using ModelContextProtocol;
using ModelContextProtocol.Client;
using ModelContextProtocol.Protocol;

if (args.Length < 4 || args[0] is not ("stdio" or "http"))
{
    Console.Error.WriteLine("Usage: E2EClient stdio <agent-exe> <config> <request> | http <endpoint> <unused> <request>");
    return 2;
}

IClientTransport transport = args[0] == "stdio"
    ? new StdioClientTransport(new StdioClientTransportOptions
    {
        Name = "agent-mcp-operational-e2e",
        Command = Path.GetFullPath(args[1]),
        Arguments = [Path.GetFullPath(args[2])],
        WorkingDirectory = Path.GetDirectoryName(Path.GetFullPath(args[1]))!
    })
    : new HttpClientTransport(new HttpClientTransportOptions
    {
        Name = "agent-mcp-operational-e2e-http",
        Endpoint = new Uri(args[1], UriKind.Absolute),
        TransportMode = HttpTransportMode.StreamableHttp
    });

await using McpClient client = await McpClient.CreateAsync(transport);
IList<McpClientTool> tools = await client.ListToolsAsync();
if (!tools.Select(static tool => tool.Name).Order(StringComparer.Ordinal).SequenceEqual(["agent_run", "agent_status"]))
    throw new InvalidOperationException("Unexpected MCP public tool surface.");

_ = await ExecuteTask(client, args[3], null);
if (args.Length >= 5) _ = await ExecuteTask(client, args[4], null);
return 0;

static async Task<(Guid TaskId, Guid SessionId)> ExecuteTask(McpClient client, string request, Guid? sessionId)
{
    var runArguments = new Dictionary<string, object?> { ["request"] = request, ["temperature"] = 0.0 };
    if (sessionId is not null) runArguments["session_id"] = sessionId.Value;
    CallToolResult run = await client.CallToolAsync("agent_run", runArguments);
    if (run.IsError is true) throw new InvalidOperationException(Text(run));
    string accepted = Text(run);
    Guid taskId = ReadGuid(accepted, "task_id");
    Guid acceptedSessionId = ReadGuid(accepted, "session_id");
    Console.WriteLine(accepted);
    for (int poll = 0; poll < 600; poll++)
    {
        await Task.Delay(500);
        CallToolResult status = await client.CallToolAsync("agent_status", new Dictionary<string, object?> { ["task_id"] = taskId, ["session_id"] = acceptedSessionId });
        string text = Text(status);
        string state = ReadValue(text, "status");
        if (state is "completed" or "failed" or "cancelled")
        {
            Console.WriteLine(text);
            if (state != "completed") throw new InvalidOperationException($"Task {taskId} ended in state {state}.");
            return (taskId, acceptedSessionId);
        }
    }
    throw new TimeoutException($"Task {taskId} did not reach a terminal state.");
}

static string Text(CallToolResult result) => string.Join('\n', result.Content.OfType<TextContentBlock>().Select(static block => block.Text));
static Guid ReadGuid(string text, string key) => Guid.Parse(ReadValue(text, key));
static string ReadValue(string text, string key)
{
    string prefix = key + ":";
    return text.Split('\n').First(line => line.StartsWith(prefix, StringComparison.Ordinal))[prefix.Length..].Trim();
}