<template>
  <v-card class="fc-post-card" variant="outlined">
    <div class="fc-post-card__head">
      <!-- Posts with no live subscription have source=null (alembic 0030);
           show a "filesystem import" affordance instead of a platform chip. -->
      <v-chip size="x-small" variant="tonal">
        {{ post.source?.platform ?? 'filesystem import' }}
      </v-chip>
      <RouterLink
        :to="{ name: 'artist', params: { slug: post.artist.slug } }"
        class="fc-post-card__artist"
      >{{ post.artist.name }}</RouterLink>
      <span class="fc-post-card__date" :title="absoluteDate">{{ relativeDate }}</span>
      <span v-if="totalImages" class="fc-post-card__meta">
        · {{ totalImages }} image{{ totalImages === 1 ? '' : 's' }}
      </span>
      <v-spacer />
      <PostSeriesMenu :post="post" />
      <v-btn
        v-if="post.post_url"
        :href="post.post_url" target="_blank" rel="noopener"
        icon="mdi-open-in-new" size="x-small" variant="text"
        :aria-label="`open original post on ${post.source?.platform ?? 'web'}`"
      />
    </div>

    <div class="fc-post-card__body">
      <div class="fc-post-card__media">
        <template v-if="images.length">
          <!-- Images open the post-scoped image modal (look bigger + arrow
               through ALL the post's images) — the card never expands. -->
          <button
            type="button" class="fc-post-card__hero"
            aria-label="Open images" @click="openModal(hero.image_id)"
          >
            <img :src="hero.thumbnail_url" alt="hero thumbnail" loading="lazy" />
          </button>
          <div
            v-if="rail.length || moreCount" class="fc-post-card__rail"
            :style="{ '--fc-rail-cols': railCols }"
          >
            <button
              v-for="t in rail" :key="t.image_id" type="button"
              class="fc-post-card__rail-cell"
              aria-label="Open image" @click="openModal(t.image_id)"
            >
              <img :src="t.thumbnail_url" alt="thumbnail" loading="lazy" />
            </button>
            <button
              v-if="moreCount > 0" type="button"
              class="fc-post-card__rail-more"
              :aria-label="`Open ${moreCount} more images`"
              @click="openModalAtMore"
            >+{{ moreCount }}</button>
          </div>
        </template>
        <PostEmptyThumbs v-else />
      </div>

      <div class="fc-post-card__text">
        <h3 v-if="plainTitle" class="fc-post-card__title">{{ plainTitle }}</h3>
        <h3 v-else class="fc-post-card__title fc-post-card__title--missing">
          Post {{ post.external_post_id }}
        </h3>

        <p
          v-if="hasDescription" ref="descEl"
          class="fc-post-card__desc"
          :class="{ 'fc-post-card__desc--clamped': !descExpanded }"
        >{{ descText }}</p>
        <p v-else class="fc-post-card__desc fc-post-card__desc--missing">
          (no description)
        </p>

        <!-- The ONLY in-place expansion: the post text, and only when it's
             actually truncated (server flag or a CSS-clamp overflow). -->
        <button
          v-if="canExpand" type="button" class="fc-post-card__more"
          @click="toggleDesc"
        >{{ descExpanded ? 'Show less' : 'Show more' }}</button>

        <div v-if="attachments.length" class="fc-post-card__atts">
          <a
            v-for="att in attachments" :key="att.id"
            :href="att.download_url" download class="fc-post-card__att"
          >
            <v-icon size="small" class="fc-post-card__att-icon">mdi-paperclip</v-icon>
            <span>{{ att.original_filename }}</span>
            <span class="fc-post-card__att-size">({{ formatBytes(att.size_bytes) }})</span>
          </a>
        </div>
      </div>
    </div>
  </v-card>
</template>

<script setup>
import { computed, nextTick, onBeforeUnmount, onMounted, ref } from 'vue'
import { RouterLink } from 'vue-router'

import { useModalStore } from '../../stores/modal.js'
import { usePostsStore } from '../../stores/posts.js'
import { toPlainText } from '../../utils/htmlSanitize.js'
import PostEmptyThumbs from './PostEmptyThumbs.vue'
import PostSeriesMenu from './PostSeriesMenu.vue'

const props = defineProps({
  post: { type: Object, required: true },
})

const postsStore = usePostsStore()
const modal = useModalStore()

// Full detail (uncapped thumbnails + full description), fetched lazily — only
// when opening the modal for a post with >6 images, or expanding a
// server-truncated description.
const detail = ref(null)

const attachments = computed(() => props.post.attachments || [])
const images = computed(() => props.post.thumbnails || [])
const totalImages = computed(() => images.value.length + (props.post.thumbnails_more || 0))
const plainTitle = computed(() => toPlainText(props.post.post_title))

const hero = computed(() => images.value[0])
// The thumbnail strip spans the hero's full width (CSS grid, equal columns),
// rather than a fixed 3-cell cap. Show up to RAIL_MAX cells; when there are
// more images than fit, the last cell becomes a "+N" overflow tile so the
// count stays accurate.
const RAIL_MAX = 5
const serverMore = computed(() => props.post.thumbnails_more || 0)
const afterHero = computed(() => images.value.slice(1))
const hasOverflow = computed(
  () => serverMore.value > 0 || afterHero.value.length > RAIL_MAX,
)
const rail = computed(() =>
  hasOverflow.value
    ? afterHero.value.slice(0, RAIL_MAX - 1)
    : afterHero.value.slice(0, RAIL_MAX),
)
const visibleCount = computed(() => (images.value.length ? 1 + rail.value.length : 0))
const moreCount = computed(() => {
  if (!hasOverflow.value) return 0
  return serverMore.value + Math.max(0, images.value.length - visibleCount.value)
})
// Columns = thumbnails shown plus the overflow tile, so the strip fills the
// hero's full width with equal cells.
const railCols = computed(() => rail.value.length + (moreCount.value > 0 ? 1 : 0))

const sortDateIso = computed(() => props.post.post_date || props.post.downloaded_at)
const absoluteDate = computed(() => new Date(sortDateIso.value).toLocaleString())
const relativeDate = computed(() => {
  const then = new Date(sortDateIso.value).getTime()
  const diff = (Date.now() - then) / 1000
  if (diff < 60) return `${Math.floor(diff)}s ago`
  if (diff < 3600) return `${Math.floor(diff / 60)}m ago`
  if (diff < 86400) return `${Math.floor(diff / 3600)}h ago`
  if (diff < 86400 * 30) return `${Math.floor(diff / 86400)}d ago`
  return new Date(sortDateIso.value).toLocaleDateString()
})

// --- images → post-scoped modal ---------------------------------------
async function fullImageIds () {
  // Feed caps thumbnails at 6; load detail for the complete id list only when
  // there are more, so the modal can arrow through ALL of the post's images.
  if ((props.post.thumbnails_more || 0) === 0) {
    return images.value.map((t) => t.image_id)
  }
  if (!detail.value) {
    try {
      detail.value = await postsStore.getPostFull(props.post.id)
    } catch { /* fall back to the capped feed list */ }
  }
  return (detail.value?.thumbnails || images.value).map((t) => t.image_id)
}

async function openModal (imageId) {
  modal.open(imageId, { postImageIds: await fullImageIds() })
}

async function openModalAtMore () {
  const ids = await fullImageIds()
  const first = ids[visibleCount.value] ?? ids[0]
  if (first != null) modal.open(first, { postImageIds: ids })
}

// --- description "Show more" (text-only, in place, only when truncated) ----
const descExpanded = ref(false)
const cssOverflow = ref(false)
const descEl = ref(null)

const hasDescription = computed(() => !!props.post.description_plain)
const fullDescription = computed(() => detail.value?.description_full || null)
const descText = computed(() =>
  descExpanded.value
    ? (fullDescription.value || props.post.description_plain)
    : props.post.description_plain,
)
// Show the toggle iff the server truncated the text OR the clamp is cutting it.
const canExpand = computed(
  () => props.post.description_truncated === true || cssOverflow.value,
)

function measureOverflow () {
  const el = descEl.value
  cssOverflow.value = !!el && el.scrollHeight > el.clientHeight + 1
}

let ro = null
onMounted(() => {
  nextTick(measureOverflow)
  // Re-measure when the card resizes (the container-query clamp differs by
  // width). Guarded for happy-dom / older runtimes without ResizeObserver.
  if (typeof ResizeObserver !== 'undefined' && descEl.value) {
    ro = new ResizeObserver(() => { if (!descExpanded.value) measureOverflow() })
    ro.observe(descEl.value)
  }
})
onBeforeUnmount(() => { if (ro) { ro.disconnect(); ro = null } })

async function toggleDesc () {
  if (!descExpanded.value) {
    if (props.post.description_truncated && !fullDescription.value && !detail.value) {
      try {
        detail.value = await postsStore.getPostFull(props.post.id)
      } catch { /* render the truncated text rather than nothing */ }
    }
    descExpanded.value = true
  } else {
    descExpanded.value = false
    nextTick(measureOverflow)
  }
}

function formatBytes (n) {
  if (!n) return '0 B'
  if (n < 1024) return `${n} B`
  if (n < 1024 * 1024) return `${(n / 1024).toFixed(1)} KB`
  if (n < 1024 * 1024 * 1024) return `${(n / 1024 / 1024).toFixed(1)} MB`
  return `${(n / 1024 / 1024 / 1024).toFixed(1)} GB`
}
</script>

<style scoped>
.fc-post-card {
  padding: 1rem;
  margin-bottom: 1rem;
  container-type: inline-size;
}

.fc-post-card__head {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 0.8rem;
  color: rgb(var(--v-theme-on-surface-variant));
  margin-bottom: 12px;
  flex-wrap: wrap;
}
.fc-post-card__artist {
  color: rgb(var(--v-theme-on-surface));
  text-decoration: none;
  font-weight: 600;
}
.fc-post-card__artist:hover { color: rgb(var(--v-theme-accent)); }
.fc-post-card__date,
.fc-post-card__meta { white-space: nowrap; }

.fc-post-card__body {
  display: flex;
  flex-direction: column;
  gap: 16px;
}
@container (min-width: 800px) {
  .fc-post-card__body {
    flex-direction: row;
    gap: 24px;
  }
  .fc-post-card__media { flex: 0 0 50%; }
  .fc-post-card__text  { flex: 1 1 0; min-width: 0; }
}

/* Image tiles are buttons (open the post-scoped modal) — reset button chrome. */
.fc-post-card__hero,
.fc-post-card__rail-cell,
.fc-post-card__rail-more {
  display: block; padding: 0; border: 0; background: none;
  cursor: pointer;
}
.fc-post-card__hero {
  width: 100%;
  aspect-ratio: 16 / 10;
  overflow: hidden;
  border-radius: 6px;
}
.fc-post-card__hero img {
  width: 100%; height: 100%;
  object-fit: cover; display: block;
  transition: transform 0.2s ease, filter 0.2s ease;
}
.fc-post-card__hero:hover img,
.fc-post-card__rail-cell:hover img { transform: scale(1.03); filter: brightness(1.08); }

/* Equal columns spanning the hero's full width — cells stretch horizontally
   (1fr) at a fixed height, so the strip always reaches the edge of the hero
   regardless of how many thumbnails the post has. */
.fc-post-card__rail {
  display: grid;
  grid-template-columns: repeat(var(--fc-rail-cols, 3), 1fr);
  gap: 6px; margin-top: 6px;
}
.fc-post-card__rail-cell {
  width: 100%; height: 84px;
  overflow: hidden; border-radius: 4px;
}
.fc-post-card__rail-cell img {
  width: 100%; height: 100%;
  object-fit: cover; display: block;
}
.fc-post-card__rail-more {
  width: 100%; height: 84px;
  display: flex; align-items: center; justify-content: center;
  border: 1px dashed rgb(var(--v-theme-on-surface-variant));
  border-radius: 4px;
  color: rgb(var(--v-theme-on-surface-variant));
  font-size: 0.85rem;
}
.fc-post-card__rail-more:hover {
  border-color: rgb(var(--v-theme-accent));
  color: rgb(var(--v-theme-accent));
}

.fc-post-card__title {
  font-family: 'Fraunces', Georgia, serif;
  font-size: 18px; font-weight: 700;
  margin: 0 0 8px 0;
  color: rgb(var(--v-theme-on-surface));
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.fc-post-card__title--missing {
  font-style: italic;
  color: rgb(var(--v-theme-on-surface-variant));
}
@container (min-width: 800px) {
  .fc-post-card__title {
    font-size: 20px;
    -webkit-line-clamp: 1;
    white-space: nowrap;
    text-overflow: ellipsis;
  }
}

.fc-post-card__desc {
  font-size: 0.9rem;
  line-height: 1.5;
  color: rgb(var(--v-theme-on-surface));
  margin: 0;
  white-space: pre-wrap;
}
/* Clamp ONLY while collapsed; expanding drops the clamp to show it all. */
.fc-post-card__desc--clamped {
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
@container (min-width: 800px) {
  .fc-post-card__desc--clamped { -webkit-line-clamp: 5; }
}
.fc-post-card__desc--missing {
  font-style: italic;
  color: rgb(var(--v-theme-on-surface-variant));
}

.fc-post-card__more {
  margin-top: 6px;
  padding: 0;
  background: none; border: 0; cursor: pointer;
  color: rgb(var(--v-theme-accent));
  font-size: 0.85rem; font-weight: 600;
}
.fc-post-card__more:hover { text-decoration: underline; }

.fc-post-card__atts {
  display: flex; flex-wrap: wrap; gap: 8px;
  margin-top: 12px;
}
.fc-post-card__att {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border: 1px solid rgb(var(--v-theme-on-surface-variant));
  border-radius: 999px;
  color: rgb(var(--v-theme-on-surface));
  text-decoration: none;
  font-size: 0.85rem;
}
.fc-post-card__att:hover {
  color: rgb(var(--v-theme-accent));
  border-color: rgb(var(--v-theme-accent));
}
.fc-post-card__att-icon { color: rgb(var(--v-theme-on-surface-variant)); }
.fc-post-card__att-size { color: rgb(var(--v-theme-on-surface-variant)); }
</style>
