import 'dart:io';
import 'dart:math' as math;
import 'dart:ui' as ui;

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

import '../../../api/geo_api.dart';
import '../../../api/photo_api.dart';
import '../../../core/network/api_exception.dart';
import '../../../models/watermark.dart';
import '../../../providers/watermark_provider.dart';
import '../../../utils/toast.dart';
import '../../../widgets/state_views.dart';
import 'watermark_painter.dart';
import 'widgets/watermark_content_sheet.dart';
import 'widgets/watermark_settings_sheet.dart';

/// 水印编辑页：预览（照片 + 水印）+ 拖动定位 + 保存到相册
///
/// 水印是**本地合成**的 —— 服务器那份只是原图备份。
class WatermarkEditPage extends ConsumerStatefulWidget {
  const WatermarkEditPage({super.key, required this.imagePath});

  final String imagePath;

  @override
  ConsumerState<WatermarkEditPage> createState() => _WatermarkEditPageState();
}

enum _UploadStatus { waiting, uploading, done, failed }

class _WatermarkEditPageState extends ConsumerState<WatermarkEditPage> {
  Size? _imageSize;
  String? _imageError;

  late WatermarkData _data;

  bool _locating = false;
  String? _locateError;

  /// 定位到的坐标（上传原图时一并存到服务器）
  double? _latitude;
  double? _longitude;

  _UploadStatus _upload = _UploadStatus.waiting;
  String? _uploadError;
  bool _saving = false;

  @override
  void initState() {
    super.initState();
    _data = WatermarkData(time: DateTime.now());
    _loadImageSize();
    // 先定位、再上传 —— 这样服务器那份记录能带上地址和天气
    _locateThenUpload();
  }

  // ---------------- 图片尺寸 ----------------

  Future<void> _loadImageSize() async {
    setState(() => _imageError = null);
    try {
      // 只读文件头拿尺寸，不整张解码（12MP 全解码要 48MB 内存）
      final bytes = await File(widget.imagePath).readAsBytes();
      final buffer = await ui.ImmutableBuffer.fromUint8List(bytes);
      final descriptor = await ui.ImageDescriptor.encoded(buffer);
      final size = Size(descriptor.width.toDouble(), descriptor.height.toDouble());
      descriptor.dispose();
      buffer.dispose();
      if (!mounted) return;
      setState(() => _imageSize = size);
    } catch (_) {
      if (!mounted) return;
      setState(() => _imageError = '这张照片读不出来，换一张试试');
    }
  }

  // ---------------- 定位 ----------------

  Future<void> _locateThenUpload() async {
    await _locate();
    await _uploadOriginal();
  }

  Future<void> _locate() async {
    if (!mounted) return;
    setState(() {
      _locating = true;
      _locateError = null;
    });

    final snapshot = await ref.read(geoApiProvider).resolve();
    if (!mounted) return;

    setState(() {
      _locating = false;
      _locateError = snapshot.error;
      _latitude = snapshot.latitude;
      _longitude = snapshot.longitude;
      _data = _data.copyWith(
        address: snapshot.address,
        weather: snapshot.weather,
        temperature: snapshot.temperature,
      );
    });
  }

  // ---------------- 上传原图 ----------------

  Future<void> _uploadOriginal() async {
    if (!mounted) return;
    setState(() {
      _upload = _UploadStatus.uploading;
      _uploadError = null;
    });

    try {
      await ref.read(photoApiProvider).upload(
            filePath: widget.imagePath,
            latitude: _latitude,
            longitude: _longitude,
            address: _data.address,
            weather: _weatherText(),
            remark: _data.remark,
            takenTime: _data.time,
          );
      if (!mounted) return;
      setState(() => _upload = _UploadStatus.done);
    } on ApiException catch (e) {
      if (!mounted) return;
      setState(() {
        _upload = _UploadStatus.failed;
        _uploadError = e.message;
      });
    } catch (_) {
      if (!mounted) return;
      setState(() {
        _upload = _UploadStatus.failed;
        _uploadError = '网络异常';
      });
    }
  }

  String _weatherText() {
    final joined = '${_data.weather} ${_data.temperature}'.trim();
    return joined;
  }

  // ---------------- 保存 ----------------

  Future<void> _save() async {
    if (_saving) return;
    final settings = ref.read(watermarkSettingsProvider);
    final brandIcon = ref.read(brandIconProvider).value;

    setState(() => _saving = true);
    try {
      final bytes = await File(widget.imagePath).readAsBytes();
      final jpeg = await composeWatermarkedJpeg(
        originalBytes: bytes,
        settings: settings,
        data: _data,
        brandIcon: brandIcon,
      );

      // gal 的约定：name 不带扩展名
      await Gal.putImageBytes(jpeg, name: 'qiangbao_${_timestamp()}');

      if (!mounted) return;
      showToast(context, '已保存到相册', icon: 'check');
    } on GalException catch (e) {
      if (!mounted) return;
      showToast(context, e.type.message, error: true);
    } catch (e) {
      if (!mounted) return;
      showToast(context, '保存失败，请重试', error: true);
    } finally {
      if (mounted) setState(() => _saving = false);
    }
  }

  String _timestamp() {
    final t = DateTime.now();
    String two(int n) => n.toString().padLeft(2, '0');
    return '${t.year}${two(t.month)}${two(t.day)}_${two(t.hour)}${two(t.minute)}${two(t.second)}';
  }

  // ---------------- 拖动 ----------------

  Size _fitSize(Size source, Size box) {
    if (source.width <= 0 || source.height <= 0 || box.width <= 0 || box.height <= 0) {
      return Size.zero;
    }
    final scale = math.min(box.width / source.width, box.height / source.height);
    return Size(source.width * scale, source.height * scale);
  }

  void _onDrag(DragUpdateDetails details, Size displaySize, WatermarkSettings settings) {
    final layout = layoutWatermark(displaySize, settings, _data);
    if (layout.isEmpty) return; // 正文都关掉了，没什么可拖

    // 位置公式和绘制共用 layoutWatermark，所以拖到哪就画到哪
    final nextX = layout.origin.dx + details.delta.dx;
    final nextY = layout.origin.dy + details.delta.dy;

    final maxX = math.max(0.0, displaySize.width - layout.cardWidth);
    final maxY = math.max(0.0, displaySize.height - layout.cardHeight);

    ref.read(watermarkSettingsProvider.notifier).updatePosition(
          nextX.clamp(0.0, maxX) / displaySize.width,
          nextY.clamp(0.0, maxY) / displaySize.height,
        );
  }

  // ---------------- 构建 ----------------

  @override
  Widget build(BuildContext context) {
    return PopScope(
      canPop: !_saving,
      child: Scaffold(
        appBar: AppBar(
          title: const Text('加水印'),
          actions: [
            TextButton(
              onPressed: _saving ? null : _save,
              child: _saving
                  ? const SizedBox(
                      width: 16,
                      height: 16,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : const Text(
                      '保存',
                      style: TextStyle(
                        fontSize: 15,
                        fontWeight: FontWeight.w600,
                        color: Color(0xFFC8956E),
                      ),
                    ),
            ),
            const SizedBox(width: 8),
          ],
        ),
        body: Column(
          children: [
            _uploadBar(),
            _locationBar(),
            Expanded(child: _preview()),
            const Padding(
              padding: EdgeInsets.symmetric(vertical: 6),
              child: Text(
                '按住水印可以拖动位置',
                style: TextStyle(fontSize: 11.5, color: Color(0xFFBCAAA4)),
              ),
            ),
            _toolbar(),
          ],
        ),
      ),
    );
  }

  Widget _preview() {
    if (_imageError != null) {
      return Center(
        child: ErrorView(message: _imageError!, onRetry: _loadImageSize),
      );
    }
    final imageSize = _imageSize;
    if (imageSize == null) {
      return const Center(child: LoadingView(tip: '正在读取照片...'));
    }

    final settings = ref.watch(watermarkSettingsProvider);
    final brandIcon = ref.watch(brandIconProvider).value;

    return LayoutBuilder(
      builder: (context, constraints) {
        final displaySize = _fitSize(imageSize, constraints.biggest);
        if (displaySize.width <= 0 || displaySize.height <= 0) {
          return const SizedBox.shrink();
        }
        return Center(
          child: GestureDetector(
            onPanUpdate: (d) => _onDrag(d, displaySize, settings),
            // 松手才落盘：拖动过程每帧都写 SharedPreferences 太浪费
            onPanEnd: (_) =>
                ref.read(watermarkSettingsProvider.notifier).persistPosition(),
            onPanCancel: () =>
                ref.read(watermarkSettingsProvider.notifier).persistPosition(),
            child: SizedBox(
              width: displaySize.width,
              height: displaySize.height,
              child: Stack(
                fit: StackFit.expand,
                children: [
                  Image.file(
                    File(widget.imagePath),
                    fit: BoxFit.fill, // 尺寸已按 contain 算好，这里填满即可
                    gaplessPlayback: true,
                  ),
                  CustomPaint(
                    painter: WatermarkPainter(
                      settings: settings,
                      data: _data,
                      brandIcon: brandIcon,
                    ),
                  ),
                ],
              ),
            ),
          ),
        );
      },
    );
  }

  /// 原图上传状态条
  Widget _uploadBar() {
    final (String text, Color color) = switch (_upload) {
      _UploadStatus.waiting => ('准备上传原图', const Color(0xFFBCAAA4)),
      _UploadStatus.uploading => ('正在上传原图…', const Color(0xFF8D6E63)),
      _UploadStatus.done => ('原图已备份到服务器', const Color(0xFF19BE6B)),
      _UploadStatus.failed => (
          _uploadError == null ? '原图上传失败' : '原图上传失败：$_uploadError',
          const Color(0xFFE53935),
        ),
    };

    return Container(
      width: double.infinity,
      color: const Color(0xFFF7F4F1),
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
      child: Row(
        children: [
          Icon(Icons.circle, size: 8, color: color),
          const SizedBox(width: 8),
          Expanded(
            child: Text(
              text,
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
              style: TextStyle(fontSize: 12, color: color),
            ),
          ),
          if (_upload == _UploadStatus.failed)
            GestureDetector(
              onTap: _uploadOriginal,
              child: const Text(
                '重试',
                style: TextStyle(
                  fontSize: 12,
                  color: Color(0xFFC8956E),
                  fontWeight: FontWeight.w600,
                ),
              ),
            ),
        ],
      ),
    );
  }

  /// 定位/地址条
  Widget _locationBar() {
    final String text;
    if (_locating) {
      text = '正在定位…';
    } else if (_locateError != null) {
      text = _locateError!;
    } else if (_data.address.isEmpty) {
      text = '未获取到位置';
    } else {
      text = _data.address;
    }

    return Container(
      width: double.infinity,
      color: Colors.white,
      padding: const EdgeInsets.fromLTRB(16, 10, 12, 10),
      child: Row(
        children: [
          const Icon(Icons.location_on_outlined, size: 16, color: Color(0xFFC8956E)),
          const SizedBox(width: 6),
          Expanded(
            child: Text(
              text,
              maxLines: 2,
              overflow: TextOverflow.ellipsis,
              style: TextStyle(
                fontSize: 13,
                height: 1.4,
                color: _locateError != null
                    ? const Color(0xFFE53935)
                    : const Color(0xFF5D4037),
              ),
            ),
          ),
          TextButton(
            onPressed: _locating ? null : _locate,
            child: const Text(
              '刷新',
              style: TextStyle(fontSize: 13, color: Color(0xFFC8956E)),
            ),
          ),
        ],
      ),
    );
  }

  Widget _toolbar() {
    return Container(
      color: Colors.white,
      padding: const EdgeInsets.fromLTRB(8, 8, 8, 8),
      child: SafeArea(
        top: false,
        child: Row(
          children: [
            _toolButton(
              icon: Icons.camera_alt_outlined,
              label: '重拍',
              // 回到入口页重新拍 —— 入口页本身就是拍照页，比在这里再塞一个相机逻辑干净
              onTap: () => Navigator.of(context).maybePop(),
            ),
            _toolButton(
              icon: Icons.edit_outlined,
              label: '编辑内容',
              onTap: _editContent,
            ),
            _toolButton(
              icon: Icons.tune,
              label: '水印设置',
              onTap: () => showWatermarkSettingsSheet(context),
            ),
          ],
        ),
      ),
    );
  }

  Future<void> _editContent() async {
    final updated = await showWatermarkContentSheet(context, initial: _data);
    if (updated == null || !mounted) return;
    setState(() => _data = updated);
  }

  Widget _toolButton({
    required IconData icon,
    required String label,
    required VoidCallback onTap,
  }) {
    return Expanded(
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(12),
        child: Padding(
          padding: const EdgeInsets.symmetric(vertical: 8),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Icon(icon, size: 21, color: const Color(0xFF8D6E63)),
              const SizedBox(height: 4),
              Text(
                label,
                style: const TextStyle(fontSize: 12, color: Color(0xFF8D6E63)),
              ),
            ],
          ),
        ),
      ),
    );
  }
}