// stats_page.dart — 统计页(月/周/日 周期卡 + 设备下拉 + 最近两周流量折线)。
// 单一数据源:近30天每日用量(usageProvider,autoDispose 进页重取),月/周/日 + 折线全从此聚合。
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../l10n/app_text.dart';
import '../models/device.dart';
import '../models/usage_point.dart';
import '../pangolin_theme.dart';
import '../state/account_providers.dart';
import '../state/app_providers.dart';
import '../state/auth_provider.dart';
import '../widgets/app_top_bar.dart';
import '../widgets/pangolin_icons.dart';
import '../widgets/period_card.dart';
import '../widgets/usage_line_chart.dart';

class StatsPage extends ConsumerWidget {
  const StatsPage({super.key, required this.isWide});
  final bool isWide;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final c = context.pangolin;
    final t = ref.watch(appTextProvider);
    // 选中设备(#10②):null=全部=账户级;否则只算该设备的本地日曲线。
    final selDevice = ref.watch(statsDeviceProvider);
    final usageKey = (days: 30, device: selDevice);
    final usageAsync = ref.watch(usageProvider(usageKey));
    final usage = usageAsync.valueOrNull ?? const <UsagePoint>[];
    // 先拉数据再渲染(不闪默认 0):auth 还在读 token,或已登录但 usage 还在拉 → 整页转圈。
    // (auth 加载期 isLoggedIn=false → usage 会同步返回空,故必须并上 auth.isLoading。)
    final loading = ref.watch(authProvider).isLoading || usageAsync.isLoading;

    // 周期聚合:取最后 N 天的点求和。最后一点即今日(避开 UTC/本地日期换算)。
    (int down, int up, int min) sumLast(int days) {
      var d = 0, u = 0, m = 0;
      final start = usage.length > days ? usage.length - days : 0;
      for (var i = start; i < usage.length; i++) {
        d += usage[i].bytesDown;
        u += usage[i].bytesUp;
        m += usage[i].minutesUsed;
      }
      return (d, u, m);
    }

    List<StatMetric> metricsFor(int days) {
      final (d, u, m) = sumLast(days);
      final dn = _fmtBytes(d), up = _fmtBytes(u);
      return [
        StatMetric(dn.$1, dn.$2, '↓ ${t.statDown}'),
        StatMetric(up.$1, up.$2, '↑ ${t.statUp}'),
        StatMetric((m / 60.0).toStringAsFixed(1), 'h', t.statDuration),
      ];
    }

    // 折线:最后 14 天每日总流量(GB) + 对应日期(X 轴标注)。
    final chartPts = usage.length > 14 ? usage.sublist(usage.length - 14) : usage;
    final chartVals = chartPts.map((p) => p.gbTotal).toList();
    final chartDates = chartPts.map((p) => p.date).toList();

    final body = loading
        ? Center(child: CircularProgressIndicator(color: c.accent, strokeWidth: 2.6))
        : RefreshIndicator(
      color: c.accent,
      backgroundColor: c.surface,
      onRefresh: () async {
        ref.invalidate(usageProvider(usageKey));
        ref.invalidate(deviceUsageProvider(30));
        await ref.read(meProvider.notifier).refresh();
      },
      child: ListView(
        padding: EdgeInsets.fromLTRB(isWide ? 32 : 20, isWide ? 8 : 4, isWide ? 32 : 20, 24),
        children: [
          // 顶行:标题(宽屏) + 设备下拉(右上角)
          Row(mainAxisAlignment: MainAxisAlignment.spaceBetween, children: [
            if (isWide)
              Text(t.statsTitle,
                  style: PangolinText.display.copyWith(color: c.fg1, fontSize: 20, fontWeight: FontWeight.w700))
            else
              const SizedBox.shrink(),
            _DeviceDropdown(t: t),
          ]),
          const SizedBox(height: 14),
          PeriodCard(period: t.periodMonth, metrics: metricsFor(30)),
          const SizedBox(height: 12),
          PeriodCard(period: t.periodWeek, metrics: metricsFor(7)),
          const SizedBox(height: 12),
          PeriodCard(period: t.periodToday, metrics: metricsFor(1)),
          const SizedBox(height: 20),
          // 折线卡
          Container(
            padding: const EdgeInsets.fromLTRB(16, 16, 16, 10),
            decoration: BoxDecoration(
              color: c.surface,
              borderRadius: BorderRadius.circular(PangolinRadius.lg),
              border: Border.all(color: c.border),
              boxShadow: PangolinShadow.sm,
            ),
            child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
              Row(mainAxisAlignment: MainAxisAlignment.spaceBetween, children: [
                Text(t.chartTwoWeeks,
                    style: PangolinText.sm.copyWith(color: c.fg1, fontWeight: FontWeight.w600, fontSize: 13)),
                Text('GB', style: PangolinText.mono.copyWith(color: c.fg3, fontSize: 11)),
              ]),
              const SizedBox(height: 10),
              UsageLineChart(
                values: chartVals,
                dates: chartDates,
                accent: c.accent,
                grid: c.border,
                axis: c.fg3,
                surface: c.surface,
              ),
            ]),
          ),
        ],
      ),
    );

    if (isWide) return body;
    return Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
      AppTopBar(brand: t.brand),
      PageTitle(title: t.statsTitle),
      Expanded(child: body),
    ]);
  }
}

/// 字节 → (数值, 单位):<1GB 显示 MB,否则 GB(各 1 位小数)。
(String, String) _fmtBytes(int bytes) {
  const gb = 1024 * 1024 * 1024, mb = 1024 * 1024;
  if (bytes >= gb) return ((bytes / gb).toStringAsFixed(1), 'GB');
  return ((bytes / mb).toStringAsFixed(1), 'MB');
}

/// 统计页选中的设备(null = 全部;否则 device uuid)。第②层(按设备过滤卡/图)
/// 待 per-device 每日曲线 API(#10)；本层先把下拉内容接成真实设备。
final statsDeviceProvider = StateProvider<String?>((ref) => null);

/// 设备下拉(右上角):「全部」+ 用户**已登录的真实设备**(来自 devicesProvider,
/// 即 GET /v1/me/devices)。选某台 → 卡片/折线只算那台(#10②)。
class _DeviceDropdown extends ConsumerWidget {
  const _DeviceDropdown({required this.t});
  final AppText t;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final c = context.pangolin;
    final devices = ref.watch(devicesProvider).valueOrNull ?? const <Device>[];
    final selected = ref.watch(statsDeviceProvider);
    String nameOf(String uuid) {
      final d = devices.where((e) => e.uuid == uuid);
      return d.isEmpty ? '' : (d.first.name.isNotEmpty ? d.first.name : d.first.platform);
    }

    final label = selected == null
        ? t.allDevices
        : (nameOf(selected).isNotEmpty ? nameOf(selected) : t.allDevices);

    return PopupMenuButton<String>(
      tooltip: '',
      offset: const Offset(0, 38),
      color: c.surface,
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(PangolinRadius.md),
        side: BorderSide(color: c.border),
      ),
      onSelected: (v) => ref.read(statsDeviceProvider.notifier).state = v.isEmpty ? null : v,
      itemBuilder: (_) => [
        PopupMenuItem(value: '', child: Text(t.allDevices, style: PangolinText.sm.copyWith(color: c.fg1))),
        for (final d in devices)
          PopupMenuItem(
            value: d.uuid,
            child: Text(d.name.isNotEmpty ? d.name : d.platform, style: PangolinText.sm.copyWith(color: c.fg1)),
          ),
      ],
      child: Container(
        padding: const EdgeInsets.fromLTRB(12, 6, 10, 6),
        decoration: BoxDecoration(
          color: c.surface,
          border: Border.all(color: c.borderStrong),
          borderRadius: BorderRadius.circular(PangolinRadius.full),
        ),
        child: Row(mainAxisSize: MainAxisSize.min, children: [
          Icon(PangolinIcons.smartphone, size: 14, color: c.accent),
          const SizedBox(width: 7),
          Text(label, style: PangolinText.caption.copyWith(color: c.fg2, fontWeight: FontWeight.w600, fontSize: 12.5)),
          const SizedBox(width: 5),
          Icon(PangolinIcons.chevronDown, size: 13, color: c.fg3),
        ]),
      ),
    );
  }
}