import type {
  CustomWorldCoverProfile,
  CustomWorldPlayableNpc,
  CustomWorldProfile,
} from '../types';

export type CustomWorldCoverRenderMode = 'image' | 'scene_with_roles';

export type CustomWorldCoverPresentation = {
  imageSrc: string | null;
  renderMode: CustomWorldCoverRenderMode;
  characterImageSrcs: string[];
  sourceType: CustomWorldCoverProfile['sourceType'];
};

function resolveOpeningSceneFirstActImageSrc(profile: CustomWorldProfile) {
  return profile.sceneChapterBlueprints?.[0]?.acts?.[0]?.backgroundImageSrc?.trim() || null;
}

function resolveOpeningSceneImageSrc(profile: CustomWorldProfile) {
  // 默认封面优先取开局场景第一幕图，避免草稿页与作品库继续沿用旧的营地兜底策略。
  const firstActImageSrc = resolveOpeningSceneFirstActImageSrc(profile);
  if (firstActImageSrc) {
    return firstActImageSrc;
  }

  const campImageSrc = profile.camp?.imageSrc?.trim() || '';
  if (campImageSrc) {
    return campImageSrc;
  }

  return (
    profile.landmarks
      .map((landmark) => landmark.imageSrc?.trim() || '')
      .find(Boolean) || null
  );
}

function resolvePlayableCoverImageSrc(role: CustomWorldPlayableNpc) {
  const explicitImageSrc = role.imageSrc?.trim() || '';
  if (explicitImageSrc) {
    return explicitImageSrc;
  }

  return null;
}

function normalizeCoverCharacterRoleIds(
  profile: Pick<CustomWorldProfile, 'playableNpcs'>,
  roleIds?: string[] | null,
) {
  const availableIds = new Set(
    profile.playableNpcs.map((role) => role.id.trim()).filter(Boolean),
  );
  const selectedIds = Array.isArray(roleIds)
    ? [
        ...new Set(
          roleIds
            .map((roleId) => roleId.trim())
            .filter((roleId) => roleId && availableIds.has(roleId)),
        ),
      ].slice(0, 3)
    : [];

  if (selectedIds.length > 0) {
    return selectedIds;
  }

  return profile.playableNpcs
    .map((role) => role.id.trim())
    .filter(Boolean)
    .slice(0, 3);
}

export function buildDefaultCustomWorldCoverProfile(
  profile: Pick<CustomWorldProfile, 'playableNpcs'>,
): CustomWorldCoverProfile {
  return {
    sourceType: 'default',
    imageSrc: null,
    characterRoleIds: normalizeCoverCharacterRoleIds(profile),
  };
}

export function resolveCustomWorldCoverPresentation(
  profile: CustomWorldProfile,
): CustomWorldCoverPresentation {
  const cover = profile.cover;
  const sourceType =
    cover?.sourceType === 'uploaded' || cover?.sourceType === 'generated'
      ? cover.sourceType
      : 'default';
  const explicitImageSrc = cover?.imageSrc?.trim() || '';

  if (sourceType !== 'default' && explicitImageSrc) {
    return {
      imageSrc: explicitImageSrc,
      renderMode: 'image',
      characterImageSrcs: [],
      sourceType,
    };
  }

  const openingSceneImageSrc = resolveOpeningSceneImageSrc(profile);
  const roleById = new Map(
    profile.playableNpcs.map((role) => [role.id.trim(), role] as const),
  );
  const characterImageSrcs = normalizeCoverCharacterRoleIds(
    profile,
    cover?.characterRoleIds,
  )
    .map((roleId) => roleById.get(roleId))
    .map((role) => (role ? resolvePlayableCoverImageSrc(role) : null))
    .filter((imageSrc): imageSrc is string => Boolean(imageSrc));
  const leadPlayableImageSrc =
    profile.playableNpcs
      .map((role) => resolvePlayableCoverImageSrc(role))
      .find(Boolean) || null;

  return {
    imageSrc: openingSceneImageSrc || leadPlayableImageSrc,
    renderMode:
      openingSceneImageSrc && characterImageSrcs.length > 0
        ? 'scene_with_roles'
        : 'image',
    characterImageSrcs:
      openingSceneImageSrc && characterImageSrcs.length > 0
        ? characterImageSrcs
        : [],
    sourceType: 'default',
  };
}