using System;
using UnityEngine;

namespace DanieleMarotta.RiversongCodeShowcase
{
    [RequiresWorldReadyForUpdate]
    [GameSystemGroup(typeof(EarlyGameSystemGroup))]
    public class WorldTimeSystem : GameSystem, IUpdatable
    {
        [InjectService]
        private GameConfig _config;

        [InjectService]
        private World _world;

        [InjectService]
        private ISignalBus _signalBus;

        public WorldTimeSystem(IServiceLocator serviceLocator) : base(serviceLocator)
        {
        }

        public void Update()
        {
            AdvanceCalendar();
            AdvanceDayNightCycle();
        }

        private void AdvanceCalendar()
        {
            var timeState = _world.TimeState;
            if (timeState.DayNightCycleStep != DayNightCycleStep.Day) return;

            var weekDuration = _config.Time.WeekDuration;

            timeState.WeekTime += Time.deltaTime;

            if (timeState.WeekTime > weekDuration)
            {
                timeState.WeekTime -= weekDuration;

                timeState.TotalWeeks++;

                timeState.WeekNumber = (timeState.WeekNumber + 1) % 4;
                if (timeState.WeekNumber > 0)
                {
                    _signalBus.Raise(new EndOfWeekSignal());
                    return;
                }

                timeState.MonthNumber = (timeState.MonthNumber + 1) % 12;
                if (timeState.MonthNumber > 0)
                {
                    _signalBus.Raise(new EndOfWeekSignal());
                    _signalBus.Raise(new EndOfMonthSignal());
                    return;
                }

                timeState.YearNumber++;
                _signalBus.Raise(new EndOfWeekSignal());
                _signalBus.Raise(new EndOfMonthSignal());
                _signalBus.Raise(new EndOfYearSignal());
            }
        }

        private void AdvanceDayNightCycle()
        {
            var timeState = _world.TimeState;
            var config = _config.Time;

            timeState.DayNightCycleTime += Time.deltaTime;

            var stepDuration = timeState.DayNightCycleStep switch
            {
                DayNightCycleStep.Day => config.DayDuration,
                DayNightCycleStep.DayToNight => config.DayToNightDuration,
                DayNightCycleStep.Night => config.NightDuration,
                DayNightCycleStep.NightToDay => config.NightToDayDuration,
                _ => throw new ArgumentException()
            };

            while (timeState.DayNightCycleTime > stepDuration)
            {
                timeState.DayNightCycleTime -= stepDuration;
                timeState.DayNightCycleStep = (DayNightCycleStep)(((int)timeState.DayNightCycleStep + 1) % 4);

                _signalBus.Raise(new DayNightCycleStepChangedSignal(timeState.DayNightCycleStep));

                switch (timeState.DayNightCycleStep)
                {
                    case DayNightCycleStep.Night:
                        _signalBus.Raise(new NightStartedSignal());
                        break;
                    case DayNightCycleStep.Day:
                        _signalBus.Raise(new DayStartedSignal());
                        break;
                }
            }

            timeState.NightBlend = timeState.DayNightCycleStep switch
            {
                DayNightCycleStep.Day => 0,
                DayNightCycleStep.DayToNight => Mathf.Clamp01(timeState.DayNightCycleTime / config.DayToNightDuration),
                DayNightCycleStep.Night => 1,
                DayNightCycleStep.NightToDay => 1 - Mathf.Clamp01(timeState.DayNightCycleTime / config.NightToDayDuration),
                _ => throw new ArgumentException()
            };
        }
    }
}