const Memory = {
  /**
   * @type {State}
   */
  state: new State(),


  /**
   * @returns {(Object|State)}
   */
  saveToObject () {
    const prepareSaveData = (saveData) => {
      const prepareMonster = (monster) => {
        if (monster.statusEffect && monster.statusEffect.slug === 'lifeleech') {
          monster.statusEffect = null;
        }

        return monster;
      };

      for (const idx in saveData.monsters) {
        saveData.monsters[idx] = prepareMonster(saveData.monsters[idx]);
      }
      for (const idx in saveData.player.monsters) {
        saveData.player.monsters[idx] = prepareMonster(saveData.player.monsters[idx]);
      }
      for (const idx in saveData.opponent.monsters) {
        saveData.opponent.monsters[idx] = prepareMonster(saveData.opponent.monsters[idx]);
      }

      return JSON.parse(JSON.stringify(saveData));
    };

    const saveMonster = (monsterData, monsterState) => {
      monsterData.level = monsterState.level;
      monsterData.hp = monsterState.hp;

      return monsterData;
    };

    /**
     * @type {State}
     */
    const saveData = prepareSaveData(Object.assign({}, Memory.state));

    // monsters
    for (const idx in saveData.monsters) {
      saveData.monsters[idx] = saveMonster(saveData.monsters[idx], Memory.state.monsters[idx]);
    }

    // player - monsters
    for (const idx in saveData.player.monsters) {
      saveData.player.monsters[idx] = saveMonster(saveData.player.monsters[idx], Memory.state.player.monsters[idx]);
    }

    saveData.player.activeMonsterIdx = Memory.state.player.monsters.indexOf(Memory.state.player.activeMonster);

    // opponent - monsters
    for (const idx in saveData.opponent.monsters) {
      saveData.opponent.monsters[idx] = saveMonster(saveData.opponent.monsters[idx], Memory.state.opponent.monsters[idx]);
    }

    saveData.opponent.activeMonsterIdx = Memory.state.opponent.monsters.indexOf(Memory.state.opponent.activeMonster);

    return saveData;
  },

  /**
   * @returns {string}
   */
  saveToString () {
    // hash
    return btoa(JSON.stringify(Memory.saveToObject()));
  },

  saveToLocalStorage () {
    const lastWrite = new Date(localStorage.getItem('lastWrite'));
    if (Math.abs(new Date() - lastWrite) / (1000 * 60 * 60 * 24) >= 1) {
      localStorage.setItem(`state_${(new Date()).toLocaleDateString()}`, localStorage.getItem('state'));
    }

    localStorage.setItem('state', Memory.saveToString());
    localStorage.setItem('lastWrite', new Date());
  },

  /**
   * @param {(Object|State)} saveData
   */
  async loadFromObject (saveData) {
    /**
     * @param {Area} areaData
     */
    const loadArea = async (areaData) => {
      const area = await fetchArea(areaData.slug);

      area.monsterProgress = areaData.monsterProgress;
      area.trainerProgress = areaData.trainerProgress;

      return area;
    };

    /**
     * @param {Monster} monsterData
     */
    const loadMonster = async (monsterData) => {
      const monster = await fetchMonster(monsterData.slug);

      monster.level = monsterData.level;
      monster.hp = monsterData.hp;
      monster.exp = monsterData.exp;
      monster.tasteWarm = monsterData.tasteWarm;
      monster.tasteCold = monsterData.tasteCold;
      monster.gender = monsterData.gender;
      monster.heldItem = await loadItem(monsterData.heldItem);
      monster.statusEffect = await loadStatusEffect(monsterData.statusEffect);
      monster.statModifiers = monsterData.statModifiers;
      monster.experienceModifier = monsterData.experienceModifier;
      monster.moneyModifier = monsterData.moneyModifier;
      monster.activeTechniques = await Promise.all(monsterData.activeTechniques.map(async (technique) => {
        return loadTechnique(technique);
      }));

      return monster;
    };

    /**
     * @param {InventoryItem} inventoryItemData
     */
    const loadInventoryItem = async (inventoryItemData) => {
      const inventoryItem = new InventoryItem(await fetchItem(inventoryItemData.item.slug));

      inventoryItem.quantity = inventoryItemData.quantity;

      return inventoryItem;
    };

    /**
     * @param {Item} itemData
     */
    const loadItem = async (itemData) => {
      if (!itemData) {
        return null;
      }

      const item = await fetchItem(itemData.slug);

      return item;
    };

    /**
     * @param {StatusEffect} statusEffectData
     */
    const loadStatusEffect = async (statusEffectData) => {
      if (!statusEffectData) {
        return null;
      }

      const statusEffect = await fetchStatusEffect(statusEffectData.slug);

      statusEffect.turnsLeft = statusEffectData.turnsLeft;

      return statusEffect;
    };

    /**
     * @param {Trainer} trainerData
     */
    const loadTrainer = async (trainerData) => {
      const trainer = new Trainer(trainerData);

      return trainer;
    };

    /**
     * @param {Technique} techniqueData
     */
    const loadTechnique = async (techniqueData) => {
      const technique = await fetchTechnique(techniqueData.slug);

      technique.turnLastUse = techniqueData.turnLastUse;

      return technique;
    };

    /**
     * @type {State}
     */
    const loadedState = saveData;

    const loadActions = [
      async () => Memory.state.Settings.name = loadedState.Settings.name,
      async () => Memory.state.Settings.language = loadedState.Settings.language,
      async () => {
        await fetchTranslation(Memory.state.Settings.language);
        applyTranslation();
      },
      async () => Memory.state.Settings.currency = loadedState.Settings.currency,
      async () => Memory.state.Settings.logMaxLength = loadedState.Settings.logMaxLength,


      async () => {
        if (loadedState.Game) { // backwards compat: TODO: remove check later
          Memory.state.Game.isInBattle = loadedState.Game.isInBattle;
        }
      },


      ...Object.keys(loadedState.areaProgress).map((areaSlug) => async () => {
          const areaData = loadedState.areaProgress[areaSlug];
          Memory.state.areaProgress[areaSlug] = await loadArea(areaData);
      }),
      async () => Memory.state.currentArea = await loadArea(loadedState.currentArea),
      async () => Memory.state.lastVisitedTown = loadedState.lastVisitedTown,
      async () => Memory.state.storyProgress = loadedState.storyProgress || {}, // backwards compat: TODO: remove check later
      async () => Memory.state.currentStory = loadedState.currentStory || '', // backwards compat: TODO: remove check later


      async () => Memory.state.turn = loadedState.turn,
      async () => Memory.state.money = loadedState.money,


      async () => Memory.state.monsters = [],
      ...loadedState.monsters.map((monsterData) => async () => Memory.state.monsters.push(await loadMonster(monsterData))),
      async () => Memory.state.player = await loadTrainer(loadedState.player),
      ...loadedState.player.monsters.map((monsterData) => async () => Memory.state.player.monsters.push(await loadMonster(monsterData))),
      ...loadedState.player.inventory.map((itemData) => async () => Memory.state.player.inventory.push(await loadInventoryItem(itemData))),
      async () => Memory.state.player.activeMonster = Memory.state.player.monsters[loadedState.player.activeMonsterIdx],
      async () => Memory.state.opponent = await loadTrainer(loadedState.opponent),
      ...loadedState.opponent.monsters.map((monsterData) => async () => Memory.state.opponent.monsters.push(await loadMonster(monsterData))),
      ...loadedState.opponent.inventory.map((itemData) => async () => Memory.state.opponent.inventory.push(await loadInventoryItem(itemData))),
      async () => Memory.state.opponent.activeMonster = Memory.state.opponent.monsters[loadedState.opponent.activeMonsterIdx],
      async () => Memory.state.rivalMonster = loadedState.rivalMonster,
      async () => Memory.state.activeTechnique = await loadTechnique(loadedState.activeTechnique),

      async () => {
        if (typeof loadedState.activeBall === 'string') { // backwards compat: TODO: remove check later
          Memory.state.activeBall = loadedState.activeBall;
        } else {
          Memory.state.activeBall = loadedState.activeBall && loadedState.activeBall.slug;
        }
      },


      // draw game
      async () => {
        if (!Game.isTown(Memory.state.currentArea)) {
          UI.drawOpponentMonster();
          UI.drawActiveMonster();
          UI.drawActiveTechniques();
        }
        UI.drawArea();
        UI.drawStatus();
      },


      async () => Story.progress(Memory.state.currentStory),
    ];

    await UI.showLoading(loadActions);
  },

  /**
   * @param {string} saveData
   */
  loadFromString (saveData) {
    Memory.loadFromObject(JSON.parse(atob(saveData)));
  },

  loadFromLocalStorage () {
    Memory.loadFromString(localStorage.getItem('state'));
  },
};

async function initializeState () {
  Memory.state.currentArea = await fetchArea('paper-town');
  Memory.state.player = new Trainer({ monsters: [] });
  Memory.state.opponent = new Trainer({ monsters: [] });
  Memory.state.activeTechnique = await fetchTechnique('all_in');
}