/// Hand-written client for `/api/v1/goals`.
///
/// **Temporary.** The goal routes are not in `openapi/openapi.json` yet, so
/// `app/packages/api_client` has no generated models or methods for them. Everything here
/// follows `docs/ai/phase4-contract.md` §4 literally and is meant to be **replaced by the
/// generated client** once the routes land in the spec and `just gen-client` runs.
///
/// Raw Dio comes from `ref.read(apiProvider).dio`: base URL, bearer header and the one-shot
/// refresh on 401 are already wired there.
library;

import 'package:dio/dio.dart';

import '../../../core/utils/json.dart';

class Goal {
  const Goal({
    required this.id,
    required this.name,
    required this.scope,
    required this.targetAmount,
    required this.currency,
    this.targetDate,
    this.monthlyContribution,
    this.note,
    this.archived = false,
  });

  final int id;
  final String name;
  final String scope;
  final String targetAmount;
  final String currency;
  final DateTime? targetDate;
  final String? monthlyContribution;
  final String? note;
  final bool archived;

  /// The create/patch body. `id` is never sent; `null` fields are omitted so a PATCH that
  /// touches one field does not blank the rest.
  Map<String, dynamic> toJson() => {
        'name': name,
        'scope': scope,
        'target_amount': targetAmount,
        'currency': currency,
        'target_date': ?_isoDate(targetDate),
        'monthly_contribution': ?monthlyContribution,
        'note': ?note,
        'archived': archived,
      };

  static Goal fromJson(Map<String, dynamic> json) => Goal(
        id: asInt(json['id']) ?? 0,
        name: asString(json['name']) ?? 'Без названия',
        scope: asString(json['scope']) ?? 'all',
        targetAmount: asString(json['target_amount']) ?? '0',
        currency: asString(json['currency']) ?? 'RUB',
        targetDate: asDate(json['target_date']),
        monthlyContribution: asString(json['monthly_contribution']),
        note: asString(json['note']),
        archived: asBool(json['archived']),
      );

  static String? _isoDate(DateTime? d) => d == null
      ? null
      : '${d.year.toString().padLeft(4, '0')}-'
          '${d.month.toString().padLeft(2, '0')}-'
          '${d.day.toString().padLeft(2, '0')}';
}

class GoalProgress {
  const GoalProgress({
    required this.goalId,
    required this.basis,
    required this.onTrack,
    this.asOf,
    this.currentValueRub,
    this.targetAmountRub,
    this.progress,
    this.projectedDate,
    this.assumedRate,
    this.monthlyNeededRub,
  });

  final int goalId;
  final DateTime? asOf;
  final String? currentValueRub;
  final String? targetAmountRub;

  /// A share: `"0.4128"` is 41,28 %.
  final String? progress;

  /// **Null means the goal is not reached at the current trend** — an honest answer, and the
  /// contract forbids substituting a far-off date for it. The UI must say so in words.
  final DateTime? projectedDate;

  /// `xirr | contribution | none` — what the projection is built on.
  final String basis;
  final String? assumedRate;
  final String? monthlyNeededRub;
  final bool onTrack;

  /// The projection exists only when a date came back. `basis == 'none'` means there was
  /// nothing to project from in the first place.
  bool get isUnreachable => projectedDate == null && basis != 'none';

  static GoalProgress fromJson(Map<String, dynamic> json) => GoalProgress(
        goalId: asInt(json['goal_id']) ?? 0,
        asOf: asDate(json['as_of']),
        currentValueRub: asString(json['current_value_rub']),
        targetAmountRub: asString(json['target_amount_rub']),
        progress: asString(json['progress']),
        projectedDate: asDate(json['projected_date']),
        basis: asString(json['basis']) ?? 'none',
        assumedRate: asString(json['assumed_rate']),
        monthlyNeededRub: asString(json['monthly_needed_rub']),
        onTrack: asBool(json['on_track']),
      );
}

class GoalsApi {
  const GoalsApi(this._dio);

  final Dio _dio;

  static const _base = '/api/v1/goals';

  Future<List<Goal>> list() async {
    final r = await _dio.get<List<dynamic>>(_base);
    return (r.data ?? const [])
        .map((e) => Goal.fromJson(Map<String, dynamic>.from(e as Map)))
        .toList();
  }

  Future<Goal> create(Goal goal) async {
    final r = await _dio.post<Map<String, dynamic>>(_base, data: goal.toJson());
    return Goal.fromJson(r.data ?? const {});
  }

  Future<Goal> patch(int id, Map<String, dynamic> changes) async {
    final r = await _dio.patch<Map<String, dynamic>>('$_base/$id', data: changes);
    return Goal.fromJson(r.data ?? const {});
  }

  Future<void> delete(int id) => _dio.delete<void>('$_base/$id');

  Future<GoalProgress> progress(int id) async {
    final r = await _dio.get<Map<String, dynamic>>('$_base/$id/progress');
    return GoalProgress.fromJson(r.data ?? const {});
  }
}