// The post page's SSR payload: the post with its body sanitized (h1 demoted
// to h2 while the Journal H1 setting is on), without the raw `content`
// source or `translations`, and with related posts as list rows. Kept apart from view.ts because it loads the sanitizer, which list
// pages and cards do not need.

import { sanitizeJournalHtml } from './htmlGate.ts'
import type { JournalPostDetail } from './types.ts'
import { toListPost } from './view.ts'

/**
 * True while the post's body h1 headings become h2 (the Journal API's
 * content_h1_to_h2; absent on an older Journal, which counts as on).
 */
export function demotesH1(post: { content_h1_to_h2?: boolean | null } | null | undefined): boolean {
  return post?.content_h1_to_h2 !== false
}

/**
 * The previous and next links of a post page: the neighbours within the
 * post's first category when the Journal answers them (its opt-in scored
 * mode) and at least one exists, else the site-wide previous_post and
 * next_post.
 */
export function postNeighbours(post: {
  previous_post?: { slug: string; title: string } | null
  next_post?: { slug: string; title: string } | null
  previous_in_category?: { slug: string; title: string } | null
  next_in_category?: { slug: string; title: string } | null
}): { previous: { slug: string; title: string } | null; next: { slug: string; title: string } | null; inCategory: boolean } {
  if (post.previous_in_category || post.next_in_category) {
    return { previous: post.previous_in_category ?? null, next: post.next_in_category ?? null, inCategory: true }
  }
  return { previous: post.previous_post ?? null, next: post.next_post ?? null, inCategory: false }
}

/** A post page's data: the post with its body sanitized and no source or translations. */
export type JournalPostView = JournalPostDetail

export function toPostView(post: JournalPostDetail): JournalPostView {
  return {
    ...post,
    content: null,
    translations: null,
    content_html: sanitizeJournalHtml(post.content_html, { demoteH1: demotesH1(post) }),
    related_posts: (post.related_posts ?? []).map(toListPost),
  }
}