import { writable, derived } from "svelte/store";

import slApi from "../api/stufflog";
import Activity, { ActivityUpdate } from "../models/activity";
import Period, { PeriodUpdate } from "../models/period";

const UNKNOWN_GOAL = Object.freeze({name: "(Unknown)", subGoals: []});
const NO_SUB_GOAL = Object.freeze({name: "(None)"});
const UNKNOWN_SUB_GOAL = Object.freeze({name: "(Unknown)"});
const UNKNOWN_ACTIVITY = Object.freeze({name: "(Unknown)", subActivities: []});
const UNKNOWN_SUB_ACTIVITY = Object.freeze({name: "(Unknown)", unitName: "unit"});

function calculateTotalScore(period) {
  return period.goals.reduce((o, g) => o = ({...o, [g.id]: (
    period.logs.filter(l => l.goalId === g.id)
               .map(l => l.score.total)
               .reduce((n, m) => n + m, 0)
  )}), {})
}

function replaceActivity(d, activity) {
  const data = {
    ...d,
    activities: [
      ...d.activities.filter(a => a.id !== activity.id),
      activity,
    ].sort((a,b) => a.name.localeCompare(b.name)),
  };

  data.periods = data.periods.map(p => ({
    ...p,
    scores: calculateTotalScore(p),
  }));

  return data;
}

function replacePeriod(d, period) {
  return {
    ...d,
    periods: [
      ...d.periods.filter(a => a.id !== period.id),
      {
        ...period,
        scores: calculateTotalScore(period),
      },
    ].sort((a,b) => b.from - a.from),
  };
}

function deleteActivity(d, id) {
  return {
    ...d,
    activities: d.activities.filter(a => a.id !== id),
  };
}

function deletePeriod(d, id) {
  return {
    ...d,
    periods: d.periods.filter(a => a.id !== id),
  };
}

function createStufflogStore() {
  /** @type {{activities: Activity[], periods: Period[], logTables: {}}} */
  const initialData = {activities: [], periods: [], logTables: {}};

  const {set, update, subscribe} = writable(initialData);

  return {
    subscribe,

    async listActivities() {
      const activities = await slApi.listActivities();
      update(d => ({
        ...d,
        activities: activities.sort((a,b) => a.name.localeCompare(b.name)),
        periods: d.periods.map(p => ({
          ...p, 
          scores: calculateTotalScore(p),
        })),
      }));
    },

    async loadActivity(id) {
      const activity = await slApi.findActivity(id);
      update(d => replaceActivity(d, activity));
    },

    async listPeriods() {
      const periods = await slApi.listPeriods();
      update(d => ({
        ...d, 
        periods: periods.sort((a,b) => b.from - a.from).map(p => ({
          ...p, 
          scores: calculateTotalScore(p),
        })),
      }));
    },

    async loadPeriods(id) {
      const period = await slApi.findPeriod(id);
      update(d => replacePeriod(d, period));
    },

    /**
     * Create period
     * 
     * @param {Period} input 
     */
    async createPeriod(input) {
      const period = await slApi.postPeriod(input);
      update(d => replacePeriod(d, period));
    },

    /**
     * Create an activity
     * 
     * @param {Activity} input 
     */
    async createActivity(input) {
      const activity = await slApi.postActivity(input);
      update(d => replaceActivity(d, activity))
    },

    /**
     * Update activities
     * 
     * @param {string} id 
     * @param {...ActivityUpdate} updates 
     */
    async updateActivity(id, ...updates) {
      const activity = await slApi.patchActivity(id, ...updates);
      update(d => replaceActivity(d, activity));
    },

    /**
     * Update periods
     * 
     * @param {string} id 
     * @param {...PeriodUpdate} updates 
     */
    async updatePeriod(id, ...updates) {
      const period = await slApi.patchPeriod(id, ...updates);
      update(d => replacePeriod(d, period));
    },

    /**
     * Delete an activity
     * 
     * @param {string} id 
     */
    async deleteActivity(id) {
      const activity = await slApi.deleteActivity(id);
      update(d => deleteActivity(d, activity.id));
    },

    /**
     * Delete a period
     * 
     * @param {string} id 
     */
    async deletePeriod(id) {
      const period = await slApi.deletePeriod(id);
      update(d => deletePeriod(d, period.id));
    },

    /**
     * Clear all data. This does not do any API call.
     */
    clearAll() {
      set({activities: [], periods: []});
    },
  }
};

const stufflog = createStufflogStore();

export default stufflog;