commit 5232eb612a12a87db6ad9b7ea316f241e915a092
Author: Grief <iamgrief@gmail.com>
Date:   Mon Sep 5 20:42:19 2022 +0300

    has-copy

diff --git a/bin/has-copy b/bin/has-copy
new file mode 100755
index 0000000..b54f9c0
--- /dev/null
+++ b/bin/has-copy
@@ -0,0 +1,206 @@
+#!/usr/bin/env node
+const {open, readdir, stat, rmdir} = require('node:fs/promises');
+const {join} = require('node:path');
+const {unlink} = require('node:fs/promises');
+const {Buffer} = require('node:buffer');
+
+
+const Kilobyte = 1024;
+const Megabyte = Kilobyte * 1024;
+const Gigabyte = Megabyte * 1024;
+
+const BLOCK_SIZE = 16 * Megabyte;
+
+const locale = 'en-US';
+
+/** @type {Buffer} */
+const BufferA = Buffer.alloc(BLOCK_SIZE);
+/** @type {Buffer} */
+const BufferB = Buffer.alloc(BLOCK_SIZE);
+
+
+const Terminal = Object.freeze({
+  fg: {
+    red: (text) => `\u001b[31m${text}\u001b[0m`,
+    green: (text) => `\u001b[32m${text}\u001b[0m`,
+    yellow: (text) => `\u001b[33m${text}\u001b[0m`,
+    blue: (text) => `\u001b[34m${text}\u001b[0m`,
+  }
+});
+
+/**
+ * @typedef {{bySize: {[key: string]: string[]}}} Cache
+ */
+
+/**
+ * @param {function(typeof Terminal)|string} param
+ */
+function log(param) {
+  console.log(typeof param === 'string' ? param : param(Terminal))
+}
+
+/**
+ * @param {Number} size
+ * @returns {*}
+ */
+function formatSize(size) {
+  let suffix = '';
+  let digits = 0;
+  if (size >= Megabyte) {
+    digits = 1;
+    if (size >= Gigabyte) {
+      size /= Gigabyte;
+      suffix = ' G';
+    } else {
+      size /= Megabyte;
+      suffix = ' M';
+    }
+  } else if (size >= Kilobyte) {
+    digits = 1;
+    size /= Kilobyte;
+    suffix = ' K'
+  }
+  return `${size.toLocaleString(locale, {
+    minimumFractionDigits: digits,
+    maximumFractionDigits: digits,
+    useGrouping: false
+  })}${suffix}`
+}
+
+/**
+ * @param path
+ * @returns {Promise<{files: Dirent[], dirs: Dirent[]}>}
+ */
+async function dirEntries(path) {
+  return (await readdir(path, {withFileTypes: true}))
+    .reduce((acc, file) => {
+      (file.isDirectory() ? acc.dirs : acc.files).push(file)
+      return acc;
+    }, {files: [], dirs: []})
+}
+
+async function compareFiles(localPath, remotePath, size) {
+  const localFile = await open(localPath),
+    remoteFile = await open(remotePath);
+  try {
+    for (let i = 0; ;) {
+      const start = process.hrtime.bigint();
+      const a = await localFile.read(BufferA, 0, BLOCK_SIZE);
+      const b = await remoteFile.read(BufferB, 0, BLOCK_SIZE);
+
+      if (a.bytesRead !== b.bytesRead || BufferA.compare(BufferB) !== 0) {
+        log(f => f.fg.yellow(`  files are different`));
+        console.log();
+        return false;
+      }
+      if (a.bytesRead === 0) {
+        console.log();
+        return true;
+      }
+      const seconds = Number(process.hrtime.bigint() - start) / 1_000_000_000;
+      i += a.bytesRead;
+      process.stdout.write(`\r${(i * 100 / size).toLocaleString(locale, {
+        minimumFractionDigits: 2,
+        maximumFractionDigits: 2
+      })}% ${formatSize((a.bytesRead + b.bytesRead) / seconds)}Bytes/sec`)
+    }
+    console.log('')
+
+  } finally {
+    Promise.allSettled([localFile.close(), remoteFile.close()]);
+  }
+}
+
+/**
+ * @param local
+ * @param {Cache} cache
+ * @param options
+ * @returns {Promise<boolean>}
+ */
+async function compareDirs(local, cache, options) {
+  try {
+    let canRemoveDir = true;
+    const entries = await dirEntries(local)
+    loop: for (const file of entries.files) {
+      const localPath = join(local, file.name);
+      const localStat = await stat(localPath);
+
+      const sameSize = cache.bySize[localStat.size];
+      if (!sameSize) {
+        canRemoveDir = false;
+        continue;
+      }
+
+      log(f => `${f.fg.green(localPath)} (${f.fg.green(`${formatSize(localStat.size)}B`)})`)
+      for (let i = 0; i < sameSize.length; i++) {
+        const remotePath = sameSize[i];
+        const remoteStat = await stat(remotePath);
+
+
+        if (localStat.ino === remoteStat.ino) {
+          log(f => f.fg.red('This is the same file'));
+        } else {
+          log(f => `Comparing with ${f.fg.blue(remotePath)}`)
+          if (await compareFiles(localPath, remotePath, localStat.size)) {
+            if (options.delete) {
+              log(f => `  ${f.fg.red('files are the same - deleting')}`);
+              await unlink(localPath)
+            }
+            continue loop;
+          }
+        }
+      }
+      canRemoveDir = false;
+    }
+    for (const dir of entries.dirs) {
+      if (!await compareDirs(join(local, dir.name), cache, options)) canRemoveDir = false;
+    }
+    if (canRemoveDir && options.delete) {
+      log(f => `Directory ${f.fg.yellow(local)} is empty, removed`)
+      await rmdir(local)
+    }
+    return canRemoveDir;
+  } catch (err) {
+    console.error(err);
+    return false;
+  }
+}
+
+const options = {
+  delete: false
+};
+
+if (process.argv[3] === 'delete') {
+  options.delete = true;
+}
+
+/**
+ * @param path
+ * @param result
+ * @returns {Promise<Cache>}
+ */
+async function scanDir(path, result) {
+  const entries = await dirEntries(path)
+  for (const file of entries.files) {
+    let absPath = join(path, file.name);
+    let {size} = (await stat(absPath));
+    let bySize = result.bySize[size];
+    if (bySize) {
+      bySize.push(absPath);
+    } else {
+      bySize = [absPath];
+      result.bySize[size] = bySize;
+    }
+  }
+  for (const dir of entries.dirs) {
+    await scanDir(join(path, dir.name), result)
+  }
+  return result;
+}
+
+(async function () {
+  log('Scanning target directory...')
+  const scan = await scanDir(process.argv[2], {bySize: {}})
+  log('Comparing...')
+  await compareDirs(process.cwd(), scan, options);
+})();