using System;
using System.Threading;
using System.Threading.Tasks;
using Svrnty.CQRS.Sagas.Abstractions;

namespace Svrnty.CQRS.Sagas.Builders;

/// <summary>
/// Base class for saga step definitions.
/// </summary>
public abstract class SagaStepDefinition
{
    /// <summary>
    /// Unique name for this step.
    /// </summary>
    public string Name { get; set; } = string.Empty;

    /// <summary>
    /// Order of the step in the saga.
    /// </summary>
    public int Order { get; set; }

    /// <summary>
    /// Whether this step has a compensation action.
    /// </summary>
    public abstract bool HasCompensation { get; }

    /// <summary>
    /// Whether this step is a remote step (sends a command).
    /// </summary>
    public abstract bool IsRemote { get; }

    /// <summary>
    /// Timeout for this step.
    /// </summary>
    public TimeSpan? Timeout { get; set; }

    /// <summary>
    /// Maximum number of retries.
    /// </summary>
    public int MaxRetries { get; set; }

    /// <summary>
    /// Delay between retries.
    /// </summary>
    public TimeSpan RetryDelay { get; set; } = TimeSpan.FromSeconds(1);
}

/// <summary>
/// Definition for a local saga step.
/// </summary>
/// <typeparam name="TData">The saga data type.</typeparam>
public class LocalSagaStepDefinition<TData> : SagaStepDefinition
    where TData : class, ISagaData
{
    /// <summary>
    /// The execution action.
    /// </summary>
    public Func<TData, ISagaContext, CancellationToken, Task>? ExecuteAction { get; set; }

    /// <summary>
    /// The compensation action.
    /// </summary>
    public Func<TData, ISagaContext, CancellationToken, Task>? CompensateAction { get; set; }

    /// <inheritdoc />
    public override bool HasCompensation => CompensateAction != null;

    /// <inheritdoc />
    public override bool IsRemote => false;
}

/// <summary>
/// Definition for a remote saga step.
/// </summary>
/// <typeparam name="TData">The saga data type.</typeparam>
/// <typeparam name="TCommand">The command type.</typeparam>
public class RemoteSagaStepDefinition<TData, TCommand> : SagaStepDefinition
    where TData : class, ISagaData
    where TCommand : class
{
    /// <summary>
    /// Function to build the command.
    /// </summary>
    public Func<TData, ISagaContext, TCommand>? CommandBuilder { get; set; }

    /// <summary>
    /// Handler for successful response.
    /// </summary>
    public Func<TData, ISagaContext, CancellationToken, Task>? ResponseHandler { get; set; }

    /// <summary>
    /// Type of the compensation command.
    /// </summary>
    public Type? CompensationCommandType { get; set; }

    /// <summary>
    /// Function to build the compensation command.
    /// </summary>
    public Func<TData, ISagaContext, object>? CompensationBuilder { get; set; }

    /// <inheritdoc />
    public override bool HasCompensation => CompensationBuilder != null;

    /// <inheritdoc />
    public override bool IsRemote => true;
}

/// <summary>
/// Definition for a remote saga step with result.
/// </summary>
/// <typeparam name="TData">The saga data type.</typeparam>
/// <typeparam name="TCommand">The command type.</typeparam>
/// <typeparam name="TResult">The result type.</typeparam>
public class RemoteSagaStepDefinition<TData, TCommand, TResult> : SagaStepDefinition
    where TData : class, ISagaData
    where TCommand : class
{
    /// <summary>
    /// Function to build the command.
    /// </summary>
    public Func<TData, ISagaContext, TCommand>? CommandBuilder { get; set; }

    /// <summary>
    /// Handler for successful response with result.
    /// </summary>
    public Func<TData, ISagaContext, TResult, CancellationToken, Task>? ResponseHandler { get; set; }

    /// <summary>
    /// Type of the compensation command.
    /// </summary>
    public Type? CompensationCommandType { get; set; }

    /// <summary>
    /// Function to build the compensation command.
    /// </summary>
    public Func<TData, ISagaContext, object>? CompensationBuilder { get; set; }

    /// <summary>
    /// The expected result type.
    /// </summary>
    public Type ResultType => typeof(TResult);

    /// <inheritdoc />
    public override bool HasCompensation => CompensationBuilder != null;

    /// <inheritdoc />
    public override bool IsRemote => true;
}