Fulfillment Service

/**
 * Static property identifying this as a fulfillment service
 */
static _isFulfillmentService: boolean;

/**
 * Checks if an object is a fulfillment service
 * @param {object} obj - Object to check
 * @returns {boolean} True if obj is a fulfillment service
 */
static isFulfillmentService(obj: object): boolean;

/**
 * Returns the service identifier from constructor
 * @returns {string} Service identifier
 */
getIdentifier(): string;

/**
 * Returns all fulfillment options that the provider can be used with
 * Called before a shipping option is created in Admin
 * @returns {any} Available fulfillment options
 * @throws {Error} If not overridden by child class
 */
getFulfillmentOptions(): any;

/**
 * Validates fulfillment option exists before creating shipping option in Admin
 * @param {object} data - Option data to validate
 * @returns {any} Validation result
 * @throws {Error} If not overridden by child class
 */
validateOption(data: object): any;

/**
 * Validates data sent with shipping method before setting on cart
 * @param {object} optionData - The option data to validate
 * @param {object} data - The shipping method data to validate
 * @param {object} cart - The cart the shipping method will be applied to
 * @returns {object} Data to populate cart.shipping_methods.$.data
 * @throws {Error} If not overridden by child class
 */
validateFulfillmentData(optionData: object, data: object, cart?: object): object;

/**
 * Determines if fulfillment service can calculate price for given data
 * @param {object} data - Data to check for price calculation capability
 * @returns {any} True if price can be calculated
 * @throws {Error} If not overridden by child class
 */
canCalculate(data: object): any;

/**
 * Calculates price for a given shipping option
 * @param {object} optionData - Shipping option data
 * @param {object} data - Additional calculation data
 * @param {object} cart - Cart object for calculation context
 * @returns {any} Calculated price
 * @throws {Error} If not overridden by child class
 */
calculatePrice(optionData: object, data: object, cart: object): any;

/**
 * Creates a fulfillment for an order
 * @param {object} data - Fulfillment data
 * @param {array} items - Items to fulfill
 * @param {object} order - Order object
 * @param {object} fulfillment - Fulfillment object
 * @returns {any} Created fulfillment result
 * @throws {Error} If not overridden by child class
 */
createFulfillment(data: object, items: array, order: object, fulfillment: object): any;

/**
 * Cancels an existing fulfillment
 * @param {object} fulfillment - Fulfillment to cancel
 * @returns {any} Cancellation result
 * @throws {Error} If not overridden by child class
 */
cancelFulfillment(fulfillment: object): any;

/**
 * Creates a return order with necessary data for future operations
 * @param {object} fromData - Data to create return from
 * @returns {any} Return order data
 * @throws {Error} If not overridden by child class
 */
createReturn(fromData: object): any;

/**
 * Retrieves documents associated with a fulfillment
 * @param {object} data - Fulfillment data
 * @returns {array} Array of fulfillment documents (empty by default)
 */
getFulfillmentDocuments(data: object): array;

/**
 * Retrieves documents related to a return order
 * @param {object} data - Return data
 * @returns {array} Array of return documents (empty by default)
 */
getReturnDocuments(data: object): array;

/**
 * Retrieves documents related to a shipment
 * @param {object} data - Shipment data
 * @returns {array} Array of shipment documents (empty by default)
 */
getShipmentDocuments(data: object): array;

/**
 * Retrieves documents based on fulfillment data and document type
 * @param {object} fulfillmentData - Fulfillment data
 * @param {string} documentType - Type of document to retrieve
 * @returns {any} Retrieved documents
 * @throws {Error} If not overridden by child class
 */
retrieveDocuments(fulfillmentData: object, documentType: string): any;

import { FulfillmentService } from "medusa-interfaces";

class CustomFulfillmentService extends FulfillmentService {
  static identifier = "custom-fulfillment";
  
  constructor(options) {
    super();
    this.options_ = options;
  }

  getFulfillmentOptions() {
    return [
      {
        id: "standard",
        name: "Standard Shipping",
        description: "5-7 business days"
      },
      {
        id: "express",
        name: "Express Shipping", 
        description: "1-2 business days"
      }
    ];
  }

  validateOption(data) {
    const validOptions = ["standard", "express"];
    if (!validOptions.includes(data.id)) {
      throw new Error("Invalid fulfillment option");
    }
    return true;
  }

  validateFulfillmentData(optionData, data, cart) {
    // Validate shipping method data
    if (optionData.id === "express" && !data.express_service_type) {
      throw new Error("Express service type required");
    }
    
    return {
      service_type: optionData.id,
      validated_data: data
    };
  }

  canCalculate(data) {
    // Check if we have necessary data for price calculation
    return data.destination_address && data.items;
  }

  calculatePrice(optionData, data, cart) {
    // Calculate shipping price based on option and cart data
    const basePrice = optionData.id === "express" ? 15.00 : 5.00;
    const weightMultiplier = cart.items.reduce((total, item) => total + item.quantity, 0) * 0.5;
    
    return Math.round((basePrice + weightMultiplier) * 100); // Return in cents
  }

  async createFulfillment(data, items, order, fulfillment) {
    // Create fulfillment with external provider
    const shipment = await this.externalProvider.createShipment({
      items: items,
      address: order.shipping_address,
      service_type: data.service_type
    });
    
    return {
      tracking_number: shipment.tracking_number,
      tracking_url: shipment.tracking_url,
      data: shipment
    };
  }

  async cancelFulfillment(fulfillment) {
    // Cancel fulfillment with external provider
    await this.externalProvider.cancelShipment(fulfillment.data.id);
    
    return {
      status: "cancelled"
    };
  }

  async createReturn(fromData) {
    // Create return order
    const returnOrder = await this.externalProvider.createReturn({
      original_fulfillment: fromData.fulfillment_id,
      items: fromData.items,
      reason: fromData.reason
    });
    
    return {
      return_id: returnOrder.id,
      return_label_url: returnOrder.label_url,
      data: returnOrder
    };
  }

  getFulfillmentDocuments(data) {
    return [
      {
        type: "shipping_label",
        url: data.label_url
      },
      {
        type: "tracking_info", 
        url: data.tracking_url
      }
    ];
  }

  getReturnDocuments(data) {
    return [
      {
        type: "return_label",
        url: data.return_label_url
      }
    ];
  }

  retrieveDocuments(fulfillmentData, documentType) {
    switch (documentType) {
      case "shipping_label":
        return this.getFulfillmentDocuments(fulfillmentData);
      case "return_label":
        return this.getReturnDocuments(fulfillmentData);
      default:
        return [];
    }
  }
}