// Embed expansion (Phase 16.2, D-17). The Blog Editor stores the placeholder
// <figure data-embed="youtube" data-id="ID"></figure>; the sinks render
// expandEmbeds(sanitizeJournalHtml(html)), so the sanitizer runs first and the
// only iframe in the output is the one built from a validated placeholder.
import { test } from 'node:test'
import assert from 'node:assert/strict'
import { readFileSync } from 'node:fs'
import { EMBED_PLACEHOLDER, EMBED_PROVIDERS, expandEmbeds } from '../app/utils/embeds.ts'
import { sanitizeJournalHtml } from '../app/utils/htmlGate.ts'

const ID = 'dQw4w9WgXcQ'
const PLACEHOLDER = `<figure data-embed="youtube" data-id="${ID}"></figure>`
const IFRAME =
  '<figure class="journal-embed journal-embed--youtube">' +
  `<iframe src="https://www.youtube-nocookie.com/embed/${ID}" title="YouTube video" loading="lazy" ` +
  'referrerpolicy="strict-origin-when-cross-origin" allow="encrypted-media; picture-in-picture; fullscreen" allowfullscreen></iframe>' +
  '</figure>'

// The sink: sanitize, then expand last.
const sink = (html: string) => expandEmbeds(sanitizeJournalHtml(html))
// The payload transform sanitizes, and the sink sanitizes again before expanding.
const payloadThenSink = (html: string) => expandEmbeds(sanitizeJournalHtml(sanitizeJournalHtml(html)))

const iframeCount = (html: string) => (html.match(/<iframe/g) ?? []).length

test('the placeholder expands to the privacy-enhanced YouTube iframe', () => {
  assert.equal(expandEmbeds(PLACEHOLDER), IFRAME)
  assert.equal(expandEmbeds(`<p>a</p>${PLACEHOLDER}<p>b</p>`), `<p>a</p>${IFRAME}<p>b</p>`)
})

test('the provider table holds YouTube only, on youtube-nocookie.com', () => {
  assert.deepEqual(Object.keys(EMBED_PROVIDERS), ['youtube'])
  assert.equal(EMBED_PROVIDERS.youtube!.src(ID), `https://www.youtube-nocookie.com/embed/${ID}`)
  assert.ok(EMBED_PLACEHOLDER.global)
})

test('malformed or unknown placeholders stay unchanged and inert', () => {
  const inert = [
    `<figure data-embed="youtube" data-id="${ID.slice(0, 10)}"></figure>`,
    `<figure data-embed="youtube" data-id="${ID}Q"></figure>`,
    `<figure data-embed="youtube" data-id="dQw4w9WgX/Q"></figure>`,
    `<figure data-embed="vimeo" data-id="${ID}"></figure>`,
    `<figure data-embed="constructor" data-id="${ID}"></figure>`,
    `<figure data-embed="__proto__" data-id="${ID}"></figure>`,
    `<figure data-embed="youtube" data-id="${ID}" class="x"></figure>`,
    `<figure class="x" data-embed="youtube" data-id="${ID}"></figure>`,
    `<figure data-id="${ID}" data-embed="youtube"></figure>`,
    `<figure data-embed="youtube" data-id="${ID}"><figcaption>c</figcaption></figure>`,
    `<figure data-embed='youtube' data-id='${ID}'></figure>`,
  ]
  for (const html of inert) assert.equal(expandEmbeds(html), html, html)
})

test('empty input gives ""', () => {
  for (const html of [null, undefined, '']) assert.equal(expandEmbeds(html), '')
})

test('the sink turns a stored placeholder into the iframe', () => {
  assert.equal(sink(PLACEHOLDER), IFRAME)
  assert.equal(sink(`<h2>Title</h2>\n${PLACEHOLDER}\n<p>After</p>`), `<h2>Title</h2>\n${IFRAME}\n<p>After</p>`)
})

test('a raw iframe in stored HTML is stripped; only the placeholder becomes an iframe', () => {
  const stored =
    '<p>Before</p>' +
    '<iframe src="https://evil.test/"></iframe>' +
    `<iframe src="https://www.youtube-nocookie.com/embed/${ID}"></iframe>` +
    PLACEHOLDER +
    '<p>After</p>'
  for (const run of [sink, payloadThenSink]) {
    const out = run(stored)
    assert.equal(out, `<p>Before</p>${IFRAME}<p>After</p>`)
    assert.equal(iframeCount(out), 1)
    assert.doesNotMatch(out, /evil\.test/)
  }
})

test('a placeholder smuggling an iframe or extra attributes expands only its validated parts', () => {
  const stored = `<figure data-embed="youtube" data-id="${ID}" data-src="https://evil.test/" onload="alert(1)"><iframe src="https://evil.test/"></iframe></figure>`
  assert.equal(sink(stored), IFRAME)
  assert.equal(payloadThenSink(stored), IFRAME)
})

test('a malformed placeholder stays an empty figure after the sink', () => {
  assert.equal(sink(`<figure data-embed="youtube" data-id="short"></figure>`), '<figure data-embed="youtube"></figure>')
  assert.equal(sink(`<figure data-embed="vimeo" data-id="${ID}"></figure>`), `<figure data-id="${ID}"></figure>`)
  assert.equal(iframeCount(sink(`<figure data-embed="vimeo" data-id="${ID}"></figure>`)), 0)
})

test('the payload-then-sink pipeline gives the same result as the sink', () => {
  const stored = `<p>x</p>${PLACEHOLDER}<script>alert(1)</script><p>y</p>`
  assert.equal(payloadThenSink(stored), sink(stored))
  assert.equal(sink(stored), `<p>x</p>${IFRAME}<p>y</p>`)
})

test('two placeholders in one body both expand', () => {
  const other = 'abcdefghijk'
  const out = sink(`${PLACEHOLDER}<p>between</p><figure data-embed="youtube" data-id="${other}"></figure>`)
  assert.equal(iframeCount(out), 2)
  assert.equal(out, `${IFRAME}<p>between</p>${IFRAME.replace(ID, other)}`)
})

test('the editor corpus embed entries expand after sanitizing', () => {
  const corpus = JSON.parse(
    readFileSync(new URL('./fixtures/editor-corpus.json', import.meta.url), 'utf8'),
  ) as Array<{ name: string; html: string }>
  const embed = corpus.find((e) => e.name === 'embed-youtube')
  assert.ok(embed)
  assert.equal(payloadThenSink(embed.html), IFRAME)
  const combined = corpus.find((e) => e.name === 'combined')
  assert.ok(combined)
  const out = payloadThenSink(combined.html)
  assert.ok(out.startsWith(IFRAME), out)
  assert.equal(iframeCount(out), 1)
  // Entries without a placeholder pass through the expansion unchanged.
  for (const entry of corpus.filter((e) => !e.html.includes('data-embed'))) {
    const clean = sanitizeJournalHtml(entry.html)
    assert.equal(expandEmbeds(clean), clean, entry.name)
  }
})