/**
 * 能力目录（架构设计 2 / 4：registry 模块）。
 *
 * 保存已注册 Provider 与它们声明的能力；上层按身份取「能力清单」（A4 起按策略过滤，
 * 当前只做注册与查找）。能力目录是唯一来源——引擎的工具列表是它的投影。
 */
import type { Capability, Provider, ProviderManifest } from '@aps/provider-sdk';

export interface RegisteredProvider {
  manifest: ProviderManifest;
  provider: Provider;
}

export interface ResolvedCapability {
  capability: Capability;
  provider: Provider;
  providerId: string;
  /** 该系统是否需要平台用户绑定账号（A4.1）；缺省 true */
  requiresIdentity: boolean;
  /** 登录方式声明（ADR-0012）；没声明表示该系统没有账号概念 */
  authKind?: 'oauth' | 'password-exchange' | 'apikey';
}

export class CapabilityRegistry {
  private readonly providers = new Map<string, RegisteredProvider>();

  async register(provider: Provider): Promise<ProviderManifest> {
    const manifest = await provider.describe();
    if (manifest.platformVersion !== 1) {
      throw new Error(`Provider ${manifest.id} 声明兼容平台版本 ${manifest.platformVersion}，当前平台只支持 1`);
    }
    this.providers.set(manifest.id, { manifest, provider });
    return manifest;
  }

  list(): Capability[] {
    return [...this.providers.values()].flatMap((entry) => entry.manifest.capabilities);
  }

  resolve(capabilityId: string): ResolvedCapability | undefined {
    for (const entry of this.providers.values()) {
      const capability = entry.manifest.capabilities.find((item) => item.id === capabilityId);
      if (capability) {
        return {
          capability,
          provider: entry.provider,
          providerId: entry.manifest.id,
          requiresIdentity: entry.manifest.requiresIdentity !== false,
          ...(entry.manifest.auth === undefined ? {} : { authKind: entry.manifest.auth.kind }),
        };
      }
    }
    return undefined;
  }

  /** 某个 Provider 的 manifest（绑定流程要读它的 auth 声明） */
  manifest(providerId: string): ProviderManifest | undefined {
    return this.providers.get(providerId)?.manifest;
  }

  /** 某个 Provider 实例（绑定流程要用它的 exchange / checkCredential） */
  provider(providerId: string): Provider | undefined {
    return this.providers.get(providerId)?.provider;
  }

  providerIds(): string[] {
    return [...this.providers.keys()];
  }

  async health(): Promise<Array<{ providerId: string; status: string; detail?: string }>> {
    const results: Array<{ providerId: string; status: string; detail?: string }> = [];
    for (const [providerId, entry] of this.providers) {
      try {
        const health = await entry.provider.health();
        results.push(health.detail === undefined ? { providerId, status: health.status } : { providerId, status: health.status, detail: health.detail });
      } catch (error) {
        results.push({ providerId, status: 'down', detail: error instanceof Error ? error.message : '健康探测失败' });
      }
    }
    return results;
  }
}