sqlinsight-pro/src/SQLInsight.Core/Data/HighAvailability.cs

namespace SQLInsight.Core.Data;

/// <summary>
/// Always On availability group state as seen from this instance. A primary sees all replicas; a secondary only itself.
/// </summary>
public sealed record AvailabilityGroupSnapshot
{
    public required DateTimeOffset CapturedAt { get; init; }
    public required IReadOnlyList<ReplicaState> Replicas { get; init; }
    public required IReadOnlyList<DatabaseReplicaState> Databases { get; init; }

    /// <summary>The Windows cluster's nodes and witness (sys.dm_hadr_cluster_members); empty without a WSFC.</summary>
    public IReadOnlyList<ClusterMember> ClusterMembers { get; init; } = [];
}

public sealed record ReplicaState
{
    public required string Group { get; init; }
    public required string Replica { get; init; }
    public bool IsLocal { get; init; }

    /// <summary>PRIMARY, SECONDARY or RESOLVING; null when this instance cannot see the replica's state.</summary>
    public string? Role { get; init; }

    public string? ConnectedState { get; init; }

    /// <summary>HEALTHY, PARTIALLY_HEALTHY or NOT_HEALTHY.</summary>
    public string? SynchronizationHealth { get; init; }

    public string? AvailabilityMode { get; init; }
    public string? FailoverMode { get; init; }
}

public sealed record DatabaseReplicaState
{
    public required string Group { get; init; }
    public required string Database { get; init; }
    public required string Replica { get; init; }
    public bool IsLocal { get; init; }
    public bool IsPrimaryReplica { get; init; }
    public string? SynchronizationState { get; init; }
    public string? SynchronizationHealth { get; init; }
    public bool IsSuspended { get; init; }
    public string? SuspendReason { get; init; }

    /// <summary>Log not yet sent to this secondary, in KB.</summary>
    public long? LogSendQueueKb { get; init; }

    public long? LogSendRateKbPerSecond { get; init; }

    /// <summary>Log received but not yet redone on this secondary, in KB.</summary>
    public long? RedoQueueKb { get; init; }

    public long? RedoRateKbPerSecond { get; init; }
    public DateTime? LastCommitTime { get; init; }
}

/// <summary>
/// SQL Server Agent: whether it runs, and the latest outcome of each job.
/// </summary>
public sealed record AgentJobSnapshot
{
    public required DateTimeOffset CapturedAt { get; init; }

    /// <summary>False when no SQL Agent session exists (the service is stopped).</summary>
    public required bool IsAgentRunning { get; init; }

    public required IReadOnlyList<AgentJob> Jobs { get; init; }
}

public sealed record AgentJob
{
    public required string Name { get; init; }
    public bool IsEnabled { get; init; }

    /// <summary>0 failed, 1 succeeded, 2 retry, 3 canceled, 4 in progress; null if never run.</summary>
    public int? LastRunStatus { get; init; }

    public DateTime? LastRunAt { get; init; }

    /// <summary>The message of the most recent failed step, which says why (the job-level message does not).</summary>
    public string? LastFailedStepMessage { get; init; }

    public string? LastFailedStepName { get; init; }
    public int FailuresLastDay { get; init; }

    public bool LastRunFailed => LastRunStatus == 0;
}

/// <param name="Type">CLUSTER_NODE, DISK_WITNESS, FILE_SHARE_WITNESS, CLOUD_WITNESS.</param>
/// <param name="State">0 offline, 1 up.</param>
public sealed record ClusterMember(string Name, string Type, int State, string StateText, int? QuorumVotes)
{
    public bool IsUp => State == 1;
}