export const PROTOCOLS = ['vmess', 'trojan', 'shadowsocks', 'hysteria2'] as const;
export type Protocol = (typeof PROTOCOLS)[number];

export const CLIENTS = ['surge', 'shadowrocket', 'clash'] as const;
export type ClientType = (typeof CLIENTS)[number];

export const CLIENT_LABELS: Record<ClientType, string> = {
  surge: 'Surge (macOS)',
  shadowrocket: 'ShadowRocket (iOS)',
  clash: 'FlClash',
};

export type Egress = 'direct' | 'warp' | 'unknown';

/** Surge 与 Clash 使用 IETF 命名，Xray 分享链接使用简名 */
export const SS_CIPHER_ALIASES: Record<string, string> = {
  'chacha20-poly1305': 'chacha20-ietf-poly1305',
  'xchacha20-poly1305': 'xchacha20-ietf-poly1305',
};

export function normalizeSsCipher(method: string): string {
  return SS_CIPHER_ALIASES[method] ?? method;
}

export interface NodeCapabilityInput {
  protocol: Protocol;
  network: 'tcp' | 'ws';
  alterId?: number;
  security?: string;
}

export interface CapabilityVerdict {
  ok: boolean;
  reason?: string;
}

/**
 * 客户端能力矩阵：不支持的组合在下发订阅时自动屏蔽。
 * Surge 的 ss 类型没有 WebSocket 传输（仅 simple-obfs），SS over WS 线路必须排除。
 */
export function clientSupports(client: ClientType, node: NodeCapabilityInput): CapabilityVerdict {
  if (client === 'surge' && node.protocol === 'shadowsocks' && node.network === 'ws') {
    return { ok: false, reason: 'Surge 不支持 Shadowsocks over WebSocket' };
  }
  if (client === 'surge' && node.protocol === 'vmess') {
    if ((node.alterId ?? 0) !== 0) return { ok: false, reason: 'Surge 下发仅支持 alterId=0 的 VMess AEAD 节点' };
    if (!['auto', 'aes-128-gcm', 'chacha20-poly1305', 'chacha20-ietf-poly1305'].includes(node.security ?? 'auto')) {
      return { ok: false, reason: `Surge 不支持该 VMess 加密方式：${node.security}` };
    }
  }
  if (client === 'clash' && node.protocol === 'vmess'
    && !['auto', 'none', 'zero', 'aes-128-gcm', 'chacha20-poly1305', 'chacha20-ietf-poly1305'].includes(node.security ?? 'auto')) {
    return { ok: false, reason: `Clash 不支持该 VMess 加密方式：${node.security}` };
  }
  return { ok: true };
}