feat: 底部卡片展示选中日期的相对天数、公历与农历信息

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

shared/src/commonMain/kotlin/plus/rua/project/ui/BottomCard.kt

@@ -2,27 +2,42 @@ package plus.rua.project.ui
 
 import androidx.compose.foundation.background
 import androidx.compose.foundation.gestures.detectVerticalDragGestures
+import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import kotlinx.datetime.LocalDate
 import plus.rua.project.CalendarViewModel
 
 /**
  * 底部卡片，折叠状态下支持垂直拖拽触发折叠动画。
  *
+ * 卡片顶部显示拖拽把手，下方展示选中日期信息：
+ * 左侧为相对今天的天数描述（A）和公历日期（B），
+ * 右侧为农历日期（C）。
+ *
  * @param viewModel 日历 ViewModel，用于读取折叠状态和驱动拖拽
+ * @param selectedDate 当前选中的日期
+ * @param today 今天的日期
  * @param dragRangePx 拖拽手势映射范围（像素），progress 从 0→1 对应手指移动此距离。
  *   应设为折叠时日历实际高度变化量 (weeks-1)×rowHeight，使拖拽跟手。
  * @param modifier 外部布局修饰符
@@ -30,10 +45,16 @@ import plus.rua.project.CalendarViewModel
 @Composable
 fun BottomCard(
     viewModel: CalendarViewModel,
+    selectedDate: LocalDate,
+    today: LocalDate,
     dragRangePx: Float,
     modifier: Modifier = Modifier
 ) {
     val density = LocalDensity.current
+    val relativeDesc = relativeDayDescription(selectedDate, today)
+    @Suppress("DEPRECATION") // monthNumber 无替代 API，kotlinx-datetime 尚未提供新接口
+    val solarDesc = "${selectedDate.monthNumber}月${selectedDate.day}日"
+    val lunarDesc = formatLunarDate(selectedDate)
 
     Surface(
         modifier = modifier
@@ -80,16 +101,52 @@ fun BottomCard(
         color = MaterialTheme.colorScheme.surfaceVariant,
         shadowElevation = 4.dp
     ) {
-        Box(modifier = Modifier.fillMaxSize()) {
+        Column(modifier = Modifier.fillMaxSize()) {
+            // 拖拽把手
             Box(
                 modifier = Modifier
-                    .align(Alignment.TopCenter)
                     .padding(top = 8.dp, bottom = 8.dp)
                     .clip(RoundedCornerShape(2.dp))
                     .background(MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.4f))
                     .fillMaxWidth(0.15f)
                     .height(4.dp)
+                    .align(Alignment.CenterHorizontally)
             )
+            Spacer(modifier = Modifier.height(8.dp))
+            // A / B / C 信息行
+            Row(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(horizontal = 20.dp),
+                horizontalArrangement = Arrangement.SpaceBetween,
+                verticalAlignment = Alignment.CenterVertically
+            ) {
+                // 左侧：A（相对天数）和 B（公历日期）在同一行
+                Row(
+                    verticalAlignment = Alignment.CenterVertically
+                ) {
+                    Text(
+                        text = relativeDesc,
+                        style = MaterialTheme.typography.bodyMedium,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        fontSize = 14.sp
+                    )
+                    Spacer(modifier = Modifier.width(6.dp))
+                    Text(
+                        text = solarDesc,
+                        style = MaterialTheme.typography.bodyMedium,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        fontSize = 14.sp
+                    )
+                }
+                // 右侧：C（农历日期）
+                Text(
+                    text = lunarDesc,
+                    style = MaterialTheme.typography.bodyMedium,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    fontSize = 14.sp
+                )
+            }
         }
     }
 }

shared/src/commonMain/kotlin/plus/rua/project/ui/CalendarMonthView.kt

@@ -311,6 +311,8 @@ fun CalendarMonthView(
                 if (cardHeightPx > 0) {
                     BottomCard(
                         viewModel = viewModel,
+                        selectedDate = viewModel.selectedDate,
+                        today = today,
                         dragRangePx = dragRangePx,
                         modifier = Modifier
                             .fillMaxWidth()

shared/src/commonMain/kotlin/plus/rua/project/ui/CalendarUtils.kt

@@ -1,7 +1,9 @@
 package plus.rua.project.ui
 
+import com.tyme.solar.SolarDay
 import kotlinx.datetime.DatePeriod
 import kotlinx.datetime.LocalDate
+import kotlinx.datetime.daysUntil
 import kotlinx.datetime.minus
 import kotlinx.datetime.number
 import kotlinx.datetime.plus
@@ -130,3 +132,40 @@ fun pageToWeekMonday(page: Int, initial: LocalDate): LocalDate {
     val offset = page - START_PAGE
     return initial.plus(DatePeriod(days = offset * 7))
 }
+
+/**
+ * 计算选中日期相对于今天的天数描述。
+ *
+ * 例如今天 19 日，选中 18 日返回"昨天"，17 日返回"2天前"，
+ * 20 日返回"明天"，21 日返回"2天后"，选中当天返回"今天"。
+ *
+ * @param selectedDate 选中日期
+ * @param today 今天日期
+ * @return 相对天数描述
+ */
+fun relativeDayDescription(selectedDate: LocalDate, today: LocalDate): String {
+    val diff = today.daysUntil(selectedDate)
+    return when {
+        diff == 0 -> "今天"
+        diff == -1 -> "昨天"
+        diff == 1 -> "明天"
+        diff < 0 -> "${-diff}天前"
+        else -> "${diff}天后"
+    }
+}
+
+/**
+ * 将公历日期格式化为农历日期字符串。
+ *
+ * 格式为"农历{月}{日}"，例如"农历四月初三"。
+ *
+ * @param date 公历日期
+ * @return 农历日期描述
+ */
+@Suppress("DEPRECATION") // monthNumber 无替代 API，kotlinx-datetime 尚未提供新接口
+fun formatLunarDate(date: LocalDate): String {
+    val solarDay = SolarDay.fromYmd(date.year, date.monthNumber, date.day)
+    val lunarDay = solarDay.getLunarDay()
+    val lunarMonth = lunarDay.getLunarMonth()
+    return "农历${lunarMonth.getName()}${lunarDay.getName()}"
+}