using System.Xml.Linq;
using SQLInsight.Collectors.Concurrency;

namespace SQLInsight.Collectors.Tests;

public class DeadlockParserTests
{
    private const string Graph = """
        <deadlock>
          <victim-list><victimProcess id="process1" /></victim-list>
          <process-list>
            <process id="process1" spid="60" waitresource="KEY: 5:72057594043236352 (8194443284a0)" lockMode="U" isolationlevel="read committed (2)"
                     clientapp="Sales.Api" hostname="WEB01" loginname="app" currentdb="5" currentdbname="Sales">
              <inputbuf> UPDATE dbo.Orders SET Status = 2 WHERE Id = @id </inputbuf>
            </process>
            <process id="process2" spid="61" waitresource="KEY: 5:72057594043236352 (61a06abd401c)" lockMode="U" currentdb="5">
              <inputbuf>UPDATE dbo.Orders SET Status = 3 WHERE Id = @id</inputbuf>
            </process>
          </process-list>
          <resource-list />
        </deadlock>
        """;

    [Fact]
    public void Parses_event_file_format()
    {
        var evt = XElement.Parse($"""
            <event name="xml_deadlock_report" timestamp="2026-09-29T10:15:30.123Z">
              <data name="xml_report"><value>{Graph}</value></data>
            </event>
            """);

        var deadlock = DeadlockParser.ParseEvent(evt)!;

        Assert.Equal(new DateTimeOffset(2026, 9, 29, 10, 15, 30, 123, TimeSpan.Zero), deadlock.Time);
        Assert.Equal(2, deadlock.Processes.Count);
        var victim = Assert.Single(deadlock.Processes, p => p.IsVictim);
        Assert.Equal(60, victim.SessionId);
        Assert.Equal("Sales", victim.DatabaseName);
        Assert.Equal("Sales.Api", victim.ClientApp);
        Assert.Equal("UPDATE dbo.Orders SET Status = 2 WHERE Id = @id", victim.InputBuffer);
        Assert.Equal("5", deadlock.Processes[1].DatabaseName); // no currentdbname on older builds
        Assert.StartsWith("<deadlock>", deadlock.GraphXml, StringComparison.Ordinal);
    }

    [Fact]
    public void Parses_sql2008_escaped_graph()
    {
        // SQL Server 2008 RTM–SP1 put the graph in the ring buffer as escaped text.
        var escaped = System.Security.SecurityElement.Escape(Graph);
        var evt = XElement.Parse($"""
            <event name="xml_deadlock_report" timestamp="2026-09-29T10:15:30Z">
              <data name="xml_report"><type name="unicode_string" /><value>{escaped}</value></data>
            </event>
            """);

        var deadlock = DeadlockParser.ParseEvent(evt)!;

        Assert.Equal(2, deadlock.Processes.Count);
    }

    [Fact]
    public void Garbage_is_ignored()
    {
        var evt = XElement.Parse("""<event name="xml_deadlock_report" timestamp="2026-09-29T10:15:30Z"><data name="xml_report"><value>not xml</value></data></event>""");

        Assert.Null(DeadlockParser.ParseEvent(evt));
    }
}