import { useLayoutEffect, useRef, useState, type CSSProperties, type ReactNode } from 'react';

import positionMapLeft from '../assets/facility/tunnel/position-map/left.svg';
import positionMapCenter from '../assets/facility/tunnel/position-map/center.svg';
import positionMapRight from '../assets/facility/tunnel/position-map/right.svg';
import actualDetailLeft from '../assets/facility/tunnel/actual-detail/left.svg';
import actualDetailCenter from '../assets/facility/tunnel/actual-detail/center.svg';
import actualDetailRight from '../assets/facility/tunnel/actual-detail/right.svg';

import './TunnelFacility.css';
import { CompactFacilityConnection } from './CompactFacilityConnection';

export const TUNNEL_ASSET_MAP = Object.freeze({
  positionMap: Object.freeze({
    semanticId: 'facility.tunnel.position-map',
    sourceDirectory: '시설물 표현/터널/위치도',
    left: Object.freeze({ src: positionMapLeft, width: 43, height: 93, role: 'fixed-left-terminal' }),
    center: Object.freeze({ src: positionMapCenter, width: 99, height: 93, role: 'horizontal-flex-center' }),
    right: Object.freeze({ src: positionMapRight, width: 43, height: 93, role: 'fixed-right-terminal' }),
    separatedGap: Object.freeze({ leftToCenter: 7, centerToRight: 5 }),
  }),
  actualDetail: Object.freeze({
    semanticId: 'facility.tunnel.actual-detail',
    sourceDirectory: '시설물 표현/터널/실사화',
    left: Object.freeze({ src: actualDetailLeft, width: 48, height: 95, role: 'fixed-left-terminal' }),
    center: Object.freeze({ src: actualDetailCenter, width: 84, height: 95, role: 'horizontal-flex-center' }),
    right: Object.freeze({ src: actualDetailRight, width: 48, height: 95, role: 'fixed-right-terminal' }),
    separatedGap: Object.freeze({ leftToCenter: 10, centerToRight: 9 }),
  }),
});

export type TunnelVariant = keyof typeof TUNNEL_ASSET_MAP;

const VARIANT_LABEL: Record<TunnelVariant, string> = {
  positionMap: '위치도',
  actualDetail: '실사화',
};

const SOURCE_REFERENCE_NAME = '대산2터널';
const SOURCE_REFERENCE_TOTALS = Object.freeze({
  positionMap: 210,
  actualDetail: 220,
});

function classNames(...values: Array<string | false | null | undefined>) {
  return values.filter(Boolean).join(' ');
}

export function TunnelFacility({
  name = '대산2터널',
  secondaryText = 'L=750m',
  variant = 'positionMap',
  separated = false,
  showLabels = !separated,
  className = '',
}: {
  name?: string;
  secondaryText?: string;
  variant?: TunnelVariant;
  separated?: boolean;
  showLabels?: boolean;
  className?: string;
}) {
  const asset = TUNNEL_ASSET_MAP[variant];
  if (!asset) throw new Error(`Unsupported Tunnel visual variant: ${variant}`);

  const primaryProbeRef = useRef<HTMLSpanElement>(null);
  const secondaryProbeRef = useRef<HTMLSpanElement>(null);
  const [measuredCenterWidth, setMeasuredCenterWidth] = useState<number>(asset.center.width);

  useLayoutEffect(() => {
    if (separated) {
      setMeasuredCenterWidth(asset.center.width);
      return undefined;
    }

    let active = true;
    const measure = () => {
      if (!active) return;
      const primaryWidth = primaryProbeRef.current ? Number.parseFloat(getComputedStyle(primaryProbeRef.current).width) : 0;
      const secondaryWidth = secondaryProbeRef.current ? Number.parseFloat(getComputedStyle(secondaryProbeRef.current).width) : 0;
      const referenceCenterWidth = SOURCE_REFERENCE_TOTALS[variant] - asset.left.width - asset.right.width;
      const nextWidth = name === SOURCE_REFERENCE_NAME
        ? Math.max(asset.center.width, referenceCenterWidth)
        : Math.max(asset.center.width, Math.ceil(primaryWidth), Math.ceil(secondaryWidth));
      setMeasuredCenterWidth((current) => current === nextWidth ? current : nextWidth);
    };

    measure();
    const observer = typeof ResizeObserver === 'function' ? new ResizeObserver(measure) : null;
    if (observer && primaryProbeRef.current) observer.observe(primaryProbeRef.current);
    if (observer && secondaryProbeRef.current) observer.observe(secondaryProbeRef.current);
    document.fonts?.ready.then(measure);

    return () => {
      active = false;
      observer?.disconnect();
    };
  }, [asset, name, secondaryText, separated]);

  const centerWidth = separated ? asset.center.width : measuredCenterWidth;
  const leftGap = separated ? asset.separatedGap.leftToCenter : 0;
  const rightGap = separated ? asset.separatedGap.centerToRight : 0;
  const accessibleName = [name, secondaryText, VARIANT_LABEL[variant], separated ? '분리 표현' : null]
    .filter(Boolean)
    .join(', ');
  const style = {
    '--tunnel-height': `${asset.center.height}px`,
    '--tunnel-left-width': `${asset.left.width}px`,
    '--tunnel-center-base-width': `${asset.center.width}px`,
    '--tunnel-center-width': `${centerWidth}px`,
    '--tunnel-center-scale': centerWidth / asset.center.width,
    '--tunnel-right-width': `${asset.right.width}px`,
    '--tunnel-left-gap': `${leftGap}px`,
    '--tunnel-right-gap': `${rightGap}px`,
  } as CSSProperties;

  return (
    <figure
      className={classNames('tunnel-facility', `tunnel-facility--${variant}`, separated && 'is-separated', className)}
      style={style}
      role="img"
      aria-label={accessibleName}
      data-tunnel-variant={variant}
      data-separated={separated ? 'true' : 'false'}
      data-left-width={asset.left.width}
      data-center-width={centerWidth}
      data-right-width={asset.right.width}
      data-height={asset.center.height}
      data-source-reference-total={name === SOURCE_REFERENCE_NAME ? SOURCE_REFERENCE_TOTALS[variant] : undefined}
    >
      <span className="tunnel-facility__segment tunnel-facility__segment--left" aria-hidden="true">
        <img src={asset.left.src} alt="" draggable="false" />
      </span>
      <span className="tunnel-facility__segment tunnel-facility__segment--center" aria-hidden="true">
        <img src={asset.center.src} alt="" draggable="false" />
      </span>
      <span className="tunnel-facility__segment tunnel-facility__segment--right" aria-hidden="true">
        <img src={asset.right.src} alt="" draggable="false" />
      </span>

      {showLabels && (
        <span className="tunnel-facility__labels" aria-hidden="true">
          <span className="tunnel-facility__primary">{name}</span>
          {secondaryText ? <span className="tunnel-facility__secondary">{secondaryText}</span> : null}
        </span>
      )}

      <span className="tunnel-facility__measure" aria-hidden="true">
        <span ref={primaryProbeRef} className="tunnel-facility__primary">{name}</span>
        <span ref={secondaryProbeRef} className="tunnel-facility__secondary">{secondaryText}</span>
      </span>
    </figure>
  );
}

function TunnelSample({ title, note, children }: { title: string; note?: string; children?: ReactNode }) {
  return (
    <article className="tunnel-reference__sample">
      <header>
        <strong>{title}</strong>
        {note ? <span>{note}</span> : null}
      </header>
      <div className="tunnel-reference__stage">{children}</div>
    </article>
  );
}

function CompactTunnelExample() {
  return (
    <CompactFacilityConnection className="tunnel-applied-example" routeMode="inline" segmentShape="tunnel" sourceStatus="SOURCE_RECEIVED" label="노선과 터널 시설물의 간략 적용 예제">
      <TunnelFacility name="대산2터널" secondaryText="L=750m" variant="positionMap" />
    </CompactFacilityConnection>
  );
}

export function TunnelReferenceDemo() {
  return (
    <div className="tunnel-reference">
      <div className="tunnel-reference__variant-grid">
        <TunnelSample title="Position Map" note="로컬 SVG · 위치도">
          <TunnelFacility variant="positionMap" />
        </TunnelSample>
        <TunnelSample title="Actual / Detail" note="로컬 SVG · 실사화">
          <TunnelFacility variant="actualDetail" />
        </TunnelSample>
      </div>

      <TunnelSample title="Separated" note="같은 개체 · Source 작성 부분 간격">
        <div className="tunnel-reference__row">
          <TunnelFacility variant="positionMap" separated />
          <TunnelFacility variant="actualDetail" separated />
        </div>
      </TunnelSample>

      <TunnelSample title="너비 동작" note="CENTER만 수평 확장">
        <div className="tunnel-reference__width-tests">
          <div><span>SHORT</span><TunnelFacility name="터널" secondaryText="L=80m" variant="positionMap" /></div>
          <div><span>MEDIUM</span><TunnelFacility name="대산2터널" secondaryText="L=750m" variant="positionMap" /></div>
          <div><span>LONG</span><TunnelFacility name="서해안고속도로 대산연결 제2터널" secondaryText="L=12,480m" variant="positionMap" /></div>
          <div><span>ACTUAL SHORT</span><TunnelFacility name="터널" secondaryText="L=80m" variant="actualDetail" /></div>
          <div><span>ACTUAL REF</span><TunnelFacility name="대산2터널" secondaryText="L=750m" variant="actualDetail" /></div>
          <div><span>ACTUAL LONG</span><TunnelFacility name="서해안고속도로 대산연결 제2터널" secondaryText="L=12,480m" variant="actualDetail" /></div>
        </div>
      </TunnelSample>

      <TunnelSample title="간략 적용 예제" note="노선 + 연결 + 터널 + 레이블">
        <CompactTunnelExample />
      </TunnelSample>
    </div>
  );
}