using System.Data.Common;
using Microsoft.EntityFrameworkCore.Diagnostics;

namespace BuildFlow.Workflow.Tests.Performance;

/// <summary>
/// 只统计查询命令的 EF 拦截器，用于稳定验证查询次数不随输入规模增长。
/// </summary>
public sealed class CountingCommandInterceptor : DbCommandInterceptor
{
    /// <summary>自最近一次重置后的 SELECT 命令数。</summary>
    public int SelectCount { get; private set; }

    /// <summary>清零命令计数，排除测试建数阶段。</summary>
    public void Reset() => SelectCount = 0;

    public override InterceptionResult<DbDataReader> ReaderExecuting(
        DbCommand command,
        CommandEventData eventData,
        InterceptionResult<DbDataReader> result)
    {
        Count(command);
        return result;
    }

    public override ValueTask<InterceptionResult<DbDataReader>> ReaderExecutingAsync(
        DbCommand command,
        CommandEventData eventData,
        InterceptionResult<DbDataReader> result,
        CancellationToken cancellationToken = default)
    {
        Count(command);
        return ValueTask.FromResult(result);
    }

    private void Count(DbCommand command)
    {
        if (command.CommandText.TrimStart().StartsWith(
                "SELECT",
                StringComparison.OrdinalIgnoreCase))
        {
            SelectCount++;
        }
    }
}