import React, { useEffect, useRef, CSSProperties } from 'react';
import { useAtomValue, useSetAtom } from 'jotai';
import { toastQueueAtom, dismissToastAtom, ToastNotif } from '../../state/toast';

// Inject the keyframe animation once
const STYLE_ID = 'lotus-toast-keyframes';
function ensureKeyframes() {
  if (document.getElementById(STYLE_ID)) return;
  const style = document.createElement('style');
  style.id = STYLE_ID;
  style.textContent = `
    @keyframes lotusToastIn {
      from { transform: translateX(120%); opacity: 0; }
      to   { transform: translateX(0);    opacity: 1; }
    }
    @media (prefers-reduced-motion: reduce) {
      @keyframes lotusToastIn {
        from { opacity: 0; }
        to   { opacity: 1; }
      }
    }
  `;
  document.head.appendChild(style);
}

type ToastCardProps = {
  toast: ToastNotif;
};

function ToastCard({ toast }: ToastCardProps) {
  const dismiss = useSetAtom(dismissToastAtom);
  const timerRef = useRef<ReturnType<typeof setTimeout> | null>(null);

  useEffect(() => {
    if (toast.sticky) return;
    timerRef.current = setTimeout(() => {
      dismiss(toast.id);
    }, 4000);
    return () => {
      if (timerRef.current !== null) clearTimeout(timerRef.current);
    };
  }, [dismiss, toast.id, toast.sticky]);

  const handleCardClick = () => {
    if (toast.onClick) {
      toast.onClick();
    } else {
      // window.location.hash setter auto-prepends '#', so values must not include it
      window.location.hash = toast.hashPath ?? `/room/${toast.roomId}`;
    }
    dismiss(toast.id);
  };

  const handleDismiss = (e: React.MouseEvent) => {
    e.stopPropagation();
    dismiss(toast.id);
  };

  const cardStyle: CSSProperties = {
    position: 'relative',
    background: 'var(--lt-bg-card)',
    border: toast.sticky
      ? '1px solid var(--lt-accent-cyan-border)'
      : '1px solid var(--lt-border-color)',
    borderRadius: '12px',
    padding: '12px 14px',
    minWidth: '280px',
    maxWidth: '340px',
    boxShadow: toast.sticky ? 'var(--lt-box-glow-cyan)' : 'var(--lt-box-glow-orange)',
    cursor: 'pointer',
    animation: 'lotusToastIn 0.2s ease-out both',
    userSelect: 'none',
  };

  const rowStyle: CSSProperties = {
    display: 'flex',
    alignItems: 'center',
    gap: '8px',
    marginRight: '20px',
  };

  const avatarStyle: CSSProperties = {
    width: '24px',
    height: '24px',
    borderRadius: '50%',
    objectFit: 'cover',
    flexShrink: 0,
  };

  const initialsStyle: CSSProperties = {
    width: '24px',
    height: '24px',
    borderRadius: '50%',
    background: 'var(--lt-accent-orange-dim)',
    border: '1px solid var(--lt-accent-orange-border)',
    display: 'flex',
    alignItems: 'center',
    justifyContent: 'center',
    fontSize: '10px',
    fontWeight: 700,
    color: 'var(--lt-accent-orange)',
    flexShrink: 0,
  };

  const nameStyle: CSSProperties = {
    color: toast.sticky ? 'var(--lt-accent-cyan)' : 'var(--lt-accent-orange)',
    fontWeight: 600,
    fontSize: '0.85rem',
    overflow: 'hidden',
    textOverflow: 'ellipsis',
    whiteSpace: 'nowrap',
  };

  const dismissBtnStyle: CSSProperties = {
    position: 'absolute',
    top: '8px',
    right: '10px',
    background: 'none',
    border: 'none',
    color: 'var(--lt-text-secondary)',
    cursor: 'pointer',
    fontSize: '14px',
    lineHeight: 1,
    padding: '2px 4px',
    borderRadius: '4px',
  };

  const bodyStyle: CSSProperties = {
    color: 'var(--lt-text-primary)',
    fontSize: '0.82rem',
    margin: '4px 0 2px',
    overflow: 'hidden',
    ...(toast.sticky
      ? { whiteSpace: 'normal', lineHeight: 1.4 }
      : { textOverflow: 'ellipsis', whiteSpace: 'nowrap' }),
  };

  const roomNameStyle: CSSProperties = {
    color: 'var(--lt-text-secondary)',
    fontSize: '0.75rem',
    overflow: 'hidden',
    textOverflow: 'ellipsis',
    whiteSpace: 'nowrap',
  };

  const initials = toast.displayName
    .split(' ')
    .slice(0, 2)
    .map((w) => w[0] ?? '')
    .join('')
    .toUpperCase();

  return (
    <div
      role="button"
      tabIndex={0}
      style={cardStyle}
      onClick={handleCardClick}
      onKeyDown={(e) => {
        if (e.key === 'Enter' || e.key === ' ') handleCardClick();
      }}
      aria-label={`Notification from ${toast.displayName} in ${toast.roomName}`}
    >
      <button
        type="button"
        style={dismissBtnStyle}
        onClick={handleDismiss}
        aria-label="Dismiss notification"
      >
        ×
      </button>
      <div style={rowStyle}>
        {toast.avatarUrl ? (
          <img src={toast.avatarUrl} alt="" style={avatarStyle} aria-hidden="true" />
        ) : (
          <div style={initialsStyle} aria-hidden="true">
            {initials || '?'}
          </div>
        )}
        <span style={nameStyle}>{toast.displayName}</span>
      </div>
      <div style={bodyStyle}>{toast.body}</div>
      <div style={roomNameStyle}>{toast.roomName}</div>
    </div>
  );
}

export function LotusToastContainer() {
  useEffect(() => {
    ensureKeyframes();
  }, []);

  const toasts = useAtomValue(toastQueueAtom);

  if (toasts.length === 0) return null;

  const containerStyle: CSSProperties = {
    position: 'fixed',
    bottom: '1.5rem',
    right: '1.5rem',
    zIndex: 10001,
    display: 'flex',
    flexDirection: 'column',
    gap: '8px',
    pointerEvents: 'auto',
  };

  return (
    <div style={containerStyle} aria-live="polite" aria-label="Notifications">
      {toasts.map((toast) => (
        <ToastCard key={toast.id} toast={toast} />
      ))}
    </div>
  );
}