refactor: rewrite message creation (#2774)

* Rework createMessage
- MessageAttachment is now structurally similar to FileOptions
- No longer mutates the object passed as options
- Supports more permutations of arguments

* Ignore complexity warning

* Refactor name finding

* Fix typo

* Update typings

* Default name to null for MessageAttachment

* Make Message#reply use transformOptions

* Move transformOptions

* Fix Message#reply

* Fix mutation

* Update tests

* Fix options passing

* Refactor into APIMessage

* Fix webhook send

* Expose APIMessage

* Add documentation

* Add types

* Fix type doc

* Fix another type doc

* Fix another another type doc (is this one even right!?)

* Remove trailing comma

* Properly clone split options

* Add support for sending file as stream

* Missed a doc

* Resolve files only once when splitting messages

* This looks nicer

* Assign directly

* Don't cache data and files

* Missing return type

* Use object spread instead Object.assign

* Document constructors

* Crawl is a little dot

* comp pls

* tests: sanitize local file path, disable no-await-in-loop

test/sendtest.js

@@ -0,0 +1,140 @@
+const Discord = require('../src');
+const { owner, token } = require('./auth.js');
+
+const fetch = require('node-fetch');
+const fs = require('fs');
+const path = require('path');
+const util = require('util');
+
+const client = new Discord.Client();
+
+const fill = c => Array(4).fill(c.repeat(1000));
+const buffer = l => fetch(l).then(res => res.buffer());
+const read = util.promisify(fs.readFile);
+const readStream = fs.createReadStream;
+const wait = util.promisify(setTimeout);
+
+const linkA = 'https://lolisafe.moe/iiDMtAXA.png';
+const linkB = 'https://lolisafe.moe/9hSpedPh.png';
+const fileA = path.join(__dirname, 'blobReach.png');
+
+const embed = () => new Discord.MessageEmbed();
+const attach = (attachment, name) => new Discord.MessageAttachment(attachment, name);
+
+const tests = [
+  m => m.channel.send('x'),
+  m => m.channel.send(['x', 'y']),
+
+  m => m.channel.send('x', { code: true }),
+  m => m.channel.send('1', { code: 'js' }),
+  m => m.channel.send('x', { code: '' }),
+
+  m => m.channel.send(fill('x'), { split: true }),
+  m => m.channel.send(fill('1'), { code: 'js', split: true }),
+  m => m.channel.send(fill('x'), { reply: m.author, code: 'js', split: true }),
+  m => m.channel.send(fill('xyz '), { split: { char: ' ' } }),
+
+  m => m.channel.send('x', { embed: { description: 'a' } }),
+  m => m.channel.send({ embed: { description: 'a' } }),
+  m => m.channel.send({ files: [{ attachment: linkA }] }),
+  m => m.channel.send({
+    embed: { description: 'a' },
+    files: [{ attachment: linkA, name: 'xyz.png' }],
+  }),
+
+  m => m.channel.send('x', embed().setDescription('a')),
+  m => m.channel.send(embed().setDescription('a')),
+  m => m.channel.send({ embed: embed().setDescription('a') }),
+  m => m.channel.send([embed().setDescription('a'), embed().setDescription('b')]),
+
+  m => m.channel.send('x', attach(linkA)),
+  m => m.channel.send(attach(linkA)),
+  m => m.channel.send({ files: [linkA] }),
+  m => m.channel.send({ files: [attach(linkA)] }),
+  async m => m.channel.send(attach(await buffer(linkA))),
+  async m => m.channel.send({ files: [await buffer(linkA)] }),
+  async m => m.channel.send({ files: [{ attachment: await buffer(linkA) }] }),
+  m => m.channel.send([attach(linkA), attach(linkB)]),
+
+  m => m.channel.send({ embed: { description: 'a' } }).then(m2 => m2.edit('x')),
+  m => m.channel.send(embed().setDescription('a')).then(m2 => m2.edit('x')),
+  m => m.channel.send({ embed: embed().setDescription('a') }).then(m2 => m2.edit('x')),
+
+  m => m.channel.send('x').then(m2 => m2.edit({ embed: { description: 'a' } })),
+  m => m.channel.send('x').then(m2 => m2.edit(embed().setDescription('a'))),
+  m => m.channel.send('x').then(m2 => m2.edit({ embed: embed().setDescription('a') })),
+
+  m => m.channel.send({ embed: { description: 'a' } }).then(m2 => m2.edit({ embed: null })),
+  m => m.channel.send(embed().setDescription('a')).then(m2 => m2.edit({ embed: null })),
+
+  m => m.channel.send(['x', 'y'], [embed().setDescription('a'), attach(linkB)]),
+  m => m.channel.send(['x', 'y'], [attach(linkA), attach(linkB)]),
+
+  m => m.channel.send([embed().setDescription('a'), attach(linkB)]),
+  m => m.channel.send({
+    embed: embed().setImage('attachment://two.png'),
+    files: [attach(linkB, 'two.png')],
+  }),
+  m => m.channel.send({
+    embed: embed()
+      .setImage('attachment://two.png')
+      .attachFiles([attach(linkB, 'two.png')]),
+  }),
+  async m => m.channel.send(['x', 'y', 'z'], {
+    code: 'js',
+    embed: embed()
+      .setImage('attachment://two.png')
+      .attachFiles([attach(linkB, 'two.png')]),
+    files: [{ attachment: await buffer(linkA) }],
+  }),
+
+  m => m.channel.send('x', attach(fileA)),
+  m => m.channel.send({ files: [fileA] }),
+  m => m.channel.send(attach(fileA)),
+  async m => m.channel.send({ files: [await read(fileA)] }),
+  async m => m.channel.send(fill('x'), {
+    reply: m.author,
+    code: 'js',
+    split: true,
+    embed: embed().setImage('attachment://zero.png'),
+    files: [attach(await buffer(linkA), 'zero.png')],
+  }),
+
+  m => m.channel.send('x', attach(readStream(fileA))),
+  m => m.channel.send({ files: [readStream(fileA)] }),
+  m => m.channel.send({ files: [{ attachment: readStream(fileA) }] }),
+  async m => m.channel.send(fill('xyz '), {
+    reply: m.author,
+    code: 'js',
+    split: { char: ' ', prepend: 'hello! ', append: '!!!' },
+    embed: embed().setImage('attachment://zero.png'),
+    files: [linkB, attach(await buffer(linkA), 'zero.png'), readStream(fileA)],
+  }),
+
+  m => m.channel.send('Done!'),
+];
+
+client.on('message', async message => {
+  if (message.author.id !== owner) return;
+  const match = message.content.match(/^do (.+)$/);
+  if (match && match[1] === 'it') {
+    /* eslint-disable no-await-in-loop */
+    for (const [i, test] of tests.entries()) {
+      await message.channel.send(`**#${i}**\n\`\`\`js\n${test.toString()}\`\`\``);
+      await test(message).catch(e => message.channel.send(`Error!\n\`\`\`\n${e}\`\`\``));
+      await wait(1000);
+    }
+    /* eslint-enable no-await-in-loop */
+  } else if (match) {
+    const n = parseInt(match[1]) || 0;
+    const test = tests.slice(n)[0];
+    const i = tests.indexOf(test);
+    await message.channel.send(`**#${i}**\n\`\`\`js\n${test.toString()}\`\`\``);
+    await test(message).catch(e => message.channel.send(`Error!\n\`\`\`\n${e}\`\`\``));
+  }
+});
+
+client.login(token);
+
+// eslint-disable-next-line no-console
+process.on('unhandledRejection', console.error);