Merge pull request 'feat: current-time line in day and week views' (!31) from feat/now-line into release/v2.8.0

Reviewed-on: #31

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/NowLine.kt

@@ -0,0 +1,90 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.offset
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.State
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import kotlinx.coroutines.delay
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Clock
+import kotlin.time.Instant
+
+private val DotSize = 8.dp
+private val LineThickness = 2.dp
+
+/**
+ * Current wall-clock instant that updates once a minute, re-aligning to each
+ * minute boundary (rather than ticking a fixed 60 s) so it never drifts toward
+ * the middle of a minute. Drives the "now" line in the day/week grids.
+ */
+@Composable
+private fun rememberCurrentMinute(): State<Instant> {
+    val instant = remember { mutableStateOf(Clock.System.now()) }
+    LaunchedEffect(Unit) {
+        while (true) {
+            val now = Clock.System.now()
+            instant.value = now
+            delay(60_000L - now.toEpochMilliseconds() % 60_000L)
+        }
+    }
+    return instant
+}
+
+/**
+ * A thin "current time" indicator — a leading dot plus a line — drawn across a
+ * day column. Positioned on the same [hourHeight] scale the event blocks use so
+ * it lines up with the grid, and refreshed each minute. Renders nothing unless
+ * the wall clock is on [date]; callers mount it only for the column showing
+ * today, so the per-minute tick runs on a single column.
+ */
+@Composable
+fun NowLine(
+    date: LocalDate,
+    hourHeight: Dp,
+    modifier: Modifier = Modifier,
+) {
+    val now by rememberCurrentMinute()
+    val local = now.toLocalDateTime(TimeZone.currentSystemDefault())
+    if (local.date != date) return
+
+    val minutes = local.hour * 60 + local.minute
+    val top = hourHeight * (minutes / 60f)
+    val color = MaterialTheme.colorScheme.primary
+    Box(
+        modifier = modifier
+            .fillMaxWidth()
+            .height(DotSize)
+            .offset(y = top - DotSize / 2),
+        contentAlignment = Alignment.CenterStart,
+    ) {
+        Box(
+            modifier = Modifier
+                .fillMaxWidth()
+                .height(LineThickness)
+                .background(color),
+        )
+        // The dot anchors the line to the gutter edge, mirroring the standard
+        // calendar "now" marker; drawn after the line so it sits on top.
+        Box(
+            modifier = Modifier
+                .size(DotSize)
+                .background(color, CircleShape),
+        )
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/day/DayScreen.kt

@@ -71,6 +71,7 @@ import de.jeanlucmakiola.calendula.ui.common.CalendarDrawer
 import de.jeanlucmakiola.calendula.ui.common.CalendarFabColumn
 import de.jeanlucmakiola.calendula.ui.common.CalendarFailure
 import de.jeanlucmakiola.calendula.ui.common.CalendarView
+import de.jeanlucmakiola.calendula.ui.common.NowLine
 import de.jeanlucmakiola.calendula.ui.common.ViewSwitcherPill
 import de.jeanlucmakiola.calendula.ui.common.calendarSlideTransition
 import de.jeanlucmakiola.calendula.ui.common.next
@@ -496,6 +497,7 @@ private fun Timeline(
                     blocks = state.timed,
                     dark = dark,
                     date = state.date,
+                    today = state.today,
                     onEventClick = onEventClick,
                     onCreateAt = onCreateAt,
                     modifier = Modifier
@@ -512,6 +514,7 @@ private fun DayColumnCard(
     blocks: List<TimedBlock>,
     dark: Boolean,
     date: LocalDate,
+    today: LocalDate,
     onEventClick: (EventInstance) -> Unit,
     onCreateAt: (LocalDate, Int) -> Unit,
     modifier: Modifier = Modifier,
@@ -556,6 +559,10 @@ private fun DayColumnCard(
                         .padding(horizontal = 1.dp),
                 )
             }
+            // Current-time line, on top of the events, only on today's column.
+            if (date == today) {
+                NowLine(date = date, hourHeight = HOUR_HEIGHT)
+            }
         }
     }
 }

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

@@ -76,6 +76,7 @@ import de.jeanlucmakiola.calendula.ui.common.CalendarDrawer
 import de.jeanlucmakiola.calendula.ui.common.CalendarFabColumn
 import de.jeanlucmakiola.calendula.ui.common.CalendarFailure
 import de.jeanlucmakiola.calendula.ui.common.CalendarView
+import de.jeanlucmakiola.calendula.ui.common.NowLine
 import de.jeanlucmakiola.calendula.ui.common.ViewSwitcherPill
 import de.jeanlucmakiola.calendula.ui.common.calendarSlideTransition
 import de.jeanlucmakiola.calendula.ui.common.currentLocale
@@ -610,6 +611,7 @@ private fun Timeline(
                             blocks = state.timedByDay[day].orEmpty(),
                             dark = dark,
                             date = day,
+                            today = state.today,
                             onEventClick = onEventClick,
                             onCreateAt = onCreateAt,
                             modifier = Modifier
@@ -628,6 +630,7 @@ private fun DayColumnCard(
     blocks: List<TimedBlock>,
     dark: Boolean,
     date: LocalDate,
+    today: LocalDate,
     onEventClick: (EventInstance) -> Unit,
     onCreateAt: (LocalDate, Int) -> Unit,
     modifier: Modifier = Modifier,
@@ -671,6 +674,10 @@ private fun DayColumnCard(
                         .padding(horizontal = 1.dp),
                 )
             }
+            // Current-time line, on top of the events, only on today's column.
+            if (date == today) {
+                NowLine(date = date, hourHeight = HOUR_HEIGHT)
+            }
         }
     }
 }