package org.terst.feedreader.data

import org.junit.Assert.assertEquals
import org.junit.Assert.assertTrue
import org.junit.Test

/**
 * A title for an item that doesn't have one.
 *
 * RSS only requires an item to carry a title *or* a description, and Mastodon's tag feeds
 * exercise that: every one of the 20 items in `mastodon.social/tags/giftlink.rss` has a
 * `<description>` and no `<title>` at all. Subscribing to one produced a list of blank rows.
 */
class ItemTitlesTest {

    /** Verbatim from the #giftlink feed, 2026-10-22, as the XML parser hands it over. */
    private val mastodonPost =
        """<p>This is a nice story, with lovely photos. <a href="https://infosec.exchange/tags/giftlink" """ +
            """class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>giftlink</span></a> </p>""" +
            """<p><a href="https://www.nytimes.com/2026/10/20/us/catherine-breed.html?unlocked_article_code=1.KlE" """ +
            """rel="nofollow noopener" target="_blank"><span class="invisible">https://www.</span>""" +
            """<span class="ellipsis">nytimes.com/2026/10/20/us/cath</span></a></p>"""

    @Test
    fun `a real title is left exactly as it is`() {
        assertEquals(
            "The Flipbook of the Rings",
            ItemTitles.titleFor("The Flipbook of the Rings", "<p>anything</p>", "https://kottke.org/x")
        )
    }

    @Test
    fun `a title of nothing but whitespace counts as absent`() {
        assertEquals("Hello there.", ItemTitles.titleFor("   \n ", "<p>Hello there.</p>", "https://x/y"))
    }

    @Test
    fun `a titleless post is named by its own first sentence`() {
        assertEquals(
            "This is a nice story, with lovely photos.",
            ItemTitles.titleFor("", mastodonPost, "https://infosec.exchange/@cremevax/117483063928862987")
        )
    }

    @Test
    fun `markup never reaches the title`() {
        val title = ItemTitles.titleFor("", mastodonPost, "https://x/y")

        assertTrue("got: $title", !title.contains("<") && !title.contains(">"))
    }

    @Test
    fun `html entities are resolved, since a title is shown as plain text`() {
        assertEquals(
            "Smith & Co's \"deal\" — done",
            ItemTitles.titleFor("", "<p>Smith &amp; Co&#39;s &quot;deal&quot; &mdash; done</p>", "https://x/y")
        )
    }

    @Test
    fun `a non-breaking space is a space, not a stray glyph`() {
        assertEquals("One two three", ItemTitles.titleFor("", "<p>One&nbsp;two&nbsp;three</p>", "https://x/y"))
    }

    @Test
    fun `runs of whitespace collapse, so a title stays one line`() {
        assertEquals("One two", ItemTitles.titleFor("", "<p>One</p>\n\n   <p>two</p>", "https://x/y"))
    }

    @Test
    fun `a long post is cut at a word boundary and marked as cut`() {
        val long = "<p>" + "banana ".repeat(60) + "</p>"

        val title = ItemTitles.titleFor("", long, "https://x/y")

        assertTrue("should be cut: ${title.length}", title.length <= ItemTitles.MAX_LENGTH + 1)
        assertTrue("should say it was cut: $title", title.endsWith("…"))
        assertTrue("should not cut mid-word: $title", title.startsWith("banana banana"))
        assertTrue("should not cut mid-word: $title", !title.contains("banan…"))
    }

    @Test
    fun `a very long first sentence is cut rather than used whole`() {
        val long = "<p>" + "word ".repeat(80) + ". Second sentence.</p>"

        assertTrue(ItemTitles.titleFor("", long, "https://x/y").length <= ItemTitles.MAX_LENGTH + 1)
    }

    @Test
    fun `a post with no words falls back to its link`() {
        val title = ItemTitles.titleFor("", """<p><img src="https://x/a.jpg"></p>""", "https://infosec.exchange/@a/1")

        assertEquals("infosec.exchange/@a/1", title)
    }

    @Test
    fun `no title, no content and no link still gives something to tap`() {
        assertEquals("Untitled", ItemTitles.titleFor("", null, ""))
    }

    @Test
    fun `null content falls back to the link`() {
        assertEquals("example.com/a", ItemTitles.titleFor("", null, "https://example.com/a"))
    }

    @Test
    fun `a trailing slash is not worth showing in a title`() {
        assertEquals("example.com/a", ItemTitles.titleFor("", null, "https://example.com/a/"))
    }

    @Test
    fun `a script or style block contributes no words`() {
        val html = "<style>p{color:red}</style><script>var x=1;</script><p>Actual words.</p>"

        assertEquals("Actual words.", ItemTitles.titleFor("", html, "https://x/y"))
    }

    /**
     * Mastodon splits a hashtag and a URL across inline spans -- `#<span>giftlink</span>` and
     * `<span class="invisible">https://</span><span class="ellipsis">wapo.st/x</span>`. Turning
     * every tag into a space broke both apart, which showed live as titles reading
     * "# HumaneRights # USPolitics" and "the loophole https:// wapo.".
     */
    @Test
    fun `an inline tag does not insert a space into a word`() {
        assertEquals(
            "Tagged #giftlink today.",
            ItemTitles.titleFor("", "<p>Tagged #<span>giftlink</span> today.</p>", "https://x/y")
        )
    }

    @Test
    fun `a url split across spans stays one url`() {
        val html = """<p>Read <a href="https://wapo.st/x"><span class="invisible">https://</span>""" +
            """<span class="ellipsis">wapo.st/x</span></a> now</p>"""

        assertEquals("Read https://wapo.st/x now", ItemTitles.titleFor("", html, "https://x/y"))
    }

    @Test
    fun `a block boundary still separates words`() {
        assertEquals("One two", ItemTitles.titleFor("", "<p>One</p><p>two</p>", "https://x/y"))
    }

    @Test
    fun `a line break separates words`() {
        assertEquals("One two", ItemTitles.titleFor("", "One<br>two", "https://x/y"))
    }

    @Test
    fun `a dot inside a domain does not end the sentence`() {
        assertEquals(
            "The $580 loophole https://wapo.st/abc is open.",
            ItemTitles.titleFor("", "<p>The $580 loophole https://wapo.st/abc is open. And more.</p>", "https://x/y")
        )
    }

    @Test
    fun `a sentence still ends at a full stop followed by a space`() {
        assertEquals(
            "The first sentence here.",
            ItemTitles.titleFor("", "<p>The first sentence here. Second one.</p>", "https://x/y")
        )
    }

    @Test
    fun `a two-word opening fragment is not a title on its own`() {
        // "Wow." says nothing. Keep reading rather than name the article after an interjection.
        assertEquals(
            "Wow. Here is what the article actually says.",
            ItemTitles.titleFor("", "<p>Wow. Here is what the article actually says.</p>", "https://x/y")
        )
    }

    @Test
    fun `a sentence ending the text needs no trailing space`() {
        assertEquals("Only sentence here.", ItemTitles.titleFor("", "<p>Only sentence here.</p>", "https://x/y"))
    }
}