import type { FastifyInstance } from "fastify";
import { requireRole } from "../auth.js";
import {
  InvalidCashMovementError,
  NoOpenShiftError,
  ShiftAlreadyOpenError,
  type ShiftService,
} from "../shift-service.js";

interface CashMovementBody {
  /** Signed minor units: positive = load INTO drawer, negative = remove FROM drawer. */
  amountMinor: number;
  reason?: string;
  currency?: string;
}

// Shift endpoints (manned mode). The operator is the logged-in user; a shift is
// opened/closed explicitly (not time-based — see wiki/concepts/shift.md and
// local-jwt-auth.md "until logout"). End Shift signs a shift_z_report + prints it.

export async function shiftRoutes(app: FastifyInstance, shift: ShiftService): Promise<void> {
  // Cashier/operator/admin run shifts; readonly can't.
  const guard = requireRole("admin", "operator", "cashier");

  // The SITE-WIDE shift state (at most one shift open at a time). The UI uses this
  // to render the header control: no shift → "Open"; my shift → "Close" (enabled);
  // someone else's shift → disabled. Also returns the live drawer balance.
  //  - open:    the open shift { startedAt, operator } or null (site-wide)
  //  - isMine:  true iff the open shift belongs to the requesting operator
  //  - operator: the requesting user (for the UI's own identity)
  app.get("/api/shift/current", { preHandler: guard }, async (req) => {
    const me = req.user.username;
    const open = shift.currentOpenShift();
    const heldBy = open?.identity ?? null;
    const drawer = shift.drawerBalance();
    return {
      operator: me,
      open: open ? { startedAt: open.occurredAt, operator: heldBy } : null,
      isMine: open != null && heldBy === me,
      drawerMinor: drawer.balanceMinor,
      currency: drawer.currency,
    };
  });

  // Admin loads/removes physical drawer cash (the float). Signed cash_movement
  // event. ADMIN ONLY — an operator takes payments but cannot move the float.
  // amountMinor is signed: + load IN, − remove OUT. See wiki/concepts/shift.md.
  app.post<{ Body: CashMovementBody }>(
    "/api/cash-movement",
    { preHandler: requireRole("admin") },
    async (req, reply) => {
      const { amountMinor, reason, currency } = req.body ?? ({} as CashMovementBody);
      try {
        return await shift.recordCashMovement(req.user.username, amountMinor, reason ?? "", currency);
      } catch (err) {
        if (err instanceof InvalidCashMovementError) return reply.code(400).send({ error: err.message });
        return reply.code(500).send({ error: (err as Error).message });
      }
    },
  );

  app.post("/api/shift/open", { preHandler: guard }, async (req, reply) => {
    try {
      return await shift.open(req.user.username);
    } catch (err) {
      if (err instanceof ShiftAlreadyOpenError) return reply.code(409).send({ error: err.message });
      return reply.code(500).send({ error: (err as Error).message });
    }
  });

  app.post("/api/shift/close", { preHandler: guard }, async (req, reply) => {
    try {
      return await shift.close(req.user.username);
    } catch (err) {
      if (err instanceof NoOpenShiftError) return reply.code(409).send({ error: err.message });
      return reply.code(500).send({ error: (err as Error).message });
    }
  });
}