/**

* @title Read and change file metadata

* @difficulty beginner

* @tags cli

* @run -R -W <url>

* @resource {https://docs.deno.com/api/deno/~/Deno.stat} Doc: Deno.stat

* @resource {https://docs.deno.com/api/deno/~/Deno.FileInfo} Doc: Deno.FileInfo

* @group File System

*

* Every file carries metadata besides its contents: size, timestamps, type

* and permissions. This example reads that metadata with Deno.stat, changes

* permissions with Deno.chmod, and sets timestamps with Deno.utime.

*/

// We set up a temporary directory with a small file to inspect.

const dir = await Deno.makeTempDir();

const path = `${dir}/data.txt`;

await Deno.writeTextFile(path, "twelve bytes");

// Deno.stat returns a FileInfo object with the size in bytes, the type and

// the timestamps. The timestamps are Date objects (or null on platforms

// that do not record them).

const info = await Deno.stat(path);

console.log(info.size); // 12

console.log(info.isFile); // true

console.log(info.mtime instanceof Date); // true

console.log(info.birthtime instanceof Date); // true

// On a symlink, stat follows the link and describes the target, while

// lstat describes the link itself.

await Deno.symlink(path, `${dir}/link.txt`);

console.log((await Deno.stat(`${dir}/link.txt`)).isFile); // true

console.log((await Deno.lstat(`${dir}/link.txt`)).isSymlink); // true

// The mode field holds the raw Unix permission bits. Masking with 0o777

// keeps just the permission part, in the familiar octal form.

console.log((info.mode! & 0o777).toString(8)); // 644

// Deno.chmod changes those permission bits. Here we drop access for group

// and others. On Windows only the write permission can be changed, and

// stat reports mode as null there.

await Deno.chmod(path, 0o600);

const after = await Deno.stat(path);

console.log((after.mode! & 0o777).toString(8)); // 600

// Deno.utime sets the access and modification times to any date you like,

// which is handy for tools like build systems that compare timestamps.

const date = new Date("2020-01-02T03:04:05Z");

await Deno.utime(path, date, date);

console.log((await Deno.stat(path)).mtime?.toISOString()); // 2020-01-02T03:04:05.000Z

// Reading metadata requires the -R permission; chmod and utime require -W.

await Deno.remove(dir, { recursive: true });