import 'dart:async';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import '../../database/database.dart';
import 'package:drift/drift.dart' as drift;
import 'package:geolocator/geolocator.dart';

enum RideState { idle, ready, riding, paused, finished }

class RideSession {
  final int? dbId;
  final RideState state;
  final double tripDistanceMiles;
  final double topSpeedMph;
  final double maxLeanLeft;
  final double maxLeanRight;
  final double maxAccelG;
  final double maxBrakingG;
  final DateTime? startTime;

  RideSession({
    this.dbId,
    this.state = RideState.idle,
    this.tripDistanceMiles = 0.0,
    this.topSpeedMph = 0.0,
    this.maxLeanLeft = 0.0,
    this.maxLeanRight = 0.0,
    this.maxAccelG = 0.0,
    this.maxBrakingG = 0.0,
    this.startTime,
  });

  RideSession copyWith({
    int? dbId,
    RideState? state,
    double? tripDistanceMiles,
    double? topSpeedMph,
    double? maxLeanLeft,
    double? maxLeanRight,
    double? maxAccelG,
    double? maxBrakingG,
    DateTime? startTime,
  }) {
    return RideSession(
      dbId: dbId ?? this.dbId,
      state: state ?? this.state,
      tripDistanceMiles: tripDistanceMiles ?? this.tripDistanceMiles,
      topSpeedMph: topSpeedMph ?? this.topSpeedMph,
      maxLeanLeft: maxLeanLeft ?? this.maxLeanLeft,
      maxLeanRight: maxLeanRight ?? this.maxLeanRight,
      maxAccelG: maxAccelG ?? this.maxAccelG,
      maxBrakingG: maxBrakingG ?? this.maxBrakingG,
      startTime: startTime ?? this.startTime,
    );
  }
}

class RideStateMachine extends StateNotifier<RideSession> {
  final AppDatabase db;
  Position? _lastPosition;

  RideStateMachine(this.db) : super(RideSession());

  void setReady() {
    state = state.copyWith(state: RideState.ready);
  }

  Future<void> startRide() async {
    final id = await db.startRide();
    state = state.copyWith(
      dbId: id,
      state: RideState.riding,
      startTime: DateTime.now(),
      tripDistanceMiles: 0,
      topSpeedMph: 0,
    );
    _lastPosition = null;
  }

  void pauseRide() {
    state = state.copyWith(state: RideState.paused);
  }

  void resumeRide() {
    state = state.copyWith(state: RideState.riding);
    _lastPosition = null; // reset so we don't jump distance
  }

  Future<void> finishRide() async {
    if (state.dbId != null) {
      await db.endRide(
        state.dbId!,
        RidesCompanion(
          distanceMiles: drift.Value(state.tripDistanceMiles),
          topSpeedMph: drift.Value(state.topSpeedMph),
          maxLeanLeft: drift.Value(state.maxLeanLeft),
          maxLeanRight: drift.Value(state.maxLeanRight),
          maxAccelG: drift.Value(state.maxAccelG),
          maxBrakingG: drift.Value(state.maxBrakingG),
        ),
      );
    }
    state = state.copyWith(state: RideState.finished);
  }

  void reset() {
    state = RideSession();
  }

  void updateTelemetry({
    Position? position,
    double? speedMph,
    double? leanAngle,
    double? accelG,
    double? lateralG,
  }) {
    if (state.state != RideState.riding) return;

    double newTopSpeed = state.topSpeedMph;
    double newMaxLeanLeft = state.maxLeanLeft;
    double newMaxLeanRight = state.maxLeanRight;
    double newMaxAccelG = state.maxAccelG;
    double newMaxBrakingG = state.maxBrakingG;
    double newDistance = state.tripDistanceMiles;

    if (speedMph != null && speedMph > state.topSpeedMph) {
      newTopSpeed = speedMph;
    }

    if (leanAngle != null) {
      if (leanAngle < 0 && leanAngle.abs() > state.maxLeanLeft) {
        newMaxLeanLeft = leanAngle.abs();
      } else if (leanAngle > 0 && leanAngle > state.maxLeanRight) {
        newMaxLeanRight = leanAngle;
      }
    }

    if (accelG != null) {
      if (accelG > 0 && accelG > state.maxAccelG) {
        newMaxAccelG = accelG;
      } else if (accelG < 0 && accelG.abs() > state.maxBrakingG) {
        newMaxBrakingG = accelG.abs();
      }
    }

    if (position != null) {
      if (_lastPosition != null) {
        // Calculate distance in meters
        final distMeters = Geolocator.distanceBetween(
          _lastPosition!.latitude,
          _lastPosition!.longitude,
          position.latitude,
          position.longitude,
        );
        newDistance += distMeters / 1609.34; // convert to miles
      }
      _lastPosition = position;
    }

    state = state.copyWith(
      topSpeedMph: newTopSpeed,
      maxLeanLeft: newMaxLeanLeft,
      maxLeanRight: newMaxLeanRight,
      maxAccelG: newMaxAccelG,
      maxBrakingG: newMaxBrakingG,
      tripDistanceMiles: newDistance,
    );
  }
}

final rideStateMachineProvider = StateNotifierProvider<RideStateMachine, RideSession>((ref) {
  final db = ref.watch(databaseProvider);
  return RideStateMachine(db);
});