const Game = {
  phases: {
    preAction: {
      opponent: [],
      player: [],
    },
    action: {
      opponent: [],
      player: [],
    },
    postAction: {
      opponent: [],
      player: [],
    },
  },

  isLoadingArea: false,
  isProgressingTurn: false,
  playerIsChoosingNextMonster: false,
  doBattleAnimation: true,
  opponentActionTimeout: null,
  isInBattle: false,
  didTechniqueHit: false,

  /* Battle */

  async progressTurn () {
    Game.isProgressingTurn = true;
    Memory.state.turn++;

    // status effects
    await Game.applyStatusEffect(Memory.state.opponent.activeMonster);
    await Game.applyStatusEffect(Memory.state.player.activeMonster);

    // Phases
    for (const phaseKey of Object.keys(Game.phases)) {
      for (const event of Game.phases[phaseKey].player) {
        event();

        await Game.handleDefeatOpponent();
        if (!Game.playerIsChoosingNextMonster) await Game.handleDefeatPlayer();
      }
      Game.phases[phaseKey].player = [];

      Game.doBattleAnimation = false;
      for (const event of Game.phases[phaseKey].opponent) {
        event();

        await Game.handleDefeatOpponent();
        if (!Game.playerIsChoosingNextMonster) await Game.handleDefeatPlayer();
      }
      Game.doBattleAnimation = true;
      Game.phases[phaseKey].opponent = [];
    }

    UI.progressTurn();
    Game.isProgressingTurn = false;
  },

  async handleDefeatOpponent () {
    if (Memory.state.opponent.activeMonster.hp <= 0) {
      clearTimeout(Game.opponentActionTimeout);
      Game.opponentActionTimeout = null;
      for (const phase of Object.keys(Game.phases)) {
        Game.removePhaseEvents(phase, 'opponent');
      }
      Game.removePhaseEvents('action', 'player');

      // money
      Memory.state.money += Memory.state.opponent.activeMonster.level * Memory.state.opponent.activeMonster.moneyModifier;

      // exp
      Memory.state.player.activeMonster.exp += calculateAwardedExperience(Memory.state.opponent.activeMonster, [Memory.state.player.activeMonster])[0];

      if (Memory.state.player.activeMonster.canLevelUp()) {
        Memory.state.player.activeMonster.levelUp();
      }
      if (Memory.state.player.activeMonster.canEvolve('standard')) {
        await Game.evolveMonster(Memory.state.player.activeMonster);
      }

      Game.isInBattle = false;

      if (Memory.state.opponent.type === 'monster') {
        Memory.state.currentArea.monsterProgress++;
        await Game.encounterWildMonster();
      } else if (Memory.state.opponent.type === 'trainer') {
        if (Memory.state.opponent.activeMonster === Memory.state.opponent.monsters[Memory.state.opponent.monsters.length - 1]) {
          Memory.state.currentArea.trainerProgress++;
          if (Memory.state.currentArea.encounters.length > 0) {
            await Game.encounterWildMonster();
          } else {
            await Game.progressToNextArea();
          }
        } else {
          await Game.encounterNextTrainerMonster();
        }
      }
    }
  },

  async handleDefeatPlayer () {
    if (Memory.state.player.activeMonster.hp <= 0) {
      clearTimeout(Game.opponentActionTimeout);
      Game.opponentActionTimeout = null;
      for (const phase of Object.keys(Game.phases)) {
        Game.removePhaseEvents(phase, 'player');
      }
      Game.removePhaseEvents('action', 'opponent');

      // whole party defeated
      if (!Memory.state.player.monsters.some((monster) => monster.hp > 0)) {
        if (Game.isBattleType('trainer')) {
          if (Memory.state.currentArea.encounters.length > 0) {
            await Game.encounterWildMonster();
          } else {
            await Game.encounterTrainer();
          }
        }

        else if (Game.isBattleType('monster')) {
          if (Memory.state.currentArea.monsterProgress < Memory.state.currentArea.requiredEncounters) {
            Memory.state.currentArea.monsterProgress = 0;
            UI.drawStatus();
          }

          await Game.encounterWildMonster();
        }

        // heal all monsters full
        for (const monster of Memory.state.player.monsters) {
          monster.hp = monster.stats.hp;
        }
      }

      // party members still left
      else {
        Game.playerIsChoosingNextMonster = true;
        const monsterSelectionNode = UI.createPlayerDefeatedMonsterSelection();
        UI.openPlayerDefeatedMonsterSelection(monsterSelectionNode);
      }
    }
  },

  /**
   * @param {Object} phase
   * @param {Monster} monster
   * @param {Function} event
   */
  addPhaseEvent (phase, monster, event) {
    if (monster === Memory.state.player.activeMonster) {
      phase.player.push(event);
    } else {
      phase.opponent.push(event);
    }
  },

  /**
   * @param {('preAction' | 'action' | 'postAction')} phase
   * @param {('player' | 'opponent')} type
   */
  removePhaseEvents (phase, type) {
    Game.phases[phase][type] = [];
  },

  clearAllPhaseEvents () {
    Game.removePhaseEvents('preAction', 'player');
    Game.removePhaseEvents('preAction', 'opponent');
    Game.removePhaseEvents('action', 'player');
    Game.removePhaseEvents('action', 'opponent');
    Game.removePhaseEvents('postAction', 'player');
    Game.removePhaseEvents('postAction', 'opponent');
  },

  clearCurrentTurn () {
    Game.clearAllPhaseEvents();
    clearTimeout(Game.opponentActionTimeout);
    Game.opponentActionTimeout = null;
  },

  /**
   * @param {Technique} technique
   * @param {Monster} user
   * @param {Monster} target
   */
  async tryUseTechnique (technique, user, target) {
    let canUse = true;

    // recharge
    if (technique.isRecharging()) {
      if (Game.doBattleAnimation) {
        const feedbackNode = UI.createActionFeedback('recharge');
        feedbackNode.classList.add('recharge');
        UI.drawActionFeedback(feedbackNode);
      }

      canUse = false;
    }

    // noddingoff
    if (user.statusEffect && user.statusEffect.slug === StatusEffectType.noddingoff) {
      if (Game.doBattleAnimation) {
        const feedbackNode = UI.createActionFeedback('noddingoff');
        UI.drawActionFeedback(feedbackNode);
      }

      canUse = false;
    }

    if (canUse) {

      // hit?
      const accuracy = Math.random();
      Game.didTechniqueHit = technique.accuracy >= accuracy;
      if (!Game.didTechniqueHit) {
        technique.use();
        Game.doBattleAnimation && UI.drawDamageMiss(UI.createDamageMiss());

        return;
      }

      await Game.useTechnique(technique, user, target);
    }
  },

  /**
   * @param {Technique} technique
   * @param {Monster} user
   * @param {Monster} target
   */
  async useTechnique (technique, user, target) {
    technique.use();

    for (const techniqueEffectCode of technique.effects) {
      const techniqueEffect = new TechniqueEffect(techniqueEffectCode);
      techniqueEffect.setUser(user);
      techniqueEffect.setTarget(target);

      // damage
      if (['damage', 'splash', 'area'].includes(techniqueEffect.type)) {
        Game.addPhaseEvent(Game.phases.action, user, () => {
          const damage = simpleDamageCalculation(technique, user, target);

          target.hp -= damage;

          if (Game.doBattleAnimation) {
            const damageNode = UI.createDamage(damage);
            UI.applyMultiplierToDamage(damageNode, simpleDamageMultiplier(technique.types, target.types));
            UI.applyTechniqueToDamage(damageNode, technique);
            UI.drawDamage(damageNode);
            UI.drawTechniqueAnimation(technique);
          }
        });
      }

      // money
      else if (techniqueEffect.type === 'money') {
        Game.addPhaseEvent(Game.phases.action, user, () => {
          const money = Math.max(1, Math.floor(Math.random() * target.level));
          Memory.state.money += money;

          if (Game.doBattleAnimation) {
            const damageNode = UI.createDamage(`${money} €`);
            UI.applyTechniqueToDamage(damageNode, technique);
            UI.drawDamage(damageNode);
            UI.drawTechniqueAnimation(technique);
          }
        });
      }

      // healing
      else if (techniqueEffect.type === 'healing') {
        for (const recipient of techniqueEffect.recipients) {
          recipient.hp += (user.level + 7) * technique.healingPower;
        }
      }

      // switch
      else if (techniqueEffect.type === 'switch') {
        techniqueEffect.recipient.types = [techniqueEffect.switchType];
      }

      // enhance
      else if (techniqueEffect.type === 'enhance') {
        Game.doBattleAnimation && UI.drawTechniqueAnimation(technique);
      }

      // status effect
      else if (techniqueEffect.type === 'status') {
        const statusEffect = await fetchStatusEffect(techniqueEffect.statusEffect);

        if (statusEffect.slug === 'lifeleech') {
          statusEffect.issuer = user;
        }

        Game.addPhaseEvent(Game.phases.postAction, user, () => {
          // add status effect
          const potency = Math.random();
          const success = technique.potency >= potency;

          if (success) {
            for (const recipient of techniqueEffect.recipients) {
              // TODO: check replace
              if (recipient.statusEffect) continue;

              recipient.statusEffect = statusEffect;
            }
          }
        });

        Game.doBattleAnimation && UI.drawTechniqueAnimation(technique);
      }
    }
  },

  /**
   * @param {Monster} monster
   */
  async applyStatusEffect (monster) {
    if (!monster.statusEffect) {
      return;
    }

    if (monster.statusEffect.turnsLeft === 0) {
      Game.addPhaseEvent(Game.phases.preAction, monster, () => {
        monster.statusEffect.onRemove && monster.statusEffect.onRemove();

        // if still 0 turns left after remove action
        if (monster.statusEffect.turnsLeft === 0) {
          monster.statusEffect = null;
        } else {
          Game.applyStatusEffect(monster);
        }
      });

      return;
    }

    // poison / burn
    if (monster.statusEffect.slug === 'poison' || monster.statusEffect.slug === 'burn') {
      const statusEffectDamage = Math.floor(monster.stats.hp / 8);

      Game.addPhaseEvent(Game.phases.postAction, monster, () => {
        monster.hp -= statusEffectDamage;

        if (Game.doBattleAnimation) {
          const damageNode = UI.createDamage(statusEffectDamage);
          UI.applyStatusEffectToDamage(damageNode, monster.statusEffect);
          UI.drawDamage(damageNode);
        }
      });
    }

    // lifeleech
    else if (monster.statusEffect.slug === 'lifeleech') {
      const statusEffectLeech = Math.floor(monster.stats.hp / 16);

      Game.addPhaseEvent(Game.phases.postAction, monster, () => {
        // if issuer is defeated => don't
        if (monster.statusEffect.issuer.hp <= 0) {
          return;
        }

        monster.hp -= statusEffectLeech;
        monster.statusEffect.issuer.hp += statusEffectLeech;

        if (Game.doBattleAnimation) {
          const damageNode = UI.createDamage(statusEffectLeech);
          UI.applyStatusEffectToDamage(damageNode, monster.statusEffect);
          UI.drawDamage(damageNode);
        }
      });
    }

    // recover
    else if (monster.statusEffect.slug === 'recover') {
      const statusEffectHeal = Math.floor(monster.stats.hp / 16);

      Game.addPhaseEvent(Game.phases.postAction, monster, () => {
        monster.hp += statusEffectHeal;

        if (Game.doBattleAnimation) {
          const feedbackNode = UI.createActionFeedback(statusEffectHeal);
          UI.applyStatusEffectToDamage(feedbackNode, monster.statusEffect);
          UI.drawActionFeedback(feedbackNode);
        }
      });
    }

    // stuck
    else if (monster.statusEffect.slug === 'stuck') {
      for (const technique of monster.activeTechniques) {
        if ([TechniqueRange.melee, TechniqueRange.touch].includes(technique.range)) {
          Game.addPhaseEvent(Game.phases.preAction, monster, () => {
            technique.potency = technique.stats.potency * 0.5;
            technique.power = technique.stats.power * 0.5;
          });

          monster.statusEffect.onRemove = () => {
            technique.resetStats();
          };
        }
      }
    }

    // grabbed
    else if (monster.statusEffect.slug === 'grabbed') {
      for (const technique of monster.activeTechniques) {
        if ([TechniqueRange.ranged, TechniqueRange.reach].includes(technique.range)) {
          Game.addPhaseEvent(Game.phases.preAction, monster, () => {
            technique.potency = technique.stats.potency * 0.5;
            technique.power = technique.stats.power * 0.5;
          });

          monster.statusEffect.onRemove = () => {
            technique.resetStats();
          };
        }
      }
    }

    // charging
    else if (monster.statusEffect.slug === 'charging') {
      const nextStatusEffect = await fetchStatusEffect('chargedup');

      monster.statusEffect.onRemove = () => {
        monster.statusEffect = nextStatusEffect;
      };
    }

    // statchange
    else if (monster.statusEffect.effects.includes('statchange')) {
      monster.resetStatModifiers();

      for (const statType in monster.statusEffect.stats) {
        const statChange = monster.statusEffect.stats[statType];
        const modifiedValue = Math.floor(eval(`${monster.stats[statType]} ${statChange.operation} ${statChange.value}`));

        Game.addPhaseEvent(Game.phases.preAction, monster, () => {
          monster.setStatModifier(statType, modifiedValue);
        });
      }

      monster.statusEffect.onRemove = () => {
        monster.resetStatModifiers();
      };
    }

    Game.addPhaseEvent(Game.phases.postAction, monster, () => {
      monster.statusEffect.turnsLeft--;
    });
  },

  /**
   * @param {MouseEvent} event
   */
  async battleClick (event) {
    if (Game.isLoadingArea || Game.isProgressingTurn) {
      return;
    }

    Game.isInBattle = true;
    UI.battleClickEvent = event;

    // player
    await Game.tryUseTechnique(Memory.state.activeTechnique, Memory.state.player.activeMonster, Memory.state.opponent.activeMonster);

    // opponent
    if (!Game.opponentActionTimeout) {
      let speedDifference = Memory.state.opponent.activeMonster.stats.speed - Memory.state.player.activeMonster.stats.speed;
      if (speedDifference > 0) speedDifference = speedDifference / 2;
      else if (speedDifference < 0) speedDifference = speedDifference * 2;

      const opponentActiveMonster = Memory.state.opponent.activeMonster;
      Game.opponentActionTimeout = setTimeout(async () => {
        if (opponentActiveMonster.hp <= 0) {
          Game.opponentActionTimeout = null;
          return;
        }

        // technique
        Game.doBattleAnimation = false;
        await Game.tryUseTechnique(
          await fetchTechnique(Memory.state.opponent.activeMonster.getLearnableTechniques()[Math.floor(Math.random() * Memory.state.opponent.activeMonster.getLearnableTechniques().length)].technique),
          Memory.state.opponent.activeMonster,
          Memory.state.player.activeMonster
        );
        Game.doBattleAnimation = true;

        await Game.progressTurn();

        // item
        if (Memory.state.opponent.inventory.length > 0) {
        }

        Game.opponentActionTimeout = null;
      }, Math.max(500, 2000 - (speedDifference * 10)));
      console.log(
        'Opponent Attack Timeout',
        Memory.state.opponent.activeMonster.stats.speed, Memory.state.player.activeMonster.stats.speed,
        2000 - (speedDifference * 10)
      );
    }

    await Game.progressTurn();
  },

  /**
   * @param {MouseEvent} event
   */
  techniqueClick (event) {
    if (event.target === UI.elements.techniques) {
      return;
    }

    let target = event.target;
    while (target.dataset.gameElementType !== 'menuBattleTechniquesTechnique') {
      target = target.parentNode;
    }

    const idx = [...UI.elements.techniques.children].indexOf(target);
    Memory.state.activeTechnique = Memory.state.player.activeMonster.activeTechniques[idx];

    // trigger battle click
    const rect = UI.elements.battleOpponent.getBoundingClientRect();
    const xMin = rect.left + 64;
    const xMax = rect.right - 64;
    const yMin = rect.top + 32;
    const yMax = rect.bottom - 32;
    UI.elements.battleOpponent.dispatchEvent(new MouseEvent('click', {
      clientX: Math.random() * (xMax - xMin) + xMin,
      clientY: Math.random() * (yMax - yMin) + yMin,
    }));
  },


  /* Progression */

  async encounterWildMonster () {
    const randomMonster = Memory.state.currentArea.encounters[Math.floor(Math.random() * Memory.state.currentArea.encounters.length)];
    const randomLevel = Math.floor(Math.random() * (randomMonster.level_range[1] - randomMonster.level_range[0]) + randomMonster.level_range[0]);

    const monster = await fetchMonster(randomMonster.monster);
    monster.level = randomLevel;

    const wildMonster = new Trainer({ monsters: [monster] });
    wildMonster.type = 'monster';
    await wildMonster.initialize();
    Memory.state.opponent = wildMonster;

    UI.drawOpponentMonster();
  },

  async encounterTrainer () {
    Game.clearCurrentTurn();

    const nextTrainer = Memory.state.currentArea.trainers[Memory.state.currentArea.trainerProgress];

    const trainer = new Trainer(nextTrainer);
    if (nextTrainer.name === 'Rival') {
      trainer.monsters.push(Memory.state.rivalMonster);
    }
    await trainer.initialize()
    Memory.state.opponent = trainer;

    UI.drawOpponentMonster();
    UI.drawStatus();
  },

  async encounterNextTrainerMonster () {
    const activeMonsterIdx = Memory.state.opponent.monsters.indexOf(Memory.state.opponent.activeMonster);
    Memory.state.opponent.activeMonster = Memory.state.opponent.monsters[activeMonsterIdx + 1];

    UI.drawOpponentMonster();
  },

  async progressToNextArea () {
    Game.isLoadingArea = true;
    Game.clearCurrentTurn();

    const currentArea = Memory.state.currentArea;
    const nextArea = await fetchArea(currentArea.nextArea);

    await Game.jumpToArea(nextArea);

    if (nextArea.encounters.length > 0) {
      await Game.encounterWildMonster();
    } else {
      await Game.encounterTrainer();
    }

    UI.drawStatus();

    Game.isLoadingArea = false;
  },

  /**
   * @param {Area} area
   */
  async jumpToArea (area) {
    Game.clearCurrentTurn();

    Memory.state.currentArea = area;

    UI.drawArea(area);
  },


  /* Menu - Inventory */

  /**
   * @param {InventoryItem} item
   * @param {Monster} monster
   *
   * @returns {boolean}
   */
  canUseItem (item, monster = null) {
    let isApplicable = true;

    for (const itemConditionCode of item.conditions) {
      const itemCondition = new ItemCondition(itemConditionCode);
      let conditionIsApplicable = true;

      if (itemCondition.what === 'current_hp') {
        const value = parseInt(itemCondition.value) * monster.stats.hp;
        conditionIsApplicable = eval(`${monster.hp} ${itemCondition.comparator} ${value}`);
      }

      else if (itemCondition.what === 'wild_monster') {
        conditionIsApplicable = Game.isBattleType('monster');
      }

      else if (itemCondition.what === 'threat') {
        conditionIsApplicable = Memory.state.opponent.activeMonster.category === 'threat';
      }

      else {
        conditionIsApplicable = false;
      }

      if (itemCondition.is === 'not') {
        conditionIsApplicable = !conditionIsApplicable;
      }

      isApplicable = isApplicable && conditionIsApplicable;
    }

    return isApplicable;
  },

  /**
   * @param {InventoryItem}
   * @param {Monster}
   */
  async useItem (item, monster) {
    for (const itemEffectCode of item.effects) {
      const itemEffect = new ItemEffect(itemEffectCode);

      if (itemEffect.type === 'heal') {
        monster.hp += itemEffect.amount;
        item.quantity--;
      }

      else if (itemEffect.type === 'capture') {
        Memory.state.activeBall = item;
        UI.drawActiveBall();
      }

      else if (itemEffect.type === 'evolve') {
        const evolution = Memory.state.player.activeMonster.getPossibleEvolutions('item')[0];
        if (evolution) {
          await fetchMonster(evolution.monster_slug);
          Memory.state.player.activeMonster.evolve(evolution);
          UI.drawActiveMonster();

          item.quantity--;
        }
      }
    }
  },

  /**
   * @param {Array} inventory
   * @param {InventoryItem} item
   */
  removeItemFromInventory (inventory, item) {
    inventory.splice(inventory.indexOf(item), 1);
  },


  /* Menu - Catch */

  /**
   * @returns {boolean}
   */
  canCatchMonster () {
    return Game.isBattleType('monster') && Memory.state.activeBall;
  },

  async catchMonster () {
    if (!Game.canCatchMonster()) {
      return;
    }

    Game.clearCurrentTurn();

    Memory.state.activeBall.quantity--;
    if (Memory.state.activeBall.quantity === 0) {
      Game.removeItemFromInventory(Memory.state.player.inventory, Memory.state.activeBall);
      Memory.state.activeBall = null;
      UI.drawActiveBall();
    }

    const caughtMonster = new Monster(Memory.state.opponent.activeMonster.slug);
    caughtMonster.initialize();
    caughtMonster.level = Memory.state.opponent.activeMonster.level;
    caughtMonster.hp = Memory.state.opponent.activeMonster.hp;

    Memory.state.player.monsters.push(caughtMonster);

    await Game.encounterWildMonster();
    await Game.progressTurn();
  },


  /* Helper */

  /**
   * @param {Monster} monster
   */
  setActivePlayerMonster (monster) {
    Memory.state.player.activeMonster = monster;
    Memory.state.activeTechnique = Memory.state.player.activeMonster.activeTechniques[0];

    UI.drawActiveMonster();
    UI.drawActiveTechniques();
  },

  /**
   * @param {Monster} monster
   */
  async evolveMonster (monster) {
    await fetchMonster(monster.evolutions[0].monster_slug);
    monster.evolve(monster.evolutions[0]);
  },

  /**
   * @param {string} type
   *
   * @returns {boolean}
   */
  isBattleType (type) {
    return Memory.state.opponent.type === type;
  },

  getStageOfDaySimple () {
    const hours = (new Date()).getHours();
    if (hours >= 6 && hours < 18) {
      return 'day';
    } else {
      return 'night';
    }
  },
};

// Game click bindings
UI.elements.nextTrainer.addEventListener('click', Game.encounterTrainer);
UI.elements.nextArea.addEventListener('click', Game.progressToNextArea);
UI.elements.battleOpponent.addEventListener('click', Game.battleClick);
UI.elements.techniques.addEventListener('click', Game.techniqueClick);
UI.elements.menuCatch.addEventListener('click', Game.catchMonster);