feat: Show posts that mention a trending link (#1153)

Mastodon 4.3 introduced a new API to fetch a timeline of posts that
mention a trending link.

Use that to display a "See <n> posts about ths link" message in a
trending link's preview card (if supported by the server).

Define a new timeline type with associated API call to fetch the
timeline.

Add an accessibilty action to support this.

While I'm here also support author's in preview cards that don't have a
related Fediverse account; show their name in this case.

Fixes #1123

app/src/main/java/app/pachli/TabViewData.kt

@@ -161,6 +161,7 @@ data class TabViewData(
                 icon = R.drawable.ic_favourite_filled_24dp,
                 fragment = { TimelineFragment.newInstance(pachliAccountId, timeline) },
             )
+            is Timeline.Link -> throw IllegalArgumentException("can't add to tab: $timeline")
             is Timeline.User.Pinned -> throw IllegalArgumentException("can't add to tab: $timeline")
             is Timeline.User.Posts -> throw IllegalArgumentException("can't add to tab: $timeline")
             is Timeline.User.Replies -> throw IllegalArgumentException("can't add to tab: $timeline")

app/src/main/java/app/pachli/adapter/StatusBaseViewHolder.kt

@@ -895,7 +895,7 @@ abstract class StatusBaseViewHolder<T : IStatusViewData> protected constructor(
             (!viewData.isCollapsible || !viewData.isCollapsed)
         ) {
             cardView.visibility = View.VISIBLE
-            cardView.bind(card, viewData.actionable.sensitive, statusDisplayOptions) { card, target ->
+            cardView.bind(card, viewData.actionable.sensitive, statusDisplayOptions, false) { card, target ->
                 if (target == PreviewCardView.Target.BYLINE) {
                     card.authors?.firstOrNull()?.account?.id?.let {
                         context.startActivity(AccountActivityIntent(context, pachliAccountId, it))

app/src/main/java/app/pachli/components/timeline/TimelineFragment.kt

@@ -772,6 +772,7 @@ class TimelineFragment :
             Timeline.Notifications,
             Timeline.TrendingHashtags,
             Timeline.TrendingLinks,
+            is Timeline.Link,
             -> return
         }
     }

app/src/main/java/app/pachli/components/timeline/viewmodel/NetworkTimelineRemoteMediator.kt

@@ -121,6 +121,7 @@ class NetworkTimelineRemoteMediator(
             Timeline.PublicFederated -> api.publicTimeline(local = false, maxId = maxId, minId = minId, limit = loadSize)
             Timeline.PublicLocal -> api.publicTimeline(local = true, maxId = maxId, minId = minId, limit = loadSize)
             Timeline.TrendingStatuses -> api.trendingStatuses(limit = LIMIT_TRENDING_STATUSES)
+            is Timeline.Link -> api.linkTimeline(url = timeline.url, maxId = maxId, minId = minId, limit = loadSize)
             is Timeline.Hashtags -> {
                 val firstHashtag = timeline.tags.first()
                 val additionalHashtags = timeline.tags.subList(1, timeline.tags.size)

app/src/main/java/app/pachli/components/trending/TrendingLinkViewHolder.kt

@@ -29,9 +29,15 @@ class TrendingLinkViewHolder(
 ) : RecyclerView.ViewHolder(binding.root) {
     internal lateinit var link: TrendsLink
 
-    fun bind(link: TrendsLink, statusDisplayOptions: StatusDisplayOptions) {
+    /**
+     * @param link
+     * @param statusDisplayOptions
+     * @param showTimelineLink True if the UI to view a timeline of statuses about this link
+     * should be shown.
+     */
+    fun bind(link: TrendsLink, statusDisplayOptions: StatusDisplayOptions, showTimelineLink: Boolean) {
         this.link = link
 
-        binding.statusCardView.bind(link, sensitive = false, statusDisplayOptions, onClick)
+        binding.statusCardView.bind(link, sensitive = false, statusDisplayOptions, showTimelineLink, onClick)
     }
 }

app/src/main/java/app/pachli/components/trending/TrendingLinksAccessibilityDelegate.kt

@@ -36,6 +36,9 @@ import dagger.hilt.android.EntryPointAccessors
  * Each item shows an action to open the link.
  *
  * If present, an item to show the author's account is also included.
+ *
+ * If supported, an item to show a timeline of statuses that mention this link
+ * is included.
  */
 internal class TrendingLinksAccessibilityDelegate(
     private val recyclerView: RecyclerView,
@@ -59,6 +62,11 @@ internal class TrendingLinksAccessibilityDelegate(
         context.getString(R.string.action_open_byline_account),
     )
 
+    private val openTimelineLinkAction = AccessibilityActionCompat(
+        app.pachli.core.ui.R.id.action_timeline_link,
+        context.getString(R.string.action_timeline_link),
+    )
+
     private val delegate = object : ItemDelegate(this) {
         override fun onInitializeAccessibilityNodeInfo(host: View, info: AccessibilityNodeInfoCompat) {
             super.onInitializeAccessibilityNodeInfo(host, info)
@@ -72,6 +80,10 @@ internal class TrendingLinksAccessibilityDelegate(
             viewHolder.link.authors?.firstOrNull()?.account?.let {
                 info.addAction(openBylineAccountAction)
             }
+
+            if ((recyclerView.adapter as? TrendingLinksAdapter)?.showTimelineLink == true) {
+                info.addAction(openTimelineLinkAction)
+            }
         }
 
         override fun performAccessibilityAction(host: View, action: Int, args: Bundle?): Boolean {
@@ -93,6 +105,11 @@ internal class TrendingLinksAccessibilityDelegate(
                     listener.onClick(viewHolder.link, Target.BYLINE)
                     true
                 }
+                app.pachli.core.ui.R.id.action_timeline_link -> {
+                    interrupt()
+                    listener.onClick(viewHolder.link, Target.TIMELINE_LINK)
+                    true
+                }
                 else -> super.performAccessibilityAction(host, action, args)
             }
         }

app/src/main/java/app/pachli/components/trending/TrendingLinksAdapter.kt

@@ -27,8 +27,15 @@ import app.pachli.core.network.model.TrendsLink
 import app.pachli.databinding.ItemTrendingLinkBinding
 import app.pachli.view.PreviewCardView
 
+/**
+ * @param statusDisplayOptions
+ * @param showTimelineLink If true, show a link to a timeline with statuses that
+ * mention this link.
+ * @param onViewLink
+ */
 class TrendingLinksAdapter(
     statusDisplayOptions: StatusDisplayOptions,
+    showTimelineLink: Boolean,
     private val onViewLink: PreviewCardView.OnClickListener,
 ) : ListAdapter<TrendsLink, TrendingLinkViewHolder>(diffCallback) {
     var statusDisplayOptions = statusDisplayOptions
@@ -37,6 +44,14 @@ class TrendingLinksAdapter(
             notifyItemRangeChanged(0, itemCount)
         }
 
+    var showTimelineLink = showTimelineLink
+        set(value) {
+            if (field != value) {
+                field = value
+                notifyItemRangeChanged(0, itemCount)
+            }
+        }
+
     init {
         stateRestorationPolicy = StateRestorationPolicy.PREVENT_WHEN_EMPTY
     }
@@ -49,7 +64,7 @@ class TrendingLinksAdapter(
     }
 
     override fun onBindViewHolder(holder: TrendingLinkViewHolder, position: Int) {
-        holder.bind(getItem(position), statusDisplayOptions)
+        holder.bind(getItem(position), statusDisplayOptions, showTimelineLink)
     }
 
     override fun getItemViewType(position: Int): Int {

app/src/main/java/app/pachli/components/trending/TrendingLinksFragment.kt

@@ -45,7 +45,9 @@ import app.pachli.core.common.extensions.hide
 import app.pachli.core.common.extensions.show
 import app.pachli.core.common.extensions.viewBinding
 import app.pachli.core.designsystem.R as DR
+import app.pachli.core.model.ServerOperation
 import app.pachli.core.navigation.AccountActivityIntent
+import app.pachli.core.navigation.TimelineActivityIntent
 import app.pachli.core.network.model.PreviewCard
 import app.pachli.core.ui.ActionButtonScrollListener
 import app.pachli.core.ui.BackgroundMessage
@@ -60,8 +62,11 @@ import com.mikepenz.iconics.typeface.library.googlematerial.GoogleMaterial
 import com.mikepenz.iconics.utils.colorInt
 import com.mikepenz.iconics.utils.sizeDp
 import dagger.hilt.android.AndroidEntryPoint
+import dagger.hilt.android.lifecycle.withCreationCallback
+import io.github.z4kn4fein.semver.constraints.toConstraint
 import kotlin.properties.Delegates
 import kotlinx.coroutines.flow.collectLatest
+import kotlinx.coroutines.flow.distinctUntilChangedBy
 import kotlinx.coroutines.launch
 import retrofit2.HttpException
 import timber.log.Timber
@@ -74,7 +79,13 @@ class TrendingLinksFragment :
     RefreshableFragment,
     MenuProvider {
 
-    private val viewModel: TrendingLinksViewModel by viewModels()
+    private val viewModel: TrendingLinksViewModel by viewModels(
+        extrasProducer = {
+            defaultViewModelCreationExtras.withCreationCallback<TrendingLinksViewModel.Factory> { factory ->
+                factory.create(requireArguments().getLong(ARG_PACHLI_ACCOUNT_ID))
+            }
+        },
+    )
 
     private val binding by viewBinding(FragmentTrendingLinksBinding::bind)
 
@@ -99,11 +110,6 @@ class TrendingLinksFragment :
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         requireActivity().addMenuProvider(this, viewLifecycleOwner, Lifecycle.State.RESUMED)
 
-        trendingLinksAdapter = TrendingLinksAdapter(viewModel.statusDisplayOptions.value, ::onOpenLink)
-
-        setupSwipeRefreshLayout()
-        setupRecyclerView()
-
         (activity as? ActionButtonActivity)?.actionButton?.let { actionButton ->
             actionButton.show()
 
@@ -119,68 +125,91 @@ class TrendingLinksFragment :
             }
         }
 
+        trendingLinksAdapter = TrendingLinksAdapter(
+            viewModel.statusDisplayOptions.value,
+            false,
+            ::onOpenLink,
+        )
+
+        setupSwipeRefreshLayout()
+        setupRecyclerView()
+
         viewLifecycleOwner.lifecycleScope.launch {
-            viewModel.loadState.collectLatest {
+            viewLifecycleOwner.repeatOnLifecycle(Lifecycle.State.STARTED) {
-                when (it) {
+                launch {
-                    LoadState.Initial -> {
+                    viewModel.pachliAccountFlow.distinctUntilChangedBy { it.server }.collect { account ->
-                        viewModel.accept(InfallibleUiAction.Reload)
+                        trendingLinksAdapter.showTimelineLink = account.server.can(
+                            ServerOperation.ORG_JOINMASTODON_TIMELINES_LINK,
+                            ">=1.0.0".toConstraint(),
+                        )
                     }
+                }
 
-                    LoadState.Loading -> {
+                launch {
-                        if (!binding.swipeRefreshLayout.isRefreshing) {
+                    viewModel.loadState.collect {
-                            binding.progressBar.show()
+                        when (it) {
-                        } else {
+                            LoadState.Loading -> bindLoading()
-                            binding.progressBar.hide()
+                            is LoadState.Success -> bindSuccess(it)
+                            is LoadState.Error -> bindError(it)
                         }
                     }
-
+                }
-                    is LoadState.Success -> {
+                launch {
-                        trendingLinksAdapter.submitList(it.data)
+                    viewModel.statusDisplayOptions.collectLatest {
-                        binding.progressBar.hide()
+                        trendingLinksAdapter.statusDisplayOptions = it
-                        binding.swipeRefreshLayout.isRefreshing = false
-                        if (it.data.isEmpty()) {
-                            binding.messageView.setup(BackgroundMessage.Empty())
-                            binding.messageView.show()
-                        } else {
-                            binding.messageView.hide()
-                            binding.recyclerView.show()
-                        }
-                    }
-
-                    is LoadState.Error -> {
-                        binding.progressBar.hide()
-                        binding.swipeRefreshLayout.isRefreshing = false
-                        binding.recyclerView.hide()
-                        if (trendingLinksAdapter.itemCount != 0) {
-                            val snackbar = Snackbar.make(
-                                binding.root,
-                                it.throwable.message ?: "Error",
-                                Snackbar.LENGTH_INDEFINITE,
-                            )
-
-                            if (it.throwable !is HttpException || it.throwable.code() != 404) {
-                                snackbar.setAction("Retry") { viewModel.accept(InfallibleUiAction.Reload) }
-                            }
-                            snackbar.show()
-                        } else {
-                            if (it.throwable !is HttpException || it.throwable.code() != 404) {
-                                binding.messageView.setup(it.throwable) {
-                                    viewModel.accept(InfallibleUiAction.Reload)
-                                }
-                            } else {
-                                binding.messageView.setup(it.throwable)
-                            }
-                            binding.messageView.show()
-                        }
                     }
                 }
             }
         }
 
-        viewLifecycleOwner.lifecycleScope.launch {
+        viewModel.accept(InfallibleUiAction.Reload)
-            viewModel.statusDisplayOptions.collectLatest {
+    }
-                trendingLinksAdapter.statusDisplayOptions = it
+
+    private fun bindLoading() {
+        if (!binding.swipeRefreshLayout.isRefreshing) {
+            binding.progressBar.show()
+        } else {
+            binding.progressBar.hide()
+        }
+    }
+
+    private fun bindSuccess(loadState: LoadState.Success) {
+        trendingLinksAdapter.submitList(loadState.data)
+        binding.progressBar.hide()
+        binding.swipeRefreshLayout.isRefreshing = false
+        if (loadState.data.isEmpty()) {
+            binding.messageView.setup(BackgroundMessage.Empty())
+            binding.messageView.show()
+        } else {
+            binding.messageView.hide()
+            binding.recyclerView.show()
+        }
+    }
+
+    private fun bindError(loadState: LoadState.Error) {
+        binding.progressBar.hide()
+        binding.swipeRefreshLayout.isRefreshing = false
+        binding.recyclerView.hide()
+        if (trendingLinksAdapter.itemCount != 0) {
+            val snackbar = Snackbar.make(
+                binding.root,
+                loadState.throwable.message ?: "Error",
+                Snackbar.LENGTH_INDEFINITE,
+            )
+
+            if (loadState.throwable !is HttpException || loadState.throwable.code() != 404) {
+                snackbar.setAction("Retry") { viewModel.accept(InfallibleUiAction.Reload) }
             }
+            snackbar.show()
+        } else {
+            if (loadState.throwable !is HttpException || loadState.throwable.code() != 404) {
+                binding.messageView.setup(loadState.throwable) {
+                    viewModel.accept(InfallibleUiAction.Reload)
+                }
+            } else {
+                binding.messageView.setup(loadState.throwable)
+            }
+            binding.messageView.show()
         }
     }
 
@@ -238,14 +267,22 @@ class TrendingLinksFragment :
     }
 
     private fun onOpenLink(card: PreviewCard, target: Target) {
-        if (target == Target.BYLINE) {
+        when (target) {
-            card.authors?.firstOrNull()?.account?.id?.let {
+            Target.CARD -> requireContext().openLink(card.url)
+            Target.IMAGE -> requireContext().openLink(card.url)
+            Target.BYLINE -> card.authors?.firstOrNull()?.account?.id?.let {
                 startActivity(AccountActivityIntent(requireContext(), pachliAccountId, it))
             }
-            return
-        }
 
-        requireContext().openLink(card.url)
+            Target.TIMELINE_LINK -> {
+                val intent = TimelineActivityIntent.link(
+                    requireContext(),
+                    pachliAccountId,
+                    card.url,
+                )
+                startActivity(intent)
+            }
+        }
     }
 
     override fun onResume() {

app/src/main/java/app/pachli/components/trending/viewmodel/TrendingLinksViewModel.kt

@@ -19,7 +19,9 @@ package app.pachli.components.trending.viewmodel
 
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import app.pachli.components.account.AccountViewModel
 import app.pachli.components.trending.TrendingLinksRepository
+import app.pachli.core.common.extensions.stateFlow
 import app.pachli.core.common.extensions.throttleFirst
 import app.pachli.core.data.repository.AccountManager
 import app.pachli.core.data.repository.StatusDisplayOptionsRepository
@@ -27,20 +29,22 @@ import app.pachli.core.network.model.TrendsLink
 import app.pachli.core.preferences.PrefKeys
 import app.pachli.core.preferences.SharedPreferencesRepository
 import at.connyduck.calladapter.networkresult.fold
+import dagger.assisted.Assisted
+import dagger.assisted.AssistedFactory
+import dagger.assisted.AssistedInject
 import dagger.hilt.android.lifecycle.HiltViewModel
-import javax.inject.Inject
 import kotlinx.coroutines.flow.MutableSharedFlow
-import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharingStarted
-import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.flow.filter
 import kotlinx.coroutines.flow.filterIsInstance
+import kotlinx.coroutines.flow.filterNotNull
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.flow.onStart
 import kotlinx.coroutines.flow.shareIn
-import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
 
 sealed interface UiAction
@@ -50,23 +54,38 @@ sealed interface InfallibleUiAction : UiAction {
 }
 
 sealed interface LoadState {
-    data object Initial : LoadState
     data object Loading : LoadState
     data class Success(val data: List<TrendsLink>) : LoadState
     data class Error(val throwable: Throwable) : LoadState
 }
 
-@HiltViewModel
+@HiltViewModel(assistedFactory = TrendingLinksViewModel.Factory::class)
-class TrendingLinksViewModel @Inject constructor(
+class TrendingLinksViewModel @AssistedInject constructor(
+    @Assisted private val pachliAccountId: Long,
     private val repository: TrendingLinksRepository,
     sharedPreferencesRepository: SharedPreferencesRepository,
     statusDisplayOptionsRepository: StatusDisplayOptionsRepository,
     accountManager: AccountManager,
 ) : ViewModel() {
-    val activeAccount = accountManager.activeAccount!!
+    val pachliAccountFlow = accountManager.getPachliAccountFlow(pachliAccountId)
+        .filterNotNull()
+        .shareIn(viewModelScope, SharingStarted.WhileSubscribed(5000), replay = 1)
 
-    private val _loadState = MutableStateFlow<LoadState>(LoadState.Initial)
+    private val reload = MutableSharedFlow<Unit>(replay = 1)
-    val loadState = _loadState.asStateFlow()
+
+    val loadState = stateFlow(viewModelScope, LoadState.Loading) {
+        reload.flatMapLatest {
+            flow {
+                emit(LoadState.Loading)
+                emit(
+                    repository.getTrendingLinks().fold(
+                        { list -> LoadState.Success(list) },
+                        { throwable -> LoadState.Error(throwable) },
+                    ),
+                )
+            }
+        }.flowWhileShared(SharingStarted.WhileSubscribed(5000))
+    }
 
     val showFabWhileScrolling = sharedPreferencesRepository.changes
         .filter { it == null || it == PrefKeys.FAB_HIDE }
@@ -85,17 +104,14 @@ class TrendingLinksViewModel @Inject constructor(
             uiAction
                 .throttleFirst()
                 .filterIsInstance<InfallibleUiAction.Reload>()
-                .onEach { invalidate() }
+                .onEach { reload.emit(Unit) }
                 .collect()
         }
     }
 
-    private fun invalidate() = viewModelScope.launch {
+    @AssistedFactory
-        _loadState.update { LoadState.Loading }
+    interface Factory {
-        val response = repository.getTrendingLinks()
+        /** Creates [AccountViewModel] with [pachliAccountId] as the active account. */
-        response.fold(
+        fun create(pachliAccountId: Long): TrendingLinksViewModel
-            { list -> _loadState.update { LoadState.Success(list) } },
-            { throwable -> _loadState.update { LoadState.Error(throwable) } },
-        )
     }
 }

app/src/main/java/app/pachli/view/PreviewCardView.kt

@@ -21,19 +21,21 @@ import android.content.Context
 import android.graphics.drawable.Drawable
 import android.util.AttributeSet
 import android.view.LayoutInflater
-import android.view.View
 import android.view.ViewGroup
 import android.widget.LinearLayout
 import androidx.constraintlayout.widget.ConstraintLayout
+import androidx.core.text.HtmlCompat
 import app.pachli.R
 import app.pachli.core.activity.decodeBlurHash
 import app.pachli.core.activity.emojify
 import app.pachli.core.common.extensions.hide
 import app.pachli.core.common.extensions.show
 import app.pachli.core.common.string.unicodeWrap
+import app.pachli.core.common.util.formatNumber
 import app.pachli.core.data.model.StatusDisplayOptions
 import app.pachli.core.designsystem.R as DR
 import app.pachli.core.network.model.PreviewCard
+import app.pachli.core.network.model.TrendsLink
 import app.pachli.databinding.PreviewCardBinding
 import com.bumptech.glide.Glide
 import com.bumptech.glide.load.MultiTransformation
@@ -66,6 +68,9 @@ class PreviewCardView @JvmOverloads constructor(
 
         /** The author byline */
         BYLINE,
+
+        /** The link timeline */
+        TIMELINE_LINK,
     }
 
     fun interface OnClickListener {
@@ -114,12 +119,15 @@ class PreviewCardView @JvmOverloads constructor(
      * @param card The card to bind
      * @param sensitive True if the status that contained this card was marked sensitive
      * @param statusDisplayOptions
+     * @param showTimelineLink True if the UI to view a timeline of statuses about this link
+     * should be shown.
      * @param listener
      */
     fun bind(
         card: PreviewCard,
         sensitive: Boolean,
         statusDisplayOptions: StatusDisplayOptions,
+        showTimelineLink: Boolean,
         listener: OnClickListener,
     ): Unit = with(binding) {
         cardTitle.text = card.title
@@ -135,9 +143,8 @@ class PreviewCardView @JvmOverloads constructor(
 
         previewCardWrapper.setOnClickListener { listener.onClick(card, Target.CARD) }
         cardImage.setOnClickListener { listener.onClick(card, Target.IMAGE) }
-        byline.referencedIds.forEach { id ->
+        authorInfo.setOnClickListener { listener.onClick(card, Target.BYLINE) }
-            root.findViewById<View>(id).setOnClickListener { listener.onClick(card, Target.BYLINE) }
+        timelineLink.setOnClickListener { listener.onClick(card, Target.TIMELINE_LINK) }
-        }
 
         cardLink.text = card.url
 
@@ -177,14 +184,60 @@ class PreviewCardView @JvmOverloads constructor(
             cardImage.hide()
         }
 
-        card.authors?.firstOrNull()?.account?.let { account ->
+        var showBylineDivider = false
-            val name = account.name.unicodeWrap().emojify(account.emojis, authorInfo, false)
+        bylineDivider.hide()
-            authorInfo.text = authorInfo.context.getString(R.string.preview_card_byline_fmt, name)
 
-            Glide.with(authorInfo.context).load(account.avatar).transform(bylineAvatarTransformation)
+        // Determine how to show the author info (if present)
-                .placeholder(DR.drawable.avatar_default).into(bylineAvatarTarget)
+        val author = card.authors?.firstOrNull()
-            byline.show()
+        when {
-        } ?: byline.hide()
+            // Author has an account, link to that, with their avatar.
+            author?.account != null -> {
+                val name = author.account?.name.unicodeWrap().emojify(author.account?.emojis, authorInfo, false)
+                authorInfo.text = HtmlCompat.fromHtml(
+                    authorInfo.context.getString(R.string.preview_card_byline_fediverse_account_fmt, name),
+                    HtmlCompat.FROM_HTML_MODE_LEGACY,
+                )
+
+                Glide.with(authorInfo.context).load(author.account?.avatar).transform(bylineAvatarTransformation)
+                    .placeholder(DR.drawable.avatar_default).into(bylineAvatarTarget)
+                authorInfo.show()
+                showBylineDivider = true
+            }
+
+            // Author has a name but no account. Show the name, clear the avatar.
+            // It's not enough that the name is present, it can't be empty, because of
+            // https://github.com/mastodon/mastodon/issues/33139).
+            !author?.name.isNullOrBlank() -> {
+                authorInfo.text = HtmlCompat.fromHtml(
+                    authorInfo.context.getString(R.string.preview_card_byline_name_only_fmt, author?.name),
+                    HtmlCompat.FROM_HTML_MODE_LEGACY,
+                )
+                authorInfo.setCompoundDrawablesRelativeWithIntrinsicBounds(null, null, null, null)
+                authorInfo.show()
+                showBylineDivider = true
+            }
+
+            else -> authorInfo.hide()
+        }
+
+        // TrendsLink cards have data about the usage. Show this if the server
+        // can generate the timeline.
+        if (card is TrendsLink && showTimelineLink) {
+            val count = card.history.sumOf { it.uses }
+            timelineLink.text = HtmlCompat.fromHtml(
+                context.getString(
+                    R.string.preview_card_timeline_link_fmt,
+                    formatNumber(count.toLong()),
+                ),
+                HtmlCompat.FROM_HTML_MODE_LEGACY,
+            )
+            timelineLink.show()
+            showBylineDivider = true
+        } else {
+            timelineLink.hide()
+        }
+
+        if (showBylineDivider) bylineDivider.show()
     }
 
     /** Adjusts the layout parameters to place the image above the information views */

app/src/main/res/layout/preview_card.xml

@@ -126,12 +126,25 @@
                 tools:ignore="SelectableText"
                 tools:text="@tools:sample/lorem" />
 
-            <androidx.constraintlayout.widget.Group
+            <TextView
-                android:id="@+id/byline"
+                android:id="@+id/timeline_link"
-                android:layout_width="wrap_content"
+                android:layout_width="0dp"
                 android:layout_height="wrap_content"
-                android:visibility="visible"
+                android:background="?selectableItemBackground"
-                app:constraint_referenced_ids="byline_divider,author_info" />
+                android:drawablePadding="10dp"
+                android:ellipsize="end"
+                android:gravity="start|center"
+                android:lines="1"
+                android:paddingStart="2dp"
+                android:paddingTop="6dp"
+                android:paddingEnd="2dp"
+                android:paddingBottom="2dp"
+                android:textSize="?attr/status_text_medium"
+                app:layout_constraintEnd_toEndOf="parent"
+                app:layout_constraintStart_toStartOf="parent"
+                app:layout_constraintTop_toBottomOf="@id/author_info"
+                tools:ignore="SelectableText"
+                tools:text="@tools:sample/lorem" />
         </androidx.constraintlayout.widget.ConstraintLayout>
     </androidx.constraintlayout.widget.ConstraintLayout>
 </merge>

app/src/main/res/values-es/strings.xml

@@ -638,7 +638,7 @@
     <string name="error_media_uploader_upload_not_found_fmt">no se encontró la subida de medios con ID de %1$s</string>
     <string name="error_prepare_media_unknown_file_size">no se pudo determinar el tamaño del archivo</string>
     <string name="error_prepare_media_unknown_mime_type">se desconoce el tipo de archivo</string>
-    <string name="preview_card_byline_fmt">Ver más de %1$s</string>
+    <string name="preview_card_byline_fediverse_account_fmt">Ver más de %1$s</string>
     <string name="action_open_byline_account">Mostrar el perfil del autor del artículo</string>
     <string name="action_open_link">Abrir enlace</string>
     <string name="compose_warn_language_dialog_title">Comprueba el idioma de la publicación</string>

app/src/main/res/values-fi/strings.xml

@@ -628,7 +628,7 @@
     <string name="error_prepare_media_content_resolver_unsupported_scheme_fmt">sisältöselvittäjä-URI:n kaavaa ei tueta: %1$s</string>
     <string name="error_prepare_media_unknown_mime_type">tuntematon tiedostotyyppi</string>
     <string name="error_pick_media_fmt">Julkaisuun ei voitu liittää tiedostoa: %1$s</string>
-    <string name="preview_card_byline_fmt">Katso lisää täältä: %1$s</string>
+    <string name="preview_card_byline_fediverse_account_fmt">Katso lisää täältä: %1$s</string>
     <string name="action_open_byline_account">Näytä julkaisun tekijän profiili</string>
     <string name="action_open_link">Avaa linkki</string>
     <string name="error_prepare_media_unknown_file_size">tiedoston kokoa ei voitu määrittää</string>
@@ -793,4 +793,4 @@
     <string name="main_viewmodel_error_refresh_account">Tilin päivittäminen epäonnistui, virhe oli:\n\n%1$s\n\nVoit jatkaa, mutta listasi ja suodattimesi saattavat olla eivät ehkä ole ajan tasalla.</string>
     <string name="action_relogin">Kirjaudu uudestaan</string>
     <string name="upload_failed_modify_attachment">Muokkaa liitettä</string>
-</resources>
+</resources>

app/src/main/res/values-ga/strings.xml

@@ -692,7 +692,7 @@
     <string name="pref_title_notification_method">Modh fógartha</string>
     <string name="pref_notification_method_all_pull">Fetched thart ar uair amháin gach 15 nóiméad. Tapáil le haghaidh sonraí.</string>
     <string name="pref_title_notification_battery_optimisation">Leas iomlán a bhaint ceallraí</string>
-    <string name="preview_card_byline_fmt">Féach níos mó ó %1$s</string>
+    <string name="preview_card_byline_fediverse_account_fmt">Féach níos mó ó %1$s</string>
     <string name="action_open_byline_account">Taispeáin próifíl údar an ailt</string>
     <string name="action_open_link">Oscail nasc</string>
     <string name="search_operator_attachment_dialog_title">Teorainn le poist leis na meáin?</string>
@@ -824,4 +824,4 @@
     <string name="filter_action_none">Taispeáin</string>
     <string name="pref_account_notification_filters_label_not_followed">… ní leanann tú</string>
     <string name="account_filter_placeholder_type_follow_fmt">Lean úsáideoir @<b>%1s</b> tú</string>
-</resources>
+</resources>

app/src/main/res/values-gl/strings.xml

@@ -626,7 +626,7 @@
     <string name="error_prepare_media_unknown_mime_type">tipo de ficheiro descoñecido</string>
     <string name="error_prepare_media_unsupported_mime_type_fmt">o servidor non é compatible co tipo de ficheiro: %1$s</string>
     <string name="error_pick_media_fmt">Non se anexou o ficheiro á publicación: %1$s</string>
-    <string name="preview_card_byline_fmt">Le máis de %1$s</string>
+    <string name="preview_card_byline_fediverse_account_fmt">Le máis de %1$s</string>
     <string name="error_load_filter_failed_fmt">Fallou a carga do filtro: %1$s</string>
     <string name="error_save_filter_failed_fmt">Non se gardou o filtro: %1$s</string>
     <string name="search_operator_attachment_dialog_image_label">Imaxes</string>

app/src/main/res/values-nb-rNO/strings.xml

@@ -735,7 +735,7 @@
     <string name="search_operator_attachment_no_media_label">Ingen media</string>
     <string name="error_prepare_media_unknown_mime_type">filtypen er ukjent</string>
     <string name="error_pick_media_fmt">Kunne ikke legge filen ved innlegget: %1$s</string>
-    <string name="preview_card_byline_fmt">Se mer fra %1$s</string>
+    <string name="preview_card_byline_fediverse_account_fmt">Se mer fra %1$s</string>
     <string name="action_open_byline_account">Vis artikkelforfatterens profil</string>
     <string name="action_open_link">Åpne lenk</string>
     <string name="error_load_filter_failed_fmt">Innlasting av filter mislyktes: %1$s</string>
@@ -777,4 +777,4 @@
     </plurals>
     <string name="main_viewmodel_error_refresh_account">Å gjenoppfriske kontoen mislyktes med den følgende feilen:\n\n%1$s\n\nDu kan fortsette, men det kan hende at dine lister og filtere kan være ufullstendige.</string>
     <string name="action_relogin">Logg inn på nytt</string>
-</resources>
+</resources>

app/src/main/res/values/strings.xml

@@ -733,10 +733,14 @@
     <string name="error_prepare_media_unknown_mime_type">file\'s type is not known</string>
 
     <string name="error_pick_media_fmt">Could not attach file to post: %1$s</string>
-    <string name="preview_card_byline_fmt">See more from %1$s</string>
+    <string name="preview_card_byline_fediverse_account_fmt">By &lt;b>%1$s&lt;/b>. See more posts</string>
+    <string name="preview_card_byline_name_only_fmt">By &lt;b>%1$s&lt;/b></string>
     <string name="action_open_byline_account">Show article author\'s profile</string>
     <string name="action_open_link">Open link</string>
 
+    <string name="preview_card_timeline_link_fmt">See &lt;b>%1$s&lt;/b> posts about this link</string>
+    <string name="action_timeline_link">Posts about this link</string>
+
     <string name="error_load_filter_failed_fmt">Loading filter failed: %1$s</string>
     <string name="error_save_filter_failed_fmt">Saving filter failed: %1$s</string>
     <string name="error_delete_filter_failed_fmt">Deleting filter failed: %1$s</string>

core/data/src/main/kotlin/app/pachli/core/data/model/Server.kt

@@ -58,6 +58,7 @@ import app.pachli.core.model.ServerOperation.ORG_JOINMASTODON_SEARCH_QUERY_IS_SE
 import app.pachli.core.model.ServerOperation.ORG_JOINMASTODON_SEARCH_QUERY_LANGUAGE
 import app.pachli.core.model.ServerOperation.ORG_JOINMASTODON_STATUSES_SCHEDULED
 import app.pachli.core.model.ServerOperation.ORG_JOINMASTODON_STATUSES_TRANSLATE
+import app.pachli.core.model.ServerOperation.ORG_JOINMASTODON_TIMELINES_LINK
 import app.pachli.core.network.R
 import app.pachli.core.network.model.InstanceV1
 import app.pachli.core.network.model.InstanceV2
@@ -333,6 +334,11 @@ data class Server(
                             c[ORG_JOINMASTODON_SEARCH_QUERY_FROM] = "1.0.0".toVersion()
                         }
                     }
+
+                    // Link timelines
+                    when {
+                        v >= "4.3.0".toVersion() -> c[ORG_JOINMASTODON_TIMELINES_LINK] = "1.0.0".toVersion()
+                    }
                 }
 
                 GOTOSOCIAL -> {

core/model/src/main/kotlin/app/pachli/core/model/ContentFilters.kt

@@ -137,6 +137,7 @@ enum class FilterContext {
             Timeline.TrendingStatuses,
             Timeline.TrendingHashtags,
             Timeline.TrendingLinks,
+            is Timeline.Link,
             -> PUBLIC
             Timeline.Conversations -> null
         }

core/model/src/main/kotlin/app/pachli/core/model/ServerOperation.kt

@@ -111,4 +111,13 @@ enum class ServerOperation(id: String, versions: List<Version>) {
             Version(major = 1),
         ),
     ),
+
+    /** Fetch statuses that mention a specific URL. */
+    ORG_JOINMASTODON_TIMELINES_LINK(
+        "org.joinmastodon.timelines.link",
+        listOf(
+            // Initial introduction in Mastodon 4.3.0
+            Version(major = 1),
+        ),
+    ),
 }

core/model/src/main/kotlin/app/pachli/core/model/Timeline.kt

@@ -112,6 +112,12 @@ sealed interface Timeline : Parcelable {
     @TypeLabel("trending_statuses")
     data object TrendingStatuses : Timeline
 
+    /** Timeline of statuses that mention [url]. */
+    @Parcelize
+    @TypeLabel("link")
+    @JsonClass(generateAdapter = true)
+    data class Link(val url: String) : Timeline
+
     // TODO: DRAFTS
 
     // TODO: SCHEDULED

core/navigation/src/main/kotlin/app/pachli/core/navigation/Navigation.kt

@@ -585,6 +585,16 @@ class TimelineActivityIntent private constructor(context: Context, pachliAccount
             putExtra(EXTRA_TIMELINE, Timeline.Hashtags(listOf(hashtag)))
         }
 
+        /**
+         * Show statuses that reference a trending link.
+         *
+         * @param context
+         *
+         */
+        fun link(context: Context, pachliAccountId: Long, url: String) = TimelineActivityIntent(context, pachliAccountId).apply {
+            putExtra(EXTRA_TIMELINE, Timeline.Link(url))
+        }
+
         /**
          * Show statuses from a list.
          *

core/network/src/main/kotlin/app/pachli/core/network/model/FilterContext.kt

@@ -73,6 +73,7 @@ enum class FilterContext {
             Timeline.TrendingStatuses,
             Timeline.TrendingHashtags,
             Timeline.TrendingLinks,
+            is Timeline.Link,
             -> PUBLIC
             Timeline.Conversations -> null
         }

core/network/src/main/kotlin/app/pachli/core/network/retrofit/MastodonApi.kt

@@ -152,6 +152,14 @@ interface MastodonApi {
         @Query("limit") limit: Int? = null,
     ): Response<List<Status>>
 
+    @GET("api/v1/timelines/link")
+    suspend fun linkTimeline(
+        @Query("url") url: String,
+        @Query("max_id") maxId: String? = null,
+        @Query("min_id") minId: String? = null,
+        @Query("limit") limit: Int? = null,
+    ): Response<List<Status>>
+
     @GET("api/v1/notifications")
     suspend fun notifications(
         /** Return results older than this ID */

core/ui/src/main/res/values/actions.xml

@@ -46,6 +46,9 @@
     <!-- Open the link in a preview card -->
     <item name="action_open_link" type="id" />
 
+    <!-- Open the timeline of statuses that mention a link. -->
+    <item name="action_timeline_link" type="id" />
+
     <!-- Copy the item -->
     <item name="action_copy_item" type="id" />