/**
 * 光湖知识库 · API 客户端
 * Agent 和前端 UI 共用同一套接口。
 */

const BASE = typeof window !== 'undefined' && window.location.protocol === 'file:'
  ? 'http://127.0.0.1:3890/api'
  : '/api';

async function request<T>(path: string, options?: RequestInit): Promise<T> {
  const res = await fetch(`${BASE}${path}`, {
    headers: { 'Content-Type': 'application/json' },
    ...options,
  });
  const data = await res.json();
  if (!data.ok) throw new Error(data.error || '请求失败');
  return data as T;
}

// ─── 类型（与 server 保持一致） ───

export interface DocMeta {
  id: string;
  title: string;
  slug: string;
  parentPath: string;
  createdAt: string;
  updatedAt: string;
  author: string;
  tags: string[];
}

export interface DocContent {
  meta: DocMeta;
  body: string;
}

export interface DocTreeNode {
  name: string;
  path: string;
  type: 'folder' | 'document';
  children?: DocTreeNode[];
}

export interface VersionEntry {
  hash: string;
  shortHash: string;
  author: string;
  date: string;
  message: string;
}

export interface SearchResult {
  path: string;
  title: string;
  snippet: string;
  line: number;
}

export interface ModuleManifest {
  id: string;
  name: string;
  version: string;
  kind: 'native-application';
  state: 'LIVE';
  description: string;
  capabilities: string[];
  dataPolicy: string;
}

export interface ChannelModuleState {
  id: string;
  installed: boolean;
  mounted: boolean;
  order: number;
}

export interface ChannelState {
  schema: 'hololake.personal-channel-state/v1';
  channelId: string;
  revision: number;
  updatedAt: string;
  modules: ChannelModuleState[];
}

export interface ChannelReceipt {
  id: string;
  after: ChannelState;
  reversible: true;
}

export interface DiffResult {
  additions: number;
  deletions: number;
  hunks: { oldStart: number; newStart: number; lines: string[] }[];
}

// ─── API 方法 ───

export const api = {
  async getModules(): Promise<ModuleManifest[]> {
    const data = await request<{ registry: ModuleManifest[] }>('/modules');
    return data.registry;
  },

  async getChannel(): Promise<ChannelState> {
    const data = await request<{ channel: ChannelState }>('/channel');
    return data.channel;
  },

  async patchChannel(input: { operation: 'set_module_state'; moduleId: string; installed?: boolean; mounted?: boolean }): Promise<{ channel: ChannelState; receipt: ChannelReceipt }> {
    return request('/channel/patch', { method: 'POST', body: JSON.stringify(input) });
  },

  async undoChannel(receiptId: string): Promise<{ channel: ChannelState; receipt: ChannelReceipt }> {
    return request(`/channel/undo/${encodeURIComponent(receiptId)}`, { method: 'POST' });
  },
  /** 获取文档树 */
  getTree: () =>
    request<{ ok: true; tree: DocTreeNode[] }>('/tree').then(d => d.tree),

  /** 读取文档 */
  getDoc: (path: string) =>
    request<{ ok: true; doc: DocContent }>(`/docs/${path}`).then(d => d.doc),

  /** 创建文档 */
  createDoc: (path: string, title: string, body: string, author = 'anonymous') =>
    request<{ ok: true; doc: DocContent }>(`/docs/${path}`, {
      method: 'POST',
      body: JSON.stringify({ title, body, author }),
    }).then(d => d.doc),

  /** 更新文档 */
  updateDoc: (path: string, title: string, body: string, author = 'anonymous') =>
    request<{ ok: true; doc: DocContent }>(`/docs/${path}`, {
      method: 'PUT',
      body: JSON.stringify({ title, body, author }),
    }).then(d => d.doc),

  /** 删除文档 */
  deleteDoc: (path: string) =>
    request<{ ok: true }>(`/docs/${path}`, { method: 'DELETE' }),

  /** 移动文档 */
  moveDoc: (oldPath: string, newPath: string) =>
    request<{ ok: true }>('/move', {
      method: 'POST',
      body: JSON.stringify({ oldPath, newPath }),
    }),

  /** 获取版本历史 */
  getHistory: (path: string, max = 50) =>
    request<{ ok: true; history: VersionEntry[] }>(`/history/${path}?max=${max}`).then(d => d.history),

  /** 获取某版本内容 */
  getDocAtVersion: (path: string, hash: string) =>
    request<{ ok: true; content: string }>(`/version/${hash}/${path}`).then(d => d.content),

  /** 版本对比 */
  diffVersions: (path: string, from: string, to: string) =>
    request<{ ok: true; diff: DiffResult }>(`/diff/${path}?from=${from}&to=${to}`).then(d => d.diff),

  /** 搜索 */
  search: (query: string) =>
    request<{ ok: true; results: SearchResult[]; count: number }>(`/search?q=${encodeURIComponent(query)}`)
      .then(d => d.results),
};