import React, { useEffect, useState, useCallback } from 'react';
import { useTranslation } from 'react-i18next';
import { TutorialHint } from './tutorialSteps';

interface Rect {
  top: number;
  left: number;
  width: number;
  height: number;
}

interface TooltipPos {
  top: number;
  left: number;
}

interface TutorialOverlayProps {
  hints: TutorialHint[];
  currentIndex: number;
  onNext: () => void;
  onPrev: () => void;
  onSkip: () => void;
}

const PADDING = 8;

function getTargetRect(selector: string): Rect | null {
  const el = document.querySelector(selector);
  if (!el) return null;
  const r = el.getBoundingClientRect();
  return { top: r.top, left: r.left, width: r.width, height: r.height };
}

function getSpotlightRect(
  rect: Rect,
  padding: number,
  override?: { top?: number; right?: number; bottom?: number; left?: number }
): Rect {
  const pTop = override?.top ?? padding;
  const pRight = override?.right ?? padding;
  const pBottom = override?.bottom ?? padding;
  const pLeft = override?.left ?? padding;
  const left = Math.max(0, Math.floor(rect.left - pLeft));
  const top = Math.max(0, Math.floor(rect.top - pTop));
  const right = Math.min(window.innerWidth, Math.ceil(rect.left + rect.width + pRight));
  const bottom = Math.min(window.innerHeight, Math.ceil(rect.top + rect.height + pBottom));

  return {
    top,
    left,
    width: Math.max(0, right - left),
    height: Math.max(0, bottom - top),
  };
}

function calcTooltipPos(rect: Rect, position: TutorialHint['position']): TooltipPos {
  const tooltipW = 300;
  const tooltipH = 140;

  switch (position) {
    case 'bottom':
      return {
        top: Math.min(rect.top + rect.height + PADDING, window.innerHeight - tooltipH - 8),
        left: Math.min(Math.max(rect.left + rect.width / 2 - tooltipW / 2, 8), window.innerWidth - tooltipW - 8),
      };
    case 'top':
      return {
        top: Math.max(rect.top - tooltipH - PADDING, 8),
        left: Math.min(Math.max(rect.left + rect.width / 2 - tooltipW / 2, 8), window.innerWidth - tooltipW - 8),
      };
    case 'right':
      return {
        top: Math.min(Math.max(rect.top + rect.height / 2 - tooltipH / 2, 8), window.innerHeight - tooltipH - 8),
        left: Math.min(rect.left + rect.width + PADDING, window.innerWidth - tooltipW - 8),
      };
    case 'left':
      return {
        top: Math.min(Math.max(rect.top + rect.height / 2 - tooltipH / 2, 8), window.innerHeight - tooltipH - 8),
        left: Math.max(rect.left - tooltipW - PADDING, 8),
      };
  }
}

const TutorialOverlay: React.FC<TutorialOverlayProps> = ({
  hints,
  currentIndex,
  onNext,
  onPrev,
  onSkip,
}) => {
  const { t } = useTranslation();
  const [targetRect, setTargetRect] = useState<Rect | null>(null);

  const hint = hints[currentIndex];
  const isLast = currentIndex === hints.length - 1;

  const updateRect = useCallback(() => {
    if (!hint) return;
    setTargetRect(getTargetRect(hint.targetSelector));
  }, [hint]);

  useEffect(() => {
    updateRect();
    window.addEventListener('resize', updateRect);
    window.addEventListener('scroll', updateRect, true);
    return () => {
      window.removeEventListener('resize', updateRect);
      window.removeEventListener('scroll', updateRect, true);
    };
  }, [updateRect]);

  useEffect(() => {
    if (!hint) return;
    let retryTimer: number | undefined;
    let rectTimer: number | undefined;
    let cleanupTarget: (() => void) | undefined;

    const bindToTarget = (el: HTMLElement) => {
      el.scrollIntoView({ behavior: 'smooth', block: 'center' });
      rectTimer = window.setTimeout(updateRect, 200);

      const shouldClickAdvance = hint.clickToAdvance !== false;
      if (shouldClickAdvance) {
        el.style.cursor = 'pointer';
        el.addEventListener('click', onNext);
      }

      cleanupTarget = () => {
        if (shouldClickAdvance) {
          el.style.cursor = '';
          el.removeEventListener('click', onNext);
        }
      };
    };

    const tryBind = (): boolean => {
      const el = document.querySelector(hint.targetSelector) as HTMLElement | null;
      if (!el) return false;
      bindToTarget(el);
      return true;
    };

    if (!tryBind()) {
      retryTimer = window.setInterval(() => {
        if (tryBind() && retryTimer) {
          window.clearInterval(retryTimer);
          retryTimer = undefined;
        }
      }, 80);
    }

    return () => {
      if (retryTimer) window.clearInterval(retryTimer);
      if (rectTimer) window.clearTimeout(rectTimer);
      cleanupTarget?.();
    };
  }, [hint, updateRect, onNext]);

  if (!hint) return null;

  const tooltipPos: TooltipPos = targetRect
    ? calcTooltipPos(targetRect, hint.position)
    : {
        top: window.innerHeight / 2 - 70,
        left: window.innerWidth / 2 - 150,
      };

  const spotlightPadding = hint.spotlightPadding ?? PADDING;
  const spotlightRect = targetRect ? getSpotlightRect(targetRect, spotlightPadding, hint.spotlightPaddingOverride) : null;

  return (
    <div className="tutorial-overlay-root">
      {spotlightRect ? (
        <>
          <div
            className="tutorial-overlay-blocker"
            style={{ top: 0, left: 0, right: 0, height: spotlightRect.top }}
          />
          <div
            className="tutorial-overlay-blocker"
            style={{
              top: spotlightRect.top,
              left: 0,
              width: spotlightRect.left,
              height: spotlightRect.height,
            }}
          />
          <div
            className="tutorial-overlay-blocker"
            style={{
              top: spotlightRect.top,
              left: spotlightRect.left + spotlightRect.width,
              right: 0,
              height: spotlightRect.height,
            }}
          />
          <div
            className="tutorial-overlay-blocker"
            style={{
              top: spotlightRect.top + spotlightRect.height,
              left: 0,
              right: 0,
              bottom: 0,
            }}
          />
          <div
            className="tutorial-spotlight-ring"
            style={{
              top: spotlightRect.top,
              left: spotlightRect.left,
              width: spotlightRect.width,
              height: spotlightRect.height,
            }}
          />
        </>
      ) : (
        <div className="tutorial-overlay-blocker" style={{ inset: 0 }} />
      )}

      <div
        className="tutorial-tooltip"
        style={{ top: tooltipPos.top, left: tooltipPos.left }}
        onClick={(e) => e.stopPropagation()}
      >
        <p className="tutorial-tooltip-title">{t(hint.titleKey)}</p>
        <p className="tutorial-tooltip-desc">{t(hint.descriptionKey)}</p>

        <div className="tutorial-tooltip-footer">
          <span className="tutorial-tooltip-counter">
            {currentIndex + 1} / {hints.length}
          </span>
          <div className="tutorial-tooltip-actions">
            <button className="tutorial-btn-skip" onClick={onSkip}>
              {t('tutorial.skip')}
            </button>
            {currentIndex > 0 && (
              <button className="tutorial-btn-prev" onClick={onPrev}>
                {t('tutorial.prev')}
              </button>
            )}
            {(hint.clickToAdvance !== true || isLast) && (
              <button className="tutorial-btn-next" onClick={onNext}>
                {isLast ? t('tutorial.finish') : t('tutorial.next')}
              </button>
            )}
          </div>
        </div>
      </div>
    </div>
  );
};

export default TutorialOverlay;

interface TutorialRestartPopupProps {
  onConfirm: () => void;
  onCancel: () => void;
}

export const TutorialRestartPopup: React.FC<TutorialRestartPopupProps> = ({ onConfirm, onCancel }) => {
  const { t } = useTranslation();
  return (
    <div className="tutorial-restart-backdrop">
      <div className="tutorial-restart-popup" onClick={(e) => e.stopPropagation()}>
        <p className="tutorial-restart-title">{t('tutorial.restart.title')}</p>
        <p className="tutorial-restart-desc">{t('tutorial.restart.desc')}</p>
        <div className="tutorial-restart-actions">
          <button className="tutorial-restart-cancel" onClick={onCancel}>
            {t('tutorial.restart.cancel')}
          </button>
          <button className="tutorial-restart-confirm" onClick={onConfirm}>
            {t('tutorial.restart.confirm')}
          </button>
        </div>
      </div>
    </div>
  );
};