import { useState, useEffect } from 'react';
import { useNavigate, useParams } from 'react-router-dom';
import styles from './Sign.module.css';

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

interface SigningSession {
  sessionId: string;
  walletName: string;
  messageHash: string;
  threshold: { t: number; n: number };
  currentParticipants: number;
  initiator: string;
}

export default function Sign() {
  const { sessionId: urlSessionId } = useParams<{ sessionId?: string }>();
  const navigate = useNavigate();

  const [step, setStep] = useState<'select' | 'join' | 'signing' | 'completed' | 'failed'>('select');
  const [shares, setShares] = useState<ShareItem[]>([]);
  const [selectedShare, setSelectedShare] = useState<ShareItem | null>(null);
  const [sessionCode, setSessionCode] = useState(urlSessionId || '');
  const [password, setPassword] = useState('');
  const [signingSession, setSigningSession] = useState<SigningSession | null>(null);
  const [signature, setSignature] = useState<string | null>(null);
  const [isLoading, setIsLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [progress, setProgress] = useState({ current: 0, total: 0 });

  // 加载本地保存的 shares
  useEffect(() => {
    loadShares();
  }, []);

  // 如果 URL 中有 sessionId，自动进入加入流程
  useEffect(() => {
    if (urlSessionId && shares.length > 0) {
      setStep('join');
    }
  }, [urlSessionId, shares]);

  const loadShares = async () => {
    try {
      if (window.electronAPI) {
        const result = await window.electronAPI.storage.listShares();
        if (result.success && result.data) {
          setShares(result.data as ShareItem[]);
        }
      }
    } catch (error) {
      console.error('Failed to load shares:', error);
    }
  };

  const handleImportShare = async () => {
    try {
      if (window.electronAPI) {
        const filePath = await window.electronAPI.dialog.selectFile([
          { name: 'Share Backup', extensions: ['dat', 'json'] }
        ]);
        if (filePath) {
          const importPassword = window.prompt('请输入备份文件的密码:');
          if (!importPassword) return;

          const result = await window.electronAPI.storage.importShare(filePath, importPassword);
          if (result.success && result.share) {
            await loadShares();
            setSelectedShare(result.share as ShareItem);
          } else {
            setError(result.error || '导入失败');
          }
        }
      }
    } catch (err) {
      setError('导入失败: ' + (err as Error).message);
    }
  };

  const handleValidateSession = async () => {
    if (!sessionCode.trim()) {
      setError('请输入签名会话码');
      return;
    }

    setIsLoading(true);
    setError(null);

    try {
      const result = await window.electronAPI.grpc.validateSigningSession(sessionCode);
      if (result.success && result.session) {
        setSigningSession(result.session);
        setStep('join');
      } else {
        setError(result.error || '无效的签名会话码');
      }
    } catch (err) {
      setError('验证失败: ' + (err as Error).message);
    } finally {
      setIsLoading(false);
    }
  };

  const handleJoinSigning = async () => {
    if (!selectedShare) {
      setError('请选择要使用的钱包份额');
      return;
    }
    // 密码是可选的，如果创建时没有设置密码，这里也不需要输入

    setIsLoading(true);
    setError(null);
    setStep('signing');

    try {
      // 获取解密后的 share
      const shareData = await window.electronAPI.storage.getShare(selectedShare.id, password);
      if (!shareData) {
        setError('密码错误或份额数据损坏');
        setStep('join');
        setIsLoading(false);
        return;
      }

      // 加入签名会话
      const result = await window.electronAPI.grpc.joinSigningSession({
        sessionId: signingSession!.sessionId,
        shareId: selectedShare.id,
        password: password,
      });

      if (result.success) {
        // 订阅签名进度
        window.electronAPI.grpc.subscribeSigningProgress(
          signingSession!.sessionId,
          (event) => {
            if (event.type === 'progress') {
              setProgress({ current: event.current || 0, total: event.total || 0 });
            } else if (event.type === 'completed') {
              setSignature(event.signature || '');
              setStep('completed');
              setIsLoading(false);
            } else if (event.type === 'failed') {
              setError(event.error || '签名失败');
              setStep('failed');
              setIsLoading(false);
            }
          }
        );
      } else {
        setError(result.error || '加入签名会话失败');
        setStep('join');
        setIsLoading(false);
      }
    } catch (err) {
      setError('签名过程出错: ' + (err as Error).message);
      setStep('failed');
      setIsLoading(false);
    }
  };

  const handleCopySignature = async () => {
    if (signature) {
      try {
        await navigator.clipboard.writeText(signature);
      } catch (err) {
        console.error('Failed to copy:', err);
      }
    }
  };

  const handlePaste = async () => {
    try {
      const text = await navigator.clipboard.readText();
      setSessionCode(text.trim());
    } catch (err) {
      console.error('Failed to read clipboard:', err);
    }
  };

  return (
    <div className={styles.container}>
      <div className={styles.card}>
        <h1 className={styles.title}>参与签名</h1>
        <p className={styles.subtitle}>使用您的钱包份额参与多方签名</p>

        {step === 'select' && (
          <div className={styles.form}>
            {/* 选择本地 Share */}
            <div className={styles.section}>
              <h3 className={styles.sectionTitle}>选择钱包份额</h3>
              {shares.length === 0 ? (
                <div className={styles.emptyShares}>
                  <p>暂无本地保存的钱包份额</p>
                  <button className={styles.linkButton} onClick={handleImportShare}>
                    导入备份文件
                  </button>
                </div>
              ) : (
                <div className={styles.shareList}>
                  {shares.map((share) => (
                    <div
                      key={share.id}
                      className={`${styles.shareItem} ${selectedShare?.id === share.id ? styles.shareItemSelected : ''}`}
                      onClick={() => setSelectedShare(share)}
                    >
                      <div className={styles.shareInfo}>
                        <span className={styles.shareName}>{share.walletName}</span>
                        <span className={styles.shareThreshold}>
                          {share.threshold.t}-of-{share.threshold.n}
                        </span>
                      </div>
                      <code className={styles.shareKey}>
                        {share.publicKey.slice(0, 8)}...{share.publicKey.slice(-8)}
                      </code>
                    </div>
                  ))}
                  <button className={styles.linkButton} onClick={handleImportShare}>
                    + 导入其他备份文件
                  </button>
                </div>
              )}
            </div>

            {/* 输入签名会话码 */}
            <div className={styles.inputGroup}>
              <label className={styles.label}>签名会话码</label>
              <div className={styles.inputWrapper}>
                <input
                  type="text"
                  value={sessionCode}
                  onChange={(e) => setSessionCode(e.target.value)}
                  placeholder="粘贴签名会话码或扫描二维码"
                  className={styles.input}
                  disabled={isLoading}
                />
                <button
                  className={styles.pasteButton}
                  onClick={handlePaste}
                  disabled={isLoading}
                >
                  粘贴
                </button>
              </div>
            </div>

            {error && <div className={styles.error}>{error}</div>}

            <div className={styles.actions}>
              <button
                className={styles.secondaryButton}
                onClick={() => navigate('/')}
                disabled={isLoading}
              >
                取消
              </button>
              <button
                className={styles.primaryButton}
                onClick={handleValidateSession}
                disabled={isLoading || !selectedShare || !sessionCode.trim()}
              >
                {isLoading ? '验证中...' : '下一步'}
              </button>
            </div>
          </div>
        )}

        {step === 'join' && signingSession && (
          <div className={styles.form}>
            {/* 显示签名会话信息 */}
            <div className={styles.sessionInfo}>
              <h3 className={styles.sectionTitle}>签名会话信息</h3>
              <div className={styles.infoGrid}>
                <div className={styles.infoItem}>
                  <span className={styles.infoLabel}>钱包名称</span>
                  <span className={styles.infoValue}>{signingSession.walletName}</span>
                </div>
                <div className={styles.infoItem}>
                  <span className={styles.infoLabel}>发起者</span>
                  <span className={styles.infoValue}>{signingSession.initiator}</span>
                </div>
                <div className={styles.infoItem}>
                  <span className={styles.infoLabel}>阈值</span>
                  <span className={styles.infoValue}>
                    {signingSession.threshold.t}-of-{signingSession.threshold.n}
                  </span>
                </div>
                <div className={styles.infoItem}>
                  <span className={styles.infoLabel}>当前参与者</span>
                  <span className={styles.infoValue}>
                    {signingSession.currentParticipants} / {signingSession.threshold.t}
                  </span>
                </div>
              </div>

              <div className={styles.messageHashSection}>
                <span className={styles.infoLabel}>待签名消息哈希</span>
                <code className={styles.messageHash}>{signingSession.messageHash}</code>
              </div>
            </div>

            {/* 已选择的 Share */}
            <div className={styles.selectedShare}>
              <span className={styles.infoLabel}>使用的钱包份额</span>
              <div className={styles.shareItem}>
                <div className={styles.shareInfo}>
                  <span className={styles.shareName}>{selectedShare?.walletName}</span>
                </div>
              </div>
            </div>

            {/* 输入密码 */}
            <div className={styles.inputGroup}>
              <label className={styles.label}>解锁密码</label>
              <input
                type="password"
                value={password}
                onChange={(e) => setPassword(e.target.value)}
                placeholder="输入您的份额解锁密码"
                className={styles.input}
                disabled={isLoading}
              />
            </div>

            {error && <div className={styles.error}>{error}</div>}

            <div className={styles.actions}>
              <button
                className={styles.secondaryButton}
                onClick={() => {
                  setStep('select');
                  setSigningSession(null);
                  setError(null);
                }}
                disabled={isLoading}
              >
                返回
              </button>
              <button
                className={styles.primaryButton}
                onClick={handleJoinSigning}
                disabled={isLoading}
              >
                {isLoading ? '加入中...' : '参与签名'}
              </button>
            </div>
          </div>
        )}

        {step === 'signing' && (
          <div className={styles.signing}>
            <div className={styles.spinner}></div>
            <h3 className={styles.signingTitle}>签名进行中</h3>
            <p className={styles.signingText}>
              正在与其他参与方协同完成签名...
            </p>
            {progress.total > 0 && (
              <div className={styles.progressSection}>
                <div className={styles.progressBar}>
                  <div
                    className={styles.progressFill}
                    style={{ width: `${(progress.current / progress.total) * 100}%` }}
                  />
                </div>
                <span className={styles.progressText}>
                  轮次 {progress.current} / {progress.total}
                </span>
              </div>
            )}
          </div>
        )}

        {step === 'completed' && signature && (
          <div className={styles.form}>
            <div className={styles.successIcon}>✓</div>
            <h3 className={styles.successTitle}>签名完成</h3>

            <div className={styles.signatureSection}>
              <label className={styles.label}>签名结果</label>
              <div className={styles.signatureWrapper}>
                <code className={styles.signature}>{signature}</code>
                <button className={styles.copyButton} onClick={handleCopySignature}>
                  复制
                </button>
              </div>
            </div>

            <div className={styles.actions}>
              <button
                className={styles.primaryButton}
                onClick={() => navigate('/')}
              >
                返回首页
              </button>
            </div>
          </div>
        )}

        {step === 'failed' && (
          <div className={styles.form}>
            <div className={styles.failureIcon}>!</div>
            <h3 className={styles.failureTitle}>签名失败</h3>
            <p className={styles.failureText}>{error}</p>

            <div className={styles.actions}>
              <button
                className={styles.secondaryButton}
                onClick={() => {
                  setStep('select');
                  setError(null);
                }}
              >
                重试
              </button>
              <button
                className={styles.primaryButton}
                onClick={() => navigate('/')}
              >
                返回首页
              </button>
            </div>
          </div>
        )}
      </div>
    </div>
  );
}