/// 连拍页（P3 计划 Task 9，R17 连拍入队 / O01 现场反馈）。
///
/// 进入时选定目标相册与分类（相册详情 FAB 传入）；快门每张立即经准备器
/// 入队（preparing→queued，不逐张确认）；常驻信息层：相册名 + 分类（可
/// 切换，**仅影响之后拍摄**——引擎只读任务行归属，切换不改既有任务）+
/// 待传/失败徽章（TaskStore 写通知实时刷新）。相册多选按钮补充入队；
/// 退出时若有待传任务弹确认（任务在后台继续——Android 原生 WorkManager
/// 承担，见 native_transport.dart）。
///
/// 相机/相册经注入点（[captureSourceFactoryProvider]/[multiImagePickerProvider]）
/// 隔离平台通道，widget 测试注入替身驱动。
library;

import 'dart:async';

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

import '../features/albums/models.dart';
import '../features/uploads/enqueue.dart';
import '../features/uploads/queue_controller.dart';
import '../l10n/app_localizations.dart';

// ── 相机源抽象（生产=camera 插件；测试替身） ─────────────────────────────

/// 拍摄源：初始化/拍摄/预览/释放。
abstract class CaptureSource {
  /// 初始化（权限缺失/失败抛异常；权限拒绝抛 [CameraException]）。
  Future<void> initialize();

  /// 拍摄一张（返回源文件）。
  Future<XFile> capture();

  /// 取景预览。
  Widget buildPreview();

  /// 释放底层资源。
  Future<void> dispose();
}

/// 生产拍摄源：camera 插件（后摄优先，最高分辨率，静音连拍）。
class CameraPluginSource implements CaptureSource {
  CameraPluginSource._(this._controller);

  /// 创建并初始化（后摄优先）。
  static Future<CameraPluginSource> create() async {
    final cameras = await availableCameras();
    if (cameras.isEmpty) {
      throw CameraException('noCamera', 'no camera available');
    }
    final back = cameras.firstWhere(
      (c) => c.lensDirection == CameraLensDirection.back,
      orElse: () => cameras.first,
    );
    final controller = CameraController(back, ResolutionPreset.max,
        enableAudio: false);
    await controller.initialize();
    return CameraPluginSource._(controller);
  }

  final CameraController _controller;

  @override
  Future<void> initialize() async {}

  @override
  Future<XFile> capture() => _controller.takePicture();

  @override
  Widget buildPreview() => CameraPreview(_controller);

  @override
  Future<void> dispose() => _controller.dispose();
}

/// 拍摄源工厂 Provider（测试 override 为替身）。
final captureSourceFactoryProvider =
    Provider<Future<CaptureSource> Function()>((ref) => CameraPluginSource.create);

// ── 连拍页 ────────────────────────────────────────────────────────────────

/// 连拍页参数：目标相册（相册详情 FAB 进入时固定）与分类候选。
class CaptureTarget {
  const CaptureTarget({
    required this.accountId,
    required this.albumId,
    required this.albumTitle,
    this.categories = const <Category>[],
  });

  /// 入队账号（TaskStore 隔离键）。
  final String accountId;

  /// 目标相册 ID。
  final String albumId;

  /// 目标相册展示名（信息层常驻显示）。
  final String albumTitle;

  /// 相册分类（空 = 无可切换项，仅默认分类）。
  final List<Category> categories;
}

/// 连拍页。
class CapturePage extends ConsumerStatefulWidget {
  const CapturePage({required this.target, super.key});

  final CaptureTarget target;

  @override
  ConsumerState<CapturePage> createState() => _CapturePageState();
}

enum _CameraPhase { loading, ready, denied, failed }

class _CapturePageState extends ConsumerState<CapturePage> {
  CaptureSource? _source;
  _CameraPhase _phase = _CameraPhase.loading;

  /// 当前分类（null = 相册默认分类；切换仅影响之后拍摄）。
  String? _categoryId;

  /// 连拍串行链：快门连点逐张落地（相机硬件本就串行）。
  Future<void> _shotTail = Future<void>.value();

  @override
  void initState() {
    super.initState();
    _initCamera();
  }

  @override
  void dispose() {
    _source?.dispose().ignore();
    super.dispose();
  }

  Future<void> _initCamera() async {
    setState(() => _phase = _CameraPhase.loading);
    try {
      final source = await ref.read(captureSourceFactoryProvider)();
      await source.initialize();
      if (!mounted) {
        await source.dispose();
        return;
      }
      _source = source;
      setState(() => _phase = _CameraPhase.ready);
    } on Object catch (error) {
      if (!mounted) return;
      setState(() => _phase = _isPermissionDenied(error)
          ? _CameraPhase.denied
          : _CameraPhase.failed);
    }
  }

  /// camera 插件的权限拒绝错误码族（CameraAccessDenied /
  /// CameraAccessDeniedWithoutD restriction 等）。
  static bool _isPermissionDenied(Object error) =>
      error is CameraException &&
      (error.code.toLowerCase().contains('denied') ||
          error.code.toLowerCase().contains('permission'));

  /// 快门：立即入队（R17 不逐张确认）；连点串行不丢张。
  void _shoot() {
    final source = _source;
    if (source == null || _phase != _CameraPhase.ready) return;
    final categoryId = _categoryId;
    _shotTail = _shotTail.then((_) async {
      final photo = await source.capture();
      if (!mounted) return;
      await enqueueForUpload(
        ref,
        accountId: widget.target.accountId,
        albumId: widget.target.albumId,
        categoryId: categoryId,
        sourcePaths: [photo.path],
      );
    }).catchError((Object _) {
      // 单张失败吞掉（连拍不中断；失败任务/错误在徽章与队列页可见）。
    });
  }

  /// 相册多选入队（目标 = 当前相册与分类）。
  Future<void> _pickFromGallery() async {
    final paths = await ref.read(multiImagePickerProvider)();
    if (paths.isEmpty || !mounted) return;
    final l10n = AppLocalizations.of(context);
    final messenger = ScaffoldMessenger.of(context);
    final count = await enqueueForUpload(
      ref,
      accountId: widget.target.accountId,
      albumId: widget.target.albumId,
      categoryId: _categoryId,
      sourcePaths: paths,
    );
    if (!mounted) return;
    messenger.showSnackBar(
      SnackBar(content: Text(l10n.uploadEnqueuedCount(count))),
    );
  }

  void _switchCategory(String? categoryId) {
    if (categoryId == _categoryId) return;
    setState(() => _categoryId = categoryId);
    // 归属不变提示（A15）：仅影响之后拍摄。
    ScaffoldMessenger.of(context)
      ..hideCurrentSnackBar()
      ..showSnackBar(
        SnackBar(content: Text(AppLocalizations.of(context).captureSwitchHint)),
      );
  }

  Future<void> _confirmExit() async {
    final l10n = AppLocalizations.of(context);
    final leave = await showDialog<bool>(
      context: context,
      builder: (dialogContext) => AlertDialog(
        title: Text(l10n.captureExitTitle),
        content: Text(
          l10n.captureExitBody(pendingCountOf(ref.read(taskCountsProvider))),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(dialogContext).pop(false),
            child: Text(l10n.captureKeepShooting),
          ),
          FilledButton(
            onPressed: () => Navigator.of(dialogContext).pop(true),
            child: Text(l10n.captureExitConfirm),
          ),
        ],
      ),
    );
    if (leave == true && mounted) {
      Navigator.of(context).pop();
    }
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final counts = ref.watch(taskCountsProvider);
    final pending = pendingCountOf(counts);
    final failed = failedCountOf(counts);
    final categories = widget.target.categories;

    return PopScope(
      // 有待传任务 → 拦截退出弹确认（后台继续文案）；无任务直接退出。
      canPop: pending == 0,
      onPopInvokedWithResult: (didPop, _) {
        if (didPop) return;
        _confirmExit();
      },
      child: Scaffold(
        backgroundColor: Colors.black,
        appBar: AppBar(
          backgroundColor: Colors.black87,
          foregroundColor: Colors.white,
          title: Text(l10n.captureTitle),
        ),
        body: Stack(
          fit: StackFit.expand,
          children: [
            _buildCameraArea(l10n),
            // 常驻信息层：相册 + 分类 + 待传/失败徽章（R17/O01）。
            SafeArea(
              child: Column(
                children: [
                  _TargetOverlay(
                    albumTitle: widget.target.albumTitle,
                    categories: categories,
                    categoryId: _categoryId,
                    onCategorySelected: _switchCategory,
                    pending: pending,
                    failed: failed,
                  ),
                ],
              ),
            ),
          ],
        ),
        bottomNavigationBar: _buildBottomBar(l10n),
      ),
    );
  }

  Widget _buildCameraArea(AppLocalizations l10n) {
    final source = _source;
    switch (_phase) {
      case _CameraPhase.ready:
        return source!.buildPreview();
      case _CameraPhase.loading:
        return const Center(
          child: CircularProgressIndicator(color: Colors.white),
        );
      case _CameraPhase.denied:
        return _CameraMessageView(
          icon: Icons.no_photography_outlined,
          message: l10n.cameraPermissionDenied,
          actionLabel: l10n.retry,
          onAction: _initCamera,
        );
      case _CameraPhase.failed:
        return _CameraMessageView(
          icon: Icons.error_outline,
          message: l10n.cameraInitFailed,
          actionLabel: l10n.retry,
          onAction: _initCamera,
        );
    }
  }

  Widget _buildBottomBar(AppLocalizations l10n) {
    return BottomAppBar(
      color: Colors.black87,
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
        children: [
          IconButton(
            tooltip: l10n.capturePickFromGallery,
            icon: const Icon(Icons.photo_library_outlined,
                color: Colors.white),
            onPressed: _pickFromGallery,
          ),
          _ShutterButton(onPressed: _shoot, enabled: _phase == _CameraPhase.ready),
          // 占位对齐（快门居中）。
          const SizedBox(width: 48),
        ],
      ),
    );
  }
}

// ── 信息层组件 ────────────────────────────────────────────────────────────

/// 顶部常驻信息层：相册名 + 分类 chips（切换仅影响之后拍摄）+ 待传/失败
/// 徽章。
class _TargetOverlay extends StatelessWidget {
  const _TargetOverlay({
    required this.albumTitle,
    required this.categories,
    required this.categoryId,
    required this.onCategorySelected,
    required this.pending,
    required this.failed,
  });

  final String albumTitle;
  final List<Category> categories;
  final String? categoryId;
  final void Function(String?) onCategorySelected;
  final int pending;
  final int failed;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    return Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        Padding(
          padding: const EdgeInsets.fromLTRB(16, 8, 16, 0),
          child: Row(
            children: [
              const Icon(Icons.photo_album_outlined,
                  size: 16, color: Colors.white70),
              const SizedBox(width: 6),
              Expanded(
                child: Text(
                  albumTitle,
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                  style: const TextStyle(color: Colors.white),
                ),
              ),
              const SizedBox(width: 8),
              _Badge(
                label: l10n.capturePendingBadge(pending),
                color: Colors.white24,
                foreground: Colors.white,
              ),
              if (failed > 0) ...[
                const SizedBox(width: 6),
                _Badge(
                  label: l10n.captureFailedBadge(failed),
                  color: Colors.red,
                  foreground: Colors.white,
                ),
              ],
            ],
          ),
        ),
        if (categories.isNotEmpty)
          SizedBox(
            height: 44,
            child: ListView(
              scrollDirection: Axis.horizontal,
              padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 6),
              children: [
                ChoiceChip(
                  label: Text(l10n.captureCategoryDefault),
                  selected: categoryId == null,
                  onSelected: (_) => onCategorySelected(null),
                  labelStyle: const TextStyle(color: Colors.white),
                  selectedColor: Colors.white24,
                  backgroundColor: Colors.black38,
                ),
                for (final category in categories) ...[
                  const SizedBox(width: 8),
                  ChoiceChip(
                    label: Text(_categoryLabel(category, l10n)),
                    selected: categoryId == category.id,
                    onSelected: (_) => onCategorySelected(category.id),
                    labelStyle: const TextStyle(color: Colors.white),
                    selectedColor: Colors.white24,
                    backgroundColor: Colors.black38,
                  ),
                ],
              ],
            ),
          ),
      ],
    );
  }

  static String _categoryLabel(Category category, AppLocalizations l10n) {
    final lang = l10n.localeName.split('-').first.toLowerCase();
    CategoryTranslation? match;
    for (final t in category.translations) {
      if (t.locale.toLowerCase() == l10n.localeName.toLowerCase() ||
          t.locale.toLowerCase().split('-').first == lang) {
        match = t;
        break;
      }
    }
    if (match != null) return match.name;
    return category.translations.isEmpty
        ? category.id
        : category.translations.first.name;
  }
}

/// 徽章（待传/失败计数）。
class _Badge extends StatelessWidget {
  const _Badge({
    required this.label,
    required this.color,
    required this.foreground,
  });

  final String label;
  final Color color;
  final Color foreground;

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
      decoration: BoxDecoration(
        color: color,
        borderRadius: BorderRadius.circular(999),
      ),
      child: Text(
        label,
        style: TextStyle(color: foreground, fontSize: 12),
      ),
    );
  }
}

/// 快门按钮（连拍：不进入模态确认，逐张自动入队）。
class _ShutterButton extends StatelessWidget {
  const _ShutterButton({required this.onPressed, required this.enabled});

  final VoidCallback onPressed;
  final bool enabled;

  @override
  Widget build(BuildContext context) {
    return Semantics(
      button: true,
      label: AppLocalizations.of(context).captureShutter,
      child: IconButton(
        onPressed: enabled ? onPressed : null,
        iconSize: 64,
        icon: Container(
          width: 64,
          height: 64,
          decoration: BoxDecoration(
            shape: BoxShape.circle,
            border: Border.all(color: Colors.white, width: 4),
          ),
          child: const Icon(Icons.camera, color: Colors.white),
        ),
      ),
    );
  }
}

/// 相机不可用视图（权限拒绝/初始化失败）：说明 + 重试。
class _CameraMessageView extends StatelessWidget {
  const _CameraMessageView({
    required this.icon,
    required this.message,
    required this.actionLabel,
    required this.onAction,
  });

  final IconData icon;
  final String message;
  final String actionLabel;
  final VoidCallback onAction;

  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.black87,
      child: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(icon, size: 48, color: Colors.white70),
            const SizedBox(height: 12),
            Padding(
              padding: const EdgeInsets.symmetric(horizontal: 32),
              child: Text(
                message,
                textAlign: TextAlign.center,
                style: const TextStyle(color: Colors.white),
              ),
            ),
            const SizedBox(height: 16),
            FilledButton.icon(
              onPressed: onAction,
              icon: const Icon(Icons.refresh),
              label: Text(actionLabel),
            ),
          ],
        ),
      ),
    );
  }
}