import { mkdir, stat } from 'node:fs/promises';
import path from 'node:path';
import { spawn } from 'node:child_process';

export const MAX_LONG_EDGE = 1280;

export class FrameNormalizer {
  constructor({ helper = path.resolve(new URL('./py/normalize_frame.py', import.meta.url).pathname), python = 'python3', spawnImpl = spawn, tmpDir = '/tmp/jarvis-cu', maxLongEdge = MAX_LONG_EDGE, quality = 70 } = {}) {
    Object.assign(this, { helper, python, spawnImpl, tmpDir, maxLongEdge, quality });
  }
  async normalize(input, output = path.join(this.tmpDir, `frame-${Date.now()}.webp`), rect) {
    await mkdir(path.dirname(output), { recursive: true });
    const crop = rect ? rect.map(Number).map(value => String(Math.round(value))) : [];
    let metadata = {};
    await new Promise((resolve, reject) => {
      const child = this.spawnImpl(this.python, [this.helper, input, output, String(this.maxLongEdge), String(this.quality), ...crop], { stdio: ['ignore', 'pipe', 'pipe'] });
      let stderr = '', stdout = '';
      const timer = setTimeout(() => { child.kill('SIGTERM'); reject(new Error('frame normalization timed out')); }, 8000);
      child.stdout?.on('data', data => { stdout += data; });
      child.stderr?.on('data', data => { stderr += data; });
      child.on('error', error => { clearTimeout(timer); reject(error); });
      child.on('close', code => {
        clearTimeout(timer);
        try { metadata = JSON.parse(stdout || '{}'); } catch {}
        code === 0 ? resolve() : reject(new Error(stderr || `frame normalization exited ${code}`));
      });
    });
    const info = await stat(output);
    const ext = path.extname(output).toLowerCase();
    const mime = metadata.mime || (ext === '.png' ? 'image/png' : ext === '.jpg' || ext === '.jpeg' ? 'image/jpeg' : 'image/webp');
    return { ...metadata, path: output, bytes: info.size, maxLongEdge: this.maxLongEdge, mime };
  }
}