'use strict';

const path = require('path');
const fs   = require('fs');

/* eslint-disable no-param-reassign */

/**
 * copyToWorkDir
 * Copies the source file to the worker's local workDir before processing.
 *
 * Use this plugin BEFORE any transcode/extract plugin when:
 *   - The source file lives on a network share / mapped drive
 *   - You want the worker to encode from a local copy to avoid I/O bottleneck
 *   - The network path is slow or unreliable during long encodes
 *
 * Flow:
 *   1. Copies source → workDir/<basename><ext>  (streams, no RAM load)
 *   2. Updates outputFileObj._id to the local copy path
 *   3. Downstream plugins operate on the local copy
 *   4. Tdarr replaces the original with the final output as usual
 */

const details = () => ({
  name: 'Copy Source to Work Dir',
  description:
    'Copies the source file into the worker local workDir before processing. '
    + 'Use before transcode plugins when the source is on a slow network share '
    + 'to avoid I/O bottleneck during encode. '
    + 'The local copy is used by all subsequent plugins in this flow.',
  style: { borderColor: '#607D8B' },
  tags: 'utility',
  isStartPlugin: false,
  pType: '',
  requiresVersion: '2.11.01',
  sidebarPosition: 0,
  icon: 'faCopy',
  inputs: [
    {
      label: 'Skip if already local',
      name: 'skipIfLocal',
      type: 'boolean',
      defaultValue: 'true',
      inputUI: {
        type: 'dropdown',
        options: ['true', 'false'],
      },
      tooltip:
        'If true, skip the copy when the source file is already inside workDir '
        + 'or on the same drive as workDir (avoids double-copy on mapped nodes).',
    },
  ],
  outputs: [
    { number: 1, tooltip: 'File is ready in workDir — continue to next plugin' },
  ],
});

// ─── Plugin ───────────────────────────────────────────────────────────────────

const plugin = async (args) => {
  const { jobLog, inputFileObj, variables, workDir } = args;

  const inputFile = inputFileObj._id;
  const ext       = path.extname(inputFile);
  const baseName  = path.basename(inputFile, ext);
  const localCopy = path.join(workDir, `${baseName}${ext}`);

  jobLog(`[copyToWorkDir] Source : ${inputFile}\n`);
  jobLog(`[copyToWorkDir] WorkDir: ${workDir}\n`);

  // ── Skip only if file is already located inside workDir ──────────────────
  const skipIfLocal = (args.inputs.skipIfLocal || 'true') === 'true';
  if (skipIfLocal && inputFile.startsWith(workDir)) {
    jobLog('[copyToWorkDir] Source file is already inside workDir — skipping copy.\n');
    return { outputNumber: 1, outputFileObj: inputFileObj, variables };
  }

  // ── Preserve original library paths for downstream plugins ──────────────
  if (!variables.originalLibraryFile) {
    variables.originalLibraryFile = inputFile;
    variables.originalLibraryDir  = path.dirname(inputFile);
  }

  // ── Copy using streams (no RAM spike for large files) ────────────────────
  const sourceSize = fs.statSync(inputFile).size;
  const sourceSizeMb = (sourceSize / 1024 / 1024).toFixed(1);
  jobLog(`[copyToWorkDir] Copying ${sourceSizeMb} MB to: ${localCopy}\n`);

  const startMs = Date.now();
  let copiedBytes = 0;
  let nextProgressPercent = 10;

  await new Promise((resolve, reject) => {
    const rd = fs.createReadStream(inputFile);
    const wr = fs.createWriteStream(localCopy);

    rd.on('error', reject);
    wr.on('error', reject);
    wr.on('finish', resolve);
    rd.on('data', (chunk) => {
      copiedBytes += chunk.length;
      if (sourceSize <= 0) return;

      const percent = Math.floor((copiedBytes / sourceSize) * 100);
      if (percent < nextProgressPercent) return;

      const elapsedSeconds = Math.max((Date.now() - startMs) / 1000, 0.1);
      const copiedMb = (copiedBytes / 1024 / 1024).toFixed(1);
      const speedMbPerSecond = (copiedBytes / 1024 / 1024 / elapsedSeconds).toFixed(1);
      jobLog(`[copyToWorkDir] Progress: ${Math.min(percent, 100)}% (${copiedMb}/${sourceSizeMb} MB, ${speedMbPerSecond} MB/s)\n`);
      nextProgressPercent = (Math.floor(percent / 10) + 1) * 10;
    });
    rd.pipe(wr);
  });

  const elapsed = ((Date.now() - startMs) / 1000).toFixed(1);
  const sizeMb  = (fs.statSync(localCopy).size / 1024 / 1024).toFixed(1);
  jobLog(`[copyToWorkDir] Done: ${sizeMb} MB copied in ${elapsed}s\n`);

  // Return updated inputFileObj pointing to the local copy
  return {
    outputNumber: 1,
    outputFileObj: { ...inputFileObj, _id: localCopy },
    variables,
  };
};

module.exports.details = details;
module.exports.plugin = plugin;