import type { ProjectManifest } from '../project/types';
import { resolveProjectMap } from './MapLoader';
import { composeProjectMap } from './MapComposer';
import { composePhysicalMap } from './physicalMap';
import { isSystemTerrainPreset, type PlacedMapAsset } from './types';

export interface MapStackComposition {
  data: Uint8Array;
  geomCount: number;
  warnings: string[];
}

/** 将全部已放置地图实例依次合成到同一 MJCF；源地图条目本身不会自动进入场景。 */
export function composePlacedMapAssets(
  source: Uint8Array,
  generatedScenePath: string,
  manifest: ProjectManifest,
  assets: readonly PlacedMapAsset[],
): MapStackComposition {
  let data = source;
  let geomCount = 0;
  const warnings: string[] = [];
  const spawnOwnerId = assets.find(
    (asset) => asset.selection.kind === 'project' && asset.selection.spawnPointId,
  )?.id;
  // 程序地形最后合成，确保工程地图或机器人自带的无限 plane 不会覆盖沟壑/深坑。
  const orderedAssets = [
    ...assets.filter(
      (asset) =>
        asset.selection.kind !== 'builtin' || !isSystemTerrainPreset(asset.selection.config.preset),
    ),
    ...assets.filter(
      (asset) =>
        asset.selection.kind === 'builtin' && isSystemTerrainPreset(asset.selection.config.preset),
    ),
  ];

  for (const asset of orderedAssets) {
    if (asset.selection.kind === 'builtin') {
      const composed = composePhysicalMap(data, asset.selection.config, {
        instanceId: asset.id,
        preserveExistingGround: true,
      });
      data = composed.data;
      geomCount += composed.geomCount;
      if (composed.summary) warnings.push(`${asset.name}：${composed.summary}`);
      continue;
    }

    const resolvedMap = resolveProjectMap(manifest, asset.selection.descriptorPath);
    const composed = composeProjectMap(
      data,
      generatedScenePath,
      manifest,
      resolvedMap,
      asset.selection,
      {
        instanceId: asset.id,
        applySpawnPoint: asset.id === spawnOwnerId,
      },
    );
    data = composed.data;
    geomCount += composed.geomCount;
    warnings.push(...composed.warnings, `${asset.name}：${composed.summary}`);
  }

  return { data, geomCount, warnings };
}