feat: 日期检查器页面实现商品过期检查功能

- 顶部生产日期选择器（TextField + DatePickerDialog）
- 默认三行（30/60/180天），天数与到期日期双向联动
- 滑动删除行
- 底部右侧 FAB 添加新行
- 日期格式 ISO YYYY-MM-DD

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

core/src/main/kotlin/plus/rua/project/ui/DateCheckerScreen.kt

@@ -1,76 +1,451 @@
+@file:OptIn(ExperimentalMaterial3Api::class)
+
 package plus.rua.project.ui
 
 import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.background
+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.size
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.DatePicker
+import androidx.compose.material3.DatePickerDialog
 import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.FloatingActionButton
+import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Scaffold
+import androidx.compose.material3.SwipeToDismissBox
+import androidx.compose.material3.SwipeToDismissBoxValue
 import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
 import androidx.compose.material3.TopAppBar
+import androidx.compose.material3.rememberDatePickerState
+import androidx.compose.material3.rememberSwipeToDismissBoxState
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
 import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.StrokeCap
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.text.input.KeyboardType
 import androidx.compose.ui.unit.dp
+import kotlin.time.Clock
+import kotlinx.datetime.DatePeriod
+import kotlin.time.Instant
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.atStartOfDayIn
+import kotlinx.datetime.daysUntil
+import kotlinx.datetime.plus
+import kotlinx.datetime.toLocalDateTime
+import kotlinx.datetime.todayIn
+
+private data class ExpiryRow(val id: Int, val days: Int? = null)
+
+private sealed class DatePickerTarget {
+    data object Production : DatePickerTarget()
+    data class Row(val rowId: Int) : DatePickerTarget()
+}
 
 /**
- * 日期检查器页面。
+ * 日期检查器页面，商品过期检查工具。
+ *
+ * 顶部设置生产日期，下方多行显示天数与到期日期的双向联动计算。
+ * 支持滑动删除行、FAB 添加新行。
  *
  * @param onBack 返回回调
  * @param modifier 布局修饰符
  */
-@OptIn(ExperimentalMaterial3Api::class)
 @Composable
-fun DateCheckerScreen(
+fun DateCheckerScreen(onBack: () -> Unit, modifier: Modifier = Modifier) {
-    onBack: () -> Unit,
+    val today = remember { Clock.System.todayIn(TimeZone.currentSystemDefault()) }
-    modifier: Modifier = Modifier
+
-) {
+    var productionDate by remember { mutableStateOf(today) }
+    var rows by remember {
+        mutableStateOf(
+            listOf(
+                ExpiryRow(0, 30),
+                ExpiryRow(1, 60),
+                ExpiryRow(2, 180)
+            )
+        )
+    }
+    var nextId by remember { mutableIntStateOf(3) }
+
+    var showDatePicker by remember { mutableStateOf(false) }
+    var datePickerTarget by remember { mutableStateOf<DatePickerTarget?>(null) }
+
     Scaffold(
         topBar = {
             TopAppBar(
                 title = { Text("日期检查器") },
                 navigationIcon = {
                     IconButton(onClick = onBack) {
-                        val arrowColor = MaterialTheme.colorScheme.onSurface
+                        BackArrowIcon()
-                        Canvas(modifier = Modifier.size(24.dp)) {
-                            val strokeWidth = 2.dp.toPx()
-                            drawLine(
-                                color = arrowColor,
-                                start = Offset(size.width * 0.75f, size.height * 0.15f),
-                                end = Offset(size.width * 0.25f, size.height * 0.5f),
-                                strokeWidth = strokeWidth,
-                                cap = StrokeCap.Round
-                            )
-                            drawLine(
-                                color = arrowColor,
-                                start = Offset(size.width * 0.25f, size.height * 0.5f),
-                                end = Offset(size.width * 0.75f, size.height * 0.85f),
-                                strokeWidth = strokeWidth,
-                                cap = StrokeCap.Round
-                            )
-                        }
                     }
                 }
             )
         },
+        floatingActionButton = {
+            FloatingActionButton(
+                onClick = {
+                    rows = rows + ExpiryRow(nextId, null)
+                    nextId++
+                },
+                shape = CircleShape,
+                containerColor = MaterialTheme.colorScheme.primaryContainer,
+                contentColor = MaterialTheme.colorScheme.onPrimaryContainer
+            ) {
+                PlusIcon(color = MaterialTheme.colorScheme.onPrimaryContainer)
+            }
+        },
         modifier = modifier
     ) { innerPadding ->
-        Box(
+        Column(
             modifier = Modifier
                 .fillMaxSize()
-                .padding(innerPadding),
+                .padding(innerPadding)
-            contentAlignment = Alignment.Center
+                .padding(horizontal = 16.dp)
         ) {
+            Spacer(modifier = Modifier.height(16.dp))
+
             Text(
-                text = "日期检查器",
+                text = "生产日期",
-                style = MaterialTheme.typography.bodyLarge,
+                style = MaterialTheme.typography.labelLarge,
                 color = MaterialTheme.colorScheme.onSurfaceVariant
             )
+
+            Spacer(modifier = Modifier.height(8.dp))
+
+            ProductionDateField(
+                date = productionDate,
+                onDateChange = { productionDate = it },
+                onShowDatePicker = {
+                    datePickerTarget = DatePickerTarget.Production
+                    showDatePicker = true
+                }
+            )
+
+            Spacer(modifier = Modifier.height(24.dp))
+            HorizontalDivider()
+            Spacer(modifier = Modifier.height(16.dp))
+
+            LazyColumn(
+                modifier = Modifier.fillMaxWidth(),
+                verticalArrangement = Arrangement.spacedBy(12.dp)
+            ) {
+                items(rows, key = { it.id }) { row ->
+                    val expiryDate = row.days?.let { productionDate.plus(DatePeriod(days = it)) }
+
+                    ExpiryRowItem(
+                        days = row.days,
+                        expiryDate = expiryDate,
+                        onDaysChange = { newDays ->
+                            rows = rows.map {
+                                if (it.id == row.id) it.copy(days = newDays) else it
+                            }
+                        },
+                        onExpiryDateChange = { newDate ->
+                            val newDays = productionDate.daysUntil(newDate)
+                            rows = rows.map {
+                                if (it.id == row.id) it.copy(days = newDays) else it
+                            }
+                        },
+                        onShowDatePicker = {
+                            datePickerTarget = DatePickerTarget.Row(row.id)
+                            showDatePicker = true
+                        },
+                        onDelete = {
+                            rows = rows.filter { it.id != row.id }
+                        }
+                    )
+                }
+            }
+        }
+    }
+
+    if (showDatePicker) {
+        val initialMillis = when (val target = datePickerTarget) {
+            is DatePickerTarget.Production -> productionDate.toEpochMillis()
+            is DatePickerTarget.Row -> {
+                val row = rows.find { it.id == target.rowId }
+                row?.days?.let {
+                    productionDate.plus(DatePeriod(days = it)).toEpochMillis()
+                } ?: productionDate.toEpochMillis()
+            }
+            null -> productionDate.toEpochMillis()
+        }
+
+        val datePickerState = rememberDatePickerState(initialSelectedDateMillis = initialMillis)
+
+        DatePickerDialog(
+            onDismissRequest = { showDatePicker = false },
+            confirmButton = {
+                TextButton(onClick = {
+                    datePickerState.selectedDateMillis?.let { millis ->
+                        val selected = millis.toLocalDate()
+                        when (val target = datePickerTarget) {
+                            is DatePickerTarget.Production -> productionDate = selected
+                            is DatePickerTarget.Row -> {
+                                val newDays = productionDate.daysUntil(selected)
+                                rows = rows.map {
+                                    if (it.id == target.rowId) it.copy(days = newDays) else it
+                                }
+                            }
+                            null -> {}
+                        }
+                    }
+                    showDatePicker = false
+                }) {
+                    Text("确定")
+                }
+            },
+            dismissButton = {
+                TextButton(onClick = { showDatePicker = false }) {
+                    Text("取消")
+                }
+            }
+        ) {
+            DatePicker(state = datePickerState)
+        }
+    }
+}
+
+@Composable
+private fun ProductionDateField(
+    date: LocalDate,
+    onDateChange: (LocalDate) -> Unit,
+    onShowDatePicker: () -> Unit,
+    modifier: Modifier = Modifier
+) {
+    var text by remember(date) { mutableStateOf(date.toString()) }
+    var isError by remember { mutableStateOf(false) }
+
+    OutlinedTextField(
+        value = text,
+        onValueChange = {
+            text = it
+            isError = false
+            try {
+                onDateChange(LocalDate.parse(it))
+            } catch (_: Exception) {
+                isError = true
+            }
+        },
+        label = { Text("生产日期") },
+        isError = isError,
+        singleLine = true,
+        keyboardOptions = KeyboardOptions(
+            keyboardType = KeyboardType.Text,
+            imeAction = ImeAction.Done
+        ),
+        trailingIcon = {
+            IconButton(onClick = onShowDatePicker) {
+                CalendarIcon(color = MaterialTheme.colorScheme.onSurfaceVariant)
+            }
+        },
+        modifier = modifier.fillMaxWidth()
+    )
+}
+
+@Composable
+private fun ExpiryRowItem(
+    days: Int?,
+    expiryDate: LocalDate?,
+    onDaysChange: (Int?) -> Unit,
+    onExpiryDateChange: (LocalDate) -> Unit,
+    onShowDatePicker: () -> Unit,
+    onDelete: () -> Unit,
+    modifier: Modifier = Modifier
+) {
+    var daysText by remember(days) { mutableStateOf(days?.toString() ?: "") }
+    var dateText by remember(expiryDate) { mutableStateOf(expiryDate?.toString() ?: "") }
+
+    val dismissState = rememberSwipeToDismissBoxState(
+        confirmValueChange = { value ->
+            if (value == SwipeToDismissBoxValue.EndToStart) {
+                onDelete()
+                true
+            } else {
+                false
+            }
+        }
+    )
+
+    SwipeToDismissBox(
+        state = dismissState,
+        backgroundContent = {
+            Box(
+                modifier = Modifier
+                    .fillMaxSize()
+                    .clip(RoundedCornerShape(12.dp))
+                    .background(MaterialTheme.colorScheme.errorContainer)
+                    .padding(horizontal = 20.dp),
+                contentAlignment = Alignment.CenterEnd
+            ) {
+                Text(
+                    text = "删除",
+                    color = MaterialTheme.colorScheme.onErrorContainer,
+                    style = MaterialTheme.typography.labelLarge
+                )
+            }
+        },
+        modifier = modifier
+    ) {
+        Row(
+            modifier = Modifier
+                .fillMaxWidth()
+                .clip(RoundedCornerShape(12.dp))
+                .background(MaterialTheme.colorScheme.surfaceContainerHigh)
+                .padding(horizontal = 12.dp, vertical = 12.dp),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(12.dp)
+        ) {
+            OutlinedTextField(
+                value = daysText,
+                onValueChange = { newValue ->
+                    daysText = newValue.filter { it.isDigit() }
+                    onDaysChange(daysText.toIntOrNull())
+                },
+                label = { Text("天数") },
+                singleLine = true,
+                keyboardOptions = KeyboardOptions(
+                    keyboardType = KeyboardType.Number,
+                    imeAction = ImeAction.Done
+                ),
+                modifier = Modifier.weight(1f)
+            )
+
+            OutlinedTextField(
+                value = dateText,
+                onValueChange = { newValue ->
+                    dateText = newValue
+                    try {
+                        onExpiryDateChange(LocalDate.parse(newValue))
+                    } catch (_: Exception) {
+                    }
+                },
+                label = { Text("到期日期") },
+                singleLine = true,
+                keyboardOptions = KeyboardOptions(
+                    keyboardType = KeyboardType.Text,
+                    imeAction = ImeAction.Done
+                ),
+                trailingIcon = {
+                    IconButton(onClick = onShowDatePicker) {
+                        CalendarIcon(
+                            color = MaterialTheme.colorScheme.onSurfaceVariant,
+                            modifier = Modifier.size(20.dp)
+                        )
+                    }
+                },
+                modifier = Modifier.weight(1.5f)
+            )
         }
     }
 }
+
+// region Icons
+
+@Composable
+private fun BackArrowIcon(modifier: Modifier = Modifier) {
+    val color = MaterialTheme.colorScheme.onSurface
+    Canvas(modifier = modifier.size(24.dp)) {
+        val strokeWidth = 2.dp.toPx()
+        drawLine(
+            color = color,
+            start = Offset(size.width * 0.75f, size.height * 0.15f),
+            end = Offset(size.width * 0.25f, size.height * 0.5f),
+            strokeWidth = strokeWidth,
+            cap = StrokeCap.Round
+        )
+        drawLine(
+            color = color,
+            start = Offset(size.width * 0.25f, size.height * 0.5f),
+            end = Offset(size.width * 0.75f, size.height * 0.85f),
+            strokeWidth = strokeWidth,
+            cap = StrokeCap.Round
+        )
+    }
+}
+
+@Composable
+private fun PlusIcon(color: Color, modifier: Modifier = Modifier) {
+    Canvas(modifier = modifier.size(24.dp)) {
+        val strokeWidth = 2.dp.toPx()
+        val cx = size.width / 2
+        val cy = size.height / 2
+        val half = size.minDimension * 0.35f
+        drawLine(
+            color = color,
+            start = Offset(cx, cy - half),
+            end = Offset(cx, cy + half),
+            strokeWidth = strokeWidth,
+            cap = StrokeCap.Round
+        )
+        drawLine(
+            color = color,
+            start = Offset(cx - half, cy),
+            end = Offset(cx + half, cy),
+            strokeWidth = strokeWidth,
+            cap = StrokeCap.Round
+        )
+    }
+}
+
+@Composable
+private fun CalendarIcon(color: Color, modifier: Modifier = Modifier) {
+    Canvas(modifier = modifier.size(24.dp)) {
+        val strokeWidth = 1.5f.dp.toPx()
+        val pad = 3.dp.toPx()
+        val topY = pad + 4.dp.toPx()
+        val bottomY = size.height - pad
+        val leftX = pad
+        val rightX = size.width - pad
+
+        // 外框
+        drawLine(color, Offset(leftX, topY), Offset(rightX, topY), strokeWidth)
+        drawLine(color, Offset(leftX, topY), Offset(leftX, bottomY), strokeWidth)
+        drawLine(color, Offset(rightX, topY), Offset(rightX, bottomY), strokeWidth)
+        drawLine(color, Offset(leftX, bottomY), Offset(rightX, bottomY), strokeWidth)
+
+        // 顶部挂环
+        val h1 = size.width * 0.3f
+        val h2 = size.width * 0.7f
+        drawLine(color, Offset(h1, pad), Offset(h1, topY), strokeWidth)
+        drawLine(color, Offset(h2, pad), Offset(h2, topY), strokeWidth)
+    }
+}
+
+// endregion
+
+// region Helpers
+
+private fun LocalDate.toEpochMillis(): Long =
+    this.atStartOfDayIn(TimeZone.UTC).toEpochMilliseconds()
+
+private fun Long.toLocalDate(): LocalDate =
+    Instant.fromEpochMilliseconds(this).toLocalDateTime(TimeZone.UTC).date
+
+// endregion