed=false,
// is_admin=true) FIRST — FK constraint on member_credentials requires the user
// row to exist before inserting the credential (Pitfall 5).
//
// Then calls validateEncryptAndStoreCredential() to validate + encrypt + store
// the Fastmail app password (D-09 — reuses shared helper, no new crypto).
//
// Security (T-12-05 / Pitfall 7):
//   - noEchoHook prevents Zod error details from including the app password.
//   - app password is NEVER logged or echoed.
//   - CredentialValidationError maps to generic 400.
// ---------------------------------------------------------------------------

setupRouter.post('/credential', zValidator('json', credentialSchema, noEchoHook), async (c) => {
  const locked = await isSetupLocked();
  if (locked) return c.json({ error: 'Setup already complete' }, 423);

  const { fastmailEmail, appPassword } = c.req.valid('json');
  // T-12-05: NEVER log appPassword or c.req.valid('json') here

  // Steps 1 + 2 run inside a serialising transaction (WR-02 TOCTOU fix).
  // SELECT … FOR UPDATE on the unclaimed-user count acquires a row/gap lock so that
  // two concurrent credential requests cannot both observe count=0 and both insert.
  // The transaction commits before validateEncryptAndStoreCredential (which does its
  // own DB write) so the FK constraint is satisfied on that call.
  let localUser: typeof users.$inferSelect | undefined;
  try {
    localUser = await db.transaction(async (tx) => {
      // Serialise: at most one unclaimed wizard bootstrap row may exist (WR-02).
      // The filter is (oidc_iss IS NULL AND claimed = false) — the precise definition
      // of a "pending wizard bootstrap user" — so that OIDC-created rows (which are
      // born with claimed=true after WR-01 fix, but could theoretically be claimed=false
      // on legacy data) are never counted here (WR-01 defense-in-depth).
      // Cast through unknown — Drizzle mysql2 execute() returns [rows, fields] for SELECTs;
      // the generic type parameter on execute() is not sufficient to type the result correctly.
      const countRows = (await tx.execute(
        sql`SELECT COUNT(*) AS count FROM users WHERE oidc_iss IS NULL AND claimed = false FOR UPDATE`,
      )) as unknown as [{ count: string | number }[], unknown];
      const unclaimedCount = Number(countRows[0][0]?.count ?? 0);
      if (unclaimedCount > 0) {
        throw Object.assign(new Error('An unclaimed user already exists'), { code: 'DUPLICATE_UNCLAIMED' });
      }

      // Step 1: Assign color (first unused from palette, or round-robin fallback)
      const usedRows = await tx.select({ color: users.color }).from(users);
      const usedColors = new Set(usedRows.map((r) => r.color));
      const color =
        COLOR_PALETTE.find((col) => !usedColors.has(col)) ??
        COLOR_PALETTE[usedColors.size % COLOR_PALETTE.length];

      // Step 2: Insert the local user (oidcIss=null, oidcSub=null, claimed=false)
      // mysql2 has no RETURNING clause — use $returningId() then re-select (Pattern 4)
      const [inserted] = await tx
        .insert(users)
        .values({
          oidcIss: null,
          oidcSub: null,
          displayName: null,
          color,
          isAdmin: true,
          claimed: false,
        })
        .$returningId();

      const [row] = await tx
        .select()
        .from(users)
        .where(eq(users.id, inserted.id))
        .limit(1);

      return row;
    });
  } catch (err) {
    if (err instanceof Error && (err as NodeJS.ErrnoException & { code?: string }).code === 'DUPLICATE_UNCLAIMED') {
      // A concurrent request already created the unclaimed admin row
      return c.json({ error: 'Setup already in progress' }, 409);
    }
    console.error('[setup/POST /credential] Transaction error:', err instanceof Error ? err.message : String(err));
    return c.json({ error: 'Service unavailable' }, 503);
  }

  if (!localUser) {
    // Clean up the just-inserted user row to avoid an orphaned unclaimed admin
    // (WR-01: the catch block below does not cover this early-return path).
    // This path is extremely unlikely if the transaction committed but the re-select
    // returned nothing — a transient DB issue. No row ID is available here since
    // the transaction already committed with the row. The FOR UPDATE guard above
    // means no second unclaimed row will exist; the orphan (if any) is claimed on
    // first login via upsertUser, making this a safe degraded-mode path.
    return c.json({ error: 'Service unavailable' }, 503);
  }

  // Step 3: Validate + encrypt + store the credential via the shared helper (D-09)
  // The user row MUST exist before this call (Pitfall 5 — FK constraint).
  try {
    await validateEncryptAndStoreCredential(
      localUser.id,
      fastmailEmail,
      appPassword,
      'caldav',
    );
  } catch (err) {
    // Roll back the local user insert on credential failure to avoid orphaned rows
    await db.delete(users).where(eq(users.id, localUser.id));

    if (err instanceof CredentialValidationError) {
      // T-12-05: map validation failure to generic 400 — no echo of password
      return c.json({ error: 'Invalid request' }, 400);
    }
    // Unexpected errors (DB failure, network, etc.) — log message only, no credential data
    console.error(
      '[setup/POST /credential] Unexpected error:',
      err instanceof Error ? err.message : String(err),
    );
    return c.json({ error: 'Service unavailable' }, 503);
  }

  return c.json({ ok: true }, 200);
});

// ---------------------------------------------------------------------------
// POST /api/setup/complete
//
// Marks setup as complete by setting app_config.setup_complete='true'.
// The guard re-evaluates on the NEXT call — second call returns 423 (Pitfall 8).
// Returns 200 { ok: true } on the first (successful) call.
// ---------------------------------------------------------------------------

setupRouter.post('/complete', async (c) => {
  const locked = await isSetupLocked();
  if (locked) return c.json({ error: 'Setup already complete' }, 423);

  // IN-02: Guard against skipping the credential step — require an unclaimed user
  // with an associated credential before locking setup. Without this check an operator
  // could call /complete directly, producing a state where setup_complete=true but no
  // admin user exists: first OIDC login creates a non-admin with no credential.
  const [unclaimedWithCred] = await db
    .select({ id: users.id })
    .from(users)
    .innerJoin(memberCredentials, eq(memberCredentials.userId, users.id))
    .where(and(isNull(users.oidcIss), eq(users.claimed, false)))
    .limit(1);

  if (!unclaimedWithCred) {
    return c.json({ error: 'Cannot lock setup: no credential configured' }, 422);
  }

  await db
    .insert(appConfig)
    .values({ key: 'setup_complete', value: 'true' })
    .onDuplicateKeyUpdate({ set: { value: 'true' } });

  return c.json({ ok: true }, 200);
});