using System;
using System.Collections.Generic;
using Svrnty.CQRS.Sagas.Abstractions;

namespace Svrnty.CQRS.Sagas;

/// <summary>
/// Implementation of saga context providing runtime information during step execution.
/// </summary>
public class SagaContext : ISagaContext
{
    private readonly SagaState _state;

    /// <summary>
    /// Creates a new saga context from a saga state.
    /// </summary>
    /// <param name="state">The saga state.</param>
    public SagaContext(SagaState state)
    {
        _state = state ?? throw new ArgumentNullException(nameof(state));
    }

    /// <inheritdoc />
    public Guid SagaId => _state.SagaId;

    /// <inheritdoc />
    public Guid CorrelationId => _state.CorrelationId;

    /// <inheritdoc />
    public string SagaType => _state.SagaType;

    /// <inheritdoc />
    public int CurrentStepIndex => _state.CurrentStepIndex;

    /// <inheritdoc />
    public string CurrentStepName => _state.CurrentStepName ?? string.Empty;

    /// <inheritdoc />
    public IReadOnlyDictionary<string, object?> StepResults => _state.StepResults;

    /// <inheritdoc />
    public T? GetStepResult<T>(string stepName)
    {
        if (_state.StepResults.TryGetValue(stepName, out var value) && value is T result)
        {
            return result;
        }
        return default;
    }

    /// <inheritdoc />
    public void SetStepResult<T>(T result)
    {
        _state.StepResults[CurrentStepName] = result;
    }
}