/**
 * Admin router — role-gated admin API surface (ADMIN-01/02/03).
 *
 * Security contract:
 *   - adminRouter.use('*', requireAdmin) is the FIRST statement (Pitfall 9 / T-10-08).
 *     This guard runs before ANY route handler, so no admin route is reachable by non-admins.
 *   - POST /credentials uses noEchoHook: NEVER returns Zod's result.error (which contains
 *     .received = the submitted password). Returns { error: 'Invalid request' } only (T-10-09).
 *   - validateEncryptAndStoreCredential from credentialSync.ts is the ONLY place
 *     createFastmailClient + fetchCalendars + encryptPassword + upsert live (D-07).
 *   - No console.log of request bodies or passwords in any handler (T-10-10).
 *
 * Routes:
 *   GET   /api/admin/members                    → list members + credential status + isAdmin (UI-SPEC Surface 2)
 *   POST  /api/admin/members                    → create local member: users row + local_credentials (AUTH-LOCAL-07)
 *   PATCH /api/admin/members/:id               → update member profile: displayName and/or isAdmin (Plan 20-01)
 *   POST  /api/admin/members/:id/password       → admin reset local member password (AUTH-LOCAL-08)
 *   POST  /api/admin/credentials                → validate+encrypt+store for any member (ADMIN-01)
 *   GET   /api/admin/calendars                  → list synced calendars (UI-SPEC Surface 5)
 *   PUT   /api/admin/calendars/:id/shared       → exclusive is_shared designation (ADMIN-02)
 *
 * Mounted in index.ts: app.route('/api/admin', adminRouter)
 */

import { Hono } from 'hono';
import type { Context } from 'hono';
import { zValidator } from '@hono/zod-validator';
import { z } from 'zod';
import { eq, sql } from 'drizzle-orm';
import { db } from '../db/client.js';
import { users, memberCredentials, calendars, appConfig, localCredentials } from '../db/schema.js';
import { requireAdmin } from '../lib/requireAdmin.js';
import { isValidIanaTimezone, resolveHouseholdTimezone } from '../lib/householdTimezone.js';
import {
  validateEncryptAndStoreCredential,
  CredentialValidationError,
} from '../broker/credentialSync.js';
import { hashPassword } from '../auth/localCredentials.js';
import { resetLoginAttempts } from './localAuth.js';
import { COLOR_PALETTE } from '../auth/user.js';
// Side-effect import: brings in the ContextVariableMap augmentation for c.get('user')
import '../auth/devBypass.js';

export const adminRouter = new Hono();

// Pitfall 9: requireAdmin MUST be the first statement on the router.
// All sub-routes are protected — no path can be reached without passing this guard.
adminRouter.use('*', requireAdmin);

// ---------------------------------------------------------------------------
// Zod schema + no-echo hook for credential routes (T-10-09 / Pitfall 7)
// ---------------------------------------------------------------------------

const credentialSchema = z.object({
  userId: z.number().int().positive(),
  providerType: z.literal('caldav'),
  fastmailEmail: z.string().email().max(256),
  appPassword: z.string().min(1).max(500),
});

// Timezone schema — no noEchoHook needed (timezone strings are non-sensitive, T-18-06)
const timezoneSchema = z.object({
  timezone: z
    .string()
    .min(1)
    .max(64)
    .refine(isValidIanaTimezone, { message: 'Invalid IANA timezone identifier' }),
});

/**
 * noEchoHook: NEVER return result.error from zValidator for credential routes.
 * Zod's error object contains issues[].received which echoes the submitted value
 * (the app password) — returning it would violate T-10-09 (Pitfall 7).
 * 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);
  }
};

/**
 * WR-07: strictly parse a positive-integer route param. parseInt('12abc', 10) returns 12
 * and passes an isNaN guard, silently accepting malformed ids. Number('12abc') is NaN, so
 * Number.isInteger(Number(raw)) rejects trailing garbage. Returns null for anything that is
 * not a whole positive integer (empty, '12abc', '1.5', '-3', '0', etc.) so the caller can 400.
 */
function parsePositiveIntParam(raw: string | undefined): number | null {
  if (raw === undefined || raw.trim() === '') return null;
  const n = Number(raw);
  if (!Number.isInteger(n) || n <= 0) return null;
  return n;
}

// ---------------------------------------------------------------------------
// GET /api/admin/members
//
// Returns all household members with their credential status.
// Feeds UI-SPEC Surface 2 (member list with rotate-credential affordance).
// Includes hasLocalCredential (AUTH-LOCAL-17) alongside existing hasCredential.
// ---------------------------------------------------------------------------

adminRouter.get('/members', async (c) => {
  const rows = await db
    .select({
      id: users.id,
      displayName: users.displayName,
      color: users.color,
      isAdmin: users.isAdmin, // Plan 20-01: feeds editor admin toggle initial state (D-02)
      credentialId: memberCredentials.id,
      localCredId: localCredentials.id, // LEFT JOIN — null when no local_credentials row
    })
    .from(users)
    .leftJoin(memberCredentials, eq(memberCredentials.userId, users.id))
    .leftJoin(localCredentials, eq(localCredentials.userId, users.id)); // AUTH-LOCAL-17

  const members = rows.map((row) => ({
    id: row.id,
    displayName: row.displayName,
    color: row.color,
    isAdmin: row.isAdmin, // Plan 20-01
    hasCredential: row.credentialId !== null,
    hasLocalCredential: row.localCredId !== null, // AUTH-LOCAL-17
  }));

  return c.json({ members });
});

// ---------------------------------------------------------------------------
// POST /api/admin/members
//
// Admin creates a new local member: inserts a users row and a local_credentials
// row with a hashed initial password in a single transaction (AUTH-LOCAL-07).
// Security:
//   - noEchoHook: never echoes Zod errors containing the submitted password (T-19-06)
//   - requireAdmin: already enforced by adminRouter.use('*', requireAdmin) (T-19-05)
//   - db.transaction: rolls back both inserts on username conflict (T-19-10)
// ---------------------------------------------------------------------------

const createMemberSchema = z.object({
  displayName: z.string().min(1).max(256),
  username: z.string().min(1).max(128),
  initialPassword: z.string().min(8),
});

adminRouter.post('/members', zValidator('json', createMemberSchema, noEchoHook), async (c) => {
  const { displayName, username, initialPassword } = c.req.valid('json');
  // T-19-06: NEVER log request body, displayName, username, or initialPassword here

  // Assign the first palette color not already in use (mirrors upsertUser color logic)
  const usedRows = await db.select({ color: users.color }).from(users);
  const usedColors = new Set(usedRows.map((r) => r.color));
  const color =
    COLOR_PALETTE.find((c) => !usedColors.has(c)) ??
    COLOR_PALETTE[usedColors.size % COLOR_PALETTE.length];

  // WR-03: hash the initial password BEFORE opening the transaction so the (now async,
  // threadpool) scrypt work does not hold the DB transaction open for its duration.
  const initialPasswordHash = await hashPassword(initialPassword);

  try {
    let newUserId: number;

    // T-19-10: atomic transaction — both inserts succeed or both roll back
    await db.transaction(async (tx) => {
      // Insert the new users row (no oidcIss/oidcSub — local-only member)
      const [inserted] = await tx
        .insert(users)
        .values({
          displayName,
          color,
          isAdmin: false,
          claimed: false, // no OIDC identity bound yet
        })
        .$returningId();
      newUserId = inserted.id;

      // Insert local_credentials row with hashed initial password
      // If username is already in use, the UNIQUE constraint fires here and rolls back
      await tx.insert(localCredentials).values({
        userId: newUserId,
        username,
        passwordHash: initialPasswordHash,
      });
    });

    // Return the new user's id (the PWA uses it to navigate to the member)
    return c.json({ id: newUserId! }, 201);
  } catch (err) {
    // Username uniqueness violation — UNIQUE constraint on local_credentials.username.
    // Drizzle wraps the mysql2 error; check the cause chain or the message for ER_DUP_ENTRY.
    const isDup =
      (err instanceof Error && err.message.includes('ER_DUP_ENTRY')) ||
      (err != null &&
        typeof err === 'object' &&
        'code' in err &&
        (err as { code?: string }).code === 'ER_DUP_ENTRY') ||
      (err != null &&
        typeof err === 'object' &&
        'cause' in err &&
        (err as { cause?: { code?: string } }).cause?.code === 'ER_DUP_ENTRY');
    if (isDup) {
      return c.json({ error: 'Username already in use' }, 409);
    }
    // Unexpected errors — log message only, never the body or password
    console.error(
      '[admin/POST /members] Unexpected error:',
      err instanceof Error ? err.message : String(err),
    );
    return c.json({ error: 'Service unavailable' }, 503);
  }
});

// ---------------------------------------------------------------------------
// PATCH /api/admin/members/:id
//
// Updates a member's displayName and/or isAdmin flag (Plan 20-01, D-02, D-03).
// Security:
//   - requireAdmin: inherited from adminRouter.use('*', requireAdmin) (D-02 — no second guard)
//   - noEchoHook: applied for consistency with other admin write routes (T-20-04)
//   - D-03 last-admin guard: rejects isAdmin=false when target is the sole remaining admin (T-20-02)
//   - parsePositiveIntParam: rejects malformed ids (T-20-03)
// ---------------------------------------------------------------------------

const updateMemberSchema = z.object({
  displayName: z.string().min(1).max(256).optional(),
  isAdmin: z.boolean().optional(),
});

adminRouter.patch('/members/:id', zValidator('json', updateMemberSchema, noEchoHook), async (c) => {
  const targetId = parsePositiveIntParam(c.req.param('id'));
  if (targetId === null) {
    return c.json({ error: 'Invalid member id' }, 400);
  }

  const { displayName, isAdmin } = c.req.valid('json');
  // T-20-04: NEVER log request body

  // Verify the target user exists (404 if not)
  const [target] = await db
    .select({ id: users.id, isAdmin: users.isAdmin })
    .from(users)
    .where(eq(users.id, targetId))
    .limit(1);

  if (!target) {
    return c.json({ error: 'Member not found' }, 404);
  }

  // D-03 last-admin guard: reject demotion of the only remaining admin (T-20-02)
  if (isAdmin === false && target.isAdmin) {
    const [{ count }] = await db
      .select({ count: sql<number>`COUNT(*)` })
      .from(users)
      .where(eq(users.isAdmin, true));
    if (Number(count) <= 1) {
      return c.json({ error: 'Cannot remove the last admin' }, 409);
    }
  }

  // Build a partial set() from whichever fields are present
  const updates: { displayName?: string; isAdmin?: boolean } = {};
  if (displayName !== undefined) updates.displayName = displayName;
  if (isAdmin !== undefined) updates.isAdmin = isAdmin;

  try {
    await db.update(users).set(updates).where(eq(users.id, targetId));
    return c.json({ ok: true }, 200);
  } catch (err) {
    console.error(
      '[admin/PATCH /members/:id] Unexpected error:',
      err instanceof Error ? err.message : String(err),
    );
    return c.json({ error: 'Service unavailable' }, 503);
  }
});

// ---------------------------------------------------------------------------
// POST /api/admin/members/:id/password
//
// Admin resets a local member's password without knowing the current one (AUTH-LOCAL-08).
// Security:
//   - noEchoHook: never echoes Zod errors (T-19-06)
//   - requireAdmin: enforced by adminRouter.use('*', requireAdmin) (T-19-05)
//   - No current password required — admin-only capability
// ---------------------------------------------------------------------------

const resetPasswordSchema = z.object({
  newPassword: z.string().min(8),
});

adminRouter.post(
  '/members/:id/password',
  zValidator('json', resetPasswordSchema, noEchoHook),
  async (c) => {
    const targetId = parsePositiveIntParam(c.req.param('id'));
    if (targetId === null) {
      return c.json({ error: 'Invalid member id' }, 400);
    }

    const { newPassword } = c.req.valid('json');
    // T-19-06: NEVER log newPassword or the request body

    // Verify the target user has a local_credentials row (404 if not).
    // Also read the username so we can clear any login lockout for it (CR-04).
    const [credRow] = await db
      .select({ id: localCredentials.id, username: localCredentials.username })
      .from(localCredentials)
      .where(eq(localCredentials.userId, targetId))
      .limit(1);

    if (!credRow) {
      return c.json({ error: 'Member not found or has no local credential' }, 404);
    }

    try {
      await db
        .update(localCredentials)
        .set({ passwordHash: await hashPassword(newPassword) })
        .where(eq(localCredentials.userId, targetId));

      // CR-04: an admin password reset must immediately clear any rate-limit / lockout
      // state for this username, so a locked-out member regains access at once rather than
      // waiting for the TTL. The lockout is keyed on username (not member id).
      resetLoginAttempts(credRow.username);

      return c.json({ ok: true }, 200);
    } catch (err) {
      console.error(
        '[admin/POST /members/:id/password] Unexpected error:',
        err instanceof Error ? err.message : String(err),
      );
      return c.json({ error: 'Service unavailable' }, 503);
    }
  },
);

// ---------------------------------------------------------------------------
// POST /api/admin/credentials
//
// Admin rotates (or sets for the first time) a member's Fastmail app password.
// Validates against CalDAV (PROPFIND) before storing.
// Uses the shared validateEncryptAndStoreCredential helper — no duplicated logic here.
// ---------------------------------------------------------------------------

adminRouter.post('/credentials', zValidator('json', credentialSchema, noEchoHook), async (c) => {
  const { userId, fastmailEmail, appPassword, providerType } = c.req.valid('json');
  // T-10-10: NEVER log appPassword or c.req.valid('json') here

  try {
    await validateEncryptAndStoreCredential(userId, fastmailEmail, appPassword, providerType);
  } catch (err) {
    if (err instanceof CredentialValidationError) {
      // T-10-09: map validation failure to generic 400 — no echo of password or Zod details
      return c.json({ error: 'Invalid request' }, 400);
    }
    // Unexpected errors (DB failure, etc.) — log message only, no credential data
    console.error(
      '[admin/POST /credentials] Unexpected error:',
      err instanceof Error ? err.message : String(err),
    );
    return c.json({ error: 'Service unavailable' }, 503);
  }

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

// ---------------------------------------------------------------------------
// GET /api/admin/calendars
//
// Lists all synced calendars. Feeds UI-SPEC Surface 5 (shared-calendar picker).
// ---------------------------------------------------------------------------

adminRouter.get('/calendars', async (c) => {
  const rows = await db
    .select({
      id: calendars.id,
      displayName: calendars.displayName,
      isShared: calendars.isShared,
    })
    .from(calendars);

  return c.json({ calendars: rows });
});

// ---------------------------------------------------------------------------
// PUT /api/admin/calendars/:id/shared
//
// Exclusively marks one calendar as is_shared=true (ADMIN-02).
// Clears is_shared on any prior shared calendar first (D-06 single-select).
// Pattern 7: two sequential UPDATE statements.
// ---------------------------------------------------------------------------

adminRouter.put('/calendars/:id/shared', async (c) => {
  const targetId = parsePositiveIntParam(c.req.param('id'));
  if (targetId === null) {
    return c.json({ error: 'Invalid calendar id' }, 400);
  }

  // CR-01: verify the target exists and flip the shared lane atomically.
  // Without the existence check + transaction, a bad/stale id would clear the
  // current shared calendar in step 1 and update 0 rows in step 2 — silently
  // leaving the household with NO shared calendar while still returning ok.
  const found = await db.transaction(async (tx) => {
    const [target] = await tx
      .select({ id: calendars.id })
      .from(calendars)
      .where(eq(calendars.id, targetId))
      .limit(1);
    if (!target) return false;

    // Step 1: Clear is_shared on any currently-shared calendar
    await tx.update(calendars).set({ isShared: false }).where(eq(calendars.isShared, true));
    // Step 2: Set is_shared on the target calendar (D-06 single-select)
    await tx.update(calendars).set({ isShared: true }).where(eq(calendars.id, targetId));
    return true;
  });

  if (!found) {
    return c.json({ error: 'Calendar not found' }, 404);
  }

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

// ---------------------------------------------------------------------------
// GET /api/admin/config/timezone
//
// Returns the stored household timezone and whether it has been explicitly set
// (D-01, D-04, D-06). isExplicitlySet: false when no row is in app_config
// (the response still includes the D-06 fallback as the timezone value).
// ---------------------------------------------------------------------------

adminRouter.get('/config/timezone', async (c) => {
  const [row] = await db
    .select({ value: appConfig.value })
    .from(appConfig)
    .where(eq(appConfig.key, 'household_timezone'))
    .limit(1);

  const isExplicitlySet = row?.value != null;
  // IN-01/IN-02: reuse the row we just SELECTed and let the centralized accessor apply
  // the D-06 fallback — no second app_config round-trip, single source for the policy.
  const timezone = resolveHouseholdTimezone(row?.value ?? null);

  return c.json({ timezone, isExplicitlySet });
});

// ---------------------------------------------------------------------------
// PUT /api/admin/config/timezone
//
// Validates the IANA timezone string (server-side, T-18-04) and upserts the
// household_timezone key in app_config (D-01, D-04).
// Uses onDuplicateKeyUpdate — appConfig.key is the PK so this is a true upsert.
// No noEchoHook: timezone strings are non-sensitive (T-18-06).
// ---------------------------------------------------------------------------

adminRouter.put('/config/timezone', zValidator('json', timezoneSchema), async (c) => {
  const { timezone } = c.req.valid('json');

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

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

// ---------------------------------------------------------------------------
// POST /api/admin/config/timezone/seed
//
// Seeds household_timezone ONLY when currently unset (D-02 first-run / D-03
// no-overwrite). Used by the Phase 12 setup wizard and the Phase 18 auto-detect
// flow to store the browser-detected IANA zone without clobbering an admin's
// explicit choice.
//
// Always returns 200 with { ok: true, seeded: <bool> }.
// Uses a single INSERT IGNORE: when the household_timezone row already exists the
// insert is silently ignored (existing value untouched — D-03 no-overwrite) and
// cannot 500 on the PK constraint under a concurrent seed/PUT. `seeded` is derived
// from the result's affectedRows so it reflects what the DB actually did, accurately
// even under a genuine concurrent race (WR-02).
// ---------------------------------------------------------------------------

adminRouter.post('/config/timezone/seed', zValidator('json', timezoneSchema), async (c) => {
  const { timezone } = c.req.valid('json');

  // WR-02: always run the INSERT and let the DB be the source of truth, instead of a
  // pre-flight SELECT whose result could be stale under a concurrent race (two racers
  // both observing an empty table and both returning seeded:true). INSERT IGNORE on
  // MariaDB reports affectedRows === 1 for a real insert and 0 when the row already
  // exists (ignored, value preserved — D-03), so deriving `seeded` from affectedRows
  // is accurate: only the racer whose INSERT actually wrote the row gets seeded:true.
  // `timezone` is interpolated via drizzle's parameterized sql template (bound param,
  // not string concatenation) and is already validated as an IANA zone by timezoneSchema.
  const result = (await db.execute(
    sql`INSERT IGNORE INTO ${appConfig} (${sql.identifier('key')}, ${sql.identifier('value')}) VALUES ('household_timezone', ${timezone})`,
  )) as unknown as [{ affectedRows: number }, unknown];

  const seeded = result[0].affectedRows === 1;

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