namespace KArtSell.Modules.IdentityAccess.ManageIdentityAndRoles.Domain;

/// <summary>
/// Role Assignment workflow state (Maker-Checker pattern)
/// AEG-VS-01-03: Immutable value object for approval workflow
/// </summary>
public sealed record RoleAssignmentState
{
    public const string PendingApproval = "PENDING_APPROVAL";
    public const string ApprovedBy1 = "APPROVED_BY_1";
    public const string ApprovedBy2 = "APPROVED_BY_2";
    public const string Active = "ACTIVE";
    public const string Expired = "EXPIRED";
    public const string Revoked = "REVOKED";
    public const string Rejected = "REJECTED";

    private static readonly HashSet<string> ValidStates =
    [
        PendingApproval, ApprovedBy1, ApprovedBy2, Active, Expired, Revoked, Rejected
    ];

    public string Value { get; }

    private RoleAssignmentState(string value)
    {
        if (!ValidStates.Contains(value))
            throw new ArgumentException($"Invalid role assignment state: {value}", nameof(value));
        Value = value;
    }

    // Factory methods
    public static RoleAssignmentState CreatePending() => new(PendingApproval);
    public static RoleAssignmentState Activate() => new(Active);
    public static RoleAssignmentState Expire() => new(Expired);
    public static RoleAssignmentState Revoke() => new(Revoked);
    public static RoleAssignmentState Reject() => new(Rejected);
    public static RoleAssignmentState Parse(string value) => new(value);

    // State transitions
    public RoleAssignmentState ApproveByFirst()
    {
        return Value switch
        {
            PendingApproval => new(ApprovedBy1),
            _ => throw new InvalidOperationException($"Cannot approve from {Value}")
        };
    }

    public RoleAssignmentState ApproveBySecond()
    {
        return Value switch
        {
            ApprovedBy1 => new(ApprovedBy2),
            _ => throw new InvalidOperationException($"Cannot approve second from {Value}")
        };
    }

    public RoleAssignmentState ActivateAfterApproval()
    {
        return Value switch
        {
            ApprovedBy2 => new(Active),
            _ => throw new InvalidOperationException($"Cannot activate from {Value}")
        };
    }

    public RoleAssignmentState ExpireTimebound()
    {
        return Value switch
        {
            Active => new(Expired),
            _ => throw new InvalidOperationException($"Cannot expire from {Value}")
        };
    }

    public RoleAssignmentState RevokeActive()
    {
        return Value switch
        {
            Active or Expired => new(Revoked),
            _ => throw new InvalidOperationException($"Cannot revoke from {Value}")
        };
    }

    public RoleAssignmentState RejectRequest()
    {
        return Value switch
        {
            PendingApproval or ApprovedBy1 => new(Rejected),
            _ => throw new InvalidOperationException($"Cannot reject from {Value}")
        };
    }

    // State queries
    public bool IsPending() => Value == PendingApproval;
    public bool IsAwaitingSecondApproval() => Value == ApprovedBy1;
    public bool IsApproved() => Value == ApprovedBy2;
    public bool IsActive() => Value == Active;
    public bool IsExpired() => Value == Expired;
    public bool IsRevoked() => Value == Revoked;
    public bool IsRejected() => Value == Rejected;
    public bool CanApprove() => Value is PendingApproval or ApprovedBy1;
    public bool RequiresSecondApproval() => Value == ApprovedBy1;

    public override string ToString() => Value;
}