import * as fs from 'fs';
import * as path from 'path';
import * as db from './db.js';
import { samplePointcloudFile, type SampledPoint } from './pointcloudSample.js';

/** 与批量采样接口一致的配额 seek 采样（供热力分析作业复用） */
export async function sampleTaskPointclouds(taskId: number, budget: number): Promise<SampledPoint[]> {
  const pcRecords = await db.listTaskPointcloudFiles(taskId);
  const paths = pcRecords.map((r) => r.filePath);
  if (paths.length === 0) return [];

  const budgetClamped = Math.min(Math.max(50_000, budget), 20_000_000);
  const supportedExts = ['.ply', '.txt', '.xyz', '.pts'];

  const fileInfos = paths.map((fp) => ({
    filePath: fp,
    name: path.basename(fp),
    ext: path.extname(fp).toLowerCase(),
    size: fs.existsSync(fp) ? fs.statSync(fp).size : 0,
  }));
  const supportedFiles = fileInfos.filter((f) => supportedExts.includes(f.ext) && f.size > 0);
  const totalBytes = supportedFiles.reduce((s, f) => s + f.size, 0);
  if (supportedFiles.length === 0) return [];

  const quotaMap = new Map<string, number>();
  for (const f of supportedFiles) {
    const quota =
      totalBytes > 0
        ? Math.max(100, Math.round((f.size / totalBytes) * budgetClamped))
        : Math.floor(budgetClamped / supportedFiles.length);
    quotaMap.set(f.filePath, quota);
  }

  const sampledPerFile = await Promise.all(
    fileInfos.map((f) => {
      if (!supportedExts.includes(f.ext) || f.size === 0) {
        return Promise.resolve([] as SampledPoint[]);
      }
      return samplePointcloudFile(f.filePath, f.size, quotaMap.get(f.filePath) ?? 0);
    }),
  );
  const allPoints: SampledPoint[] = [];
  for (const pts of sampledPerFile) {
    allPoints.push(...pts);
  }
  return allPoints;
}