using System.Threading.Channels;

namespace LifeLab.Client;

// One instance per process (server process, or the browser's WebAssembly runtime).
// Write() only queues the line, so it never blocks or reorders a lifecycle method;
// a single reader sends the queued lines one at a time, in the order they were written,
// as POST /api/log. The server numbers them in arrival order.
public sealed class LifecycleLog
{
    private readonly HttpClient _http;
    private readonly Channel<string> _queue =
        Channel.CreateUnbounded<string>(new UnboundedChannelOptions { SingleReader = true });

    public LifecycleLog(HttpClient http)
    {
        _http = http;
        _ = DrainAsync();
    }

    public void Write(string method, bool? firstRender, int counter,
        string rendererName, bool isInteractive, bool isBrowser, Guid instanceId)
    {
        var fr = firstRender is null ? "-" : firstRender.Value.ToString();
        var line = $"{method,-20} | firstRender={fr,-5} | Counter={counter} | " +
                   $"Renderer={rendererName,-11} | IsInteractive={isInteractive,-5} | " +
                   $"IsBrowser={isBrowser,-5} | Instance={instanceId.ToString("N")[..8]}";
        _queue.Writer.TryWrite(line);
    }

    private async Task DrainAsync()
    {
        await foreach (var line in _queue.Reader.ReadAllAsync())
        {
            try
            {
                using var response = await _http.PostAsync("api/log", new StringContent(line));
            }
            catch (Exception ex)
            {
                Console.WriteLine($"LifecycleLog POST failed: {ex.Message}");
            }
        }
    }
}