import { Router } from 'express';
import { AppError } from '../lib/errors.js';
import { requireAuth, requirePolicy } from '../middleware/auth.js';
import { requireIdempotencyKey } from '../middleware/idempotency.js';
import { buildIdempotencyKey, readIdempotentResult, writeIdempotentResult } from '../services/idempotency-store.js';
import {
  addFavoriteStaff,
  clockIn,
  clockOut,
  createOrder,
  createStaffReview,
  updateOrder,
  cancelOrder,
  changeShiftStatus,
  assignStaffToShift,
  removeFavoriteStaff,
  acceptShift,
} from '../services/command-service.js';
import { attendanceCommandSchema } from '../contracts/commands/attendance.js';
import { favoriteStaffSchema } from '../contracts/commands/favorite-staff.js';
import { orderCancelSchema } from '../contracts/commands/order-cancel.js';
import { orderCreateSchema } from '../contracts/commands/order-create.js';
import { orderUpdateSchema } from '../contracts/commands/order-update.js';
import { shiftAssignStaffSchema } from '../contracts/commands/shift-assign-staff.js';
import { shiftAcceptSchema } from '../contracts/commands/shift-accept.js';
import { shiftStatusChangeSchema } from '../contracts/commands/shift-status-change.js';
import { staffReviewSchema } from '../contracts/commands/staff-review.js';

const defaultHandlers = {
  addFavoriteStaff,
  assignStaffToShift,
  cancelOrder,
  changeShiftStatus,
  clockIn,
  clockOut,
  createOrder,
  createStaffReview,
  removeFavoriteStaff,
  acceptShift,
  updateOrder,
};

function parseBody(schema, body) {
  const parsed = schema.safeParse(body || {});
  if (!parsed.success) {
    throw new AppError('VALIDATION_ERROR', 'Invalid command payload', 400, {
      issues: parsed.error.issues,
    });
  }
  return parsed.data;
}

async function runIdempotentCommand(req, res, work) {
  const route = `${req.baseUrl}${req.route.path}`;
  const compositeKey = buildIdempotencyKey({
    userId: req.actor.uid,
    route,
    idempotencyKey: req.idempotencyKey,
  });

  const existing = await readIdempotentResult(compositeKey);
  if (existing) {
    return res.status(existing.statusCode).json(existing.payload);
  }

  const payload = await work();
  const responsePayload = {
    ...payload,
    idempotencyKey: req.idempotencyKey,
    requestId: req.requestId,
  };
  const persisted = await writeIdempotentResult({
    compositeKey,
    userId: req.actor.uid,
    route,
    idempotencyKey: req.idempotencyKey,
    payload: responsePayload,
    statusCode: 200,
  });
  return res.status(persisted.statusCode).json(persisted.payload);
}

export function createCommandsRouter(handlers = defaultHandlers) {
  const router = Router();

  router.post(
    '/orders/create',
    requireAuth,
    requireIdempotencyKey,
    requirePolicy('orders.create', 'order'),
    async (req, res, next) => {
      try {
        const payload = parseBody(orderCreateSchema, req.body);
        return await runIdempotentCommand(req, res, () => handlers.createOrder(req.actor, payload));
      } catch (error) {
        return next(error);
      }
    }
  );

  router.post(
    '/orders/:orderId/update',
    requireAuth,
    requireIdempotencyKey,
    requirePolicy('orders.update', 'order'),
    async (req, res, next) => {
      try {
        const payload = parseBody(orderUpdateSchema, {
          ...req.body,
          orderId: req.params.orderId,
        });
        return await runIdempotentCommand(req, res, () => handlers.updateOrder(req.actor, payload));
      } catch (error) {
        return next(error);
      }
    }
  );

  router.post(
    '/orders/:orderId/cancel',
    requireAuth,
    requireIdempotencyKey,
    requirePolicy('orders.cancel', 'order'),
    async (req, res, next) => {
      try {
        const payload = parseBody(orderCancelSchema, {
          ...req.body,
          orderId: req.params.orderId,
        });
        return await runIdempotentCommand(req, res, () => handlers.cancelOrder(req.actor, payload));
      } catch (error) {
        return next(error);
      }
    }
  );

  router.post(
    '/shifts/:shiftId/change-status',
    requireAuth,
    requireIdempotencyKey,
    requirePolicy('shifts.change-status', 'shift'),
    async (req, res, next) => {
      try {
        const payload = parseBody(shiftStatusChangeSchema, {
          ...req.body,
          shiftId: req.params.shiftId,
        });
        return await runIdempotentCommand(req, res, () => handlers.changeShiftStatus(req.actor, payload));
      } catch (error) {
        return next(error);
      }
    }
  );

  router.post(
    '/shifts/:shiftId/assign-staff',
    requireAuth,
    requireIdempotencyKey,
    requirePolicy('shifts.assign-staff', 'shift'),
    async (req, res, next) => {
      try {
        const payload = parseBody(shiftAssignStaffSchema, {
          ...req.body,
          shiftId: req.params.shiftId,
        });
        return await runIdempotentCommand(req, res, () => handlers.assignStaffToShift(req.actor, payload));
      } catch (error) {
        return next(error);
      }
    }
  );

  router.post(
    '/shifts/:shiftId/accept',
    requireAuth,
    requireIdempotencyKey,
    requirePolicy('shifts.accept', 'shift'),
    async (req, res, next) => {
      try {
        const payload = parseBody(shiftAcceptSchema, {
          ...req.body,
          shiftId: req.params.shiftId,
        });
        return await runIdempotentCommand(req, res, () => handlers.acceptShift(req.actor, payload));
      } catch (error) {
        return next(error);
      }
    }
  );

  router.post(
    '/attendance/clock-in',
    requireAuth,
    requireIdempotencyKey,
    requirePolicy('attendance.clock-in', 'attendance'),
    async (req, res, next) => {
      try {
        const payload = parseBody(attendanceCommandSchema, req.body);
        return await runIdempotentCommand(req, res, () => handlers.clockIn(req.actor, payload));
      } catch (error) {
        return next(error);
      }
    }
  );

  router.post(
    '/attendance/clock-out',
    requireAuth,
    requireIdempotencyKey,
    requirePolicy('attendance.clock-out', 'attendance'),
    async (req, res, next) => {
      try {
        const payload = parseBody(attendanceCommandSchema, req.body);
        return await runIdempotentCommand(req, res, () => handlers.clockOut(req.actor, payload));
      } catch (error) {
        return next(error);
      }
    }
  );

  router.post(
    '/businesses/:businessId/favorite-staff',
    requireAuth,
    requireIdempotencyKey,
    requirePolicy('business.favorite-staff', 'staff'),
    async (req, res, next) => {
      try {
        const payload = parseBody(favoriteStaffSchema, {
          ...req.body,
          businessId: req.params.businessId,
        });
        return await runIdempotentCommand(req, res, () => handlers.addFavoriteStaff(req.actor, payload));
      } catch (error) {
        return next(error);
      }
    }
  );

  router.delete(
    '/businesses/:businessId/favorite-staff/:staffId',
    requireAuth,
    requireIdempotencyKey,
    requirePolicy('business.unfavorite-staff', 'staff'),
    async (req, res, next) => {
      try {
        const payload = parseBody(favoriteStaffSchema, {
          ...req.body,
          businessId: req.params.businessId,
          staffId: req.params.staffId,
        });
        return await runIdempotentCommand(req, res, () => handlers.removeFavoriteStaff(req.actor, payload));
      } catch (error) {
        return next(error);
      }
    }
  );

  router.post(
    '/assignments/:assignmentId/reviews',
    requireAuth,
    requireIdempotencyKey,
    requirePolicy('assignments.review-staff', 'assignment'),
    async (req, res, next) => {
      try {
        const payload = parseBody(staffReviewSchema, {
          ...req.body,
          assignmentId: req.params.assignmentId,
        });
        return await runIdempotentCommand(req, res, () => handlers.createStaffReview(req.actor, payload));
      } catch (error) {
        return next(error);
      }
    }
  );

  return router;
}