feat(details): synopsis and cast on long press

app/smartphone/src/main/java/com/m3u/smartphone/ui/material/components/ChannelDetailsSection.kt

@@ -0,0 +1,136 @@
+package com.m3u.smartphone.ui.material.components
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.rounded.Star
+import androidx.compose.material3.HorizontalDivider
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import com.m3u.data.database.model.Channel
+import com.m3u.data.database.model.ChannelDetails
+import com.m3u.i18n.R.string
+import com.m3u.smartphone.ui.material.model.LocalSpacing
+
+/**
+ * Synopsis, cast and rating for the channel a sheet was opened on.
+ *
+ * Shows nothing at all — not an error, not a placeholder — when the panel has
+ * no description to give. Live channels never have one, and a sheet opened to
+ * hide or favourite a channel should not be pushed around by an empty block.
+ */
+@Composable
+fun ChannelDetailsSection(
+    channel: Channel?,
+    modifier: Modifier = Modifier,
+) {
+    val viewModel: ChannelDetailsViewModel = hiltViewModel()
+    LaunchedEffect(channel?.id) { viewModel.load(channel) }
+    val state by viewModel.state.collectAsStateWithLifecycle()
+    val spacing = LocalSpacing.current
+
+    when (val current = state) {
+        ChannelDetailsState.Absent -> Unit
+
+        ChannelDetailsState.Loading -> {
+            if (channel == null) return
+            Text(
+                text = stringResource(string.ui_details_loading),
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = modifier.padding(horizontal = spacing.medium),
+            )
+        }
+
+        is ChannelDetailsState.Content -> Column(
+            verticalArrangement = Arrangement.spacedBy(spacing.extraSmall),
+            modifier = modifier
+                .fillMaxWidth()
+                .padding(horizontal = spacing.medium),
+        ) {
+            current.details.Headline()
+            current.details.cast?.let { cast ->
+                LabelledText(label = stringResource(string.ui_details_cast), value = cast)
+            }
+            current.details.director?.let { director ->
+                LabelledText(label = stringResource(string.ui_details_director), value = director)
+            }
+            current.details.plot?.let { plot ->
+                Text(
+                    text = plot,
+                    style = MaterialTheme.typography.bodyMedium,
+                    // Long enough to be worth reading, short enough to leave
+                    // the actions below reachable without scrolling.
+                    maxLines = 6,
+                    overflow = TextOverflow.Ellipsis,
+                    modifier = Modifier.padding(top = spacing.extraSmall),
+                )
+            }
+            HorizontalDivider(modifier = Modifier.padding(top = spacing.small))
+        }
+    }
+}
+
+/** Year, genre and rating on one line — the things read at a glance. */
+@Composable
+private fun ChannelDetails.Headline() {
+    val spacing = LocalSpacing.current
+    val year = releaseDate?.take(4)?.takeIf { it.length == 4 && it.all(Char::isDigit) }
+    val summary = listOfNotNull(year, genre).joinToString(" · ")
+    if (summary.isBlank() && rating == null) return
+    Row(
+        horizontalArrangement = Arrangement.spacedBy(spacing.small),
+        verticalAlignment = Alignment.CenterVertically,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        if (summary.isNotBlank()) {
+            Text(
+                text = summary,
+                style = MaterialTheme.typography.labelLarge,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+                modifier = Modifier.weight(1f, fill = false),
+            )
+        }
+        rating?.let { rating ->
+            Icon(
+                imageVector = Icons.Rounded.Star,
+                contentDescription = null,
+                tint = MaterialTheme.colorScheme.primary,
+                modifier = Modifier.size(16.dp),
+            )
+            Text(
+                text = rating,
+                style = MaterialTheme.typography.labelLarge,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        }
+    }
+}
+
+@Composable
+private fun LabelledText(label: String, value: String) {
+    Text(
+        text = "$label: $value",
+        style = MaterialTheme.typography.bodySmall,
+        color = MaterialTheme.colorScheme.onSurfaceVariant,
+        maxLines = 2,
+        overflow = TextOverflow.Ellipsis,
+    )
+}

app/smartphone/src/main/java/com/m3u/smartphone/ui/material/components/ChannelDetailsViewModel.kt

@@ -0,0 +1,79 @@
+package com.m3u.smartphone.ui.material.components
+
+import androidx.compose.runtime.Immutable
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.m3u.data.database.model.Channel
+import com.m3u.data.database.model.ChannelDetails
+import com.m3u.data.repository.channel.ChannelDetailsRepository
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flowOf
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import javax.inject.Inject
+
+@Immutable
+sealed interface ChannelDetailsState {
+    /** Nothing to show and nothing on its way — live channels, mostly. */
+    data object Absent : ChannelDetailsState
+
+    data object Loading : ChannelDetailsState
+
+    data class Content(val details: ChannelDetails) : ChannelDetailsState
+}
+
+/**
+ * Holds the description shown when a channel sheet opens.
+ *
+ * Cached values appear immediately; anything missing is fetched once, in the
+ * background, and lands through the database rather than being pushed here —
+ * so a sheet closed mid-request still keeps what it paid for.
+ */
+@HiltViewModel
+@OptIn(ExperimentalCoroutinesApi::class)
+class ChannelDetailsViewModel @Inject constructor(
+    private val repository: ChannelDetailsRepository,
+) : ViewModel() {
+    private val channel = MutableStateFlow<Channel?>(null)
+    private var fetching: Job? = null
+
+    val state: StateFlow<ChannelDetailsState> = channel
+        .flatMapLatest { current ->
+            if (current == null) flowOf(null) else repository.observe(current)
+        }
+        .map { details ->
+            when {
+                details == null -> ChannelDetailsState.Loading
+                details.isEmpty -> ChannelDetailsState.Absent
+                else -> ChannelDetailsState.Content(details)
+            }
+        }
+        .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), ChannelDetailsState.Loading)
+
+    fun load(channel: Channel?) {
+        if (this.channel.value?.id == channel?.id) return
+        this.channel.value = channel
+        fetching?.cancel()
+        channel ?: return
+        fetching = viewModelScope.launch { repository.fetchIfMissing(channel) }
+    }
+}
+
+/**
+ * A row the panel answered for but had nothing to say about. Kept in the
+ * database so it is not asked again, shown as nothing at all.
+ */
+private val ChannelDetails.isEmpty: Boolean
+    get() = plot.isNullOrBlank() &&
+        cast.isNullOrBlank() &&
+        director.isNullOrBlank() &&
+        genre.isNullOrBlank() &&
+        rating.isNullOrBlank() &&
+        releaseDate.isNullOrBlank()

app/smartphone/src/main/java/com/m3u/smartphone/ui/material/components/MediaSheet.kt

@@ -94,6 +94,15 @@ fun MediaSheet(
                 verticalArrangement = Arrangement.spacedBy(spacing.small),
                 modifier = Modifier.padding(spacing.medium)
             ) {
+                // Above the actions, so the description is what a long press
+                // shows first. Renders nothing when the channel has none.
+                ChannelDetailsSection(
+                    channel = when (value) {
+                        is MediaSheetValue.PlaylistScreen -> value.channel
+                        is MediaSheetValue.FavoriteScreen -> value.channel
+                        is MediaSheetValue.ForyouScreen -> null
+                    }
+                )
                 when (value) {
                     is MediaSheetValue.ForyouScreen -> {
                         value.playlist?.let { playlist ->

data/.gitignore

@@ -1,2 +1 @@
 /build
-/src/test

data/build.gradle.kts

@@ -169,6 +169,7 @@ dependencies {
 
     implementation(libs.jakewharton.disklrucache)
 
+    testImplementation(kotlin("test-junit"))
     androidTestImplementation(libs.androidx.room.testing)
     androidTestImplementation(libs.androidx.test.ext.junit)
     androidTestImplementation(libs.androidx.test.core)