// ── Town Cryer News gump sync (Protocol 2.1) ───────────────────────────────
//
// Keeps the in-game Town Cryer *News* gump in sync with the site's published
// news posts. Distinct from the scrolling town-crier lines (that's a one-shot
// announce leg in announceWorker); this is a STATE SYNC — an article stays in the
// gump while its post is published news, and is pulled when the post is
// unpublished/deleted/re-categorised.
//
// The website is the source of truth. POST /news is idempotent (re-post replaces),
// so a refresh or a reconnect re-assert is safe. Every call is best-effort and
// never throws — a sidecar/shard hiccup must never break saving or deleting a
// post. Reliability comes from reassertAll() on every WS (re)connect
// (uoLinkSocket.backfill), which re-pushes the current published set silently and
// closes the gap if an earlier live push failed.

const posts = require('../model/posts/posts.model')
const uoLinkClient = require('./uoLinkClient')
const settings = require('../model/settings/settings.model')
const { deriveExcerpt } = require('./sanitizeHtml')
const log = require('./logger')('news-gump')

const MAX_TITLE = 120
const MAX_BODY = 900

function baseUrl() {
  return (process.env.APP_BASE_URL || 'http://localhost:5173').replace(/\/+$/, '')
}

function clamp(value, max) {
  const s = String(value == null ? '' : value).replace(/\s+/g, ' ').trim()
  return s.length <= max ? s : `${s.slice(0, max - 1).trimEnd()}…`
}

// A post belongs in the gump exactly when it is published AND in the news category.
function inGump(post) {
  return Boolean(post && post.published && post.category === 'news')
}

// Optional UO gump image id for news articles (a shard art id), from the
// `news_gump_image` setting. Omitted → the sidecar uses a neutral scroll.
async function gumpImage() {
  try {
    const raw = await settings.get('news_gump_image')
    const n = Number(raw)
    return Number.isInteger(n) && n > 0 ? n : undefined
  } catch {
    return undefined
  }
}

// Build the in-game News article from a post. Body is a compact gump-HTML block
// (title centred + a plain-text excerpt) rather than the post's full rich HTML —
// the UO gump only supports a small HTML subset, so we keep it predictable. The
// "more info" URL is the public news list (news posts have no per-post route).
async function buildArticle(post, { announce = true } = {}) {
  const title = clamp(post.title, MAX_TITLE)
  const excerpt = clamp(post.excerpt || deriveExcerpt(post.body, MAX_BODY) || '', MAX_BODY)
  const body = excerpt ? `<CENTER>${title}</CENTER><BR><BR>${excerpt}` : `<CENTER>${title}</CENTER>`
  return {
    id: String(post.id),
    title,
    body,
    image: await gumpImage(),
    url: `${baseUrl()}/site/news`,
    announce,
  }
}

// Push a post to the gump (only if it belongs there). announce=true has the criers
// proclaim the title; false is a silent refresh/re-assert.
async function pushPost(post, { announce = true } = {}) {
  if (!inGump(post)) return { ok: false, skipped: true }
  const res = await uoLinkClient.postNews(await buildArticle(post, { announce }))
  if (!res.ok) log.warn('news gump push failed', { id: post.id, status: res.status, error: res.error })
  return res
}

// Remove a post from the gump. A 404 (not present) is not an error worth noting.
async function removePost(id) {
  const res = await uoLinkClient.deleteNews(String(id))
  if (!res.ok && res.status !== 404) {
    log.warn('news gump remove failed', { id, status: res.status, error: res.error })
  }
  return res
}

// Reconcile the gump after a post create/update/publish. `transition`
// ({ wasPublished, wasNews }) tells a fresh publish (announce) from an in-place
// edit (silent refresh) and catches a post leaving published-news (pull it).
async function syncPost(post, transition = {}) {
  try {
    if (inGump(post)) {
      const wasInGump = Boolean(transition.wasPublished && transition.wasNews)
      await pushPost(post, { announce: !wasInGump })
    } else if (transition.wasPublished && transition.wasNews) {
      await removePost(post.id)
    }
  } catch (err) {
    log.warn('news gump sync failed', { id: post && post.id, message: err.message })
  }
}

// Re-push every currently-published news post, silently — run on each WS
// (re)connect to reconcile the gump to our source of truth (also recovers any
// article whose original live push failed). Best-effort; never throws.
async function reassertAll() {
  try {
    const list = await posts.listAll('news')
    const published = (list || []).filter((p) => p.published)
    let pushed = 0
    for (const p of published) {
      const full = await posts.getById(p.id) // list projection may omit the body
      if (full) {
        await pushPost(full, { announce: false })
        pushed += 1
      }
    }
    if (pushed) log.info('re-asserted news gump articles', { count: pushed })
  } catch (err) {
    log.warn('news gump reassert failed', { message: err.message })
  }
}

module.exports = { inGump, buildArticle, pushPost, removePost, syncPost, reassertAll }