namespace StellaOps.Microservice.Validation;

/// <summary>
/// Exception thrown when request or response body fails schema validation.
/// </summary>
public sealed class SchemaValidationException : Exception
{
    /// <summary>
    /// Gets the endpoint path where validation failed.
    /// </summary>
    public string EndpointPath { get; }

    /// <summary>
    /// Gets the HTTP method of the endpoint.
    /// </summary>
    public string EndpointMethod { get; }

    /// <summary>
    /// Gets whether this was request or response validation.
    /// </summary>
    public SchemaDirection Direction { get; }

    /// <summary>
    /// Gets the list of validation errors.
    /// </summary>
    public IReadOnlyList<SchemaValidationError> Errors { get; }

    /// <summary>
    /// Creates a new schema validation exception.
    /// </summary>
    public SchemaValidationException(
        string endpointMethod,
        string endpointPath,
        SchemaDirection direction,
        IReadOnlyList<SchemaValidationError> errors)
        : base(BuildMessage(endpointMethod, endpointPath, direction, errors))
    {
        EndpointMethod = endpointMethod;
        EndpointPath = endpointPath;
        Direction = direction;
        Errors = errors;
    }

    private static string BuildMessage(
        string method,
        string path,
        SchemaDirection direction,
        IReadOnlyList<SchemaValidationError> errors)
    {
        var directionText = direction == SchemaDirection.Request ? "request" : "response";
        return $"Schema validation failed for {directionText} of {method} {path}: {errors.Count} error(s)";
    }
}