import type { FastifyInstance } from "fastify";
import { eq, siteConfig, type Db } from "@parking/db";
import { requireRole } from "../auth.js";
import { getOccupancy } from "../occupancy.js";

// Site config (capacity) + live occupancy. Occupancy is a fold over the signed
// ledger; capacity is an admin-set knob. The FULL gate (refuse transient entry at
// capacity) lives in the entry flow. See wiki/concepts/capacity-occupancy.md.

interface SiteConfigBody {
  /** Nominal capacity; null = no limit. */
  capacity: number | null;
}

export async function siteRoutes(app: FastifyInstance, db: Db): Promise<void> {
  const readGuard = requireRole("admin", "operator", "cashier", "readonly");
  const writeGuard = requireRole("admin");

  // Live occupancy: cars inside, capacity, free, full. Any signed-in role.
  app.get("/api/occupancy", { preHandler: readGuard }, async () => getOccupancy(db));

  // Read site config (capacity).
  app.get("/api/site-config", { preHandler: readGuard }, async () => {
    const row = db.select().from(siteConfig).where(eq(siteConfig.id, 1)).get();
    return { capacity: row?.capacity ?? null };
  });

  // Set capacity (admin). null or 0+ integer.
  app.put<{ Body: SiteConfigBody }>("/api/site-config", { preHandler: writeGuard }, async (req, reply) => {
    const { capacity } = req.body ?? ({} as SiteConfigBody);
    if (capacity != null && (!Number.isInteger(capacity) || capacity < 0)) {
      return reply.code(400).send({ error: "capacity must be a non-negative integer or null" });
    }
    const existing = db.select().from(siteConfig).where(eq(siteConfig.id, 1)).get();
    const updatedAt = new Date().toISOString();
    if (existing) {
      db.update(siteConfig).set({ capacity: capacity ?? null, updatedAt }).where(eq(siteConfig.id, 1)).run();
    } else {
      db.insert(siteConfig).values({ id: 1, capacity: capacity ?? null, updatedAt }).run();
    }
    return { capacity: capacity ?? null };
  });
}