// 真实数据层：直连本地 maestro daemon 的 REST + WS（按 ⑧ 前端 API 契约）。
// 路径用同源相对地址，dev 下经 vite.config.js 的 proxy 反代到 :4517。

async function http(method, path, body) {
  const opt = { method, headers: {} };
  if (body !== undefined) {
    opt.headers['Content-Type'] = 'application/json';
    opt.body = JSON.stringify(body);
  }
  const res = await fetch(path, opt);
  if (!res.ok) {
    let msg = res.statusText;
    try { msg = (await res.json()).error || msg; } catch { /* 非 JSON 错误体 */ }
    throw new Error(`${method} ${path} → ${res.status} ${msg}`);
  }
  if (res.status === 204) return null;
  const ct = res.headers.get('content-type') || '';
  return ct.includes('application/json') ? res.json() : res.text();
}

export const api = {
  listProjects: () => http('GET', '/api/projects'),
  projectTasks: (pid) => http('GET', `/api/projects/${pid}/tasks`),
  projectEvents: (pid) => http('GET', `/api/projects/${pid}/events`),
  agents: () => http('GET', '/api/agents'),
  approvals: () => http('GET', '/api/approvals'),
  usage: () => http('GET', '/api/usage'),
  syncProject: (pid) => http('POST', `/api/projects/${pid}/sync`),
  decide: (taskId, action, reason, merge) =>
    http('POST', `/api/tasks/${taskId}/decide`, { action, reason, merge }),
  createTask: (pid, body) => http('POST', `/api/projects/${pid}/tasks`, body),
  patchProject: (pid, body) => http('PATCH', `/api/projects/${pid}`, body),
  reorderProjects: (order) => http('POST', '/api/projects/reorder', { order }),
  createProject: (body) => http('POST', '/api/projects', body),
  getSettings: () => http('GET', '/api/settings'),
  putSettings: (data) => http('PUT', '/api/settings', data),
  takeover: (taskId) => http('POST', `/api/tasks/${taskId}/takeover`),
  patchTask: (taskId, body) => http('PATCH', `/api/tasks/${taskId}`, body),
  cancelTask: (taskId) => http('POST', `/api/tasks/${taskId}/cancel`),
  requeueTask: (taskId) => http('POST', `/api/tasks/${taskId}/requeue`),
  deleteTask: (taskId) => http('DELETE', `/api/tasks/${taskId}`),
  // 附件上传走 multipart（不能用 JSON helper，content-type 由浏览器带 boundary）
  uploadAttachments: async (taskId, files) => {
    const fd = new FormData();
    for (const f of files) fd.append('files', f, f.name);
    const res = await fetch(`/api/tasks/${taskId}/attachments`, { method: 'POST', body: fd });
    if (!res.ok) {
      let msg = res.statusText;
      try { msg = (await res.json()).error || msg; } catch { /* 非 JSON */ }
      throw new Error(`上传附件失败 → ${res.status} ${msg}`);
    }
    return res.json();
  },
};

// WS 单向订阅：连上后服务端推送 events 表记录。断线自动重连（指数退避，封顶 10s）。
export function subscribeEvents(onEvent, onStatus) {
  let ws = null;
  let backoff = 500;
  let closedByUser = false;

  function connect() {
    const proto = location.protocol === 'https:' ? 'wss' : 'ws';
    ws = new WebSocket(`${proto}://${location.host}/ws`);
    ws.onopen = () => { backoff = 500; onStatus?.('open'); };
    ws.onmessage = (msg) => {
      try { onEvent(JSON.parse(msg.data)); } catch { /* 忽略非 JSON 帧 */ }
    };
    ws.onclose = () => {
      onStatus?.('closed');
      if (closedByUser) return;
      setTimeout(connect, backoff);
      backoff = Math.min(backoff * 2, 10000);
    };
    ws.onerror = () => ws.close();
  }
  connect();

  return () => { closedByUser = true; ws?.close(); };
}