import React, { useEffect, useState, useRef } from 'react';
import { ShieldAlert, Clock, ArrowRight, X, AlertTriangle, LogOut } from 'lucide-react';
import { clearSessionAndRedirectToLanding, dismissSubordinateModals } from '../../services/sessionExpiration';

interface SessionExpiredModalProps {
  isOpen: boolean;
  onDismiss?: () => void;
  reason?: string | null;
  /** Total countdown time in seconds (defaults to 8 seconds) */
  countdownSeconds?: number;
}

export const SessionExpiredModal: React.FC<SessionExpiredModalProps> = ({
  isOpen,
  onDismiss,
  reason,
  countdownSeconds = 8,
}) => {
  const [timeLeftMs, setTimeLeftMs] = useState(countdownSeconds * 1000);
  const [isPaused, setIsPaused] = useState(false);
  const totalDurationMs = countdownSeconds * 1000;
  const isClearingRef = useRef(false);

  // When session expiration modal is displayed, dismiss all subordinate modals
  useEffect(() => {
    if (isOpen) {
      dismissSubordinateModals();
    }
  }, [isOpen]);

  // Listen for cancellation event (e.g., when activation lockout takes priority)
  useEffect(() => {
    const handleCancelled = () => {
      setTimeLeftMs(countdownSeconds * 1000);
      setIsPaused(false);
      isClearingRef.current = false;
    };
    window.addEventListener('pfm:session-expired-cancelled', handleCancelled);
    return () => {
      window.removeEventListener('pfm:session-expired-cancelled', handleCancelled);
    };
  }, [countdownSeconds]);

  // Reset or start countdown when modal opens
  useEffect(() => {
    if (!isOpen) {
      setTimeLeftMs(countdownSeconds * 1000);
      setIsPaused(false);
      isClearingRef.current = false;
      return;
    }

    const intervalMs = 50;
    const interval = setInterval(() => {
      setTimeLeftMs((prev) => {
        if (isPaused) return prev;
        const next = prev - intervalMs;
        if (next <= 0) {
          clearInterval(interval);
          handleAction();
          return 0;
        }
        return next;
      });
    }, intervalMs);

    return () => clearInterval(interval);
  }, [isOpen, isPaused, countdownSeconds]);

  const handleAction = () => {
    if (isClearingRef.current) return;
    isClearingRef.current = true;

    if (onDismiss) {
      onDismiss();
    } else {
      clearSessionAndRedirectToLanding();
    }
  };

  if (!isOpen) return null;

  const secondsRemaining = Math.max(0, Math.ceil(timeLeftMs / 1000));
  const progressPercent = Math.max(0, Math.min(100, (timeLeftMs / totalDurationMs) * 100));

  return (
    <div
      id="session-expired-modal-backdrop"
      className="fixed inset-0 z-[9999] flex items-center justify-center bg-black/85 backdrop-blur-md p-4 animate-in fade-in duration-200"
      onMouseEnter={() => setIsPaused(true)}
      onMouseLeave={() => setIsPaused(false)}
      role="dialog"
      aria-modal="true"
      aria-labelledby="session-expired-title"
    >
      <div
        id="session-expired-modal-content"
        className="relative w-full max-w-md bg-[#0c121e] border border-amber-500/40 rounded-2xl shadow-2xl shadow-black/90 p-6 overflow-hidden text-slate-200 space-y-5"
      >
        {/* Subtle decorative top accent bar */}
        <div className="absolute top-0 left-0 right-0 h-1 bg-gradient-to-r from-amber-500 via-orange-500 to-rose-500" />

        {/* Top bar with close button */}
        <div className="flex items-start justify-between pt-1">
          <div className="flex items-center gap-3">
            <div className="w-12 h-12 rounded-2xl bg-amber-500/10 border border-amber-500/30 flex items-center justify-center text-amber-400 shrink-0 shadow-lg shadow-amber-500/10">
              <ShieldAlert className="w-6 h-6" />
            </div>
            <div>
              <div className="flex items-center gap-2">
                <h3 id="session-expired-title" className="text-base font-bold text-white tracking-tight">
                  Session Expired
                </h3>
                <span className="text-[10px] font-mono font-semibold px-2 py-0.5 rounded bg-rose-950/60 text-rose-300 border border-rose-800/60">
                  HTTP 401
                </span>
              </div>
              <p className="text-xs text-slate-400 mt-0.5">Authorization token invalidated</p>
            </div>
          </div>

          <button
            id="session-expired-close-btn"
            type="button"
            onClick={handleAction}
            aria-label="Dismiss and return to landing page"
            className="p-1.5 text-slate-400 hover:text-white rounded-lg hover:bg-slate-800/80 transition-colors"
          >
            <X className="w-4 h-4" />
          </button>
        </div>

        {/* Informative Explanation (non-technical and clear) */}
        <div className="space-y-2.5 text-xs text-slate-300 leading-relaxed bg-slate-900/60 p-4 rounded-xl border border-slate-800/80">
          <p>
            Your active working session has ended or your security credentials have expired. To protect your data and prevent unauthorized changes, your session has been closed.
          </p>
          {reason && (
            <div className="flex items-start gap-2 pt-1 text-[11px] text-amber-300/90 font-mono">
              <AlertTriangle className="w-3.5 h-3.5 shrink-0 mt-0.5 text-amber-400" />
              <span className="break-words">{reason}</span>
            </div>
          )}
        </div>

        {/* Progress Bar Countdown */}
        <div className="space-y-2">
          <div className="flex items-center justify-between text-xs">
            <span className="text-slate-400 flex items-center gap-1.5">
              <Clock className="w-3.5 h-3.5 text-amber-400" />
              Returning to landing page in{' '}
              <strong className="text-white font-mono">{secondsRemaining}s</strong>
            </span>
            {isPaused && (
              <span className="text-[10px] text-amber-400/80 font-medium px-1.5 py-0.2 rounded bg-amber-950/40 border border-amber-900/60">
                Paused on hover
              </span>
            )}
          </div>

          {/* Progress bar line */}
          <div className="w-full h-2 bg-slate-800/90 rounded-full overflow-hidden border border-slate-700/60 p-0.5">
            <div
              className="h-full rounded-full bg-gradient-to-r from-amber-500 via-orange-500 to-rose-500 transition-all duration-75 ease-linear"
              style={{ width: `${progressPercent}%` }}
            />
          </div>
        </div>

        {/* Actions */}
        <div className="pt-2 flex flex-col sm:flex-row items-center gap-2.5">
          <button
            id="session-expired-return-btn"
            type="button"
            onClick={handleAction}
            className="w-full py-2.5 px-4 text-xs font-semibold text-white bg-gradient-to-r from-blue-600 to-indigo-600 hover:from-blue-500 hover:to-indigo-500 rounded-xl shadow-lg shadow-blue-500/20 transition-all flex items-center justify-center gap-2"
          >
            <LogOut className="w-4 h-4" />
            <span>Return to Landing Page Now</span>
            <ArrowRight className="w-3.5 h-3.5 ml-0.5" />
          </button>
        </div>
      </div>
    </div>
  );
};