---
import { getCollection, render } from "astro:content";
import TocList from "../../components/TocList.astro";
import Base from "../../layouts/Base.astro";

export async function getStaticPaths() {
  const writings = await getCollection("writings", ({ data }) => !data.draft);
  return writings.map((entry) => ({
    params: { slug: entry.id },
    props: { entry },
  }));
}

const { entry } = Astro.props;
const { Content, headings } = await render(entry);

const allWritings = (
  await getCollection("writings", ({ data }) => !data.draft)
).sort((a, b) => a.data.date.valueOf() - b.data.date.valueOf());
const index = allWritings.findIndex((w) => w.id === entry.id);
const prev = index > 0 ? allWritings[index - 1] : undefined;
const next =
  index < allWritings.length - 1 ? allWritings[index + 1] : undefined;

const series = entry.data.extra?.series;
const seriesEntries = series
  ? allWritings
      .filter((w) => w.data.extra?.series === series)
      .sort(
        (a, b) =>
          (a.data.extra?.series_index ?? 0) - (b.data.extra?.series_index ?? 0),
      )
  : [];

const tags = entry.data.taxonomies?.tags ?? [];
const related = tags.length
  ? allWritings
      .filter((w) => w.id !== entry.id)
      .map((w) => ({
        entry: w,
        overlap: (w.data.taxonomies?.tags ?? []).filter((t) => tags.includes(t))
          .length,
      }))
      .filter((w) => w.overlap > 0)
      .sort((a, b) => b.overlap - a.overlap)
      .slice(0, 3)
      .map((w) => w.entry)
  : [];

const description =
  entry.data.extra?.llms_description ?? entry.data.description;
const tocHeadings = headings.filter((h) => h.depth <= 3);
---

<Base title={entry.data.title} description={description} wide ogImage={`/images/og/writings/${entry.id}.png`}>
  <div class="article-layout">
    <div class="article-main">
      <h1>{entry.data.title}</h1>
      <p class="meta">
        {entry.data.date.toDateString()}
        {entry.data.readingMinutes && <> · {entry.data.readingMinutes} min read</>}
        {entry.data.updated && <> · updated {entry.data.updated.toDateString()}</>}
      </p>
      {tags.map((tag) => <a class="tag" href={`/tags/${tag}/`}>#{tag}</a>)}

      {
        series && (
          <nav class="series-nav" aria-label={`Post series: ${series}`}>
            <p class="meta">
              Series: {series} ({(entry.data.extra?.series_index ?? 0)} / {seriesEntries.length})
            </p>
            <ol>
              {seriesEntries.map((w) => (
                <li aria-current={w.id === entry.id ? "page" : undefined}>
                  <a href={`/writings/${w.id}/`}>{w.data.title}</a>
                </li>
              ))}
            </ol>
          </nav>
        )
      }

      {
        tocHeadings.length > 0 && (
          <nav class="toc toc-inline" aria-label="Table of contents">
            <TocList headings={tocHeadings} />
          </nav>
        )
      }

      <article>
        <Content />
      </article>

      <nav class="post-nav" aria-label="Post navigation">
        {prev && <a href={`/writings/${prev.id}/`}>← {prev.data.title}</a>}
        {next && <a href={`/writings/${next.id}/`}>{next.data.title} →</a>}
      </nav>

      {
        related.length > 0 && (
          <section>
            <h2>Related Posts</h2>
            {related.map((w) => (
              <div class="card">
                <h3>
                  <a href={`/writings/${w.id}/`}>{w.data.title}</a>
                </h3>
              </div>
            ))}
          </section>
        )
      }
    </div>

    {
      tocHeadings.length > 0 && (
        <nav class="toc toc-sidebar" aria-label="Table of contents">
          <TocList headings={tocHeadings} />
        </nav>
      )
    }
  </div>
</Base>

<style>
  .article-layout {
    display: grid;
    grid-template-columns: minmax(0, 42rem);
    justify-content: center;
    align-items: start;
    gap: var(--space-7);
  }

  .toc-sidebar {
    display: none;
  }

  @media (min-width: 74rem) {
    .article-layout {
      grid-template-columns: minmax(0, 42rem) 16rem;
    }

    .toc-inline {
      display: none;
    }

    .toc-sidebar {
      display: block;
      position: sticky;
      top: var(--space-6);
      max-height: calc(100vh - var(--space-7));
      overflow-y: auto;
    }
  }
</style>