import type { FastifyInstance } from 'fastify';
import { z } from 'zod';
import { eq, inArray, sql } from 'drizzle-orm';
import {
  getDb,
  users,
  firms,
  clients,
  cases,
  timeEntries,
  invoices,
  invoiceItems,
  documents,
  sessions,
} from '@lawdesk/db';
import { verifyPassword } from '../auth/password';
import { logAudit } from '../lib/audit';

export async function accountRoutes(app: FastifyInstance) {
  app.addHook('preHandler', app.requireAuth);

  // GDPR data export — full JSON dump of everything tied to the user's firm.
  app.get('/api/account/export', async (req, reply) => {
    const userId = req.user!.id;
    const firmId = req.user!.firmId;
    const db = getDb();

    const [profile] = await db
      .select({
        id: users.id,
        email: users.email,
        fullName: users.fullName,
        role: users.role,
        emailVerifiedAt: users.emailVerifiedAt,
        totpEnabled: users.totpEnabled,
        lastSeenAt: users.lastSeenAt,
        createdAt: users.createdAt,
      })
      .from(users)
      .where(eq(users.id, userId))
      .limit(1);

    if (!profile) return reply.code(404).send({ error: 'profile_not_found' });

    const dump: Record<string, unknown> = {
      exportedAt: new Date().toISOString(),
      profile,
    };

    if (firmId) {
      const [firm] = await db.select().from(firms).where(eq(firms.id, firmId)).limit(1);
      const firmClients = await db.select().from(clients).where(eq(clients.firmId, firmId));
      const firmCases = await db.select().from(cases).where(eq(cases.firmId, firmId));
      const firmTime = await db.select().from(timeEntries).where(eq(timeEntries.firmId, firmId));
      const firmInvoices = await db.select().from(invoices).where(eq(invoices.firmId, firmId));
      const invoiceIds = firmInvoices.map((i) => i.id);
      const items = invoiceIds.length
        ? await db.select().from(invoiceItems).where(inArray(invoiceItems.invoiceId, invoiceIds))
        : [];
      const docs = await db.select().from(documents).where(eq(documents.firmId, firmId));

      dump.firm = firm;
      dump.clients = firmClients;
      dump.cases = firmCases;
      dump.timeEntries = firmTime;
      dump.invoices = firmInvoices.map((i) => ({
        ...i,
        items: items.filter((it) => it.invoiceId === i.id),
      }));
      dump.documents = docs;
    }

    await logAudit({
      userId,
      firmId,
      action: 'account.export',
      ip: req.ip,
    });

    reply
      .header('Content-Type', 'application/json; charset=utf-8')
      .header(
        'Content-Disposition',
        `attachment; filename="lawdesk-export-${new Date().toISOString().slice(0, 10)}.json"`,
      );
    return JSON.stringify(dump, null, 2);
  });

  // GDPR delete — password-confirmed. Solo firms cascade everything; multi-user firms must
  // transfer ownership first (we'll add a transfer endpoint when we add team management).
  app.post('/api/account/delete', async (req, reply) => {
    const userId = req.user!.id;
    const firmId = req.user!.firmId;
    const body = z.object({ password: z.string().min(1) }).parse(req.body);

    const db = getDb();
    const [me] = await db.select().from(users).where(eq(users.id, userId)).limit(1);
    if (!me) return reply.code(404).send({ error: 'user_not_found' });

    const ok = await verifyPassword(me.passwordHash, body.password);
    if (!ok) return reply.code(401).send({ error: 'invalid_password' });

    if (firmId) {
      const [{ count }] = await db
        .select({ count: sql<number>`count(*)::int` })
        .from(users)
        .where(eq(users.firmId, firmId));
      if (count > 1) {
        return reply.code(409).send({
          error: 'firm_has_other_users',
          hint: 'Transfer firm ownership or remove other users before deleting this account.',
        });
      }
    }

    await logAudit({
      userId,
      firmId,
      action: 'account.delete',
      meta: { email: me.email },
      ip: req.ip,
    });

    await db.transaction(async (tx) => {
      await tx.delete(sessions).where(eq(sessions.userId, userId));
      // Deleting the firm cascades: clients → cases → time_entries / documents / invoices →
      // invoice_items via the foreign-key onDelete:'cascade' chain. Audit log entries pointing
      // to this user keep their row but null out user_id (set null).
      if (firmId) await tx.delete(firms).where(eq(firms.id, firmId));
      await tx.delete(users).where(eq(users.id, userId));
    });

    app.clearSessionCookie(reply);
    app.clearCsrfCookie(reply);
    return { ok: true };
  });
}