import { Writable, writable } from "svelte/store";
import Client from "./client";

import { MutationState } from "./mutationTypes";

type MutationOptions = {
  client: Client;
};

export default class MutationManager<TResults> {
  client: Client;
  mutation: string;
  setState: (newState: MutationState<TResults>) => void;
  mutationStore: Writable<MutationState<TResults>>;
  currentState: MutationState<TResults>;

  runMutation = (variables: unknown) => {
    this.setState({
      running: true,
      finished: false,
      runMutation: this.runMutation
    });

    return this.client.processMutation(this.mutation, variables).then(resp => {
      this.setState({
        running: false,
        finished: true,
        runMutation: this.runMutation
      });
      return resp;
    });
  };
  static initialState = {
    running: false,
    finished: false
  };
  updateState = (newState = {}) => {
    Object.assign(this.currentState, newState);
    this.setState(this.currentState);
  };
  constructor({ client }: MutationOptions, mutation: string) {
    this.client = client;
    this.mutation = mutation;
    this.currentState = {
      ...MutationManager.initialState,
      runMutation: this.runMutation
    };

    this.mutationStore = writable(this.currentState);
    this.setState = this.mutationStore.set;
  }
}