import { ObjectId } from "mongodb";
import type { Collection, WithId } from "mongodb";
import { getDb, getPhoneNumbersCollection } from "../index";
import type { Session } from "./sessions.types";

export const getSessionsCollection = (): Collection<Session> =>
  getDb().collection<Session>("sessions");

const buildPhoneCandidates = (phone: string): string[] => {
  const raw = (phone ?? "").trim();
  if (!raw) return [];

  const noPlus = raw.startsWith("+") ? raw.slice(1) : raw;
  const digitsOnly = raw.replace(/\D/g, "");
  const digitsOnlyNoPlus = noPlus.replace(/\D/g, "");

  return Array.from(
    new Set([raw, noPlus, digitsOnly, digitsOnlyNoPlus].filter(Boolean)),
  );
};

const buildFlowIdCandidates = (flowId: unknown): Array<string | ObjectId> => {
  if (!flowId) return [];

  // Some sessions store flow_id as string, others as ObjectId.
  if (flowId instanceof ObjectId) {
    return [flowId, flowId.toString()];
  }

  const asString = String(flowId);
  if (!asString) return [];

  if (ObjectId.isValid(asString)) {
    return [new ObjectId(asString), asString];
  }
  return [asString];
};

export const findSessionById = (
  sessionId: ObjectId,
  clientId: string,
): Promise<WithId<Session> | null> => {
  return getSessionsCollection().findOne({
    _id: sessionId,
    clientId: clientId,
  });
};

export const findSessionOfIncomingCall = async (from: string, to: string) => {
  const toCandidates = buildPhoneCandidates(to);
  const fromCandidates = buildPhoneCandidates(from);

  const receiverPhoneData = await getPhoneNumbersCollection().findOne({
    phone_number: { $in: toCandidates },
  });
  if (!receiverPhoneData) {
    return null;
  }

  const flowIdCandidates = buildFlowIdCandidates(receiverPhoneData.flow_id);

  const [session] = await getSessionsCollection()
    .aggregate<WithId<Session>>([
      {
        $match: {
          flow_id: { $in: flowIdCandidates },
          phone_numbers: {
            $elemMatch: { phoneNumber: { $in: fromCandidates } },
          },
        },
      },
      {
        $addFields: {
          phone_numbers: {
            $filter: {
              input: "$phone_numbers",
              as: "pn",
              cond: { $in: ["$$pn.phoneNumber", fromCandidates] },
            },
          },
        },
      },
      { $limit: 1 },
    ])
    .toArray();

  if (!session) {
    console.info("No session found for incoming call");
    return null;
  }
  return session;
};