import type { Db } from "@parking/db";
import type { FastifyBaseLogger } from "fastify";
import type { DeviceReadEvent, ReadOutcome } from "./device-events.js";
import type { ExitFlow } from "./exit-flow.js";
import type { PermitFlow } from "./permit-flow.js";
import { readerLaneWithAccess } from "./lane-map.js";

// Routes a credential read (ticket scan / plate / card) to the right flow. A read
// can mean a permit entry/exit OR a transient exit, so we dispatch by WHAT the
// credential is (decision 2026-06-15):
//   - matches a permit (card/QR/bound plate) → PERMIT flow (direction inferred from
//     the car's open-session state),
//   - else → transient EXIT flow (open ticket session → exit, else reject+log).
// Lane is resolved once here; both flows act on a known access-equipped lane.

export class ReadDispatcher {
  readonly #db: Db;
  readonly #exit: ExitFlow;
  readonly #permit: PermitFlow;
  readonly #logger: FastifyBaseLogger;

  constructor(db: Db, exit: ExitFlow, permit: PermitFlow, logger: FastifyBaseLogger) {
    this.#db = db;
    this.#exit = exit;
    this.#permit = permit;
    this.#logger = logger;
  }

  async dispatch(e: DeviceReadEvent): Promise<ReadOutcome> {
    const lane = await readerLaneWithAccess(this.#db, e.deviceId);
    if (lane == null) {
      return { accepted: false, reason: "reader not on an access-equipped lane" };
    }

    const permit = this.#permit.match(e);
    if (permit) {
      return this.#permit.run(lane, e, permit);
    }
    // Not a permit → transient ticket exit (the exit flow rejects+logs if unknown).
    return this.#exit.handleAt(lane, e);
  }
}