export const DIAGNOSTIC_ROLES = ["main", "split", "pit_entry", "pit_exit"];
export function createDecoderDiagnostics(now = Date.now) {
  const channels = new Map();
  function channel(role) {
    const key = DIAGNOSTIC_ROLES.includes(role) ? role : "main";
    if (!channels.has(key)) channels.set(key, { role: key, status: "disconnected", url: "", connectedAt: null, lastReceivedAt: null, frames: 0, messages: 0, passings: 0, handled: 0, ignored: 0, invalid: 0, parseErrors: 0, lastFrame: "", log: [] });
    return channels.get(key);
  }
  function log(entry, reason, sample = "") {
    entry.log.push({ at: now(), reason, sample: String(sample).slice(0, 512) });
    if (entry.log.length > 50) entry.log.splice(0, entry.log.length - 50);
  }
  return {
    socket(role, status, url = "") {
      const entry = channel(role);
      entry.status = status;
      if (url) entry.url = String(url);
      if (status === "connected") entry.connectedAt = now();
      log(entry, status);
    },
    frame(role, data) {
      const entry = channel(role);
      entry.frames++;
      entry.lastReceivedAt = now();
      entry.lastFrame = String(data).slice(0, 512);
    },
    parseError(role) {
      const entry = channel(role);
      entry.parseErrors++;
      log(entry, "invalid_json", entry.lastFrame);
    },
    message(role, msg, reason, outcome = "ignored") {
      const entry = channel(role);
      entry.messages++;
      if (String(msg?.msg || msg?.type || "").toUpperCase() === "PASSING") entry.passings++;
      if (["handled", "ignored", "invalid"].includes(outcome)) entry[outcome]++;
      let sample = "";
      try { sample = JSON.stringify({ type: msg?.msg || msg?.type, transponder: msg?.transponder ?? msg?.tran_code, rtc_time: msg?.rtc_time }); } catch {}
      log(entry, reason, sample);
    },
    snapshot() { return DIAGNOSTIC_ROLES.map(role => { const entry = channel(role); return { ...entry, log: entry.log.map(item => ({ ...item })) }; }); },
    clear(role) {
      const entry = channel(role);
      for (const key of ["frames", "messages", "passings", "handled", "ignored", "invalid", "parseErrors"]) entry[key] = 0;
      entry.lastFrame = "";
      entry.log = [];
    },
  };
}
export const decoderDiagnostics = createDecoderDiagnostics();