import {
  getForwardScenePreset,
  getScenePresetById,
  getScenePresetsByWorld,
  getTravelScenePreset,
} from '../../data/scenePresets';
import { getFunctionEffect } from '../../data/stateFunctions';
import type {
  Character,
  GameState,
  StoryOption,
  WorldType,
} from '../../types';
import { classifyCombatOption } from '../combatStoryUtils';
import { buildIdleAfterSequence } from '../idleAdventureFlow';
import {
  applyRecoveryEffectToState,
  type BattlePlan,
} from './battlePlan';
import { buildEscapeAfterSequence } from './escapeFlow';

type OptionKind = 'battle' | 'escape' | 'idle';

export type ResolvedChoiceState = {
  optionKind: OptionKind;
  battlePlan: BattlePlan | null;
  afterSequence: GameState;
};

function getShiftedScenePreset(
  worldType: WorldType | null,
  currentScenePreset: GameState['currentScenePreset'],
  sceneShift: number | undefined,
): GameState['currentScenePreset'] {
  if (!worldType || sceneShift === undefined || sceneShift === 0) return currentScenePreset;
  if (!currentScenePreset) return getScenePresetsByWorld(worldType)[0] ?? null;

  if (sceneShift > 0) {
    let nextScene = currentScenePreset;
    for (let index = 0; index < sceneShift; index += 1) {
      nextScene = getForwardScenePreset(worldType, nextScene.id) ?? nextScene;
    }
    return nextScene;
  }

  const scenes = getScenePresetsByWorld(worldType);
  if (scenes.length === 0) return currentScenePreset;
  const currentIndex = scenes.findIndex(scene => scene.id === currentScenePreset.id);
  const safeIndex = currentIndex >= 0 ? currentIndex : 0;
  const nextIndex = ((safeIndex + sceneShift) % scenes.length + scenes.length) % scenes.length;
  return scenes[nextIndex] ?? null;
}

function getSceneTargetForFunction(
  worldType: WorldType | null,
  currentScenePreset: GameState['currentScenePreset'],
  option: StoryOption,
): GameState['currentScenePreset'] {
  if (!worldType) return currentScenePreset;

  const targetSceneId =
    typeof option.runtimePayload?.targetSceneId === 'string'
      ? option.runtimePayload.targetSceneId
      : typeof option.runtimePayload?.escapeTargetSceneId === 'string'
        ? option.runtimePayload.escapeTargetSceneId
        : null;
  if (targetSceneId) {
    return getScenePresetById(worldType, targetSceneId) ?? currentScenePreset;
  }

  if (option.functionId === 'idle_travel_next_scene') {
    return getTravelScenePreset(worldType, currentScenePreset?.id) ?? currentScenePreset;
  }

  return getShiftedScenePreset(
    worldType,
    currentScenePreset,
    getFunctionEffect(option.functionId).sceneShift,
  );
}

export function buildResolvedChoiceState(params: {
  state: GameState;
  option: StoryOption;
  character: Character;
  buildBattlePlan: (state: GameState, option: StoryOption, character: Character) => BattlePlan;
}) {
  const {
    state,
    option,
    character,
    buildBattlePlan,
  } = params;
  const nextScenePreset = getSceneTargetForFunction(
    state.worldType,
    state.currentScenePreset,
    option,
  );
  const optionKind = classifyCombatOption(option);

  if (optionKind === 'battle') {
    const battlePlan = buildBattlePlan(state, option, character);
    const battleResult: GameState = {
      ...battlePlan.finalState,
      currentScenePreset: nextScenePreset ?? battlePlan.finalState.currentScenePreset,
    };

    return {
      optionKind,
      battlePlan,
      afterSequence: battleResult,
    } satisfies ResolvedChoiceState;
  }

  if (optionKind === 'escape') {
    return {
      optionKind,
      battlePlan: null,
      afterSequence: buildEscapeAfterSequence(state, option, nextScenePreset),
    } satisfies ResolvedChoiceState;
  }

  return {
    optionKind,
    battlePlan: null,
    afterSequence: buildIdleAfterSequence({
      state,
      option,
      character,
      nextScenePreset,
      applyRecoveryEffectToState,
    }),
  } satisfies ResolvedChoiceState;
}