import 'package:dio/dio.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../core/network/api_exception.dart';
import '../core/network/dio_client.dart';
import '../models/note.dart';

final noteApiProvider = Provider<NoteApi>((ref) => NoteApi(ref.watch(dioProvider)));

/// 笔记接口
class NoteApi {
  final Dio _dio;

  NoteApi(this._dio);

  /// 分页列表（不含正文）
  ///
  /// [scope] all / uncategorized / folder；[folderId] 仅在 scope=folder 时有意义，
  /// 后端会连同该目录的所有子目录一起查。
  Future<NotePage> list({
    int page = 1,
    int size = 20,
    String scope = 'all',
    int? folderId,
    String sort = 'updated',
    String? keyword,
    String? tag,
  }) async {
    try {
      final res = await _dio.get('/notes', queryParameters: {
        'page': page,
        'size': size,
        'scope': scope,
        'sort': sort,
        'folderId': ?folderId,
        if (keyword != null && keyword.isNotEmpty) 'keyword': keyword,
        if (tag != null && tag.isNotEmpty) 'tag': tag,
      });
      final data = res.data;
      if (data is Map<String, dynamic>) return NotePage.fromJson(data);
      return NotePage.empty;
    } on DioException catch (e) {
      final err = e.error;
      throw err is ApiException ? err : ApiException(-1, '笔记列表加载失败');
    }
  }

  /// 目录树
  Future<FolderTree> folderTree() async {
    try {
      final res = await _dio.get('/notes/folders');
      final data = res.data;
      if (data is Map<String, dynamic>) return FolderTree.fromJson(data);
      return FolderTree.empty;
    } on DioException catch (e) {
      final err = e.error;
      throw err is ApiException ? err : ApiException(-1, '目录加载失败');
    }
  }

  /// 把笔记移动到某个目录，[folderId] 为 null 表示移到未分类
  Future<void> assignFolder(int noteId, int? folderId) async {
    try {
      await _dio.put('/notes/$noteId/folder', data: {'folderId': folderId});
    } on DioException catch (e) {
      final err = e.error;
      throw err is ApiException ? err : ApiException(-1, '移动失败');
    }
  }

  /// 详情（含正文）
  Future<NoteDetail> detail(int id) async {
    try {
      final res = await _dio.get('/notes/$id');
      return NoteDetail.fromJson(_asMap(res.data));
    } on DioException catch (e) {
      final err = e.error;
      throw err is ApiException ? err : ApiException(-1, '笔记加载失败');
    }
  }

  /// 新建
  Future<NoteDetail> create({
    required String title,
    required String content,
    required String tags,
  }) async {
    try {
      final res = await _dio.post('/notes', data: {
        'title': title,
        'content': content,
        'tags': tags,
        'isPinned': 0,
      });
      return NoteDetail.fromJson(_asMap(res.data));
    } on DioException catch (e) {
      final err = e.error;
      throw err is ApiException ? err : ApiException(-1, '笔记保存失败');
    }
  }

  /// 更新
  ///
  /// 后端是部分更新语义：字段传 null 表示不改动，
  /// 所以这里只塞需要改的字段，不必回传全部。
  Future<NoteDetail> update(
    int id, {
    String? title,
    String? content,
    String? tags,
    bool? pinned,
  }) async {
    try {
      final res = await _dio.put('/notes/$id', data: {
        // `?value` 是 Dart 的空感知元素：值为 null 时整个键值对不写入 map，
        // 正好对应后端"字段为 null 表示不改动"的部分更新语义
        'title': ?title,
        'content': ?content,
        'tags': ?tags,
        if (pinned != null) 'isPinned': pinned ? 1 : 0,
      });
      return NoteDetail.fromJson(_asMap(res.data));
    } on DioException catch (e) {
      final err = e.error;
      throw err is ApiException ? err : ApiException(-1, '笔记保存失败');
    }
  }

  /// 删除（后端是逻辑删除）
  Future<void> delete(int id) async {
    try {
      await _dio.delete('/notes/$id');
    } on DioException catch (e) {
      final err = e.error;
      throw err is ApiException ? err : ApiException(-1, '笔记删除失败');
    }
  }

  /// 标签列表，按使用次数排序
  Future<List<String>> tags() async {
    try {
      final res = await _dio.get('/notes/tags');
      return asStringListFrom(res.data);
    } on DioException catch (e) {
      final err = e.error;
      throw err is ApiException ? err : ApiException(-1, '标签加载失败');
    }
  }

  Map<String, dynamic> _asMap(Object? data) {
    if (data is Map<String, dynamic>) return data;
    if (data is Map && data['data'] is Map) {
      return Map<String, dynamic>.from(data['data'] as Map);
    }
    return const {};
  }
}

/// 标签接口返回的是裸数组，单独处理一下
List<String> asStringListFrom(Object? data) {
  if (data is List) {
    return data.map((e) => e?.toString() ?? '').where((e) => e.isNotEmpty).toList();
  }
  if (data is Map && data['data'] is List) {
    return (data['data'] as List)
        .map((e) => e?.toString() ?? '')
        .where((e) => e.isNotEmpty)
        .toList();
  }
  return const [];
}