Bundle the timeline's shared scroll, drag and callbacks into TimelineActions

app/src/main/java/de/jeanlucmakiola/calendula/ui/week/TimelineActions.kt

@@ -0,0 +1,57 @@
+package de.jeanlucmakiola.calendula.ui.week
+
+import androidx.compose.foundation.ScrollState
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Stable
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberUpdatedState
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.ui.common.TimelineDragController
+import de.jeanlucmakiola.calendula.ui.common.TimelineDrop
+import de.jeanlucmakiola.calendula.ui.common.TimelineResizeDrop
+import kotlinx.datetime.LocalDate
+
+/**
+ * What every timeline page hands down to its day columns: the shared vertical
+ * scroll, the drag controller, and the callbacks. One instance per screen, so
+ * passing it never makes a page recompose.
+ */
+@Stable
+internal class TimelineActions(
+    val scrollState: ScrollState,
+    val dragController: TimelineDragController,
+    val onEventClick: (EventInstance) -> Unit,
+    val onOpenDay: (LocalDate) -> Unit,
+    val onCreateAt: (LocalDate, Int) -> Unit,
+    val onDrop: (TimelineDrop) -> Unit,
+    val onResize: (TimelineResizeDrop) -> Unit,
+)
+
+/** The callbacks are read through their latest values, so the holder outlives them. */
+@Composable
+internal fun rememberTimelineActions(
+    scrollState: ScrollState,
+    dragController: TimelineDragController,
+    onEventClick: (EventInstance) -> Unit,
+    onOpenDay: (LocalDate) -> Unit,
+    onCreateAt: (LocalDate, Int) -> Unit,
+    onDrop: (TimelineDrop) -> Unit,
+    onResize: (TimelineResizeDrop) -> Unit,
+): TimelineActions {
+    val eventClick = rememberUpdatedState(onEventClick)
+    val openDay = rememberUpdatedState(onOpenDay)
+    val createAt = rememberUpdatedState(onCreateAt)
+    val drop = rememberUpdatedState(onDrop)
+    val resize = rememberUpdatedState(onResize)
+    return remember(scrollState, dragController) {
+        TimelineActions(
+            scrollState = scrollState,
+            dragController = dragController,
+            onEventClick = { eventClick.value(it) },
+            onOpenDay = { openDay.value(it) },
+            onCreateAt = { date, minutes -> createAt.value(date, minutes) },
+            onDrop = { drop.value(it) },
+            onResize = { resize.value(it) },
+        )
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/week/WeekScreen.kt

@@ -39,7 +39,6 @@ import androidx.compose.foundation.layout.offset
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
-import androidx.compose.foundation.ScrollState
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.shape.RoundedCornerShape
@@ -516,7 +515,7 @@ private fun PagedTimelineScreen(
                 onRetry = viewModel::goToToday,
                 onEventClick = onEventClick,
                 onOpenDay = onOpenDay,
-                onCreateAt = { d, minutes -> onCreateEvent(d, minutes) },
+                onCreateAt = onCreateEvent,
                 onCreateDraft = onCreateDraft,
                 draftMinutes = draftMinutes,
                 modifier = Modifier
@@ -648,6 +647,16 @@ private fun WeekContent(
         }
     }
 
+    val actions = rememberTimelineActions(
+        scrollState = scrollState,
+        dragController = dragController,
+        onEventClick = openEvent,
+        onOpenDay = onOpenDay,
+        onCreateAt = onCreateAt,
+        onDrop = onDrop,
+        onResize = onResize,
+    )
+
     Box(modifier = modifier) {
         CompositionLocalProvider(LocalOpeningTimeline provides timelineScroll) {
             // Loading and failure concern the provider as a whole, so they stand in
@@ -663,17 +672,7 @@ private fun WeekContent(
                     WeekUiState.Loading -> WeekLoading(dayCount = grid.dayCount)
                     is WeekUiState.Failure -> CalendarFailure(reason = s.reason, onRetry = onRetry)
                     is WeekUiState.Success -> if (morph != null) {
-                        TimelineMorphFrame(
-                            morph = morph,
-                            today = today,
-                            scrollState = scrollState,
-                            dragController = dragController,
-                            onEventClick = openEvent,
-                            onOpenDay = onOpenDay,
-                            onCreateAt = onCreateAt,
-                            onDrop = onDrop,
-                            onResize = onResize,
-                        )
+                        TimelineMorphFrame(morph = morph, today = today, actions = actions)
                     } else WeekPager(
                         pagerState = pagerState,
                         grid = grid,
@@ -681,13 +680,7 @@ private fun WeekContent(
                         span = span,
                         today = today,
                         initialStripHeight = handoffStrip ?: s.allDayStripHeight(),
-                        scrollState = scrollState,
-                        dragController = dragController,
-                        onEventClick = openEvent,
-                        onOpenDay = onOpenDay,
-                        onCreateAt = onCreateAt,
-                        onDrop = onDrop,
-                        onResize = onResize,
+                        actions = actions,
                     )
                 }
             }
@@ -708,22 +701,16 @@ private fun WeekPager(
     span: (DaySpan) -> StateFlow<WeekUiState>,
     today: LocalDate,
     initialStripHeight: Dp,
-    scrollState: ScrollState,
-    dragController: TimelineDragController,
-    onEventClick: (EventInstance) -> Unit,
-    onOpenDay: (LocalDate) -> Unit,
-    onCreateAt: (LocalDate, Int) -> Unit,
-    onDrop: (TimelineDrop) -> Unit,
-    onResize: (TimelineResizeDrop) -> Unit,
+    actions: TimelineActions,
 ) {
+    val dragController = actions.dragController
     val stripHeights = remember { mutableStateMapOf<Int, Dp>() }
     val allDayHeight = pagedHeight(pagerState, stripHeights, initialStripHeight)
     WeekFrame(
         weekStart = grid.startForPage(pagerState.currentPage),
         showWeekNumber = kind.showWeekNumber,
         allDayHeight = allDayHeight,
-        scrollState = scrollState,
-        dragController = dragController,
+        actions = actions,
     ) {
         HorizontalPager(
             state = pagerState,
@@ -756,14 +743,8 @@ private fun WeekPager(
                     },
                     headerBias = kind.headerBias,
                     allDayHeight = allDayHeight,
-                    scrollState = scrollState,
-                    dragController = dragController,
+                    actions = actions,
                     active = page == pagerState.currentPage,
-                    onEventClick = onEventClick,
-                    onOpenDay = onOpenDay,
-                    onCreateAt = onCreateAt,
-                    onDrop = onDrop,
-                    onResize = onResize,
                 )
             }
         }
@@ -792,13 +773,7 @@ private fun emptySpan(span: DaySpan, today: LocalDate): WeekUiState.Success {
 private fun TimelineMorphFrame(
     morph: TimelineMorph,
     today: LocalDate,
-    scrollState: ScrollState,
-    dragController: TimelineDragController,
-    onEventClick: (EventInstance) -> Unit,
-    onOpenDay: (LocalDate) -> Unit,
-    onCreateAt: (LocalDate, Int) -> Unit,
-    onDrop: (TimelineDrop) -> Unit,
-    onResize: (TimelineResizeDrop) -> Unit,
+    actions: TimelineActions,
 ) {
     val fromState by morph.fromState.collectAsStateWithLifecycle()
     val toState by morph.toState.collectAsStateWithLifecycle()
@@ -836,8 +811,7 @@ private fun TimelineMorphFrame(
             allDayHeight = fromStrip,
             animatedAllDayHeight = animatedStrip,
             weekNumberAlpha = badgeAlpha,
-            scrollState = scrollState,
-            dragController = dragController,
+            actions = actions,
         ) {
             TimelinePageContent(
                 geometry = geometry,
@@ -847,14 +821,8 @@ private fun TimelineMorphFrame(
                 headerBias = headerBias,
                 allDayHeight = fromStrip,
                 animatedAllDayHeight = animatedStrip,
-                scrollState = scrollState,
-                dragController = dragController,
+                actions = actions,
                 active = false,
-                onEventClick = onEventClick,
-                onOpenDay = onOpenDay,
-                onCreateAt = onCreateAt,
-                onDrop = onDrop,
-                onResize = onResize,
             )
         }
     }
@@ -888,8 +856,7 @@ private fun WeekFrame(
     allDayHeight: Dp,
     animatedAllDayHeight: (() -> Dp)? = null,
     weekNumberAlpha: () -> Float = { 1f },
-    scrollState: ScrollState,
-    dragController: TimelineDragController,
+    actions: TimelineActions,
     pages: @Composable () -> Unit,
 ) {
     val gutterFullHeight = remember(animatedAllDayHeight) { intArrayOf(-1) }
@@ -923,10 +890,10 @@ private fun WeekFrame(
                     else maxHeight
                 val hourHeight = zoom.scale.hourHeight(fitHeight)
                 HourGutter(
-                    scrollState = scrollState,
+                    scrollState = actions.scrollState,
                     hourHeight = hourHeight,
-                    dragController = dragController,
-                    modifier = rememberTimelinePinchZoom(scrollState, fitHeight, hourHeight, zoom),
+                    dragController = actions.dragController,
+                    modifier = rememberTimelinePinchZoom(actions.scrollState, fitHeight, hourHeight, zoom),
                 )
             }
         }
@@ -941,34 +908,21 @@ internal fun WeekSuccess(
     state: WeekUiState.Success,
     showWeekNumber: Boolean = true,
     headerBias: Float = 0f,
-    scrollState: ScrollState,
     allDayHeight: Dp,
-    dragController: TimelineDragController,
-    onEventClick: (EventInstance) -> Unit,
-    onOpenDay: (LocalDate) -> Unit,
-    onCreateAt: (LocalDate, Int) -> Unit,
-    onDrop: (TimelineDrop) -> Unit,
-    onResize: (TimelineResizeDrop) -> Unit,
+    actions: TimelineActions,
 ) {
     WeekFrame(
         weekStart = state.weekStart,
         showWeekNumber = showWeekNumber,
         allDayHeight = allDayHeight,
-        scrollState = scrollState,
-        dragController = dragController,
+        actions = actions,
     ) {
         WeekPage(
             state = state,
             headerBias = headerBias,
             allDayHeight = allDayHeight,
-            scrollState = scrollState,
-            dragController = dragController,
+            actions = actions,
             active = true,
-            onEventClick = onEventClick,
-            onOpenDay = onOpenDay,
-            onCreateAt = onCreateAt,
-            onDrop = onDrop,
-            onResize = onResize,
         )
     }
 }
@@ -984,14 +938,8 @@ private fun WeekPage(
     state: WeekUiState.Success,
     headerBias: Float,
     allDayHeight: Dp,
-    scrollState: ScrollState,
-    dragController: TimelineDragController,
+    actions: TimelineActions,
     active: Boolean,
-    onEventClick: (EventInstance) -> Unit,
-    onOpenDay: (LocalDate) -> Unit,
-    onCreateAt: (LocalDate, Int) -> Unit,
-    onDrop: (TimelineDrop) -> Unit,
-    onResize: (TimelineResizeDrop) -> Unit,
 ) {
     val geometry = remember(state.weekStart, state.days.size) {
         ColumnGeometry.of(DaySpan(state.weekStart, state.days.size))
@@ -1004,14 +952,8 @@ private fun WeekPage(
         bars = bars,
         headerBias = headerBias,
         allDayHeight = allDayHeight,
-        scrollState = scrollState,
-        dragController = dragController,
+        actions = actions,
         active = active,
-        onEventClick = onEventClick,
-        onOpenDay = onOpenDay,
-        onCreateAt = onCreateAt,
-        onDrop = onDrop,
-        onResize = onResize,
     )
 }
 
@@ -1028,14 +970,8 @@ private fun TimelinePageContent(
     headerBias: Float,
     allDayHeight: Dp,
     animatedAllDayHeight: (() -> Dp)? = null,
-    scrollState: ScrollState,
-    dragController: TimelineDragController,
+    actions: TimelineActions,
     active: Boolean,
-    onEventClick: (EventInstance) -> Unit,
-    onOpenDay: (LocalDate) -> Unit,
-    onCreateAt: (LocalDate, Int) -> Unit,
-    onDrop: (TimelineDrop) -> Unit,
-    onResize: (TimelineResizeDrop) -> Unit,
 ) {
     Column(modifier = Modifier.fillMaxSize()) {
         Column(
@@ -1043,14 +979,14 @@ private fun TimelinePageContent(
                 .fillMaxWidth()
                 .background(MaterialTheme.colorScheme.surface),
         ) {
-            WeekDayHeader(geometry = geometry, today = today, bias = headerBias, onOpenDay = onOpenDay)
+            WeekDayHeader(geometry = geometry, today = today, bias = headerBias, onOpenDay = actions.onOpenDay)
             // This strip is painted on `surface`, so an outlined chip has to
             // fill with that and not with the columns' container (#230).
             CompositionLocalProvider(
                 LocalChipGround provides MaterialTheme.colorScheme.surface,
             ) {
                 AllDayStrip(geometry = geometry, bars = bars, height = allDayHeight,
-                    animatedHeight = animatedAllDayHeight, onEventClick = onEventClick)
+                    animatedHeight = animatedAllDayHeight, onEventClick = actions.onEventClick)
             }
         }
         Spacer(Modifier.height(TIMELINE_TOP_GAP))
@@ -1060,13 +996,8 @@ private fun TimelinePageContent(
             timedFor = timedFor,
             allDayHeight = allDayHeight,
             animatedAllDayHeight = animatedAllDayHeight,
-            scrollState = scrollState,
-            dragController = dragController,
+            actions = actions,
             active = active,
-            onEventClick = onEventClick,
-            onCreateAt = onCreateAt,
-            onDrop = onDrop,
-            onResize = onResize,
         )
     }
 }
@@ -1290,14 +1221,11 @@ private fun Timeline(
     timedFor: (LocalDate) -> List<TimedBlock>,
     allDayHeight: Dp,
     animatedAllDayHeight: (() -> Dp)? = null,
-    scrollState: ScrollState,
-    dragController: TimelineDragController,
+    actions: TimelineActions,
     active: Boolean,
-    onEventClick: (EventInstance) -> Unit,
-    onCreateAt: (LocalDate, Int) -> Unit,
-    onDrop: (TimelineDrop) -> Unit,
-    onResize: (TimelineResizeDrop) -> Unit,
 ) {
+    val scrollState = actions.scrollState
+    val dragController = actions.dragController
     val fullViewportHeight = remember(geometry) { intArrayOf(-1) }
     val dark = LocalFloretDarkTheme.current
     val zoom = LocalTimelineZoom.current
@@ -1390,12 +1318,7 @@ private fun Timeline(
                     columnWidth = columnWidth,
                     visibleTop = visibleTop,
                     viewportHeight = visibleViewport,
-                    dragController = dragController,
-                    onEventClick = onEventClick,
-                    onCreateAt = onCreateAt,
-                    onDrop = onDrop,
-                    onResize = onResize,
-                    scrollState = scrollState,
+                    actions = actions,
                     modifier = Modifier.fillMaxHeight(),
                 )
             }
@@ -1413,14 +1336,11 @@ private fun DayColumnCard(
     columnWidth: Dp,
     visibleTop: () -> Float,
     viewportHeight: () -> Float,
-    dragController: TimelineDragController,
-    onEventClick: (EventInstance) -> Unit,
-    onCreateAt: (LocalDate, Int) -> Unit,
-    onDrop: (TimelineDrop) -> Unit,
-    onResize: (TimelineResizeDrop) -> Unit,
-    scrollState: ScrollState,
+    actions: TimelineActions,
     modifier: Modifier = Modifier,
 ) {
+    val scrollState = actions.scrollState
+    val dragController = actions.dragController
     val density = LocalDensity.current
     val hourPx = with(density) { hourHeight.toPx() }
     val morphing = LocalViewMorph.current != null
@@ -1438,13 +1358,13 @@ private fun DayColumnCard(
     }
     // The tap detector outlives the composition that installed it — a pinch or a
     // Settings change moves the hour height without restarting it — so it reads
-    // the height and the callback through state handles instead of capturing
-    // them, or taps land on the scale the column had before the zoom (#148).
+    // the height through a state handle instead of capturing it, or taps land on
+    // the scale the column had before the zoom (#148). The actions read their
+    // callbacks' latest values themselves.
     val currentHourPx = rememberUpdatedState(hourPx)
-    val currentOnCreateAt = rememberUpdatedState(onCreateAt)
     val edges = rememberOutOfViewEdges(blocks, scrollState, hourPx)
     val currentEdges = rememberUpdatedState(edges)
-    val draftSurface = rememberDraftSurface(date, edges, hourPx, dragController, onDrop)
+    val draftSurface = rememberDraftSurface(date, edges, hourPx, dragController, actions.onDrop)
     Card(
         // Plain rectangular columns — the soft corners come from the outer
         // rounded scroll viewport, so inner rounding would look odd at the edges.
@@ -1478,7 +1398,7 @@ private fun DayColumnCard(
                             return@detectTapGestures
                         }
                         if (currentEdges.value.tap(offset.y)) return@detectTapGestures
-                        currentOnCreateAt.value(
+                        actions.onCreateAt(
                             date,
                             tappedMinuteOfDay(offset.y, currentHourPx.value),
                         )
@@ -1538,9 +1458,9 @@ private fun DayColumnCard(
                         cuts = cuts,
                         topInset = topInset,
                         dragController = dragController,
-                        onClick = { onEventClick(block.event) },
-                        onDrop = onDrop,
-                        onResize = onResize,
+                        onClick = { actions.onEventClick(block.event) },
+                        onDrop = actions.onDrop,
+                        onResize = actions.onResize,
                         modifier = Modifier
                             .laneSlot(place)
                             .offset(y = place.y + topInset)

app/src/main/java/de/jeanlucmakiola/calendula/ui/week/WeekViewPreview.kt

@@ -52,14 +52,16 @@ internal fun WeekViewPreview(
             state = state,
             showWeekNumber = dayCount == 7,
             headerBias = if (dayCount == 1) TimelineKind.Day.headerBias else 0f,
-            scrollState = scrollState,
             allDayHeight = state.allDayStripHeight(),
-            dragController = rememberTimelineDragController(),
-            onEventClick = {},
-            onOpenDay = {},
-            onCreateAt = { _, _ -> },
-            onDrop = {},
-            onResize = {},
+            actions = rememberTimelineActions(
+                scrollState = scrollState,
+                dragController = rememberTimelineDragController(),
+                onEventClick = {},
+                onOpenDay = {},
+                onCreateAt = { _, _ -> },
+                onDrop = {},
+                onResize = {},
+            ),
         )
     }
 }