/**
 * 구역 편집 인터랙션 훅
 *
 * - 맵 클릭으로 구역 선택/해제
 * - Polygon: OL Modify (꼭짓점 드래그, 변 중점 삽입) + 우클릭 꼭짓점 삭제
 * - Box: BoxResizeInteraction (모서리 드래그, 직사각형 유지)
 * - Circle: CircleResizeInteraction (테두리 드래그, 원형 재생성)
 * - 모든 유형: OL Translate (내부 드래그 → 전체 이동)
 * - ESC: 선택 해제, Delete: 구역 삭제
 * - 편집 완료 시 store 좌표 동기화
 */
import { useEffect, useRef, useCallback } from 'react';
import { Modify, Translate } from 'ol/interaction';
import Collection from 'ol/Collection';
import { Style, Fill, Stroke, Circle as CircleStyle } from 'ol/style';
import { transform } from 'ol/proj';
import { useMapStore } from '../../stores/mapStore';
import { useAreaSearchStore } from '../stores/areaSearchStore';
import { ZONE_COLORS, ZONE_DRAW_TYPES } from '../types/areaSearch.types';
import { getZoneSource } from '../utils/zoneLayerRefs';
import BoxResizeInteraction from '../interactions/BoxResizeInteraction';
import CircleResizeInteraction from '../interactions/CircleResizeInteraction';

/** 3857 좌표를 4326으로 변환 + 폐곡선 보장 */
function toWgs84Polygon(coords3857) {
  const coords4326 = coords3857.map((c) => transform(c, 'EPSG:3857', 'EPSG:4326'));
  if (coords4326.length > 0) {
    const first = coords4326[0];
    const last = coords4326[coords4326.length - 1];
    if (first[0] !== last[0] || first[1] !== last[1]) {
      coords4326.push([...first]);
    }
  }
  return coords4326;
}

/** 선택된 구역의 하이라이트 스타일 */
function createSelectedStyle(colorIndex) {
  const color = ZONE_COLORS[colorIndex] || ZONE_COLORS[0];
  return new Style({
    fill: new Fill({ color: `rgba(${color.fill[0]},${color.fill[1]},${color.fill[2]},0.25)` }),
    stroke: new Stroke({
      color: `rgba(${color.stroke[0]},${color.stroke[1]},${color.stroke[2]},1)`,
      width: 3,
      lineDash: [8, 4],
    }),
  });
}

/** Modify 인터랙션의 꼭짓점 핸들 스타일 */
const MODIFY_STYLE = new Style({
  image: new CircleStyle({
    radius: 6,
    fill: new Fill({ color: '#ffffff' }),
    stroke: new Stroke({ color: '#4a9eff', width: 2 }),
  }),
});

/** 기본 구역 스타일 복원 */
function createNormalStyle(colorIndex) {
  const color = ZONE_COLORS[colorIndex] || ZONE_COLORS[0];
  return new Style({
    fill: new Fill({ color: `rgba(${color.fill.join(',')})` }),
    stroke: new Stroke({ color: `rgba(${color.stroke.join(',')})`, width: 2 }),
  });
}

/** 호버 스타일 (스트로크 강조) */
function createHoverStyle(colorIndex) {
  const color = ZONE_COLORS[colorIndex] || ZONE_COLORS[0];
  return new Style({
    fill: new Fill({ color: `rgba(${color.fill.join(',')})` }),
    stroke: new Stroke({
      color: `rgba(${color.stroke[0]},${color.stroke[1]},${color.stroke[2]},1)`,
      width: 3,
    }),
  });
}

/** 점(p)과 선분(a-b) 사이 최소 픽셀 거리 */
function pointToSegmentDist(p, a, b) {
  const dx = b[0] - a[0];
  const dy = b[1] - a[1];
  const lenSq = dx * dx + dy * dy;
  if (lenSq === 0) return Math.hypot(p[0] - a[0], p[1] - a[1]);
  let t = ((p[0] - a[0]) * dx + (p[1] - a[1]) * dy) / lenSq;
  t = Math.max(0, Math.min(1, t));
  return Math.hypot(p[0] - (a[0] + t * dx), p[1] - (a[1] + t * dy));
}

const HANDLE_TOLERANCE = 12;

/** Polygon 꼭짓점/변 근접 검사 */
function isNearPolygonHandle(map, pixel, feature) {
  const coords = feature.getGeometry().getCoordinates()[0];
  const n = coords.length - 1;
  for (let i = 0; i < n; i++) {
    const vp = map.getPixelFromCoordinate(coords[i]);
    if (Math.hypot(pixel[0] - vp[0], pixel[1] - vp[1]) < HANDLE_TOLERANCE) {
      return true;
    }
  }
  for (let i = 0; i < n; i++) {
    const p1 = map.getPixelFromCoordinate(coords[i]);
    const p2 = map.getPixelFromCoordinate(coords[(i + 1) % n]);
    if (pointToSegmentDist(pixel, p1, p2) < HANDLE_TOLERANCE) {
      return true;
    }
  }
  return false;
}

/** Feature에서 좌표를 추출하여 store에 동기화 */
function syncZoneToStore(zoneId, feature, zone) {
  const geom = feature.getGeometry();
  const coords3857 = geom.getCoordinates()[0];
  const coords4326 = toWgs84Polygon(coords3857);

  let circleMeta;
  if (zone.type === ZONE_DRAW_TYPES.CIRCLE && zone.circleMeta) {
    // 폴리곤 중심에서 첫 번째 점까지의 거리로 반지름 재계산
    const center = computeCentroid(coords3857);
    const dx = coords3857[0][0] - center[0];
    const dy = coords3857[0][1] - center[1];
    circleMeta = { center, radius: Math.sqrt(dx * dx + dy * dy) };
  }

  useAreaSearchStore.getState().updateZoneGeometry(zoneId, coords4326, circleMeta);
}

/** 다각형 중심점 계산 */
function computeCentroid(coords) {
  let sumX = 0, sumY = 0;
  const n = coords.length - 1; // 마지막(닫힘) 좌표 제외
  for (let i = 0; i < n; i++) {
    sumX += coords[i][0];
    sumY += coords[i][1];
  }
  return [sumX / n, sumY / n];
}

export default function useZoneEdit() {
  const map = useMapStore((s) => s.map);
  const mapRef = useRef(null);
  const modifyRef = useRef(null);
  const translateRef = useRef(null);
  const customResizeRef = useRef(null);
  const selectedCollectionRef = useRef(new Collection());
  const clickListenerRef = useRef(null);
  const contextMenuRef = useRef(null);
  const keydownRef = useRef(null);
  const hoveredZoneIdRef = useRef(null);

  useEffect(() => { mapRef.current = map; }, [map]);

  /** 인터랙션 모두 제거 */
  const removeInteractions = useCallback(() => {
    const m = mapRef.current;
    if (!m) return;
    if (modifyRef.current) { m.removeInteraction(modifyRef.current); modifyRef.current = null; }
    if (translateRef.current) { m.removeInteraction(translateRef.current); translateRef.current = null; }
    if (customResizeRef.current) { m.removeInteraction(customResizeRef.current); customResizeRef.current = null; }
    selectedCollectionRef.current.clear();
  }, []);

  /** 선택된 구역에 대해 인터랙션 설정 */
  const setupInteractions = useCallback((currentMap, zone) => {
    removeInteractions();
    if (!zone || !zone.olFeature) return;

    const feature = zone.olFeature;
    const collection = selectedCollectionRef.current;
    collection.push(feature);

    // 선택 스타일 적용
    feature.setStyle(createSelectedStyle(zone.colorIndex));

    // Translate (모든 유형 공통 — 내부 드래그로 이동)
    const translate = new Translate({ features: collection });
    translate.on('translateend', () => {
      // Circle의 경우 center 업데이트
      if (zone.type === ZONE_DRAW_TYPES.CIRCLE && customResizeRef.current) {
        const coords = feature.getGeometry().getCoordinates()[0];
        const newCenter = computeCentroid(coords);
        customResizeRef.current.setCenter(newCenter);
      }
      syncZoneToStore(zone.id, feature, zone);
    });
    currentMap.addInteraction(translate);
    translateRef.current = translate;

    // 형상별 편집 인터랙션
    if (zone.type === ZONE_DRAW_TYPES.POLYGON) {
      const modify = new Modify({
        features: collection,
        style: MODIFY_STYLE,
        deleteCondition: () => false, // 기본 삭제 비활성화 (우클릭으로 대체)
      });
      modify.on('modifyend', () => {
        syncZoneToStore(zone.id, feature, zone);
      });
      currentMap.addInteraction(modify);
      modifyRef.current = modify;

    } else if (zone.type === ZONE_DRAW_TYPES.BOX) {
      const boxResize = new BoxResizeInteraction({
        feature,
        onResize: () => syncZoneToStore(zone.id, feature, zone),
      });
      currentMap.addInteraction(boxResize);
      customResizeRef.current = boxResize;

    } else if (zone.type === ZONE_DRAW_TYPES.CIRCLE) {
      const center = zone.circleMeta?.center || computeCentroid(feature.getGeometry().getCoordinates()[0]);
      const circleResize = new CircleResizeInteraction({
        feature,
        center,
        onResize: (f) => {
          // 리사이즈 후 circleMeta 업데이트
          const coords = f.getGeometry().getCoordinates()[0];
          const newCenter = computeCentroid(coords);
          const dx = coords[0][0] - newCenter[0];
          const dy = coords[0][1] - newCenter[1];
          const newRadius = Math.sqrt(dx * dx + dy * dy);
          const coords4326 = toWgs84Polygon(coords);
          useAreaSearchStore.getState().updateZoneGeometry(zone.id, coords4326, { center: newCenter, radius: newRadius });
        },
      });
      currentMap.addInteraction(circleResize);
      customResizeRef.current = circleResize;
    }
  }, [removeInteractions]);

  /** 구역 선택 해제 시 스타일 복원 */
  const restoreStyle = useCallback((zoneId) => {
    const { zones } = useAreaSearchStore.getState();
    const zone = zones.find(z => z.id === zoneId);
    if (zone && zone.olFeature) {
      zone.olFeature.setStyle(createNormalStyle(zone.colorIndex));
    }
  }, []);

  // selectedZoneId 변경 구독 → 인터랙션 설정/해제
  useEffect(() => {
    if (!map) return;

    let prevSelectedId = null;

    const unsub = useAreaSearchStore.subscribe(
      (s) => s.selectedZoneId,
      (zoneId) => {
        // 이전 선택 스타일 복원
        if (prevSelectedId) restoreStyle(prevSelectedId);
        prevSelectedId = zoneId;

        if (!zoneId) {
          removeInteractions();
          return;
        }

        const { zones } = useAreaSearchStore.getState();
        const zone = zones.find(z => z.id === zoneId);
        if (zone) {
          setupInteractions(map, zone);
        }
      },
    );

    return () => {
      unsub();
      if (prevSelectedId) restoreStyle(prevSelectedId);
      removeInteractions();
    };
  }, [map, setupInteractions, removeInteractions, restoreStyle]);

  // Drawing 모드 진입 시 편집 해제
  useEffect(() => {
    const unsub = useAreaSearchStore.subscribe(
      (s) => s.activeDrawType,
      (drawType) => {
        if (drawType) {
          useAreaSearchStore.getState().deselectZone();
        }
      },
    );
    return unsub;
  }, []);

  // 맵 singleclick → 구역 선택/해제
  useEffect(() => {
    if (!map) return;

    const handleClick = (evt) => {
      // Drawing 중이면 무시
      if (useAreaSearchStore.getState().activeDrawType) return;

      // 구역 그리기 직후 singleclick 방지 (OL singleclick 250ms 지연 레이스 컨디션)
      if (Date.now() - useAreaSearchStore.getState()._lastZoneAddedAt < 500) return;

      const source = getZoneSource();
      if (!source) return;

      // 클릭 지점의 feature 탐색
      let clickedZone = null;
      const { zones } = useAreaSearchStore.getState();

      map.forEachFeatureAtPixel(evt.pixel, (feature) => {
        if (clickedZone) return; // 이미 찾았으면 무시
        const zone = zones.find(z => z.olFeature === feature);
        if (zone) clickedZone = zone;
      }, { layerFilter: (layer) => layer.getSource() === source });

      const { selectedZoneId } = useAreaSearchStore.getState();

      if (clickedZone) {
        if (clickedZone.id === selectedZoneId) return; // 이미 선택됨

        // 결과 표시 중이면 confirmAndClearResults
        if (!useAreaSearchStore.getState().confirmAndClearResults()) return;

        useAreaSearchStore.getState().selectZone(clickedZone.id);
      } else {
        // 빈 영역 클릭 → 선택 해제
        if (selectedZoneId) {
          useAreaSearchStore.getState().deselectZone();
        }
      }
    };

    map.on('singleclick', handleClick);
    clickListenerRef.current = handleClick;

    return () => {
      map.un('singleclick', handleClick);
      clickListenerRef.current = null;
    };
  }, [map]);

  // 우클릭 꼭짓점 삭제 (Polygon 전용)
  useEffect(() => {
    if (!map) return;

    const handleContextMenu = (e) => {
      const { selectedZoneId, zones } = useAreaSearchStore.getState();
      if (!selectedZoneId) return;

      const zone = zones.find(z => z.id === selectedZoneId);
      if (!zone || zone.type !== ZONE_DRAW_TYPES.POLYGON) return;

      const feature = zone.olFeature;
      if (!feature) return;

      const geom = feature.getGeometry();
      const coords = geom.getCoordinates()[0];
      const vertexCount = coords.length - 1; // 마지막 닫힘 좌표 제외
      if (vertexCount <= 3) return; // 최소 삼각형 유지

      const pixel = map.getEventPixel(e);
      const clickCoord = map.getCoordinateFromPixel(pixel);

      // 가장 가까운 꼭짓점 탐색
      let minDist = Infinity;
      let minIdx = -1;
      for (let i = 0; i < vertexCount; i++) {
        const dx = coords[i][0] - clickCoord[0];
        const dy = coords[i][1] - clickCoord[1];
        const dist = dx * dx + dy * dy;
        if (dist < minDist) { minDist = dist; minIdx = i; }
      }

      // 픽셀 거리 검증 (10px 이내)
      const vPixel = map.getPixelFromCoordinate(coords[minIdx]);
      if (Math.hypot(pixel[0] - vPixel[0], pixel[1] - vPixel[1]) > 10) return;

      e.preventDefault();

      const newCoords = [...coords];
      newCoords.splice(minIdx, 1);
      if (minIdx === 0) {
        newCoords[newCoords.length - 1] = [...newCoords[0]];
      }
      geom.setCoordinates([newCoords]);
      syncZoneToStore(zone.id, feature, zone);
    };

    const viewport = map.getViewport();
    viewport.addEventListener('contextmenu', handleContextMenu);
    contextMenuRef.current = handleContextMenu;

    return () => {
      viewport.removeEventListener('contextmenu', handleContextMenu);
      contextMenuRef.current = null;
    };
  }, [map]);

  // 키보드: ESC → 선택 해제, Delete → 구역 삭제
  useEffect(() => {
    const handleKeyDown = (e) => {
      const { selectedZoneId, activeDrawType } = useAreaSearchStore.getState();

      if (e.key === 'Escape' && selectedZoneId && !activeDrawType) {
        useAreaSearchStore.getState().deselectZone();
      }

      if ((e.key === 'Delete' || e.key === 'Backspace') && selectedZoneId && !activeDrawType) {
        useAreaSearchStore.getState().deselectZone();
        useAreaSearchStore.getState().removeZone(selectedZoneId);
      }
    };

    window.addEventListener('keydown', handleKeyDown);
    keydownRef.current = handleKeyDown;

    return () => {
      window.removeEventListener('keydown', handleKeyDown);
      keydownRef.current = null;
    };
  }, []);

  // pointermove → 호버 피드백 (커서 + 스타일)
  useEffect(() => {
    if (!map) return;

    const viewport = map.getViewport();

    const handlePointerMove = (evt) => {
      if (evt.dragging) return;

      // Drawing 중이면 호버 해제
      if (useAreaSearchStore.getState().activeDrawType) {
        if (hoveredZoneIdRef.current) {
          restoreStyle(hoveredZoneIdRef.current);
          hoveredZoneIdRef.current = null;
        }
        viewport.style.cursor = '';
        return;
      }

      const source = getZoneSource();
      if (!source) return;

      const { selectedZoneId, zones } = useAreaSearchStore.getState();

      // 1. 선택된 구역 — 리사이즈 핸들 / 내부 커서
      if (selectedZoneId) {
        const zone = zones.find(z => z.id === selectedZoneId);
        if (zone && zone.olFeature) {
          // Box/Circle: isOverHandle
          if (customResizeRef.current && customResizeRef.current.isOverHandle) {
            const handle = customResizeRef.current.isOverHandle(map, evt.pixel);
            if (handle) {
              viewport.style.cursor = handle.cursor;
              return;
            }
          }

          // Polygon: 꼭짓점/변 근접
          if (zone.type === ZONE_DRAW_TYPES.POLYGON) {
            if (isNearPolygonHandle(map, evt.pixel, zone.olFeature)) {
              viewport.style.cursor = 'crosshair';
              return;
            }
          }

          // 선택된 구역 내부 → move
          let overSelected = false;
          map.forEachFeatureAtPixel(evt.pixel, (feature) => {
            if (feature === zone.olFeature) overSelected = true;
          }, { layerFilter: (l) => l.getSource() === source });

          if (overSelected) {
            viewport.style.cursor = 'move';
            return;
          }
        }
      }

      // 2. 비선택 구역 호버
      let hoveredZone = null;
      map.forEachFeatureAtPixel(evt.pixel, (feature) => {
        if (hoveredZone) return;
        const zone = zones.find(z => z.olFeature === feature && z.id !== selectedZoneId);
        if (zone) hoveredZone = zone;
      }, { layerFilter: (l) => l.getSource() === source });

      if (hoveredZone) {
        viewport.style.cursor = 'pointer';
        if (hoveredZoneIdRef.current !== hoveredZone.id) {
          if (hoveredZoneIdRef.current) restoreStyle(hoveredZoneIdRef.current);
          hoveredZoneIdRef.current = hoveredZone.id;
          hoveredZone.olFeature.setStyle(createHoverStyle(hoveredZone.colorIndex));
        }
      } else {
        viewport.style.cursor = '';
        if (hoveredZoneIdRef.current) {
          restoreStyle(hoveredZoneIdRef.current);
          hoveredZoneIdRef.current = null;
        }
      }
    };

    map.on('pointermove', handlePointerMove);

    return () => {
      map.un('pointermove', handlePointerMove);
      if (hoveredZoneIdRef.current) {
        restoreStyle(hoveredZoneIdRef.current);
        hoveredZoneIdRef.current = null;
      }
      viewport.style.cursor = '';
    };
  }, [map, restoreStyle]);
}