feat(heatmap): add HeatmapCanvas composable with three view layouts

- Daily: 53×7 GitHub-style grid with week grouping and left-padding
- Weekly: 52×1 single-row grid
- Cumulative: 53×7 grid using cumulative token data
- 6-level pink color gradient (light/dark mode)
- Canvas drawRoundRect with 11dp blocks, 3dp gap, 3dp radius
- Bottom month labels (Chinese), color legend, horizontal scroll
- Tap interaction with coordinate-to-cell mapping

app/src/main/java/com/rainy/token/ui/heatmap/HeatmapCanvas.kt

@@ -0,0 +1,363 @@
+package com.rainy.token.ui.heatmap
+
+import android.graphics.Paint
+import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.background
+import androidx.compose.foundation.gestures.detectTapGestures
+import androidx.compose.foundation.horizontalScroll
+import androidx.compose.foundation.isSystemInDarkTheme
+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.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.CornerRadius
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.drawscope.drawIntoCanvas
+import androidx.compose.ui.graphics.nativeCanvas
+import androidx.compose.ui.graphics.toArgb
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.rainy.token.ui.theme.inkMuted
+import java.time.Instant
+import java.time.ZoneOffset
+
+// ── 热力图颜色 ──────────────────────────────────────────────
+
+/** 亮色模式 6 级粉色梯度 */
+private val LightHeatmapColors = listOf(
+    Color(0xFFEFE0E5), // Level 0: 极浅暖灰
+    Color(0xFFFFD6E0), // Level 1: 浅樱粉
+    Color(0xFFFFB3C6), // Level 2: 草莓粉柔
+    Color(0xFFFF85A2), // Level 3: 草莓粉
+    Color(0xFFFF6B8E), // Level 4: 草莓粉深
+    Color(0xFFE84973), // Level 5: 玫红
+)
+
+/** 暗色模式 6 级粉色梯度 */
+private val DarkHeatmapColors = listOf(
+    Color(0xFF3A2A30), // Level 0: 暖深灰
+    Color(0xFF4A2E3A), // Level 1
+    Color(0xFF6B3D4A), // Level 2
+    Color(0xFF8B4D5A), // Level 3
+    Color(0xFFB86880), // Level 4
+    Color(0xFFD67F9A), // Level 5
+)
+
+/** 中文月份名称 */
+private val ChineseMonthNames = listOf(
+    "一月", "二月", "三月", "四月", "五月", "六月",
+    "七月", "八月", "九月", "十月", "十一月", "十二月",
+)
+
+// ── 辅助类型与函数 ──────────────────────────────────────────
+
+/** 月份标签 */
+private data class MonthLabel(
+    val weekIndex: Int,
+    val label: String,
+)
+
+/** 从 UTC 时间戳获取星期几 (0=Sunday, 6=Saturday) */
+private fun dayOfWeekFromTs(ts: Long): Int {
+    val dayOfWeek = Instant.ofEpochMilli(ts).atZone(ZoneOffset.UTC).dayOfWeek.value
+    return dayOfWeek % 7 // Sunday=7 → 0
+}
+
+/** 从 UTC 时间戳获取月份 (0=January) */
+private fun monthFromTs(ts: Long): Int {
+    return Instant.ofEpochMilli(ts).atZone(ZoneOffset.UTC).monthValue - 1
+}
+
+/**
+ * 将每日数据按周分组（参考 react-activity-calendar 的 groupByWeeks 逻辑）。
+ * 周起始日为周日（weekStart = 0）。
+ * 返回 List<List<HeatmapDayData?>>，外层为周，内层为星期 0-6，null 表示空位。
+ */
+private fun groupByWeeks(dailyData: List<HeatmapDayData>): List<List<HeatmapDayData?>> {
+    if (dailyData.isEmpty()) return emptyList()
+
+    val firstDow = dayOfWeekFromTs(dailyData[0].dayTs)
+
+    // 左侧填充空位，使第一周从周日开始
+    val padded = ArrayList<HeatmapDayData?>(firstDow + dailyData.size)
+    repeat(firstDow) { padded.add(null) }
+    padded.addAll(dailyData)
+
+    val numWeeks = (padded.size + 6) / 7
+    return (0 until numWeeks).map { w ->
+        (0 until 7).map { d ->
+            val idx = w * 7 + d
+            if (idx < padded.size) padded[idx] else null
+        }
+    }
+}
+
+/** 从按周分组的每日数据计算月份标签 */
+private fun getMonthLabels(weeks: List<List<HeatmapDayData?>>): List<MonthLabel> {
+    if (weeks.isEmpty()) return emptyList()
+
+    val rawLabels = mutableListOf<MonthLabel>()
+    var prevMonth = -1
+
+    for (weekIndex in weeks.indices) {
+        val firstDay = weeks[weekIndex].firstOrNull { it != null } ?: continue
+        val month = monthFromTs(firstDay.dayTs)
+
+        if (weekIndex == 0 || month != prevMonth) {
+            rawLabels.add(MonthLabel(weekIndex, ChineseMonthNames[month]))
+            prevMonth = month
+        }
+    }
+
+    return filterMonthLabels(rawLabels, weeks.size)
+}
+
+/** 从每周数据计算月份标签 */
+private fun getWeeklyMonthLabels(weeklyData: List<HeatmapWeekData>): List<MonthLabel> {
+    if (weeklyData.isEmpty()) return emptyList()
+
+    val rawLabels = mutableListOf<MonthLabel>()
+    var prevMonth = -1
+
+    for (weekIndex in weeklyData.indices) {
+        val month = monthFromTs(weeklyData[weekIndex].weekStartTs)
+
+        if (weekIndex == 0 || month != prevMonth) {
+            rawLabels.add(MonthLabel(weekIndex, ChineseMonthNames[month]))
+            prevMonth = month
+        }
+    }
+
+    return filterMonthLabels(rawLabels, weeklyData.size)
+}
+
+/**
+ * 过滤月份标签：跳过间距不足的标签（参考 react-activity-calendar 的 label.ts）。
+ * - 第一个标签：若与第二个标签间距 < minWeeks，跳过
+ * - 最后一个标签：若剩余周数 < minWeeks，跳过
+ */
+private fun filterMonthLabels(rawLabels: List<MonthLabel>, totalWeeks: Int): List<MonthLabel> {
+    val minWeeks = 3
+    return rawLabels.filterIndexed { index, label ->
+        when {
+            index == 0 -> {
+                rawLabels.getOrNull(1)?.let { it.weekIndex - label.weekIndex >= minWeeks } ?: false
+            }
+            index == rawLabels.lastIndex -> {
+                totalWeeks - label.weekIndex >= minWeeks
+            }
+            else -> true
+        }
+    }
+}
+
+// ── HeatmapCanvas Composable ───────────────────────────────
+
+/**
+ * Token 活动热力图 Canvas 绘制组件。
+ *
+ * 支持三种视图：
+ * - [HeatmapViewMode.DAILY]：53×7 格子网格，每日 Token 使用
+ * - [HeatmapViewMode.WEEKLY]：52×1 单行格子，每周 Token 总量
+ * - [HeatmapViewMode.CUMULATIVE]：53×7 格子网格，累计 Token
+ *
+ * 使用 Compose Canvas 绘制圆角矩形格子，底部显示中文月份标签，
+ * 支持水平滚动和格子点击。
+ *
+ * @param state UI 状态，包含数据与视图模式
+ * @param modifier 布局修饰符
+ * @param onDayClick 每日/累计视图格子点击回调
+ * @param onWeekClick 每周视图格子点击回调
+ */
+@Composable
+fun HeatmapCanvas(
+    state: HeatmapUiState,
+    modifier: Modifier = Modifier,
+    onDayClick: (HeatmapDayData) -> Unit = {},
+    onWeekClick: (HeatmapWeekData) -> Unit = {},
+) {
+    val darkTheme = isSystemInDarkTheme()
+    val colors = if (darkTheme) DarkHeatmapColors else LightHeatmapColors
+    val mutedColor = inkMuted()
+    val density = LocalDensity.current
+
+    // 格子参数
+    val blockSize = 11.dp
+    val gap = 3.dp
+    val cornerRadius = 3.dp
+
+    // 预计算 px 值（供 Canvas 绘制和点击检测共用）
+    val blockSizePx = with(density) { blockSize.toPx() }
+    val gapPx = with(density) { gap.toPx() }
+    val cellStepPx = blockSizePx + gapPx
+    val cornerRadiusPx = with(density) { cornerRadius.toPx() }
+
+    val isWeekly = state.viewMode == HeatmapViewMode.WEEKLY
+
+    // 构建网格数据（每日/累计视图用）
+    val gridWeeks = remember(state.dailyData, state.cumulativeData, state.viewMode) {
+        when (state.viewMode) {
+            HeatmapViewMode.DAILY -> groupByWeeks(state.dailyData)
+            HeatmapViewMode.CUMULATIVE -> groupByWeeks(state.cumulativeData)
+            HeatmapViewMode.WEEKLY -> emptyList()
+        }
+    }
+
+    // 月份标签
+    val monthLabels = remember(gridWeeks, state.weeklyData, isWeekly) {
+        if (isWeekly) getWeeklyMonthLabels(state.weeklyData) else getMonthLabels(gridWeeks)
+    }
+
+    val cols = if (isWeekly) state.weeklyData.size else gridWeeks.size
+    val rows = if (isWeekly) 1 else 7
+
+    // 加载中或无数据
+    if (state.loading || cols == 0) {
+        Box(
+            modifier = modifier
+                .fillMaxWidth()
+                .height(if (state.loading) 200.dp else 120.dp),
+            contentAlignment = Alignment.Center,
+        ) {
+            if (state.loading) {
+                CircularProgressIndicator(color = MaterialTheme.colorScheme.primary)
+            } else {
+                Text("暂无数据", color = mutedColor, fontSize = 14.sp)
+            }
+        }
+        return
+    }
+
+    // Canvas 尺寸计算
+    val canvasWidthDp = cols * (blockSize + gap) - gap
+    val gridHeightDp = rows * (blockSize + gap) - gap
+    val monthLabelHeightDp = 20.dp
+    val totalHeightDp = gridHeightDp + monthLabelHeightDp
+
+    val gridHeightPx = with(density) { gridHeightDp.toPx() }
+    val labelGapPx = with(density) { 4.dp.toPx() }
+
+    // 月份标签画笔
+    val monthLabelPaint = remember(mutedColor, density) {
+        Paint().apply {
+            textSize = with(density) { 12.sp.toPx() }
+            color = mutedColor.toArgb()
+            isAntiAlias = true
+        }
+    }
+
+    Column(
+        modifier = modifier.horizontalScroll(rememberScrollState()),
+    ) {
+        // ── 热力图网格 + 月份标签 ──
+        Canvas(
+            modifier = Modifier
+                .size(canvasWidthDp, totalHeightDp)
+                .pointerInput(state, cellStepPx, blockSizePx) {
+                    detectTapGestures(onTap = { offset ->
+                        val col = (offset.x / cellStepPx).toInt()
+                        val row = (offset.y / cellStepPx).toInt()
+
+                        if (isWeekly) {
+                            // 每周视图：单行，点击列索引对应周数据
+                            if (col >= 0 && col < state.weeklyData.size &&
+                                offset.y >= 0f && offset.y < blockSizePx
+                            ) {
+                                onWeekClick(state.weeklyData[col])
+                            }
+                        } else {
+                            // 每日/累计视图：点击 (col, row) 对应格子
+                            if (col >= 0 && col < gridWeeks.size && row >= 0 && row < 7) {
+                                val cell = gridWeeks[col][row]
+                                if (cell != null) {
+                                    onDayClick(cell)
+                                }
+                            }
+                        }
+                    })
+                },
+        ) {
+            // 绘制格子
+            if (isWeekly) {
+                // 每周视图：52 列 × 1 行
+                state.weeklyData.forEachIndexed { weekIndex, weekData ->
+                    val x = weekIndex * cellStepPx
+                    drawRoundRect(
+                        color = colors[weekData.level.coerceIn(0, 5)],
+                        topLeft = Offset(x, 0f),
+                        size = Size(blockSizePx, blockSizePx),
+                        cornerRadius = CornerRadius(cornerRadiusPx, cornerRadiusPx),
+                    )
+                }
+            } else {
+                // 每日/累计视图：53 列 × 7 行
+                gridWeeks.forEachIndexed { weekIndex, week ->
+                    week.forEachIndexed { dayIndex, dayData ->
+                        if (dayData == null) return@forEachIndexed
+                        val x = weekIndex * cellStepPx
+                        val y = dayIndex * cellStepPx
+                        drawRoundRect(
+                            color = colors[dayData.level.coerceIn(0, 5)],
+                            topLeft = Offset(x, y),
+                            size = Size(blockSizePx, blockSizePx),
+                            cornerRadius = CornerRadius(cornerRadiusPx, cornerRadiusPx),
+                        )
+                    }
+                }
+            }
+
+            // 绘制月份标签（底部）
+            drawIntoCanvas { canvas ->
+                val nativeCanvas = canvas.nativeCanvas
+                // labelY = 网格底部 + 间距 + 文字基线偏移
+                val labelY = gridHeightPx + labelGapPx - monthLabelPaint.ascent()
+                monthLabels.forEach { label ->
+                    val x = label.weekIndex * cellStepPx
+                    nativeCanvas.drawText(label.label, x, labelY, monthLabelPaint)
+                }
+            }
+        }
+
+        Spacer(Modifier.height(8.dp))
+
+        // ── 颜色图例（右下角）──
+        Row(
+            modifier = Modifier.width(canvasWidthDp),
+            horizontalArrangement = Arrangement.End,
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            Text("少", color = mutedColor, fontSize = 12.sp)
+            Spacer(Modifier.width(4.dp))
+            for (level in 0..5) {
+                Box(
+                    modifier = Modifier
+                        .size(blockSize)
+                        .background(colors[level], RoundedCornerShape(cornerRadius)),
+                )
+                if (level < 5) {
+                    Spacer(Modifier.width(gap))
+                }
+            }
+            Spacer(Modifier.width(4.dp))
+            Text("多", color = mutedColor, fontSize = 12.sp)
+        }
+    }
+}