/**
 * Transaction details page.
 * Auto-refreshes when transaction is unconfirmed to detect confirmation.
 */

import { useEffect, useState } from 'react';
import { useParams, Link } from 'react-router-dom';
import {
  ArrowRight,
  Clock,
  Hash,
  Box,
  Coins,
  CheckCircle,
  AlertCircle,
  Gift,
  RefreshCw,
  Radio,
} from 'lucide-react';
import { useTransaction } from '../hooks/useApi';
import { useWebSocket } from '../contexts/WebSocketContext';
import CopyButton from '../components/CopyButton';
import TransactionFlowDiagram from '../components/TransactionFlowDiagram';
import ConnectionStatus from '../components/ConnectionStatus';
import { formatDateTime, formatSynor, truncateHash } from '../lib/utils';

const UNCONFIRMED_REFRESH_INTERVAL = 5000; // 5 seconds

export default function Transaction() {
  const { txId } = useParams<{ txId: string }>();
  const { data: tx, isLoading, error, refetch } = useTransaction(txId || '');
  const { isConnected } = useWebSocket();
  const [isRefreshing, setIsRefreshing] = useState(false);
  const [justConfirmed, setJustConfirmed] = useState(false);

  // Auto-refresh for unconfirmed transactions
  useEffect(() => {
    if (!tx || tx.blockHash) return; // Already confirmed or no data

    const interval = setInterval(async () => {
      setIsRefreshing(true);
      await refetch();
      setIsRefreshing(false);
    }, UNCONFIRMED_REFRESH_INTERVAL);

    return () => clearInterval(interval);
  }, [tx, refetch]);

  // Detect when transaction gets confirmed
  useEffect(() => {
    if (tx?.blockHash && !justConfirmed) {
      // Check if it was previously unconfirmed (first load with blockHash won't trigger)
      const wasUnconfirmed = sessionStorage.getItem(`tx-${txId}-unconfirmed`);
      if (wasUnconfirmed === 'true') {
        setJustConfirmed(true);
        sessionStorage.removeItem(`tx-${txId}-unconfirmed`);
        // Auto-dismiss after 5 seconds
        setTimeout(() => setJustConfirmed(false), 5000);
      }
    } else if (tx && !tx.blockHash) {
      // Mark as unconfirmed for later detection
      sessionStorage.setItem(`tx-${txId}-unconfirmed`, 'true');
    }
  }, [tx, txId, justConfirmed]);

  if (!txId) {
    return <div className="card p-6 text-red-400">Transaction ID is required</div>;
  }

  if (isLoading) {
    return <TransactionSkeleton />;
  }

  if (error) {
    return (
      <div className="card p-6 text-red-400">
        Error loading transaction: {error.message}
      </div>
    );
  }

  if (!tx) {
    return <div className="card p-6 text-gray-400">Transaction not found</div>;
  }

  const isUnconfirmed = !tx.blockHash;

  return (
    <div className="space-y-6">
      {/* Just confirmed banner */}
      {justConfirmed && (
        <div className="bg-green-500/20 border border-green-500/30 rounded-xl p-4 flex items-center gap-3 animate-pulse">
          <CheckCircle size={24} className="text-green-400" />
          <div>
            <div className="font-semibold text-green-400">Transaction Confirmed!</div>
            <div className="text-sm text-green-400/80">
              This transaction has been included in a block.
            </div>
          </div>
        </div>
      )}

      {/* Modern Header */}
      <div className="relative">
        {/* Background glow */}
        <div className="absolute -top-10 left-0 w-[300px] h-[150px] bg-green-500/10 rounded-full blur-[80px] pointer-events-none" />

        <div className="relative flex flex-col md:flex-row md:items-center justify-between gap-4">
          <div className="flex items-center gap-4">
            <div className="p-3 rounded-xl bg-gradient-to-br from-green-500/20 to-synor-500/20 border border-green-500/30">
              <Hash size={28} className="text-green-400" />
            </div>
            <div>
              <h1 className="text-2xl md:text-3xl font-bold bg-gradient-to-r from-white to-gray-300 bg-clip-text text-transparent">
                Transaction Details
              </h1>
              <div className="flex items-center gap-2 mt-1">
                {tx.isCoinbase && (
                  <span className="px-2 py-0.5 text-xs font-medium bg-amber-500/20 text-amber-400 rounded-full border border-amber-500/30 flex items-center gap-1">
                    <Gift size={12} />
                    Coinbase
                  </span>
                )}
                {tx.blockHash ? (
                  <span className="px-2 py-0.5 text-xs font-medium bg-green-500/20 text-green-400 rounded-full border border-green-500/30 flex items-center gap-1">
                    <CheckCircle size={12} />
                    Confirmed
                  </span>
                ) : (
                  <span className="px-2 py-0.5 text-xs font-medium bg-amber-500/20 text-amber-400 rounded-full border border-amber-500/30 flex items-center gap-1">
                    {isRefreshing ? (
                      <RefreshCw size={12} className="animate-spin" />
                    ) : (
                      <AlertCircle size={12} />
                    )}
                    Unconfirmed
                  </span>
                )}
              </div>
            </div>
          </div>

          {/* Quick stats and status */}
          <div className="flex items-center gap-3">
            {/* Waiting for confirmation indicator */}
            {isUnconfirmed && isConnected && (
              <div className="hidden sm:flex items-center gap-2 px-3 py-1.5 rounded-lg bg-amber-500/10 border border-amber-500/30 text-amber-400 text-xs">
                <Radio size={12} className="animate-pulse" />
                <span>Waiting for confirmation...</span>
              </div>
            )}

            <ConnectionStatus size="sm" />

            <div className="px-4 py-2 rounded-xl bg-gray-800/50 border border-gray-700/50">
              <div className="text-xs text-gray-500">Total Value</div>
              <div className="text-lg font-bold text-green-400 font-mono">
                {formatSynor(tx.totalOutput, 4)}
              </div>
            </div>
            {!tx.isCoinbase && tx.fee > 0 && (
              <div className="px-4 py-2 rounded-xl bg-gray-800/50 border border-gray-700/50">
                <div className="text-xs text-gray-500">Fee</div>
                <div className="text-lg font-bold text-amber-400 font-mono">
                  {formatSynor(tx.fee, 4)}
                </div>
              </div>
            )}
          </div>
        </div>
      </div>

      {/* Unconfirmed notice */}
      {isUnconfirmed && (
        <div className="bg-amber-500/10 border border-amber-500/30 rounded-xl p-4 flex items-center gap-3">
          <Clock size={20} className="text-amber-400 flex-shrink-0" />
          <div className="flex-1">
            <div className="font-medium text-amber-400">Pending Confirmation</div>
            <div className="text-sm text-amber-400/70">
              This transaction is in the mempool and waiting to be included in a block.
              {isConnected && ' Page will auto-update when confirmed.'}
            </div>
          </div>
          {isRefreshing && (
            <RefreshCw size={16} className="text-amber-400 animate-spin flex-shrink-0" />
          )}
        </div>
      )}

      {/* Transaction Flow Diagram */}
      <TransactionFlowDiagram
        inputs={tx.inputs}
        outputs={tx.outputs}
        isCoinbase={tx.isCoinbase}
        totalInput={tx.totalInput}
        totalOutput={tx.totalOutput}
        fee={tx.fee}
      />

      {/* Transaction Info */}
      <div className="card">
        <div className="card-header">
          <h2 className="font-semibold">Transaction Information</h2>
        </div>
        <div className="divide-y divide-gray-800">
          <InfoRow label="Transaction ID">
            <div className="flex items-center gap-2">
              <span className="hash text-synor-400">{tx.id}</span>
              <CopyButton text={tx.id} />
            </div>
          </InfoRow>
          {tx.blockHash && (
            <InfoRow label="Block">
              <Link
                to={`/block/${tx.blockHash}`}
                className="flex items-center gap-2 text-synor-400 hover:text-synor-300"
              >
                <Box size={16} />
                <span className="hash">{truncateHash(tx.blockHash, 12, 12)}</span>
              </Link>
            </InfoRow>
          )}
          {tx.blockTime && (
            <InfoRow label="Timestamp">
              <div className="flex items-center gap-2">
                <Clock size={16} className="text-gray-500" />
                {formatDateTime(tx.blockTime)}
              </div>
            </InfoRow>
          )}
          <InfoRow label="Total Output">
            <span className="text-green-400 font-mono">
              {formatSynor(tx.totalOutput)}
            </span>
          </InfoRow>
          {!tx.isCoinbase && (
            <InfoRow label="Fee">
              <span className="text-gray-300 font-mono">
                {formatSynor(tx.fee)}
              </span>
            </InfoRow>
          )}
          <InfoRow label="Mass">{tx.mass.toLocaleString()}</InfoRow>
          <InfoRow label="Version">{tx.version}</InfoRow>
        </div>
      </div>

      {/* Inputs & Outputs */}
      <div className="grid md:grid-cols-2 gap-6">
        {/* Inputs */}
        <div className="card">
          <div className="card-header flex items-center gap-2">
            <Coins size={18} className="text-synor-400" />
            <h2 className="font-semibold">
              Inputs ({tx.inputs.length})
            </h2>
          </div>
          <div className="divide-y divide-gray-800 max-h-96 overflow-y-auto scrollbar-thin">
            {tx.isCoinbase ? (
              <div className="px-4 py-3 text-gray-400">
                Coinbase (Block Reward)
              </div>
            ) : (
              tx.inputs.map((input, i) => (
                <div key={i} className="px-4 py-3">
                  {input.address ? (
                    <Link
                      to={`/address/${input.address}`}
                      className="hash text-sm text-synor-400 hover:text-synor-300 block mb-1"
                    >
                      {truncateHash(input.address, 12, 12)}
                    </Link>
                  ) : (
                    <span className="hash text-sm text-gray-500 block mb-1">
                      Unknown
                    </span>
                  )}
                  {input.value !== undefined && (
                    <span className="text-sm text-red-400 font-mono">
                      -{formatSynor(input.value, 4)}
                    </span>
                  )}
                  <div className="text-xs text-gray-500 mt-1">
                    {truncateHash(input.previousTxId)}:{input.previousIndex}
                  </div>
                </div>
              ))
            )}
          </div>
        </div>

        {/* Outputs */}
        <div className="card">
          <div className="card-header flex items-center gap-2">
            <ArrowRight size={18} className="text-synor-400" />
            <h2 className="font-semibold">
              Outputs ({tx.outputs.length})
            </h2>
          </div>
          <div className="divide-y divide-gray-800 max-h-96 overflow-y-auto scrollbar-thin">
            {tx.outputs.map((output, i) => (
              <div key={i} className="px-4 py-3">
                {output.address ? (
                  <Link
                    to={`/address/${output.address}`}
                    className="hash text-sm text-synor-400 hover:text-synor-300 block mb-1"
                  >
                    {truncateHash(output.address, 12, 12)}
                  </Link>
                ) : (
                  <span className="hash text-sm text-gray-500 block mb-1">
                    {output.scriptType}
                  </span>
                )}
                <span className="text-sm text-green-400 font-mono">
                  +{formatSynor(output.value, 4)}
                </span>
              </div>
            ))}
          </div>
        </div>
      </div>
    </div>
  );
}

function InfoRow({ label, children }: { label: string; children: React.ReactNode }) {
  return (
    <div className="px-4 py-3 flex flex-col sm:flex-row sm:items-center gap-1 sm:gap-4">
      <span className="text-sm text-gray-400 sm:w-32 flex-shrink-0">{label}</span>
      <span className="text-gray-100 break-all">{children}</span>
    </div>
  );
}

function TransactionSkeleton() {
  return (
    <div className="space-y-6 animate-pulse">
      <div className="flex items-center gap-3">
        <div className="w-12 h-12 rounded-lg bg-gray-800" />
        <div>
          <div className="h-7 w-48 bg-gray-800 rounded mb-2" />
          <div className="h-5 w-24 bg-gray-800 rounded" />
        </div>
      </div>
      <div className="card">
        <div className="card-header">
          <div className="h-5 w-44 bg-gray-800 rounded" />
        </div>
        <div className="divide-y divide-gray-800">
          {Array.from({ length: 6 }).map((_, i) => (
            <div key={i} className="px-4 py-3 flex items-center gap-4">
              <div className="h-4 w-28 bg-gray-800 rounded" />
              <div className="h-4 w-48 bg-gray-800 rounded" />
            </div>
          ))}
        </div>
      </div>
    </div>
  );
}