/**
 * Cloudflare KV REST API wrapper
 * 使用 CF REST API 直接存取用戶的 KV namespace，不依賴 Wrangler CLI
 */

const CF_API_BASE = 'https://api.cloudflare.com/client/v4';

export interface CfKvClientOptions {
  accountId: string;
  namespaceId: string;
  apiToken: string;
}

export class CfKvClient {
  private base: string;
  private headers: Record<string, string>;

  constructor({ accountId, namespaceId, apiToken }: CfKvClientOptions) {
    this.base = `${CF_API_BASE}/accounts/${accountId}/storage/kv/namespaces/${namespaceId}`;
    this.headers = {
      'Authorization': `Bearer ${apiToken}`,
      'Content-Type': 'application/json',
    };
  }

  async put(key: string, value: string): Promise<void> {
    const res = await fetch(`${this.base}/values/${encodeURIComponent(key)}`, {
      method: 'PUT',
      headers: { ...this.headers, 'Content-Type': 'text/plain' },
      body: value,
    });
    if (!res.ok) {
      const err = await res.text();
      throw new Error(`KV PUT 失敗（${res.status}）：${err.slice(0, 200)}`);
    }
  }

  async get(key: string): Promise<string | null> {
    const res = await fetch(`${this.base}/values/${encodeURIComponent(key)}`, {
      headers: this.headers,
    });
    if (res.status === 404) return null;
    if (!res.ok) {
      const err = await res.text();
      throw new Error(`KV GET 失敗（${res.status}）：${err.slice(0, 200)}`);
    }
    return res.text();
  }

  async list(prefix?: string): Promise<Array<{ name: string; expiration?: number; metadata?: unknown }>> {
    const url = new URL(`${this.base}/keys`);
    if (prefix) url.searchParams.set('prefix', prefix);
    url.searchParams.set('limit', '1000');

    const res = await fetch(url.toString(), { headers: this.headers });
    if (!res.ok) {
      const err = await res.text();
      throw new Error(`KV LIST 失敗（${res.status}）：${err.slice(0, 200)}`);
    }
    const data = await res.json() as {
      result: Array<{ name: string; expiration?: number; metadata?: unknown }>;
    };
    return data.result ?? [];
  }

  async delete(key: string): Promise<void> {
    const res = await fetch(`${this.base}/values/${encodeURIComponent(key)}`, {
      method: 'DELETE',
      headers: this.headers,
    });
    if (!res.ok) {
      const err = await res.text();
      throw new Error(`KV DELETE 失敗（${res.status}）：${err.slice(0, 200)}`);
    }
  }
}

/**
 * Cloudflare Account-level API wrapper（self-hosted installer 用）。
 *
 * 負責 acr init --self-hosted 的資源建立：驗 token、建/列 KV namespace、查 workers.dev subdomain。
 * （不建 R2：R2 是 dead storage 且綁卡違背開源免費；見 init.ts step 2 + registry-canon Phase 1.5。）
 * 與 CfKvClient（綁單一 namespace 的 KV 操作）職責不同——這個是帳號層級的資源管理。
 * 對應 SDD：.agents/specs/arcrun/sdk-and-website/self-hosted-init.md §3 step 1-2
 */
export class CfAccountClient {
  private accountBase: string;
  private headers: Record<string, string>;

  constructor(accountId: string, apiToken: string) {
    this.accountBase = `${CF_API_BASE}/accounts/${accountId}`;
    this.headers = {
      'Authorization': `Bearer ${apiToken}`,
      'Content-Type': 'application/json',
    };
  }

  private async cf<T>(path: string, init?: RequestInit): Promise<T> {
    const res = await fetch(`${this.accountBase}${path}`, {
      ...init,
      headers: { ...this.headers, ...(init?.headers ?? {}) },
    });
    const data = await res.json().catch(() => null) as
      | { success: boolean; result: T; errors?: Array<{ message: string }> }
      | null;
    if (!res.ok || !data?.success) {
      const msg = data?.errors?.map(e => e.message).join('; ') ?? `HTTP ${res.status}`;
      throw new Error(`CF API ${path} 失敗：${msg}`);
    }
    return data.result;
  }

  /** 驗證 token 能存取此 account（權限不足會在後續建立操作報錯，這裡先確認 account 可達）。*/
  async verifyAccess(): Promise<void> {
    // GET /accounts/{id} 能通 = token 有此 account 的基本讀權限
    await this.cf<{ id: string; name: string }>('');
  }

  /** 列出現有 KV namespace（冪等用：已存在就重用，不重建）。回傳 title → id 對照。*/
  async listKvNamespaces(): Promise<Map<string, string>> {
    const result = await this.cf<Array<{ id: string; title: string }>>(
      '/storage/kv/namespaces?per_page=100',
    );
    const map = new Map<string, string>();
    for (const ns of result) map.set(ns.title, ns.id);
    return map;
  }

  /** 建立 KV namespace（若同名已存在則回傳既有 id，冪等）。*/
  async ensureKvNamespace(title: string, existing?: Map<string, string>): Promise<string> {
    const known = existing ?? (await this.listKvNamespaces());
    const found = known.get(title);
    if (found) return found;

    const result = await this.cf<{ id: string; title: string }>(
      '/storage/kv/namespaces',
      { method: 'POST', body: JSON.stringify({ title }) },
    );
    return result.id;
  }

  /** 查 workers.dev subdomain（cypher-executor WORKER_SUBDOMAIN 用，組對內 component URL）。*/
  async getWorkersSubdomain(): Promise<string> {
    const result = await this.cf<{ subdomain: string }>('/workers/subdomain');
    return result.subdomain;
  }

  // D1 (KBDB Base). Free on Workers Free plan, no credit card (kbdb-base Q4 verified).
  async listD1Databases(): Promise<Map<string, string>> {
    const result = await this.cf<Array<{ uuid: string; name: string }>>('/d1/database?per_page=100');
    const map = new Map<string, string>();
    for (const db of result) map.set(db.name, db.uuid);
    return map;
  }

  async ensureD1Database(name: string, existing?: Map<string, string>): Promise<string> {
    const known = existing ?? (await this.listD1Databases());
    const found = known.get(name);
    if (found) return found;
    const result = await this.cf<{ uuid: string; name: string }>(
      '/d1/database',
      { method: 'POST', body: JSON.stringify({ name }) },
    );
    return result.uuid;
  }
}
