"use strict";

const { withBrowser, navigateWithHumanBehavior, extractPricesFromPage } = require("./baseCrawler");

/**
 * Formats a date as YYYYMMDD for Naver Flights URLs.
 */
function getDStr(date) {
  const d = new Date(date);
  const yy = d.getFullYear();
  const mm = String(d.getMonth() + 1).padStart(2, "0");
  const dd = String(d.getDate()).padStart(2, "0");
  return `${yy}${mm}${dd}`;
}

/**
 * Maps internal cabin class to Naver fareType code.
 *   economy → Y, premium_economy → P, business → C, first → F
 */
function getFareType(byCabin) {
  if (byCabin.first > 0) return "F";
  if (byCabin.business > 0) return "C";
  if (byCabin.premium_economy > 0) return "P";
  return "Y";
}

/**
 * Builds a Naver Flights URL from structured search params.
 *
 * Round-trip format:
 *   /flights/international/ICN-NRT-20260315/NRT-ICN-20260322?adult=1&fareType=Y
 *
 * Multi-city format:
 *   /flights/multi?itinerary=ICN:NRT:20260315,NRT:ICN:20260322&adult=1&fareType=Y
 *
 * One-way format:
 *   /flights/international/ICN-NRT-20260315?adult=1&fareType=Y
 */
function buildNaverUrl(searchParams) {
  const segments = searchParams.segments || [];
  if (segments.length === 0) return "https://flight.naver.com";

  const tripType = searchParams.tripType;
  const adults = searchParams.passengers?.total || 1;
  const byCabin = searchParams.passengers?.byCabin || {};
  const fareType = getFareType(byCabin);

  const today = new Date();
  const tomorrow = new Date(today);
  tomorrow.setDate(tomorrow.getDate() + 1);

  if (tripType === "round_trip") {
    const from = segments[0].from.toUpperCase();
    const to = segments[0].to.toUpperCase();
    const departDate = searchParams.departureDateWindow?.from || tomorrow;
    const d1 = getDStr(departDate);

    // Return date: use stayDurationDays if available, default to 7 days
    const stayDays = searchParams.stayDurationDays?.minDays || 7;
    const returnDate = new Date(departDate);
    returnDate.setDate(returnDate.getDate() + stayDays);
    const d2 = getDStr(returnDate);

    // Naver round-trip: outbound segment / return segment (origin/dest reversed)
    return `https://flight.naver.com/flights/international/${from}-${to}-${d1}/${to}-${from}-${d2}?adult=${adults}&fareType=${fareType}`;
  }

  if (tripType === "multi_city") {
    // Naver multi-city: /flights/multi?itinerary=ICN:NRT:20260315,NRT:ICN:20260322
    let currentBaseDate = new Date(searchParams.departureDateWindow?.from || tomorrow);
    const itineraryParts = [];
    for (const seg of segments) {
      itineraryParts.push(`${seg.from.toUpperCase()}:${seg.to.toUpperCase()}:${getDStr(currentBaseDate)}`);
      currentBaseDate.setDate(currentBaseDate.getDate() + 3);
    }
    return `https://flight.naver.com/flights/multi?itinerary=${itineraryParts.join(",")}&adult=${adults}&fareType=${fareType}`;
  }

  // one_way
  const from = segments[0].from.toUpperCase();
  const to = segments[0].to.toUpperCase();
  const d1 = searchParams.departureDateWindow?.from ? getDStr(searchParams.departureDateWindow.from) : getDStr(tomorrow);
  return `https://flight.naver.com/flights/international/${from}-${to}-${d1}?adult=${adults}&fareType=${fareType}`;
}

async function scrapeNaver(searchParams) {
  const url = buildNaverUrl(searchParams);
  console.log(`[Naver] Navigating to ${url}`);

  return withBrowser(async (page) => {
    await navigateWithHumanBehavior(page, url);

    // Wait for price elements with generic selectors
    try {
      await page.waitForSelector('[class*="price"], [class*="Price"], [class*="fare"]', { timeout: 15000 });
    } catch (e) {
      console.log("[Naver] Timeout waiting for price elements.");
    }

    // Extract prices using generic Korean won patterns
    const prices = await extractPricesFromPage(page);

    if (prices.length === 0) {
      console.log("[Naver] No prices found on page.");
      return [];
    }

    return prices.map((price, i) => ({
      provider: "naver",
      price,
      currency: "KRW",
      metadata: { url, rank: i + 1 },
    }));
  });
}

module.exports = { scrapeNaver, buildNaverUrl };