import type {
  Dispatch,
  SetStateAction,
} from 'react';

import { addInventoryItems } from '../../data/npcInteractions';
import {
  findQuestById,
  markQuestCompletionNotified,
  markQuestTurnedIn,
} from '../../data/questFlow';
import {
  advanceChapterState,
  resolveCurrentChapterState,
} from '../../services/storyEngine/chapterDirector';
import { appendStoryEngineCarrierMemory } from '../../services/storyEngine/echoMemory';
import { buildGoalHandoffFromState } from '../../services/storyEngine/goalDirector';
import { createEmptyStoryEngineMemoryState } from '../../services/storyEngine/visibilityEngine';
import type {
  GameState,
  StoryMoment,
} from '../../types';
import type { CommitGeneratedState } from '../generatedState';
import { buildMapTravelResolution } from './storyGenerationState';

type BuildFallbackStoryForState = (
  state: GameState,
  character: NonNullable<GameState['playerCharacter']>,
  fallbackText?: string,
) => StoryMoment;

export function acknowledgeQuestCompletionState(
  state: GameState,
  questId: string,
): GameState {
  return {
    ...state,
    quests: markQuestCompletionNotified(state.quests, questId),
  };
}

export function applyQuestRewardClaim(
  state: GameState,
  questId: string,
): {
  nextState: GameState;
  handoff: ReturnType<typeof buildGoalHandoffFromState>;
} | null {
  const quest = findQuestById(state.quests, questId);
  if (!quest || (quest.status !== 'completed' && quest.status !== 'ready_to_turn_in')) {
    return null;
  }

  const issuerNpcState = state.npcStates[quest.issuerNpcId];

  const nextState = appendStoryEngineCarrierMemory({
    ...state,
    quests: markQuestTurnedIn(state.quests, questId),
    playerCurrency: state.playerCurrency + quest.reward.currency,
    playerInventory: addInventoryItems(state.playerInventory, quest.reward.items),
    npcStates: issuerNpcState
      ? {
          ...state.npcStates,
          [quest.issuerNpcId]: {
            ...issuerNpcState,
            affinity: issuerNpcState.affinity + quest.reward.affinityBonus,
          },
        }
      : state.npcStates,
  }, quest.reward.items);
  const chapterState = advanceChapterState({
    previousChapter:
      nextState.chapterState
      ?? nextState.storyEngineMemory?.currentChapter
      ?? null,
    nextChapter: resolveCurrentChapterState({
      state: nextState,
    }),
  });
  const storyEngineMemory =
    nextState.storyEngineMemory ?? createEmptyStoryEngineMemoryState();
  const synchronizedNextState: GameState = {
    ...nextState,
    chapterState,
    storyEngineMemory: {
      ...storyEngineMemory,
      currentChapter: chapterState,
    },
  };

  return {
    nextState: synchronizedNextState,
    handoff: buildGoalHandoffFromState(synchronizedNextState),
  };
}

export function createStorySessionActions({
  gameState,
  isLoading,
  setGameState,
  setCurrentStory,
  clearStoryRuntimeUi,
  commitGeneratedState,
  buildFallbackStoryForState,
}: {
  gameState: GameState;
  isLoading: boolean;
  setGameState: Dispatch<SetStateAction<GameState>>;
  setCurrentStory: Dispatch<SetStateAction<StoryMoment | null>>;
  clearStoryRuntimeUi: () => void;
  commitGeneratedState: CommitGeneratedState;
  buildFallbackStoryForState: BuildFallbackStoryForState;
}) {
  const acknowledgeQuestCompletion = (questId: string) => {
    setGameState(currentState => acknowledgeQuestCompletionState(currentState, questId));
  };

  const claimQuestReward = (questId: string) => {
    const rewardClaim = applyQuestRewardClaim(gameState, questId);
    if (!rewardClaim) {
      return null;
    }

    setGameState(rewardClaim.nextState);
    return {
      questId,
      handoff: rewardClaim.handoff,
    };
  };

  const resetStoryState = () => {
    setCurrentStory(null);
    clearStoryRuntimeUi();
  };

  const hydrateStoryState = (story: StoryMoment | null) => {
    setCurrentStory(story);
    clearStoryRuntimeUi();
  };

  const travelToSceneFromMap = (sceneId: string) => {
    if (!gameState.playerCharacter || isLoading || gameState.inBattle) {
      return false;
    }

    const travelResolution = buildMapTravelResolution(gameState, sceneId);
    if (!travelResolution) {
      return false;
    }

    setCurrentStory(
      buildFallbackStoryForState(
        travelResolution.nextState,
        gameState.playerCharacter,
        travelResolution.travelResultText,
      ),
    );

    void commitGeneratedState(
      travelResolution.nextState,
      gameState.playerCharacter,
      travelResolution.actionText,
      travelResolution.travelResultText,
      'idle_travel_next_scene',
    );
    return true;
  };

  return {
    acknowledgeQuestCompletion,
    claimQuestReward,
    resetStoryState,
    hydrateStoryState,
    travelToSceneFromMap,
  };
}