import { useState, useEffect, useCallback, useRef } from 'react';
import { createPortal } from 'react-dom';
import { useTranslation } from 'react-i18next';
import { useFocusTrap } from '../hooks/useFocusTrap';

interface OnboardingStep {
  target: string; // data-onboarding attribute value
  title: string;
  description: string;
  placement: 'top' | 'bottom' | 'left' | 'right';
}

interface OnboardingProps {
  steps: OnboardingStep[];
  onComplete: () => void;
  onSkip: () => void;
}

const STORAGE_KEY = 'onboarding_completed';

// eslint-disable-next-line react-refresh/only-export-components
export function useOnboarding() {
  const [isCompleted, setIsCompleted] = useState(() => {
    return localStorage.getItem(STORAGE_KEY) === 'true';
  });

  const complete = useCallback(() => {
    localStorage.setItem(STORAGE_KEY, 'true');
    setIsCompleted(true);
  }, []);

  const reset = useCallback(() => {
    localStorage.removeItem(STORAGE_KEY);
    setIsCompleted(false);
  }, []);

  return { isCompleted, complete, reset };
}

export default function Onboarding({ steps, onComplete, onSkip }: OnboardingProps) {
  const { t } = useTranslation();
  const [currentStep, setCurrentStep] = useState(0);
  const [targetRect, setTargetRect] = useState<DOMRect | null>(null);
  const [isVisible, setIsVisible] = useState(false);
  const tooltipRef = useRef<HTMLDivElement>(null);

  const onCompleteRef = useRef(onComplete);
  useEffect(() => {
    onCompleteRef.current = onComplete;
  }, [onComplete]);

  const step = steps[currentStep];

  useEffect(() => {
    let cancelled = false;
    let attempts = 0;
    const maxAttempts = 6;
    const isLastStep = currentStep === steps.length - 1;

    setIsVisible(false);
    setTargetRect(null);

    const tryFind = () => {
      if (cancelled) return;
      const target = document.querySelector(`[data-onboarding="${step.target}"]`);
      if (target) {
        const rect = target.getBoundingClientRect();
        setTargetRect(rect);
        target.scrollIntoView({ behavior: 'smooth', block: 'center' });
        window.setTimeout(() => {
          if (!cancelled) setIsVisible(true);
        }, 100);
        return;
      }
      attempts += 1;
      if (attempts < maxAttempts) {
        window.setTimeout(tryFind, 200);
        return;
      }
      if (isLastStep) {
        onCompleteRef.current();
      } else {
        setCurrentStep((prev) => Math.min(prev + 1, steps.length - 1));
      }
    };

    const timer = window.setTimeout(tryFind, 300);
    return () => {
      cancelled = true;
      window.clearTimeout(timer);
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [step.target]);

  // Recalculate position on resize/scroll
  useEffect(() => {
    const updatePosition = () => {
      const target = document.querySelector(`[data-onboarding="${step.target}"]`);
      if (target) {
        setTargetRect(target.getBoundingClientRect());
      }
    };

    window.addEventListener('resize', updatePosition);
    window.addEventListener('scroll', updatePosition, true);
    return () => {
      window.removeEventListener('resize', updatePosition);
      window.removeEventListener('scroll', updatePosition, true);
    };
  }, [step.target]);

  const handleNext = () => {
    if (currentStep < steps.length - 1) {
      setCurrentStep(currentStep + 1);
    } else {
      onComplete();
    }
  };

  const handlePrev = () => {
    if (currentStep > 0) {
      setCurrentStep(currentStep - 1);
    }
  };

  const handleSkip = () => {
    onSkip();
  };

  // Trap focus inside the tooltip while the tour runs; Esc skips it.
  // lockScroll stays off so scrollIntoView can bring each target into view.
  const trapRef = useFocusTrap<HTMLDivElement>(true, { onEscape: handleSkip, lockScroll: false });
  const setTooltipNode = useCallback(
    (node: HTMLDivElement | null) => {
      tooltipRef.current = node;
      trapRef.current = node;
    },
    [trapRef],
  );

  // Calculate tooltip position
  const getTooltipStyle = (): React.CSSProperties => {
    if (!targetRect) return { opacity: 0 };

    const padding = 16;
    const tooltipWidth = 320;
    const tooltipHeight = tooltipRef.current?.offsetHeight || 150;

    let top = 0;
    let left = 0;

    switch (step.placement) {
      case 'bottom':
        top = targetRect.bottom + padding;
        left = targetRect.left + targetRect.width / 2 - tooltipWidth / 2;
        break;
      case 'top':
        top = targetRect.top - tooltipHeight - padding;
        left = targetRect.left + targetRect.width / 2 - tooltipWidth / 2;
        break;
      case 'left':
        top = targetRect.top + targetRect.height / 2 - tooltipHeight / 2;
        left = targetRect.left - tooltipWidth - padding;
        break;
      case 'right':
        top = targetRect.top + targetRect.height / 2 - tooltipHeight / 2;
        left = targetRect.right + padding;
        break;
    }

    // Keep within viewport
    const viewportWidth = window.innerWidth;
    const viewportHeight = window.innerHeight;

    if (left < padding) left = padding;
    if (left + tooltipWidth > viewportWidth - padding) {
      left = viewportWidth - tooltipWidth - padding;
    }
    if (top < padding) top = padding;
    if (top + tooltipHeight > viewportHeight - padding) {
      top = viewportHeight - tooltipHeight - padding;
    }

    return {
      top,
      left,
      width: tooltipWidth,
      opacity: isVisible ? 1 : 0,
      transform: isVisible ? 'scale(1)' : 'scale(0.95)',
    };
  };

  // Spotlight style
  const getSpotlightStyle = (): React.CSSProperties => {
    if (!targetRect) return { opacity: 0 };

    const padding = 8;
    return {
      top: targetRect.top - padding,
      left: targetRect.left - padding,
      width: targetRect.width + padding * 2,
      height: targetRect.height + padding * 2,
      opacity: isVisible ? 1 : 0,
    };
  };

  return createPortal(
    <div className="onboarding-overlay" style={{ opacity: isVisible ? 1 : 0 }}>
      {/* Spotlight */}
      <div
        className="onboarding-spotlight"
        style={{
          ...getSpotlightStyle(),
          pointerEvents: isVisible ? 'auto' : 'none',
        }}
      />

      {/* Tooltip */}
      <div
        ref={setTooltipNode}
        role="dialog"
        aria-modal="true"
        aria-labelledby="onboarding-title"
        aria-describedby="onboarding-desc"
        className={`onboarding-tooltip tooltip-${step.placement}`}
        style={{
          ...getTooltipStyle(),
          pointerEvents: isVisible ? 'auto' : 'none',
        }}
      >
        {/* Progress indicator */}
        <div className="mb-4 flex items-center gap-1.5">
          {steps.map((s, index) => (
            <div
              key={s.target}
              className={`h-1 rounded-full transition-all duration-300 ${
                index === currentStep
                  ? 'w-6 bg-accent-500'
                  : index < currentStep
                    ? 'w-2 bg-accent-500/50'
                    : 'w-2 bg-dark-700'
              }`}
            />
          ))}
        </div>

        {/* Content */}
        <h3 id="onboarding-title" className="mb-2 text-lg font-semibold text-dark-50">
          {step.title}
        </h3>
        <p id="onboarding-desc" className="mb-5 text-sm text-dark-400">
          {step.description}
        </p>

        {/* Actions */}
        <div className="flex items-center justify-between">
          <button
            onClick={handleSkip}
            className="text-sm text-dark-500 transition-colors hover:text-dark-300"
          >
            {t('onboarding.skip', 'Skip')}
          </button>

          <div className="flex gap-2">
            {currentStep > 0 && (
              <button onClick={handlePrev} className="btn-ghost px-3 py-1.5 text-sm">
                {t('common.back', 'Back')}
              </button>
            )}
            <button onClick={handleNext} className="btn-primary px-4 py-1.5 text-sm">
              {currentStep === steps.length - 1
                ? t('onboarding.finish', 'Finish')
                : t('common.next', 'Next')}
            </button>
          </div>
        </div>
      </div>

      {/* Click handler to advance on target click — only when overlay is fully visible */}
      {targetRect && isVisible && (
        <div
          aria-hidden="true"
          className="absolute cursor-pointer"
          style={{
            top: targetRect.top,
            left: targetRect.left,
            width: targetRect.width,
            height: targetRect.height,
          }}
          onClick={handleNext}
        />
      )}
    </div>,
    document.body,
  );
}