import {
  DestinationMappingOptionsMethod,
  DestinationMappingOptionsResponseProperty,
  DestinationMappingOptionsResponseProperties,
} from "@grouparoo/core";
import { connect } from "./../connect";
import { getMergeVars, GrouparooMergeVar } from "./getMergeVars";

export type MailchimpMappingKey = "email" | "id";
export interface GetDestinationMappingOptionsMethod {
  (mappingKey: MailchimpMappingKey): DestinationMappingOptionsMethod;
}

export const getDestinationMappingOptions: GetDestinationMappingOptionsMethod =
  (mappingKey) => {
    const destinationMappingOptionsMethod: DestinationMappingOptionsMethod =
      async ({ appOptions, destinationOptions }) => {
        const client = await connect(appOptions);
        const listId = destinationOptions.listId?.toString();
        if (!listId) throw new Error("No listId provided");
        const mergeVars = await getMergeVars(client, listId);
        const properties = getProperties(mergeVars, mappingKey);

        return {
          labels: {
            property: {
              singular: "Mailchimp Merge Var",
              plural: "Mailchimp Merge Vars",
            },
            group: {
              singular: "Mailchimp Tag",
              plural: "Mailchimp Tags",
            },
          },
          properties,
        };
      };

    return destinationMappingOptionsMethod;
  };

function getProperties(
  mergeVars: GrouparooMergeVar[],
  mappingKey: MailchimpMappingKey
): DestinationMappingOptionsResponseProperties {
  const grouparooFields = {};
  for (const field of mergeVars) {
    const { key, type, important } = field;
    grouparooFields[key] = { key, type, important };
  }

  const known: DestinationMappingOptionsResponseProperty[] =
    Object.values(grouparooFields);

  let requiredField = null;
  switch (mappingKey) {
    case "email":
      requiredField = { key: "email_address", type: "email" };
      break;
    case "id":
      requiredField = { key: "mailchimp_id", type: "string" };
      // can still set email, but hide it a bit
      known.push({ key: "email_address", type: "email", important: false });
      break;
  }

  if (!requiredField) {
    throw new Error(`Unknown record mapping key: ${mappingKey}`);
  }

  return {
    known,
    required: [requiredField],
    allowOptionalFromProperties: false,
  };
}