/**
 * 항적분석 검색 결과 CSV 내보내기
 * BOM + UTF-8 인코딩 (한글 엑셀 호환)
 */
import { getShipKindName, getSignalSourceName } from '../../tracking/types/trackQuery.types';
import { getCountryIsoCode } from '../../replay/components/VesselListManager/utils/countryCodeUtils';

function formatTimestamp(ms) {
  if (!ms) return '';
  const d = new Date(ms);
  const pad = (n) => String(n).padStart(2, '0');
  return `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())} ${pad(d.getHours())}:${pad(d.getMinutes())}:${pad(d.getSeconds())}`;
}

function formatPosition(pos) {
  if (!pos || pos.length < 2) return '';
  const lon = pos[0];
  const lat = pos[1];
  const latDir = lat >= 0 ? 'N' : 'S';
  const lonDir = lon >= 0 ? 'E' : 'W';
  return `${Math.abs(lat).toFixed(4)}\u00B0${latDir} ${Math.abs(lon).toFixed(4)}\u00B0${lonDir}`;
}

function escapeCsvField(value) {
  const str = String(value ?? '');
  if (str.includes(',') || str.includes('"') || str.includes('\n')) {
    return `"${str.replace(/"/g, '""')}"`;
  }
  return str;
}

/**
 * 검색 결과를 CSV로 내보내기 (다중 방문 동적 컬럼 지원)
 *
 * @param {Array} tracks ProcessedTrack 배열
 * @param {Object} hitDetails { vesselId: [{ polygonId, visitIndex, entryTimestamp, exitTimestamp }] }
 * @param {Array} zones 구역 배열
 */
export function exportSearchResultToCSV(tracks, hitDetails, zones) {
  // 구역별 최대 방문 횟수 계산
  const maxVisitsPerZone = {};
  zones.forEach((z) => { maxVisitsPerZone[z.id] = 1; });
  Object.values(hitDetails).forEach((hits) => {
    const countByZone = {};
    (Array.isArray(hits) ? hits : []).forEach((h) => {
      countByZone[h.polygonId] = (countByZone[h.polygonId] || 0) + 1;
    });
    for (const [zoneId, count] of Object.entries(countByZone)) {
      maxVisitsPerZone[zoneId] = Math.max(maxVisitsPerZone[zoneId] || 0, count);
    }
  });

  // 헤더 구성
  const baseHeaders = [
    '신호원', '식별번호', '선박명', '선종', '국적',
    '포인트수', '이동거리(NM)', '평균속도(kn)', '최대속도(kn)',
  ];

  const zoneHeaders = [];
  zones.forEach((zone) => {
    const max = maxVisitsPerZone[zone.id] || 1;
    if (max === 1) {
      zoneHeaders.push(
        `구역${zone.name}_진입시각`, `구역${zone.name}_진입위치`,
        `구역${zone.name}_진출시각`, `구역${zone.name}_진출위치`,
      );
    } else {
      for (let v = 1; v <= max; v++) {
        zoneHeaders.push(
          `구역${zone.name}_${v}차_진입시각`, `구역${zone.name}_${v}차_진입위치`,
          `구역${zone.name}_${v}차_진출시각`, `구역${zone.name}_${v}차_진출위치`,
        );
      }
    }
  });

  const headers = [...baseHeaders, ...zoneHeaders];

  // 데이터 행 생성
  const rows = tracks.map((track) => {
    const baseRow = [
      getSignalSourceName(track.sigSrcCd),
      track.targetId || '',
      track.shipName || '',
      getShipKindName(track.shipKindCode),
      track.nationalCode ? getCountryIsoCode(track.nationalCode) : '',
      track.stats?.pointCount ?? track.geometry.length,
      track.stats?.totalDistance != null ? track.stats.totalDistance.toFixed(2) : '',
      track.stats?.avgSpeed != null ? track.stats.avgSpeed.toFixed(1) : '',
      track.stats?.maxSpeed != null ? track.stats.maxSpeed.toFixed(1) : '',
    ];

    const hits = hitDetails[track.vesselId] || [];
    const zoneData = [];
    zones.forEach((zone) => {
      const max = maxVisitsPerZone[zone.id] || 1;
      const zoneHits = hits
        .filter((h) => h.polygonId === zone.id)
        .sort((a, b) => (a.visitIndex || 1) - (b.visitIndex || 1));

      for (let v = 0; v < max; v++) {
        const hit = zoneHits[v];
        if (hit) {
          zoneData.push(
            formatTimestamp(hit.entryTimestamp),
            formatPosition(hit.entryPosition),
            formatTimestamp(hit.exitTimestamp),
            formatPosition(hit.exitPosition),
          );
        } else {
          zoneData.push('', '', '', '');
        }
      }
    });

    return [...baseRow, ...zoneData];
  });

  // CSV 문자열 생성
  const csvLines = [
    headers.map(escapeCsvField).join(','),
    ...rows.map((row) => row.map(escapeCsvField).join(',')),
  ];
  const csvContent = csvLines.join('\n');

  // BOM + UTF-8 Blob 생성 및 다운로드
  const BOM = '\uFEFF';
  const blob = new Blob([BOM + csvContent], { type: 'text/csv;charset=utf-8;' });
  const url = URL.createObjectURL(blob);

  const now = new Date();
  const pad = (n) => String(n).padStart(2, '0');
  const filename = `항적분석_${now.getFullYear()}${pad(now.getMonth() + 1)}${pad(now.getDate())}_${pad(now.getHours())}${pad(now.getMinutes())}.csv`;

  const link = document.createElement('a');
  link.href = url;
  link.download = filename;
  link.click();
  URL.revokeObjectURL(url);
}