import Fastify, { type FastifyReply, type FastifyRequest } from 'fastify';
import rateLimit from '@fastify/rate-limit';
import {
  LabelDb,
  LABEL_KINDS,
  isLabelKind,
  isAreaKind,
  AREA_KINDS,
  type ZoneLabel,
  type ParkingArea,
} from './db.js';
import { AbuseGuard, safeEqual } from './auth.js';

export interface BuildOptions {
  adminToken: string;
  /** File path for the SQLite DB, or ':memory:' (tests). Ignored if `db` is given. */
  dbPath?: string;
  db?: LabelDb;
  trustProxy?: boolean;
  rateLimitMax?: number;
  rateLimitWindow?: string;
  writeRateLimitMax?: number;
  authFailLimit?: number;
  authFailWindowMs?: number;
  blockCooldownMs?: number;
  seedBlockedIps?: string[];
}

interface ZoneParams {
  zoneId: string;
}
interface PutBody {
  kind?: unknown;
  zoneName?: unknown;
  customerId?: unknown;
  note?: unknown;
}

const str = (v: unknown): string | null => (v == null ? null : String(v));

export async function buildApp(opts: BuildOptions) {
  const db = opts.db ?? new LabelDb(opts.dbPath ?? ':memory:');
  if (opts.seedBlockedIps?.length) db.seedBlocked(opts.seedBlockedIps);

  const guard = new AbuseGuard(
    opts.authFailLimit ?? 8,
    opts.authFailWindowMs ?? 15 * 60 * 1000,
    opts.blockCooldownMs ?? 60 * 60 * 1000,
  );

  // 1 MB: zone-sync batches carry full Zone objects (policies, logos, …).
  const app = Fastify({ trustProxy: opts.trustProxy ?? true, logger: false, bodyLimit: 1024 * 1024 });

  await app.register(rateLimit, {
    max: opts.rateLimitMax ?? 120,
    timeWindow: opts.rateLimitWindow ?? '1 minute',
  });

  // Reject blocked IPs (manual denylist + auto-block) before anything else.
  app.addHook('onRequest', async (req: FastifyRequest, reply: FastifyReply) => {
    if (guard.isBlocked(req.ip, Date.now()) || db.isBlocked(req.ip)) {
      return reply.code(403).send({ error: 'forbidden' });
    }
  });

  const requireAdmin = async (req: FastifyRequest, reply: FastifyReply) => {
    const hdr = req.headers.authorization ?? '';
    const token = /^Bearer\s+(.+)$/i.exec(hdr)?.[1] ?? '';
    if (!token || !safeEqual(token, opts.adminToken)) {
      const tripped = guard.recordFail(req.ip, Date.now());
      return reply.code(401).send({ error: 'unauthorized', blocked: tripped });
    }
    guard.recordSuccess(req.ip);
  };

  const writeLimit = {
    config: { rateLimit: { max: opts.writeRateLimitMax ?? 20, timeWindow: '1 minute' } },
  };

  app.get('/healthz', async () => ({ ok: true }));

  app.get('/api/whoami', { preHandler: requireAdmin }, async () => ({ admin: true }));

  app.get('/api/labels', async () => ({ labels: db.all() }));

  app.get('/api/labels/:zoneId', async (req: FastifyRequest<{ Params: ZoneParams }>, reply) => {
    const label = db.get(req.params.zoneId);
    if (!label) return reply.code(404).send({ error: 'not_found' });
    return label;
  });

  app.put(
    '/api/labels/:zoneId',
    { preHandler: requireAdmin, ...writeLimit },
    async (req: FastifyRequest<{ Params: ZoneParams; Body: PutBody }>, reply) => {
      const body = req.body ?? {};
      if (!isLabelKind(body.kind)) {
        return reply.code(400).send({ error: 'bad_kind', allowed: LABEL_KINDS });
      }
      const label: ZoneLabel = {
        zoneId: String(req.params.zoneId),
        customerId: str(body.customerId),
        zoneName: str(body.zoneName),
        kind: body.kind,
        note: body.note == null ? null : String(body.note).slice(0, 500),
        updatedAt: Date.now(),
        updatedBy: 'admin',
      };
      db.upsert(label);
      return label;
    },
  );

  app.delete(
    '/api/labels/:zoneId',
    { preHandler: requireAdmin, ...writeLimit },
    async (req: FastifyRequest<{ Params: ZoneParams }>, reply) => {
      if (!db.delete(req.params.zoneId)) return reply.code(404).send({ error: 'not_found' });
      return { deleted: true };
    },
  );

  // ---- Zone mirror (for anonymous browsing) --------------------------------
  const coord = (v: unknown): number | null => {
    const n = Number(v);
    return Number.isFinite(n) && n !== 0 ? n : null;
  };

  app.get('/api/zones', async () => ({ zones: db.allZones(), count: db.zoneCount() }));

  // The app pushes the Zone list it just pulled (authed) from ParkSmarter so
  // anonymous users can read areas without a ParkSmarter login.
  app.post(
    '/api/zones/sync',
    { preHandler: requireAdmin, ...writeLimit },
    async (req: FastifyRequest<{ Body: { zones?: unknown[] } }>, reply) => {
      const zones = Array.isArray(req.body?.zones) ? req.body!.zones : null;
      if (!zones) return reply.code(400).send({ error: 'zones_required' });
      const rows: Array<{ zoneId: string; zoneName: string | null; lat: number | null; long: number | null; data: string }> = [];
      for (const z of zones as Array<Record<string, unknown>>) {
        if (z == null || z.ZoneId == null) continue;
        rows.push({
          zoneId: String(z.ZoneId),
          zoneName: z.ZoneName != null ? String(z.ZoneName) : null,
          lat: coord(z.Lat),
          long: coord(z.Long),
          data: JSON.stringify(z),
        });
      }
      return { synced: db.upsertZones(rows), total: db.zoneCount() };
    },
  );

  // ---- City parking-map areas ---------------------------------------------
  // The colour-coded areas from the city's printed Downtown & Waterfront parking
  // map, georeferenced. Purely local geography: none of this touches ParkSmarter,
  // which is the point — tracking time on these spots must work with no IPS call.

  const num = (v: unknown, fallback: number): number => {
    const n = Number(v);
    return Number.isFinite(n) ? n : fallback;
  };

  app.get('/api/areas', async () => ({
    areas: db.allAreas(),
    overlay: db.getOverlay(),
    count: db.areaCount(),
    updatedAt: db.areasUpdatedAt(),
  }));

  // Replace-all, not upsert: the areas come from one source document, so a partial
  // update would leave a map matching neither the old print nor the new one.
  app.put(
    '/api/areas',
    { preHandler: requireAdmin, ...writeLimit },
    async (req: FastifyRequest<{ Body: { areas?: unknown[] } }>, reply) => {
      const input = Array.isArray(req.body?.areas) ? req.body!.areas : null;
      if (!input) return reply.code(400).send({ error: 'areas_required' });

      const areas: ParkingArea[] = [];
      for (const raw of input as Array<Record<string, unknown>>) {
        if (raw == null || raw.id == null) continue;
        if (!isAreaKind(raw.kind)) {
          return reply.code(400).send({ error: 'bad_kind', id: raw.id, allowed: AREA_KINDS });
        }
        const g = raw.geometry as { type?: unknown } | null;
        if (!g || (g.type !== 'LineString' && g.type !== 'Polygon')) {
          return reply.code(400).send({ error: 'bad_geometry', id: raw.id });
        }
        areas.push({
          id: String(raw.id),
          kind: raw.kind,
          name: String(raw.name ?? raw.id),
          label: String(raw.label ?? raw.kind),
          legend: String(raw.legend ?? ''),
          hours: num(raw.hours, 0),
          color: String(raw.color ?? '#888888'),
          shape: g.type === 'Polygon' ? 'polygon' : 'line',
          geometry: g,
        });
      }
      return { replaced: db.replaceAreas(areas), total: db.areaCount() };
    },
  );

  // Whole-overlay alignment correction, set from the phone against a live GPS fix.
  app.put(
    '/api/areas/overlay',
    { preHandler: requireAdmin, ...writeLimit },
    async (req: FastifyRequest<{ Body: Record<string, unknown> }>, reply) => {
      const b = req.body ?? {};
      const scale = num(b.scale, 1);
      if (scale <= 0.5 || scale >= 2) {
        // A fit that needs more than a ±2x correction is a broken fit, not a nudge.
        return reply.code(400).send({ error: 'scale_out_of_range' });
      }
      return db.setOverlay({
        dxMeters: num(b.dxMeters, 0),
        dyMeters: num(b.dyMeters, 0),
        scale,
        rotationDeg: num(b.rotationDeg, 0),
      });
    },
  );

  app.addHook('onClose', async () => db.close());
  return app;
}