import { useState, useEffect, useCallback } from 'react';
import { useNavigate } from 'react-router-dom';
import { QRCodeSVG } from 'qrcode.react';
import styles from './Home.module.css';
import { deriveEvmAddress, formatAddress, getKavaExplorerUrl } from '../utils/address';

interface ShareItem {
  id: string;
  walletName: string;
  publicKey: string;
  threshold: { t: number; n: number };
  createdAt: string;
  lastUsedAt?: string;
  participants?: Array<{ partyId: string; name: string }>;
}

interface ShareWithAddress extends ShareItem {
  evmAddress?: string;
  kavaBalance?: string;
  balanceLoading?: boolean;
}

// Kava Testnet EVM RPC endpoint
const KAVA_TESTNET_RPC = 'https://evm.testnet.kava.io';

/**
 * 获取 KAVA 代币余额
 * @param address EVM 地址
 * @returns 余额字符串 (格式化后的 KAVA 数量)
 */
async function fetchKavaBalance(address: string): Promise<string> {
  try {
    const response = await fetch(KAVA_TESTNET_RPC, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        jsonrpc: '2.0',
        method: 'eth_getBalance',
        params: [address, 'latest'],
        id: 1,
      }),
    });

    const data = await response.json();
    if (data.result) {
      // 将 wei 转换为 KAVA (18 位小数)
      const balanceWei = BigInt(data.result);
      const balanceKava = Number(balanceWei) / 1e18;
      // 格式化显示，最多 6 位小数
      return balanceKava.toFixed(balanceKava < 0.000001 && balanceKava > 0 ? 8 : 6).replace(/\.?0+$/, '') || '0';
    }
    return '0';
  } catch (error) {
    console.error('Failed to fetch KAVA balance:', error);
    return '0';
  }
}

export default function Home() {
  const navigate = useNavigate();
  const [shares, setShares] = useState<ShareWithAddress[]>([]);
  const [loading, setLoading] = useState(true);
  const [selectedShare, setSelectedShare] = useState<ShareWithAddress | null>(null);
  const [showQrModal, setShowQrModal] = useState(false);

  const deriveAddresses = useCallback(async (shareList: ShareItem[]): Promise<ShareWithAddress[]> => {
    const sharesWithAddresses: ShareWithAddress[] = [];
    for (const share of shareList) {
      try {
        const evmAddress = await deriveEvmAddress(share.publicKey);
        sharesWithAddresses.push({ ...share, evmAddress, balanceLoading: true });
      } catch (error) {
        console.warn(`Failed to derive address for share ${share.id}:`, error);
        sharesWithAddresses.push({ ...share });
      }
    }
    return sharesWithAddresses;
  }, []);

  // 单独获取所有钱包的余额
  const fetchAllBalances = useCallback(async (sharesWithAddrs: ShareWithAddress[]) => {
    const updatedShares = await Promise.all(
      sharesWithAddrs.map(async (share) => {
        if (share.evmAddress) {
          const kavaBalance = await fetchKavaBalance(share.evmAddress);
          return { ...share, kavaBalance, balanceLoading: false };
        }
        return { ...share, balanceLoading: false };
      })
    );
    setShares(updatedShares);
  }, []);

  useEffect(() => {
    loadShares();
  }, []);

  const loadShares = async () => {
    try {
      let shareList: ShareItem[] = [];

      // 检测是否在 Electron 环境中
      if (window.electronAPI) {
        const result = await window.electronAPI.storage.listShares();
        if (result.success && result.data) {
          shareList = result.data as ShareItem[];
        }
      } else {
        // 浏览器环境，使用 localStorage 或 API
        const stored = localStorage.getItem('shares');
        if (stored) {
          shareList = JSON.parse(stored);
        }
      }

      // 为每个 share 派生 EVM 地址
      const sharesWithAddresses = await deriveAddresses(shareList);
      setShares(sharesWithAddresses);

      // 异步获取所有余额 (不阻塞 UI)
      fetchAllBalances(sharesWithAddresses);
    } catch (error) {
      console.error('Failed to load shares:', error);
    } finally {
      setLoading(false);
    }
  };

  const handleExport = async (id: string) => {
    const password = window.prompt('请输入密码以导出备份文件:');
    if (!password) return;

    try {
      if (window.electronAPI) {
        // 先让用户选择保存位置
        const savePath = await window.electronAPI.dialog.saveFile(
          `share-backup-${id.slice(0, 8)}.dat`,
          [{ name: 'Share Backup', extensions: ['dat'] }]
        );

        if (!savePath) return;

        const result = await window.electronAPI.storage.exportShare(id, password);
        if (result.success && result.data) {
          // 使用 file:write IPC 写入文件到用户选择的路径
          const dataArray = result.data instanceof ArrayBuffer ? new Uint8Array(result.data) : result.data;
          const writeResult = await window.electronAPI.file.write(savePath, dataArray);
          if (writeResult.success) {
            alert('备份文件导出成功!');
          } else {
            alert('写入文件失败: ' + (writeResult.error || '未知错误'));
          }
        } else {
          alert('导出失败: ' + (result.error || '未知错误'));
        }
      }
    } catch (error) {
      alert('导出失败: ' + (error as Error).message);
    }
  };

  const handleDelete = async (id: string) => {
    const confirmed = window.confirm('确定要删除这个钱包吗？删除后无法恢复，请确保已备份。');
    if (!confirmed) return;

    try {
      if (window.electronAPI) {
        const result = await window.electronAPI.storage.deleteShare(id);
        if (result.success) {
          setShares(shares.filter((s) => s.id !== id));
        } else {
          alert('删除失败: ' + (result.error || '未知错误'));
        }
      }
    } catch (error) {
      alert('删除失败: ' + (error as Error).message);
    }
  };

  const handleShowQr = (share: ShareWithAddress) => {
    setSelectedShare(share);
    setShowQrModal(true);
  };

  const handleCopyAddress = (address: string) => {
    navigator.clipboard.writeText(address);
    alert('地址已复制到剪贴板');
  };

  const formatDate = (dateStr: string) => {
    return new Date(dateStr).toLocaleDateString('zh-CN', {
      year: 'numeric',
      month: '2-digit',
      day: '2-digit',
      hour: '2-digit',
      minute: '2-digit',
    });
  };

  if (loading) {
    return (
      <div className={styles.loading}>
        <div className={styles.spinner} />
        <p>加载中...</p>
      </div>
    );
  }

  return (
    <div className={styles.container}>
      <header className={styles.header}>
        <h1 className={styles.title}>我的共管钱包</h1>
        <p className={styles.subtitle}>管理您参与的多方共管钱包 (3-of-5 混合托管)</p>
      </header>

      {shares.length === 0 ? (
        <div className={styles.empty}>
          <div className={styles.emptyIcon}>🔐</div>
          <h2 className={styles.emptyTitle}>暂无共管钱包</h2>
          <p className={styles.emptyText}>
            您可以创建新的共管钱包，或加入他人发起的钱包创建
          </p>
          <div className={styles.emptyActions}>
            <button
              className={styles.primaryButton}
              onClick={() => navigate('/create')}
            >
              创建钱包
            </button>
            <button
              className={styles.secondaryButton}
              onClick={() => navigate('/join')}
            >
              加入创建
            </button>
          </div>
        </div>
      ) : (
        <div className={styles.grid}>
          {shares.map((share) => (
            <div key={share.id} className={styles.card}>
              <div className={styles.cardHeader}>
                <h3 className={styles.cardTitle}>{share.walletName}</h3>
                <span className={styles.threshold}>
                  {share.threshold.t}-of-{share.threshold.n}
                </span>
              </div>
              <div className={styles.cardBody}>
                {/* 地址区域 - 可点击显示二维码 */}
                {share.evmAddress && (
                  <div
                    className={styles.addressSection}
                    onClick={() => handleShowQr(share)}
                  >
                    <div className={styles.qrPreview}>
                      <QRCodeSVG
                        value={share.evmAddress}
                        size={80}
                        level="M"
                        includeMargin={false}
                      />
                    </div>
                    <div className={styles.addressInfo}>
                      <span className={styles.addressLabel}>Kava EVM 地址</span>
                      <code className={styles.addressValue}>
                        {formatAddress(share.evmAddress)}
                      </code>
                      <span className={styles.addressHint}>点击查看完整二维码</span>
                    </div>
                  </div>
                )}

                {/* KAVA 余额显示 */}
                {share.evmAddress && (
                  <div className={styles.balanceSection}>
                    <span className={styles.balanceLabel}>KAVA 余额</span>
                    <span className={styles.balanceValue}>
                      {share.balanceLoading ? (
                        <span className={styles.balanceLoading}>加载中...</span>
                      ) : (
                        <>{share.kavaBalance || '0'} KAVA</>
                      )}
                    </span>
                  </div>
                )}

                <div className={styles.infoRow}>
                  <span className={styles.infoLabel}>参与方</span>
                  <span className={styles.infoValue}>
                    {(share.participants || []).length || share.threshold.n} 人
                  </span>
                </div>
                <div className={styles.infoRow}>
                  <span className={styles.infoLabel}>创建时间</span>
                  <span className={styles.infoValue}>
                    {formatDate(share.createdAt)}
                  </span>
                </div>
                {share.lastUsedAt && (
                  <div className={styles.infoRow}>
                    <span className={styles.infoLabel}>上次使用</span>
                    <span className={styles.infoValue}>
                      {formatDate(share.lastUsedAt)}
                    </span>
                  </div>
                )}
              </div>
              <div className={styles.cardFooter}>
                <button
                  className={`${styles.actionButton} ${styles.transferButton}`}
                  onClick={() => navigate(`/transfer?shareId=${share.id}`)}
                >
                  转账
                </button>
                <button
                  className={styles.actionButton}
                  onClick={() => handleExport(share.id)}
                >
                  导出备份
                </button>
                <button
                  className={`${styles.actionButton} ${styles.dangerButton}`}
                  onClick={() => handleDelete(share.id)}
                >
                  删除
                </button>
              </div>
            </div>
          ))}
        </div>
      )}

      {/* 二维码弹窗 */}
      {showQrModal && selectedShare && (
        <div className={styles.modalOverlay} onClick={() => setShowQrModal(false)}>
          <div className={styles.modal} onClick={(e) => e.stopPropagation()}>
            <div className={styles.modalHeader}>
              <h2 className={styles.modalTitle}>{selectedShare.walletName}</h2>
              <button
                className={styles.modalClose}
                onClick={() => setShowQrModal(false)}
              >
                ×
              </button>
            </div>
            <div className={styles.modalBody}>
              <div className={styles.qrContainer}>
                <QRCodeSVG
                  value={selectedShare.evmAddress || ''}
                  size={240}
                  level="H"
                  includeMargin={true}
                />
              </div>
              <div className={styles.fullAddress}>
                <span className={styles.addressLabelLarge}>Kava EVM 地址</span>
                <code className={styles.addressValueLarge}>
                  {selectedShare.evmAddress}
                </code>
              </div>
              <div className={styles.modalActions}>
                <button
                  className={styles.primaryButton}
                  onClick={() => handleCopyAddress(selectedShare.evmAddress || '')}
                >
                  复制地址
                </button>
                <a
                  href={getKavaExplorerUrl(selectedShare.evmAddress || '', true)}
                  target="_blank"
                  rel="noopener noreferrer"
                  className={styles.secondaryButton}
                >
                  在区块浏览器查看
                </a>
              </div>
            </div>
          </div>
        </div>
      )}
    </div>
  );
}