using System.Data;
using Microsoft.Data.SqlClient;
using ZB.MOM.WW.Auth.Abstractions.ApiKeys;

namespace ZB.MOM.WW.Auth.ApiKeys.SqlServer;

/// <summary>
/// SQL Server-backed, append-only audit store for API-key events. A one-for-one port of
/// <c>SqliteApiKeyAuditStore</c>; on a clustered host the rows from every node land in one table,
/// so the audit trail no longer has to be stitched together per node.
/// </summary>
/// <param name="connectionFactory">Factory for connections to the shared API-key database.</param>
public sealed class SqlServerApiKeyAuditStore(AuthSqlServerConnectionFactory connectionFactory) : IApiKeyAuditStore
{
    /// <inheritdoc />
    public async Task AppendAsync(ApiKeyAuditEntry entry, CancellationToken ct)
    {
        ArgumentNullException.ThrowIfNull(entry);

        string schema = connectionFactory.Schema;

        await using SqlConnection connection =
            await connectionFactory.OpenConnectionAsync(ct).ConfigureAwait(false);

        await using SqlCommand command = connectionFactory.CreateCommand(connection, $"""
            INSERT INTO [{schema}].[{SqlServerAuthSchema.ApiKeyAuditTable}] (
                key_id, event_type, remote_address, created_utc, details)
            VALUES (@key_id, @event_type, @remote_address, @created_utc, @details);
            """);
        command.Parameters.Add("@key_id", SqlDbType.NVarChar, 64).Value = (object?)entry.KeyId ?? DBNull.Value;
        command.Parameters.Add("@event_type", SqlDbType.NVarChar, 64).Value = entry.EventType;
        command.Parameters.Add("@remote_address", SqlDbType.NVarChar, 64).Value = (object?)entry.RemoteAddress ?? DBNull.Value;
        command.Parameters.Add("@created_utc", SqlDbType.DateTimeOffset).Value = entry.CreatedUtc;
        command.Parameters.Add("@details", SqlDbType.NVarChar, -1).Value = (object?)entry.Details ?? DBNull.Value;

        await command.ExecuteNonQueryAsync(ct).ConfigureAwait(false);
    }

    /// <inheritdoc />
    /// <remarks>
    /// Ordered by the IDENTITY <c>audit_id</c>, not by <c>created_utc</c>: two events stamped in the
    /// same instant still come back in insertion order. A non-positive limit short-circuits without
    /// opening a connection — <c>SELECT TOP (-1)</c> is not even legal T-SQL.
    /// </remarks>
    public async Task<IReadOnlyList<ApiKeyAuditEntry>> ListRecentAsync(int limit, CancellationToken ct)
    {
        if (limit <= 0)
        {
            return [];
        }

        string schema = connectionFactory.Schema;

        await using SqlConnection connection =
            await connectionFactory.OpenConnectionAsync(ct).ConfigureAwait(false);

        await using SqlCommand command = connectionFactory.CreateCommand(connection, $"""
            SELECT TOP (@limit) key_id, event_type, remote_address, created_utc, details
            FROM [{schema}].[{SqlServerAuthSchema.ApiKeyAuditTable}]
            ORDER BY audit_id DESC;
            """);
        command.Parameters.Add("@limit", SqlDbType.Int).Value = limit;

        List<ApiKeyAuditEntry> entries = [];

        await using SqlDataReader reader = await command.ExecuteReaderAsync(ct).ConfigureAwait(false);

        while (await reader.ReadAsync(ct).ConfigureAwait(false))
        {
            entries.Add(new ApiKeyAuditEntry(
                KeyId: reader.IsDBNull(0) ? null : reader.GetString(0),
                EventType: reader.GetString(1),
                RemoteAddress: reader.IsDBNull(2) ? null : reader.GetString(2),
                CreatedUtc: reader.GetDateTimeOffset(3),
                Details: reader.IsDBNull(4) ? null : reader.GetString(4)));
        }

        return entries;
    }
}