import { useCallback, useEffect, useRef, useState } from 'react';
import { Viewer2D } from '../viewer2d/Viewer2D';
import { parseDwgBuffer } from '../viewer2d/dwgParser';
import { parseDxfBuffer } from '../viewer2d/parseDxf';
import { isDwg, isDxf, is2D } from '../viewer2d/ext2d';
import { listCadSpaces, pickDefaultSpace, type CadSpace } from '../viewer2d/cadSpaces';
import { setDefaultFontUrl } from '../viewer2d/slugText';
import { getAllOptions, setOption } from '../lib/optionsStore';

setDefaultFontUrl('/fonts/NanumGothic-Regular.ttf');

export interface LayerRow {
  name: string;
  colorHex: string;
  count: number;
  visible: boolean;
}

export type LoadStatus = 'idle' | 'loading' | 'ready' | 'error';

export interface PersistedOptions {
  grid: boolean;
  zoomSpeed: number;
  zScale: number;
  lineweightOn: boolean | null;
  lineweightScale: number | null;
}

const DEFAULT_OPTIONS: PersistedOptions = {
  grid: false,
  zoomSpeed: 1,
  zScale: 1,
  lineweightOn: null,
  lineweightScale: null,
};

async function parseByName(name: string, buf: ArrayBuffer) {
  if (isDwg(name)) return parseDwgBuffer(new Uint8Array(buf));
  if (isDxf(name)) return parseDxfBuffer(buf);
  if (!is2D(name)) throw new Error('지원하지 않는 파일 형식입니다 (.dwg/.dxf만 지원)');
  return parseDxfBuffer(buf);
}

export function useDwgViewer() {
  const containerRef = useRef<HTMLDivElement>(null);
  const viewerRef = useRef<Viewer2D | null>(null);

  const [status, setStatus] = useState<LoadStatus>('idle');
  const [statusMessage, setStatusMessage] = useState('준비됨');
  const [loadingProgress, setLoadingProgress] = useState<number | null>(null);

  const [selectedEntity, setSelectedEntity] = useState<unknown>(null);
  const [pointerWorld, setPointerWorld] = useState<{ x: number; y: number; z: number } | null>(null);

  const [spaces, setSpaces] = useState<CadSpace[]>([]);
  const [activeSpace, setActiveSpace] = useState<string | null>(null);

  const [layers, setLayers] = useState<LayerRow[]>([]);
  const [hiddenLayers, setHiddenLayersState] = useState<Set<string>>(new Set());

  const [theme, setThemeState] = useState<'dark' | 'light'>('dark');
  const [is25D, setIs25DState] = useState(false);
  const [options, setOptions] = useState<PersistedOptions>(DEFAULT_OPTIONS);

  const refreshLayers = useCallback(() => {
    const viewer = viewerRef.current;
    if (!viewer) return;
    const info = viewer.getLayerInfo();
    setLayers(info.map((l) => ({ name: l.name, colorHex: l.colorHex, count: l.count, visible: l.visible })));
  }, []);

  const refreshSpaces = useCallback(() => {
    const viewer = viewerRef.current;
    if (!viewer) return;
    setSpaces(viewer.getSpaces());
    setActiveSpace(viewer.getActiveSpace());
  }, []);

  // mount Viewer2D once
  useEffect(() => {
    const container = containerRef.current;
    if (!container) return;
    // Viewer2D has no dispose/teardown API (permanent window/canvas
    // listeners, its own rAF loop) — defensively clear any leftover canvas
    // from a prior construction (e.g. a dev Fast Refresh remount) so it
    // never stacks two live WebGL contexts in the same container.
    container.replaceChildren();
    const viewer = new Viewer2D(container);
    viewerRef.current = viewer;
    viewer.setTheme(true);
    viewer.onSelect((entity) => setSelectedEntity(entity));
    viewer.onPointerWorld((p) => setPointerWorld(p));

    const onResize = () => viewer.resize();
    window.addEventListener('resize', onResize);

    (async () => {
      const saved = await getAllOptions();
      const next: PersistedOptions = {
        grid: typeof saved.grid === 'boolean' ? saved.grid : DEFAULT_OPTIONS.grid,
        zoomSpeed: typeof saved.zoomSpeed === 'number' ? saved.zoomSpeed : DEFAULT_OPTIONS.zoomSpeed,
        zScale: typeof saved.zScale === 'number' ? saved.zScale : DEFAULT_OPTIONS.zScale,
        lineweightOn:
          saved.lineweightOn === true || saved.lineweightOn === false ? saved.lineweightOn : null,
        lineweightScale: typeof saved.lineweightScale === 'number' ? saved.lineweightScale : null,
      };
      setOptions(next);
      viewer.setGrid(next.grid);
      viewer.setZoomSpeed(next.zoomSpeed);
      viewer.setZScale(next.zScale);
      viewer.setLineweightEnabled(next.lineweightOn);
      viewer.setLineweightScale(next.lineweightScale);
    })();

    return () => {
      window.removeEventListener('resize', onResize);
      viewer.onPointerWorld(null);
      viewerRef.current = null;
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  const loadParseResult = useCallback(
    (result: unknown) => {
      const viewer = viewerRef.current;
      if (!viewer) return;
      const spaceList = listCadSpaces(result as any);
      const def = pickDefaultSpace(spaceList);
      viewer.load(result, { spaceHandle: def?.handleHex ?? null });
      refreshSpaces();
      refreshLayers();
      setHiddenLayersState(new Set());
      setSelectedEntity(null);
    },
    [refreshSpaces, refreshLayers],
  );

  const loadArrayBuffer = useCallback(
    async (name: string, buf: ArrayBuffer) => {
      setStatus('loading');
      setStatusMessage(`불러오는 중… (${name})`);
      setLoadingProgress(null);
      try {
        const result = await parseByName(name, buf);
        loadParseResult(result);
        setStatus('ready');
        setStatusMessage(`로드 완료: ${name}`);
      } catch (err) {
        setStatus('error');
        setStatusMessage(err instanceof Error ? err.message : '파일을 불러오지 못했습니다');
      } finally {
        setLoadingProgress(null);
      }
    },
    [loadParseResult],
  );

  const loadFile = useCallback(
    async (file: File) => {
      const buf = await file.arrayBuffer();
      await loadArrayBuffer(file.name, buf);
    },
    [loadArrayBuffer],
  );

  const loadUrl = useCallback(
    async (url: string, label?: string) => {
      const name = label ?? url.split('/').pop() ?? url;
      setStatus('loading');
      setStatusMessage(`다운로드 중… (${name})`);
      setLoadingProgress(0);
      try {
        const res = await fetch(url);
        if (!res.ok) throw new Error(`다운로드 실패 (${res.status})`);
        const total = Number(res.headers.get('content-length') ?? 0);
        let buf: ArrayBuffer;
        if (total > 0 && res.body) {
          const reader = res.body.getReader();
          const chunks: Uint8Array[] = [];
          let received = 0;
          for (;;) {
            const { done, value } = await reader.read();
            if (done) break;
            if (value) {
              chunks.push(value);
              received += value.length;
              setLoadingProgress(Math.min(99, Math.round((received / total) * 100)));
            }
          }
          const merged = new Uint8Array(received);
          let offset = 0;
          for (const chunk of chunks) {
            merged.set(chunk, offset);
            offset += chunk.length;
          }
          buf = merged.buffer;
        } else {
          setLoadingProgress(null);
          buf = await res.arrayBuffer();
        }
        await loadArrayBuffer(name, buf);
      } catch (err) {
        setStatus('error');
        setStatusMessage(err instanceof Error ? err.message : '다운로드하지 못했습니다');
        setLoadingProgress(null);
      }
    },
    [loadArrayBuffer],
  );

  const fit = useCallback(() => viewerRef.current?.fit(), []);

  const zoomToSelection = useCallback(() => viewerRef.current?.zoomToSelection(), []);

  const selectSpace = useCallback(
    (handleHex: string | null) => {
      viewerRef.current?.setSpace(handleHex);
      refreshSpaces();
      refreshLayers();
    },
    [refreshSpaces, refreshLayers],
  );

  const toggleTheme = useCallback(() => {
    setThemeState((prev) => {
      const next = prev === 'dark' ? 'light' : 'dark';
      viewerRef.current?.setTheme(next === 'dark');
      refreshLayers();
      return next;
    });
  }, [refreshLayers]);

  const setGrid = useCallback((on: boolean) => {
    viewerRef.current?.setGrid(on);
    setOptions((o) => ({ ...o, grid: on }));
    void setOption('grid', on);
  }, []);

  const setZoomSpeed = useCallback((v: number) => {
    viewerRef.current?.setZoomSpeed(v);
    setOptions((o) => ({ ...o, zoomSpeed: v }));
    void setOption('zoomSpeed', v);
  }, []);

  const setZScale = useCallback((v: number) => {
    viewerRef.current?.setZScale(v);
    setOptions((o) => ({ ...o, zScale: v }));
    void setOption('zScale', v);
  }, []);

  const setLineweightOn = useCallback((on: boolean | null) => {
    viewerRef.current?.setLineweightEnabled(on);
    setOptions((o) => ({ ...o, lineweightOn: on }));
    void setOption('lineweightOn', on);
  }, []);

  const setLineweightScale = useCallback((v: number | null) => {
    viewerRef.current?.setLineweightScale(v);
    setOptions((o) => ({ ...o, lineweightScale: v }));
    void setOption('lineweightScale', v);
  }, []);

  const set25D = useCallback((on: boolean) => {
    viewerRef.current?.set25D(on);
    setIs25DState(on);
  }, []);

  const resetOptions = useCallback(() => {
    setLineweightScale(null);
    setLineweightOn(null);
    setGrid(false);
    setZoomSpeed(1);
    setZScale(1);
    set25D(false);
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  const toggleLayer = useCallback((name: string) => {
    setHiddenLayersState((prev) => {
      const next = new Set(prev);
      if (next.has(name)) next.delete(name);
      else next.add(name);
      viewerRef.current?.setHiddenLayers(next);
      return next;
    });
  }, []);

  const showAllLayers = useCallback(() => {
    setHiddenLayersState(() => {
      const next = new Set<string>();
      viewerRef.current?.setHiddenLayers(next);
      return next;
    });
  }, []);

  const hideAllLayers = useCallback(() => {
    setHiddenLayersState(() => {
      const next = new Set(layers.map((l) => l.name));
      viewerRef.current?.setHiddenLayers(next);
      return next;
    });
  }, [layers]);

  const getLineweightClasses = useCallback(() => viewerRef.current?.getLineweightClasses() ?? [], []);

  return {
    containerRef,
    viewerRef,
    status,
    statusMessage,
    setStatusMessage,
    loadingProgress,
    selectedEntity,
    pointerWorld,
    spaces,
    activeSpace,
    layers,
    hiddenLayers,
    theme,
    is25D,
    options,
    loadFile,
    loadUrl,
    fit,
    zoomToSelection,
    selectSpace,
    toggleTheme,
    set25D,
    setGrid,
    setZoomSpeed,
    setZScale,
    setLineweightOn,
    setLineweightScale,
    resetOptions,
    toggleLayer,
    showAllLayers,
    hideAllLayers,
    getLineweightClasses,
  };
}

export type UseDwgViewer = ReturnType<typeof useDwgViewer>;