import 'dart:async';
import 'dart:io';

import '../questions_db.dart';
import 'market_data_ingest.dart';
import 'trade_actuator.dart';
import 'trading_config.dart';
import 'trading_config_db.dart';
import 'trading_pipeline.dart';

/// Per-user outcome of one orchestrator tick.
class TradingTickResult {
  TradingTickResult({
    required this.firebaseUid,
    required this.skippedReason,
    this.ingest,
    this.evaluation,
    this.actuator,
  });

  final String firebaseUid;

  /// Non-null when the tick was a no-op (config disabled, missing, etc.).
  final String? skippedReason;

  final MarketDataIngestResult? ingest;
  final TradingEvaluationResult? evaluation;
  final TradeActuatorResult? actuator;

  bool get skipped => skippedReason != null;
}

/// Coordinates the per-tick trading work for a user.
///
/// One tick:
///   1. Resolve effective config (skip if missing or disabled).
///   2. Ingest market data for each [DataInputConfig] (respecting poll
///      intervals via `user_trading_state.context.ingest_last_fetch`).
///   3. Evaluate rules → create `pipeline_key=trading` questions.
///   4. Drain `pending_orders` via [TradeActuator] (test mode or Alpaca).
///
/// All three stages are best-effort: a failure in one logs and continues so
/// a transient Alpaca outage during ingest doesn't block actuation of
/// already-staged orders.
class TradingOrchestrator {
  TradingOrchestrator({
    required QuestionsDb questionsDb,
    required TradingConfigDb tradingConfigDb,
    required TradingPipeline pipeline,
    required TradeActuator actuator,
    MarketDataIngest? ingest,
    bool ingestEnabled = true,
    bool evalEnabled = true,
    DateTime Function()? clock,
  })  : _questionsDb = questionsDb,
        _tradingConfigDb = tradingConfigDb,
        _pipeline = pipeline,
        _actuator = actuator,
        _ingest = ingest,
        _ingestEnabled = ingestEnabled,
        _evalEnabled = evalEnabled,
        _clock = clock ?? DateTime.now;

  final QuestionsDb _questionsDb;
  final TradingConfigDb _tradingConfigDb;
  final TradingPipeline _pipeline;
  final TradeActuator _actuator;
  final MarketDataIngest? _ingest;
  final bool _ingestEnabled;
  final bool _evalEnabled;
  final DateTime Function() _clock;

  bool get hasIngest => _ingest != null && _ingestEnabled;

  /// Runs [tickUser] for every Firebase UID known to [QuestionsDb].
  ///
  /// Per-user errors are logged to stderr but do not abort the cycle.
  Future<void> runMaintenanceCycle() async {
    final List<String> uids = await _questionsDb.listAllUserFirebaseUids();
    for (final String uid in uids) {
      try {
        await tickUser(uid);
      } catch (e, st) {
        stderr.writeln('TradingOrchestrator tick failed for $uid: $e\n$st');
      }
    }
  }

  Future<TradingTickResult> tickUser(String firebaseUid) async {
    final EffectiveTradingConfig? config =
        await _tradingConfigDb.resolveEffectiveConfig(firebaseUid);
    if (config == null) {
      return TradingTickResult(
        firebaseUid: firebaseUid,
        skippedReason: 'no_config',
      );
    }
    if (!config.enabled) {
      return TradingTickResult(
        firebaseUid: firebaseUid,
        skippedReason: 'disabled',
      );
    }

    MarketDataIngestResult? ingestResult;
    if (hasIngest) {
      try {
        ingestResult = await _ingest!.runIfDue(
          firebaseUid: firebaseUid,
          config: config,
          now: _clock(),
        );
      } catch (e, st) {
        stderr.writeln(
          'TradingOrchestrator ingest failed for $firebaseUid: $e\n$st',
        );
      }
    }

    TradingEvaluationResult? evaluationResult;
    if (_evalEnabled) {
      try {
        evaluationResult = await _pipeline.evaluate(firebaseUid);
      } catch (e, st) {
        stderr.writeln(
          'TradingOrchestrator evaluate failed for $firebaseUid: $e\n$st',
        );
      }
    }

    TradeActuatorResult? actuatorResult;
    try {
      actuatorResult = await _actuator.processPendingOrders(firebaseUid);
    } catch (e, st) {
      stderr.writeln(
        'TradingOrchestrator actuate failed for $firebaseUid: $e\n$st',
      );
    }

    return TradingTickResult(
      firebaseUid: firebaseUid,
      skippedReason: null,
      ingest: ingestResult,
      evaluation: evaluationResult,
      actuator: actuatorResult,
    );
  }
}