/**
 * Processor for "uniteddh-preauth-submit" jobs.
 * Submits a dental pre-authorization to the United/DentalHub portal via Selenium.
 *
 * Flow:
 *   1. POST /uniteddh-preauth to Python agent → get session_id
 *   2. Emit selenium:uniteddh_preauth_started to frontend
 *   3. Poll until completed/error (emitting otp_required as needed)
 *   4. Save PDF + preAuthNumber, emit result
 */
import {
  forwardToSeleniumUnitedDHPreAuthAgent,
  getSeleniumUnitedDHPreAuthSessionStatus,
} from "../../services/seleniumUnitedDHPreAuthClient";
import { io } from "../../socket";
import { storage } from "../../storage";
import axios from "axios";
import path from "path";

function log(tag: string, msg: string, ctx?: any) {
  console.log(`${new Date().toISOString()} [${tag}] ${msg}`, ctx ?? "");
}

function emitToSocket(socketId: string | undefined, event: string, payload: any) {
  if (!socketId || !io) return;
  try {
    const socket = io.sockets.sockets.get(socketId);
    if (socket) socket.emit(event, payload);
  } catch (_) {}
}

async function pollUntilDone(
  sessionId: string,
  socketId: string | undefined,
  jobId: string,
  pollTimeoutMs = 5 * 60 * 1000
): Promise<any> {
  const maxAttempts = 600;
  const pollIntervalMs = 500;
  const maxTransientErrors = 12;
  const noProgressLimit = 240;
  let transientErrors = 0;
  let consecutiveNoProgress = 0;
  let lastStatus: string | null = null;
  const deadline = Date.now() + pollTimeoutMs;

  for (let attempt = 0; attempt < maxAttempts; attempt++) {
    if (Date.now() > deadline) {
      throw new Error(`UnitedDH preauth polling timeout for session ${sessionId}`);
    }
    try {
      const st = await getSeleniumUnitedDHPreAuthSessionStatus(sessionId);
      const status: string = st?.status ?? "unknown";
      log("uniteddh-preauth-processor", `poll attempt=${attempt}`, { sessionId, status });
      transientErrors = 0;

      const isTerminal = status === "completed" || status === "error" || status === "not_found";
      if (status === lastStatus && !isTerminal) {
        consecutiveNoProgress++;
      } else {
        consecutiveNoProgress = 0;
      }
      lastStatus = status;

      if (consecutiveNoProgress >= noProgressLimit) {
        throw new Error(`No progress from Python agent (status="${status}") after ${consecutiveNoProgress} polls`);
      }

      if (status === "waiting_for_otp") {
        emitToSocket(socketId, "selenium:otp_required", {
          session_id: sessionId,
          jobId,
          message: "OTP required. Please enter the OTP shown by the DentalHub portal.",
        });
        await new Promise((r) => setTimeout(r, pollIntervalMs));
        continue;
      }

      if (status === "completed") return st.result;
      if (status === "error" || status === "not_found") {
        throw new Error(st?.message || `UnitedDH preauth session ended with status: ${status}`);
      }
      await new Promise((r) => setTimeout(r, pollIntervalMs));
    } catch (err: any) {
      const isTerminal =
        err?.response?.status === 404 ||
        (typeof err?.message === "string" &&
          (err.message.includes("not_found") || err.message.includes("polling timeout")));
      if (isTerminal) throw err;
      transientErrors++;
      if (transientErrors > maxTransientErrors) {
        throw new Error(`Too many transient errors polling UnitedDH preauth session ${sessionId}`);
      }
      const backoff = Math.min(30_000, 500 * Math.pow(2, transientErrors - 1));
      await new Promise((r) => setTimeout(r, backoff));
    }
  }
  throw new Error(`UnitedDH preauth polling exhausted all attempts for session ${sessionId}`);
}

async function savePdfFromSelenium(pdf_url: string, patientId: number) {
  try {
    const filename = path.basename(new URL(pdf_url).pathname);
    const seleniumPort = process.env.SELENIUM_PORT || "5002";
    const localUrl = `http://localhost:${seleniumPort}/downloads/${filename}`;
    const resp = await axios.get(localUrl, { responseType: "arraybuffer", timeout: 30000 });

    let group = await storage.findPdfGroupByPatientTitleKey(patientId, "INSURANCE_CLAIM_PREAUTH");
    if (!group) {
      group = await storage.createPdfGroup(patientId, "PreAuth", "INSURANCE_CLAIM_PREAUTH");
    }
    await storage.createPdfFile(group.id!, filename, resp.data);
    log("uniteddh-preauth-processor", "PDF saved", { patientId, filename });
  } catch (err: any) {
    log("uniteddh-preauth-processor", "failed to save PDF (non-fatal)", { error: err?.message ?? err });
  }
}

export interface UnitedDHPreAuthProcessorInput {
  enrichedPayload: any;
  userId: number;
  claimId?: number;
  socketId?: string;
}

export async function runUnitedDHPreAuthProcessor(
  input: UnitedDHPreAuthProcessorInput,
  jobId: string
): Promise<{ status: string; pdf_url?: string; preAuthNumber?: string }> {
  const { enrichedPayload, userId, claimId, socketId } = input;

  log("uniteddh-preauth-processor", "starting Python agent session", { claimId });
  const agentResp = await forwardToSeleniumUnitedDHPreAuthAgent(enrichedPayload);

  if (!agentResp?.session_id) {
    throw new Error("Python agent did not return a session_id for UnitedDH preauth");
  }

  const sessionId = agentResp.session_id as string;
  log("uniteddh-preauth-processor", "got session_id", { sessionId });

  emitToSocket(socketId, "selenium:uniteddh_preauth_started", { session_id: sessionId, jobId });

  const seleniumResult = await pollUntilDone(sessionId, socketId, jobId);

  if (!seleniumResult || seleniumResult.status === "error") {
    throw new Error(seleniumResult?.message ?? "UnitedDH preauth session returned an error");
  }

  const preAuthNumber: string | undefined = seleniumResult.preAuthNumber ?? undefined;
  const pdf_url: string | undefined = seleniumResult.pdf_url ?? seleniumResult.pdf_path ?? undefined;

  if (claimId) {
    try {
      const updates: Record<string, any> = { status: "PREAUTH" };
      if (preAuthNumber) updates.preAuthNumber = preAuthNumber;
      await storage.updateClaim(claimId, updates);
      log("uniteddh-preauth-processor", "claim record updated", { claimId, preAuthNumber });

      const claim = await storage.getClaim(claimId);
      if (claim?.patientId) {
        await storage.touchPatient(claim.patientId);
        log("uniteddh-preauth-processor", "patient touched", { patientId: claim.patientId });
      }
    } catch (e) {
      log("uniteddh-preauth-processor", "failed to update claim record (non-fatal)", { error: e });
    }
  }

  // Auto-save PDF when called without a frontend socket listener
  if (pdf_url && !socketId) {
    const claim = claimId ? await storage.getClaim(claimId).catch(() => null) : null;
    const patientId = claim?.patientId ?? enrichedPayload?.claim?.patientId ?? enrichedPayload?.patientId;
    if (patientId) await savePdfFromSelenium(pdf_url, Number(patientId));
  }

  emitToSocket(socketId, "selenium:uniteddh_preauth_completed", {
    jobId,
    claimId,
    preAuthNumber,
    pdf_url,
    message: preAuthNumber
      ? `United/DentalHub pre-authorization submitted — PreAuth #: ${preAuthNumber}`
      : (seleniumResult?.message ?? "United/DentalHub pre-authorization submitted successfully"),
  });

  log("uniteddh-preauth-processor", "done", { claimId, preAuthNumber });
  return { status: "success", pdf_url, preAuthNumber };
}