/// 上传队列页（P3 计划 Task 9，需求 4.3 / R17 / O01）。
///
/// 三维筛选（相册下拉 × 状态 chips × 时间快捷）→ [QueueFilter]；任务行
/// = 缩略图（受管副本，缺失/已清理显示占位）+ 文件名 + 相册名 + 状态
/// 徽章 + 尝试/错误（本地化错误码）+ 传输进度（进度总线行级订阅）+ 按
/// 状态动作（重试/取消/删除）；失败任务存在时底部「一键重试全部失败」。
/// 列表经 TaskStore 写通知 + 200ms 防抖实时刷新（连拍风暴不逐条重建）。
library;

import 'dart:io';

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../features/albums/models.dart';
import '../features/albums/providers.dart';
import '../features/uploads/engine_scope.dart';
import '../features/uploads/enqueue.dart';
import '../features/uploads/providers.dart';
import '../features/uploads/queue_controller.dart';
import '../features/uploads/queue_l10n.dart';
import '../features/uploads/task_state.dart';
import '../features/uploads/task_store.dart';
import '../l10n/app_localizations.dart';

/// 队列 Tab（主壳 IndexedStack 内常驻）。
class QueueTab extends ConsumerWidget {
  const QueueTab({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final l10n = AppLocalizations.of(context);
    final counts = ref.watch(taskCountsProvider);
    final autoRetryable = (counts[UploadTaskState.retryableFailed] ?? 0) +
        (counts[UploadTaskState.waitingNetwork] ?? 0);
    return Scaffold(
      appBar: AppBar(
        title: Text(l10n.queue),
        actions: [
          IconButton(
            tooltip: l10n.serverHistoryEntry,
            icon: const Icon(Icons.history_outlined),
            onPressed: () =>
                Navigator.of(context).pushNamed('/server-history'),
          ),
        ],
      ),
      body: const Column(
        children: [
          _FilterBar(),
          Expanded(child: _TaskListView()),
        ],
      ),
      bottomNavigationBar: autoRetryable > 0 ? const _BatchRetryBar() : null,
    );
  }
}

// ── 筛选栏 ────────────────────────────────────────────────────────────────

/// 筛选栏：相册下拉 + 时间快捷 chips + 状态分组 chips（需求 4.3 三维）。
class _FilterBar extends ConsumerWidget {
  const _FilterBar();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final l10n = AppLocalizations.of(context);
    final theme = Theme.of(context);
    final filter = ref.watch(queueFilterProvider);
    final albums = ref.watch(albumListProvider).items;

    return Material(
      color: theme.colorScheme.surfaceContainerLow,
      child: Padding(
        padding: const EdgeInsets.fromLTRB(16, 8, 16, 4),
        child: Column(
          children: [
            Row(
              children: [
                Icon(Icons.filter_list,
                    size: 18, color: theme.colorScheme.onSurfaceVariant),
                const SizedBox(width: 8),
                Expanded(child: _AlbumDropdown(filter: filter, albums: albums)),
              ],
            ),
            const SizedBox(height: 4),
            SingleChildScrollView(
              scrollDirection: Axis.horizontal,
              child: Row(
                children: [
                  for (final (i, time) in QueueTimeFilter.values.indexed) ...[
                    if (i > 0) const SizedBox(width: 8),
                    ChoiceChip(
                      label: Text(_timeLabel(l10n, time)),
                      selected: filter.time == time,
                      onSelected: (_) => ref
                          .read(queueFilterProvider.notifier)
                          .setTime(time),
                      visualDensity: VisualDensity.compact,
                    ),
                  ],
                ],
              ),
            ),
            const SizedBox(height: 4),
            SingleChildScrollView(
              scrollDirection: Axis.horizontal,
              child: Row(
                children: [
                  for (final (i, state) in QueueStateFilter.values.indexed) ...[
                    if (i > 0) const SizedBox(width: 8),
                    ChoiceChip(
                      label: Text(_stateLabel(l10n, state)),
                      selected: filter.state == state,
                      onSelected: (_) => ref
                          .read(queueFilterProvider.notifier)
                          .setStateGroup(state),
                      visualDensity: VisualDensity.compact,
                    ),
                  ],
                ],
              ),
            ),
            const SizedBox(height: 4),
          ],
        ),
      ),
    );
  }

  static String _stateLabel(AppLocalizations l10n, QueueStateFilter state) =>
      switch (state) {
        QueueStateFilter.all => l10n.queueStateAll,
        QueueStateFilter.preparing => l10n.queueStatePreparing,
        QueueStateFilter.queued => l10n.queueStateQueued,
        QueueStateFilter.uploading => l10n.queueStateUploading,
        QueueStateFilter.waitingNetwork => l10n.queueStateWaitingNetwork,
        QueueStateFilter.failed => l10n.queueStateFailed,
        QueueStateFilter.completed => l10n.queueStateCompleted,
      };

  static String _timeLabel(AppLocalizations l10n, QueueTimeFilter time) =>
      switch (time) {
        QueueTimeFilter.all => l10n.queueTimeAll,
        QueueTimeFilter.today => l10n.queueTimeToday,
        QueueTimeFilter.last7Days => l10n.queueTimeLast7Days,
        QueueTimeFilter.last30Days => l10n.queueTimeLast30Days,
      };
}

/// 相册下拉（全部相册 + 相册列表缓存；选中相册不在列表时退回全部）。
class _AlbumDropdown extends ConsumerWidget {
  const _AlbumDropdown({required this.filter, required this.albums});

  final QueueFilter filter;
  final List<AlbumSummary> albums;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final l10n = AppLocalizations.of(context);
    final knownIds = albums.map((a) => a.id).toSet();
    final value =
        filter.albumId != null && knownIds.contains(filter.albumId)
            ? filter.albumId
            : null;
    return DropdownButton<String?>(
      value: value,
      isExpanded: true,
      underline: const SizedBox.shrink(),
      hint: Text(l10n.queueAlbumFilterAll),
      items: [
        DropdownMenuItem<String?>(
          value: null,
          child: Text(
            l10n.queueAlbumFilterAll,
            style: Theme.of(context).textTheme.bodyMedium,
          ),
        ),
        for (final album in albums)
          DropdownMenuItem<String?>(
            value: album.id,
            child: Text(
              albumDisplayTitle(album, l10n.localeName),
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
            ),
          ),
      ],
      onChanged: (albumId) =>
          ref.read(queueFilterProvider.notifier).setAlbum(albumId),
    );
  }
}

// ── 任务列表 ──────────────────────────────────────────────────────────────

class _TaskListView extends ConsumerWidget {
  const _TaskListView();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final l10n = AppLocalizations.of(context);
    final tasksAsync = ref.watch(queueTasksProvider);
    return tasksAsync.when(
      skipLoadingOnReload: true,
      loading: () => const Center(child: CircularProgressIndicator()),
      error: (error, _) => Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Text(l10n.errorGeneric),
            const SizedBox(height: 8),
            FilledButton.tonal(
              onPressed: () => ref.invalidate(queueTasksProvider),
              child: Text(l10n.retry),
            ),
          ],
        ),
      ),
      data: (tasks) {
        if (tasks.isEmpty) {
          return Center(child: Text(l10n.queueEmpty));
        }
        return ListView.builder(
          padding: const EdgeInsets.symmetric(vertical: 4),
          itemCount: tasks.length,
          itemBuilder: (context, index) =>
              _TaskTile(task: tasks[index]),
        );
      },
    );
  }
}

/// 单条任务行。
class _TaskTile extends ConsumerWidget {
  const _TaskTile({required this.task});

  final UploadTask task;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final l10n = AppLocalizations.of(context);
    final theme = Theme.of(context);
    final album = ref
        .watch(albumListProvider)
        .items
        .where((a) => a.id == task.albumId)
        .firstOrNull;
    final albumName = album != null
        ? albumDisplayTitle(album, l10n.localeName)
        : task.albumId;
    final failedLike = task.state == UploadTaskState.preparationFailed ||
        task.state == UploadTaskState.retryableFailed ||
        task.state == UploadTaskState.waitingNetwork;

    return ListTile(
      leading: _Thumb(
        path: task.cleanedAt == null ? task.sourceFilePath : null,
      ),
      title: Text(
        task.filename,
        maxLines: 1,
        overflow: TextOverflow.ellipsis,
      ),
      subtitle: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const SizedBox(height: 2),
          Row(
            children: [
              _StateChip(state: task.state),
              const SizedBox(width: 8),
              Expanded(
                child: Text(
                  albumName,
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                  style: theme.textTheme.bodySmall
                      ?.copyWith(color: theme.colorScheme.onSurfaceVariant),
                ),
              ),
            ],
          ),
          if (failedLike && task.lastError != null) ...[
            const SizedBox(height: 2),
            Text(
              task.attempt > 0
                  ? '${l10n.messageForTaskError(task.lastError!)} · '
                      '${l10n.queueAttemptCount(task.attempt)}'
                  : l10n.messageForTaskError(task.lastError!),
              maxLines: 2,
              overflow: TextOverflow.ellipsis,
              style: theme.textTheme.bodySmall
                  ?.copyWith(color: theme.colorScheme.error),
            ),
          ],
          if (task.state == UploadTaskState.uploading ||
              task.state == UploadTaskState.uploadedConfirming)
            _ProgressLine(
              taskId: task.id,
              confirming: task.state == UploadTaskState.uploadedConfirming,
            ),
        ],
      ),
      trailing: _TaskActions(task: task),
    );
  }
}

/// 缩略图：受管副本存在则显示，缺失/已清理/解码失败显示占位图标。
class _Thumb extends StatelessWidget {
  const _Thumb({required this.path});

  final String? path;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    Widget placeholder() => Container(
          width: 48,
          height: 48,
          decoration: BoxDecoration(
            color: theme.colorScheme.surfaceContainerHighest,
            borderRadius: BorderRadius.circular(6),
          ),
          child: Icon(
            Icons.image_outlined,
            size: 24,
            color: theme.colorScheme.onSurfaceVariant,
          ),
        );
    if (path == null) return placeholder();
    return ClipRRect(
      borderRadius: BorderRadius.circular(6),
      child: SizedBox(
        width: 48,
        height: 48,
        child: Image.file(
          File(path!),
          fit: BoxFit.cover,
          errorBuilder: (_, _, _) => placeholder(),
        ),
      ),
    );
  }
}

/// 状态徽章（分组配色：失败红/完成绿/进行中主色/等待橙/其余中性）。
class _StateChip extends StatelessWidget {
  const _StateChip({required this.state});

  final UploadTaskState state;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final theme = Theme.of(context);
    final (color, onColor) = switch (state) {
      UploadTaskState.preparing => (
          theme.colorScheme.surfaceContainerHighest,
          theme.colorScheme.onSurfaceVariant
        ),
      UploadTaskState.preparationFailed ||
      UploadTaskState.retryableFailed => (
          theme.colorScheme.errorContainer,
          theme.colorScheme.onErrorContainer
        ),
      UploadTaskState.queued => (
          theme.colorScheme.secondaryContainer,
          theme.colorScheme.onSecondaryContainer
        ),
      UploadTaskState.uploading ||
      UploadTaskState.uploadedConfirming => (
          theme.colorScheme.primaryContainer,
          theme.colorScheme.onPrimaryContainer
        ),
      UploadTaskState.completed => (
          theme.colorScheme.tertiaryContainer,
          theme.colorScheme.onTertiaryContainer
        ),
      UploadTaskState.waitingNetwork => (
          theme.colorScheme.tertiaryContainer,
          theme.colorScheme.onTertiaryContainer
        ),
      UploadTaskState.cancelled => (
          theme.colorScheme.surfaceContainerHighest,
          theme.colorScheme.onSurfaceVariant
        ),
    };
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
      decoration: BoxDecoration(
        color: color,
        borderRadius: BorderRadius.circular(999),
      ),
      child: Text(
        l10n.labelForTaskState(state),
        style: theme.textTheme.labelSmall?.copyWith(color: onColor),
      ),
    );
  }
}

/// 传输进度行：上传中 = 进度总线行级订阅（分数进度条）；确认中 = 不确定
/// 进度条（等待服务端核验）。
class _ProgressLine extends ConsumerWidget {
  const _ProgressLine({required this.taskId, required this.confirming});

  final String taskId;
  final bool confirming;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return Padding(
      padding: const EdgeInsets.only(top: 6, right: 8),
      child: StreamBuilder<UploadTaskProgress>(
        stream: ref
            .watch(uploadProgressHubProvider)
            .stream
            .where((p) => p.taskId == taskId),
        builder: (context, snapshot) {
          final fraction = snapshot.data?.fraction;
          return LinearProgressIndicator(
            value: confirming ? null : fraction,
            minHeight: 4,
          );
        },
      ),
    );
  }
}

/// 行级动作（按状态；未登录账号缺席时禁用）。
class _TaskActions extends ConsumerWidget {
  const _TaskActions({required this.task});

  final UploadTask task;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final l10n = AppLocalizations.of(context);
    final account = ref.watch(sessionAccountProvider).value;
    switch (task.state) {
      case UploadTaskState.preparationFailed:
        // 准备失败重试 = 重新选图（原始源路径不落库，见准备器注释）。
        return IconButton(
          tooltip: l10n.retry,
          icon: const Icon(Icons.refresh),
          onPressed: account == null
              ? null
              : () => _retryPreparation(context, ref, account),
        );
      case UploadTaskState.retryableFailed:
      case UploadTaskState.waitingNetwork:
        return IconButton(
          tooltip: l10n.retry,
          icon: const Icon(Icons.refresh),
          onPressed: account == null
              ? null
              : () => ref
                  .read(uploadEngineProvider)
                  .retryNow(account, task.id),
        );
      case UploadTaskState.queued:
      case UploadTaskState.preparing:
        return IconButton(
          tooltip: l10n.cancel,
          icon: const Icon(Icons.close),
          onPressed: account == null
              ? null
              : () => ref.read(uploadEngineProvider).cancel(account, task.id),
        );
      case UploadTaskState.completed:
      case UploadTaskState.cancelled:
        return IconButton(
          tooltip: l10n.delete,
          icon: const Icon(Icons.delete_outline),
          onPressed: account == null ? null : () => _delete(ref, account),
        );
      case UploadTaskState.uploading:
      case UploadTaskState.uploadedConfirming:
        return const SizedBox(width: 48);
    }
  }

  /// 准备失败重试：重新选图 → preparer.retry（换源重新复制入队）。
  Future<void> _retryPreparation(
    BuildContext context,
    WidgetRef ref,
    String account,
  ) async {
    final l10n = AppLocalizations.of(context);
    final sourcePath = await ref.read(singleImagePickerProvider)();
    if (sourcePath == null || !context.mounted) return;
    final messenger = ScaffoldMessenger.of(context);
    try {
      await ref.read(uploadPreparerProvider).retry(
            accountId: account,
            taskId: task.id,
            sourcePath: sourcePath,
          );
    } on Object {
      messenger.showSnackBar(
        SnackBar(content: Text(l10n.errorGeneric)),
      );
    }
  }

  /// 终态删除：删行 + 尽力删受管副本（行删除后清理执行器不再可见该文件）。
  Future<void> _delete(WidgetRef ref, String account) async {
    final store = ref.read(taskStoreProvider);
    await store.delete(task.id);
    if (task.cleanedAt == null) {
      try {
        final file = File(task.sourceFilePath);
        if (await file.exists()) {
          await file.delete();
        }
      } on Object {
        // 文件删除失败接受（无行可追责，残留由用户重装/系统清理回收）。
      }
    }
  }
}

/// 底部批量重试条（存在可自动重试的失败任务时出现）。
class _BatchRetryBar extends ConsumerWidget {
  const _BatchRetryBar();

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final l10n = AppLocalizations.of(context);
    final theme = Theme.of(context);
    final counts = ref.watch(taskCountsProvider);
    final failed = failedCountOf(counts);
    return Material(
      color: theme.colorScheme.errorContainer,
      child: SafeArea(
        child: Padding(
          padding: const EdgeInsets.fromLTRB(16, 8, 16, 8),
          child: Row(
            children: [
              Icon(Icons.error_outline, color: theme.colorScheme.onErrorContainer),
              const SizedBox(width: 8),
              Expanded(
                child: Text(
                  '${l10n.queueStateFailed} · $failed',
                  style: theme.textTheme.bodyMedium
                      ?.copyWith(color: theme.colorScheme.onErrorContainer),
                ),
              ),
              FilledButton.icon(
                style: FilledButton.styleFrom(
                  backgroundColor: theme.colorScheme.error,
                  foregroundColor: theme.colorScheme.onError,
                ),
                icon: const Icon(Icons.refresh, size: 18),
                label: Text(l10n.queueRetryAllFailed),
                onPressed: () => _retryAll(ref),
              ),
            ],
          ),
        ),
      ),
    );
  }

  /// 全部可自动重试任务（retryableFailed + waitingNetwork，跨当前筛选）
  /// 立即重新入队。
  Future<void> _retryAll(WidgetRef ref) async {
    final account = ref.read(sessionAccountProvider).value;
    if (account == null) return;
    final engine = ref.read(uploadEngineProvider);
    final tasks = await ref.read(taskStoreProvider).listByAccount(
          account,
          states: const {
            UploadTaskState.retryableFailed,
            UploadTaskState.waitingNetwork,
          },
        );
    for (final task in tasks) {
      await engine.retryNow(account, task.id);
    }
  }
}