/**
 * Success / retry classification for a PI RPC session.
 * Write() arguments in traces are never treated as deliverables.
 */

export function newSettleState() {
  return {
    retryFailed: false,
    providerTransient: false,
    lastErr: "",
    succeeded: false,
  };
}

function messageField(ev, key) {
  const msg = ev && ev.message;
  if (!msg || typeof msg !== "object") {
    return "";
  }
  const v = msg[key];
  return typeof v === "string" ? v : "";
}

export function isTransientText(s) {
  const t = String(s || "").toLowerCase();
  return t.includes("connection error") ||
    t.includes("terminated") ||
    t.includes("auto_retry") ||
    t.includes("econnreset") ||
    t.includes("socket hang up");
}

export function isPermanentReason(s) {
  const t = String(s || "").toLowerCase();
  return t.includes("prompt_empty") ||
    t.includes("unauthorized") ||
    t.includes("治理");
}

export function applyAgentEvent(state, ev) {
  if (!state || !ev || typeof ev !== "object") {
    return state;
  }
  const t = ev.type || "";
  const stop = messageField(ev, "stopReason");
  const msgErr = messageField(ev, "errorMessage") ||
    (typeof ev.errorMessage === "string" ? ev.errorMessage : "") ||
    (typeof ev.finalError === "string" ? ev.finalError : "") ||
    (ev.error && typeof ev.error.message === "string" ? ev.error.message : "");

  if (msgErr && isTransientText(msgErr)) {
    state.providerTransient = true;
    state.lastErr = msgErr;
  }
  if (stop === "error") {
    state.providerTransient = true;
    if (msgErr) {
      state.lastErr = msgErr;
    }
  }
  if (t === "auto_retry_start") {
    state.providerTransient = true;
    if (ev.errorMessage) {
      state.lastErr = String(ev.errorMessage);
    }
  }
  if (t === "auto_retry_end") {
    if (ev.success === false) {
      state.retryFailed = true;
      state.providerTransient = true;
      state.lastErr = ev.finalError || ev.errorMessage || state.lastErr || "auto_retry_failed";
    } else if (ev.success === true) {
      // SDK in-process retry recovered. Drop this-round transient so a later
      // agent_settled can succeed; later events may set a new error again.
      state.retryFailed = false;
      state.providerTransient = false;
      state.lastErr = "";
    } else {
      state.retryFailed = false;
    }
  }
  if (t === "agent_error") {
    const err = (ev.error && ev.error.message) || ev.message || "agent_error";
    const text = typeof err === "string" ? err : "agent_error";
    state.lastErr = text;
    if (isTransientText(text)) {
      state.providerTransient = true;
    }
  }
  if (t === "agent_settled") {
    // PI emits agent_settled even after exhausted SDK retries.
    state.succeeded = !state.retryFailed && !state.providerTransient;
  }
  return state;
}

export function classifyRunOutcome({
  succeeded = false,
  retryFailed = false,
  providerTransient = false,
  lastErr = "",
  missing = [],
} = {}) {
  const miss = Array.isArray(missing) ? missing.filter(Boolean) : [];
  if (isPermanentReason(lastErr)) {
    return { ok: false, retryable: false, fallback_reason: lastErr || "permanent_failure" };
  }
  if (!succeeded) {
    const reason = lastErr || "agent_not_settled";
    const retryable = (retryFailed || providerTransient || isTransientText(reason)) &&
      !isPermanentReason(reason);
    return { ok: false, retryable, fallback_reason: reason };
  }
  if (miss.length > 0) {
    return {
      ok: false,
      retryable: Boolean(retryFailed || providerTransient),
      fallback_reason: `missing target deliverable ${miss.join(",")}`,
    };
  }
  return { ok: true, retryable: false, fallback_reason: "" };
}