using GeometryTD.Definition;
using GeometryTD.Procedure;
using UnityGameFramework.Runtime;

namespace GeometryTD.UI
{
    public class EventFormUseCase : IUIUseCase
    {
        private EventItem _currentEvent;
        private RunNodeExecutionContext _currentContext;
        private readonly EventOptionExecutor _executor = new EventOptionExecutor();

        public void BindEvent(
            EventItem eventItem,
            RunNodeExecutionContext context)
        {
            _currentEvent = eventItem;
            _currentContext = context != null ? context.Clone() : null;
        }

        public void Clear()
        {
            _currentEvent = null;
            _currentContext = null;
        }

        public EventFormRawData CreateInitialModel()
        {
            if (_currentEvent == null)
            {
                return null;
            }

            return new EventFormRawData
            {
                EventId = _currentEvent.Id,
                Title = _currentEvent.Title,
                Description = _currentEvent.Description,
                OptionItems = BuildOptionItems()
            };
        }

        public bool TrySelectOption(int optionIndex)
        {
            if (_currentEvent == null || _currentEvent.Options == null)
            {
                return false;
            }

            if (optionIndex < 0 || optionIndex >= _currentEvent.Options.Length)
            {
                Log.Warning("EventFormUseCase.TrySelectOption() option index is invalid: {0}", optionIndex);
                return false;
            }

            BackpackInventoryData workingInventory = GameEntry.PlayerInventory != null
                ? GameEntry.PlayerInventory.GetInventorySnapshot()
                : new BackpackInventoryData();
            EventOptionExecutionResult executionResult = _executor.Execute(
                _currentEvent,
                optionIndex,
                _currentContext,
                workingInventory);
            if (!executionResult.IsAccepted)
            {
                Log.Warning(
                    "EventFormUseCase.TrySelectOption() rejected. EventId={0}, OptionIndex={1}, Reason={2}",
                    _currentEvent.Id,
                    optionIndex,
                    executionResult.FailureReason);
                return false;
            }

            if (GameEntry.PlayerInventory != null)
            {
                GameEntry.PlayerInventory.ReplaceInventorySnapshot(workingInventory);
            }

            GameEntry.EventNode.EndEvent();
            return true;
        }

        private EventOptionRawData[] BuildOptionItems()
        {
            EventOption[] options = _currentEvent.Options ?? System.Array.Empty<EventOption>();
            EventOptionRawData[] result = new EventOptionRawData[options.Length];
            BackpackInventoryData inventory = GameEntry.PlayerInventory != null
                ? GameEntry.PlayerInventory.GetInventorySnapshot()
                : new BackpackInventoryData();
            for (int i = 0; i < options.Length; i++)
            {
                EventOption option = options[i];
                EventOptionAvailability availability = _executor.EvaluateOption(option, inventory);
                result[i] = new EventOptionRawData
                {
                    OptionIndex = i,
                    OptionText = option?.OptionText ?? string.Empty,
                    IsSelectable = availability.IsSelectable,
                    BlockedReason = availability.BlockedReason
                };
            }

            return result;
        }
    }
}