import { useState, useEffect } from 'react';
import { Zap, Copy, Check, ExternalLink, ShieldCheck, HelpCircle } from 'lucide-react';
import { Button } from '@/components/ui/button';
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogHeader,
  DialogTitle,
} from '@/components/ui/dialog';
import {
  Tooltip,
  TooltipContent,
  TooltipProvider,
  TooltipTrigger,
} from '@/components/ui/tooltip';
import { useToast } from '@/hooks/useToast';
import { isValidNoffer } from '@/lib/types';
import { cn } from '@/lib/utils';

interface ClinkPayButtonProps {
  /** The CLINK Offer code (noffer1...) */
  noffer: string;
  /** Display name of the recipient, e.g. the provider or shop name */
  recipientName?: string;
  className?: string;
  /** Button variant — defaults to a subtle outline so it stays secondary */
  variant?: 'default' | 'outline' | 'secondary';
  size?: 'default' | 'sm' | 'lg';
  /**
   * Friendlier button label. Defaults to "Tip in Bitcoin" — CLINK is jargon,
   * so we lead with what it does and explain the tech in the tooltip/dialog.
   */
  label?: string;
}

/**
 * A self-custodial "Pay via CLINK" button.
 *
 * CLINK Offers (noffer1...) are Nostr-native, self-custodial static payment
 * codes (see https://clinkme.dev). This component does NOT transact — it hands
 * the code off to a CLINK-compatible wallet via QR, copy, or a nostr: deep link.
 * It only renders when a valid noffer is present, so it is purely additive and
 * never replaces the existing Lightning Address / zap flow.
 */
export function ClinkPayButton({
  noffer,
  recipientName,
  className,
  variant = 'outline',
  size = 'default',
  label = 'Tip in Bitcoin',
}: ClinkPayButtonProps) {
  const [open, setOpen] = useState(false);
  const [copied, setCopied] = useState(false);
  const [qrDataUrl, setQrDataUrl] = useState<string | null>(null);
  const { toast } = useToast();

  const valid = isValidNoffer(noffer);
  const nostrUri = `nostr:${noffer}`;

  useEffect(() => {
    if (!open || !valid) return;
    let cancelled = false;
    (async () => {
      try {
        const { default: QRCode } = await import('qrcode');
        const url = await QRCode.toDataURL(noffer.toUpperCase(), {
          width: 260,
          margin: 2,
          color: { dark: '#000000', light: '#ffffff' },
        });
        if (!cancelled) setQrDataUrl(url);
      } catch {
        if (!cancelled) setQrDataUrl(null);
      }
    })();
    return () => {
      cancelled = true;
    };
  }, [open, noffer, valid]);

  // Don't render anything if the code is invalid — keeps the feature opt-in.
  if (!valid) return null;

  const handleCopy = async () => {
    try {
      await navigator.clipboard.writeText(noffer);
      setCopied(true);
      setTimeout(() => setCopied(false), 2000);
      toast({ title: 'Copied', description: 'CLINK code copied to clipboard.' });
    } catch {
      toast({
        title: 'Copy failed',
        description: 'Could not access the clipboard.',
        variant: 'destructive',
      });
    }
  };

  const shortCode = `${noffer.slice(0, 12)}…${noffer.slice(-6)}`;

  return (
    <>
      <div className={cn('flex items-center gap-1.5', className)}>
        <Button
          type="button"
          variant={variant}
          size={size}
          className="flex-1 gap-2 border-indigo-500/40 text-indigo-600 hover:bg-indigo-500/10 hover:text-indigo-700 dark:text-indigo-400 dark:hover:text-indigo-300"
          onClick={() => setOpen(true)}
        >
          <Zap className="h-4 w-4" />
          {label}
        </Button>
        <TooltipProvider delayDuration={150}>
          <Tooltip>
            <TooltipTrigger asChild>
              <button
                type="button"
                onClick={() => setOpen(true)}
                aria-label="What is CLINK?"
                className="flex h-7 w-7 shrink-0 items-center justify-center rounded-full text-muted-foreground transition-colors hover:bg-indigo-500/10 hover:text-indigo-500"
              >
                <HelpCircle className="h-4 w-4" />
              </button>
            </TooltipTrigger>
            <TooltipContent side="top" className="max-w-[220px] text-xs">
              <p className="font-semibold">Pay directly with Bitcoin over Nostr</p>
              <p className="mt-1 text-muted-foreground">
                CLINK is a self-custodial payment code — no app account, no middleman.
                Scan it with a compatible Lightning wallet and the tip goes straight to
                them.
              </p>
            </TooltipContent>
          </Tooltip>
        </TooltipProvider>
      </div>

      <Dialog open={open} onOpenChange={setOpen}>
        <DialogContent className="sm:max-w-sm">
          <DialogHeader>
            <DialogTitle className="flex items-center gap-2">
              <Zap className="h-5 w-5 text-indigo-500" />
              {label}
            </DialogTitle>
            <DialogDescription>
              {recipientName
                ? `Send a self-custodial Bitcoin (Lightning) payment to ${recipientName} — no middleman.`
                : 'Send a self-custodial Bitcoin (Lightning) payment over Nostr — no middleman.'}
            </DialogDescription>
          </DialogHeader>

          <div className="flex flex-col items-center gap-4 py-2">
            {qrDataUrl ? (
              <div className="rounded-2xl bg-white p-3 shadow-sm ring-1 ring-black/5">
                <img
                  src={qrDataUrl}
                  alt="CLINK Offer QR code"
                  className="h-[220px] w-[220px]"
                />
              </div>
            ) : (
              <div className="flex h-[220px] w-[220px] items-center justify-center rounded-2xl bg-muted">
                <Zap className="h-8 w-8 animate-pulse text-muted-foreground" />
              </div>
            )}

            <div className="flex w-full items-center gap-2 rounded-lg border bg-muted/50 px-3 py-2">
              <code className="flex-1 truncate text-xs text-muted-foreground">
                {shortCode}
              </code>
              <Button
                type="button"
                variant="ghost"
                size="icon"
                className="h-7 w-7 shrink-0"
                onClick={handleCopy}
                aria-label="Copy CLINK code"
              >
                {copied ? (
                  <Check className="h-4 w-4 text-green-500" />
                ) : (
                  <Copy className="h-4 w-4" />
                )}
              </Button>
            </div>

            <Button asChild className="w-full gap-2 bg-indigo-600 hover:bg-indigo-700">
              <a href={nostrUri}>
                <ExternalLink className="h-4 w-4" />
                Open in CLINK wallet
              </a>
            </Button>

            <p className="flex items-start gap-1.5 text-center text-xs text-muted-foreground">
              <ShieldCheck className="mt-0.5 h-3.5 w-3.5 shrink-0 text-indigo-500" />
              <span>
                Scan with a CLINK-compatible wallet (e.g. ShockWallet). No custodian,
                no web server — the invoice is requested directly over Nostr.
              </span>
            </p>
          </div>
        </DialogContent>
      </Dialog>
    </>
  );
}