import type { Deal, SearchCriteria } from "../types";
import { enumerateDatePairs } from "../date";

function toLower(s: string) { return (s||"").toLowerCase(); }

export async function buildSkyscannerLinks(c: SearchCriteria): Promise<Deal[]> {
  const origin = toLower(c.origin);
  const out: Deal[] = [];
  const pairs = enumerateDatePairs(c.startDate, c.endDate, c.tripLengthMin, c.tripLengthMax, 6);

  for (const dest of c.destinations) {
    for (const p of pairs) {
      const path = `https://www.skyscanner.ca/transport/flights/${origin}/${toLower(dest)}/${p.out}/${p.back}/`;
      out.push({
        id: `sky-${origin}-${dest}-${p.out}-${p.back}`,
        title: `${c.origin} → ${dest} (${p.nights} nights)`,
        source: "Skyscanner Link",
        link: path,
        price: null,
        currency: c.currency || "CAD",
        startDate: `${p.out.slice(0,4)}-${p.out.slice(4,6)}-${p.out.slice(6,8)}`,
        endDate: `${p.back.slice(0,4)}-${p.back.slice(4,6)}-${p.back.slice(6,8)}`,
        nights: p.nights,
        origin: c.origin,
        destination: dest,
      });
    }
  }
  return out;
}

export async function buildGoogleFlightsLinks(c: SearchCriteria): Promise<Deal[]> {
  const out: Deal[] = [];
  const pairs = enumerateDatePairs(c.startDate, c.endDate, c.tripLengthMin, c.tripLengthMax, 4);
  for (const dest of c.destinations) {
    for (const p of pairs) {
      const q = encodeURIComponent(`flights from ${c.origin} to ${dest} ${p.out} to ${p.back}`);
      const link = `https://www.google.com/travel/flights?q=${q}`;
      out.push({
        id: `gfl-${c.origin}-${dest}-${p.out}-${p.back}`,
        title: `Google Flights: ${c.origin} → ${dest} (${p.nights} nights)`,
        source: "Google Flights Link",
        link,
        price: null,
        currency: c.currency || "CAD",
        startDate: `${p.out.slice(0,4)}-${p.out.slice(4,6)}-${p.out.slice(6,8)}`,
        endDate: `${p.back.slice(0,4)}-${p.back.slice(4,6)}-${p.back.slice(6,8)}`,
        nights: p.nights,
        origin: c.origin,
        destination: dest,
      });
    }
  }
  return out;
}

export async function buildAirCanadaLinks(c: SearchCriteria): Promise<Deal[]> {
  const out: Deal[] = [];
  const pairs = enumerateDatePairs(c.startDate, c.endDate, c.tripLengthMin, c.tripLengthMax, 3);
  for (const dest of c.destinations) {
    for (const p of pairs) {
      const sd = `${p.out.slice(0,4)}-${p.out.slice(4,6)}-${p.out.slice(6,8)}`;
      const ed = `${p.back.slice(0,4)}-${p.back.slice(4,6)}-${p.back.slice(6,8)}`;
      const params = new URLSearchParams({
        org1: c.origin.toUpperCase(),
        dest1: dest.toUpperCase(),
        departureDate1: sd,
        returnDate1: ed,
        tripType: "2",
        lang: "en-CA"
      });
      const link = `https://www.aircanada.com/ca/en/aco/home/book/travel.html?${params.toString()}`;
      out.push({
        id: `ac-${c.origin}-${dest}-${p.out}-${p.back}`,
        title: `Air Canada: ${c.origin} → ${dest} (${p.nights} nights)`,
        source: "Air Canada Link",
        link,
        price: null,
        currency: c.currency || "CAD",
        startDate: sd,
        endDate: ed,
        nights: p.nights,
        origin: c.origin,
        destination: dest,
      });
    }
  }
  return out;
}

export async function buildAirTransatLinks(c: SearchCriteria): Promise<Deal[]> {
  const out: Deal[] = [];
  const pairs = enumerateDatePairs(c.startDate, c.endDate, c.tripLengthMin, c.tripLengthMax, 3);
  for (const dest of c.destinations) {
    for (const p of pairs) {
      const sd = `${p.out.slice(0,4)}-${p.out.slice(4,6)}-${p.out.slice(6,8)}`;
      const ed = `${p.back.slice(0,4)}-${p.back.slice(4,6)}-${p.back.slice(6,8)}`;
      // Air Transat vacation packages search
      const params = new URLSearchParams({
        depCity: c.origin.toUpperCase(),
        destCode: dest.toUpperCase(),
        depDate: sd,
        retDate: ed,
        adults: "2",
        children: "0",
        infants: "0"
      });
      const link = `https://www.airtransat.com/en-CA/flights-hotels?${params.toString()}`;
      out.push({
        id: `at-${c.origin}-${dest}-${p.out}-${p.back}`,
        title: `Air Transat: ${c.origin} → ${dest} (${p.nights} nights)`,
        source: "Air Transat Link",
        link,
        price: null,
        currency: c.currency || "CAD",
        startDate: sd,
        endDate: ed,
        nights: p.nights,
        origin: c.origin,
        destination: dest,
      });
    }
  }
  return out;
}