// Sandbar API client. Pure functions over fetch, so it runs in the page, the service worker and tests.

export class ApiError extends Error {
  constructor(status, message) {
    super(message);
    this.status = status;
  }
}

export function normalizeServer(input) {
  let s = String(input || '').trim();
  if (!s) throw new Error('Enter the address of your Sandbar server.');
  if (!/^https?:\/\//i.test(s)) s = (/^(localhost|127\.|\[::1\])/.test(s) ? 'http://' : 'https://') + s;
  const u = new URL(s);
  return u.origin;
}

export class Client {
  constructor(server, token, fetchImpl) {
    this.server = server;
    this.token = token;
    this.fetch = fetchImpl || ((...a) => fetch(...a));
  }

  async req(method, path, body) {
    const headers = {};
    if (this.token) headers.Authorization = 'Bearer ' + this.token;
    if (body !== undefined) headers['Content-Type'] = 'application/json';
    let res;
    try {
      res = await this.fetch(this.server + path, { method, headers, body: body === undefined ? undefined : JSON.stringify(body) });
    } catch {
      throw new ApiError(0, 'Could not reach ' + this.server + '. Check the address and your connection.');
    }
    const text = await res.text();
    let data = null;
    try { data = text ? JSON.parse(text) : null; } catch { /* not JSON */ }
    if (!res.ok) throw new ApiError(res.status, (data && data.error) || 'The server answered ' + res.status + '.');
    return data;
  }

  get(p) { return this.req('GET', p); }
  post(p, b) { return this.req('POST', p, b === undefined ? {} : b); }
  del(p) { return this.req('DELETE', p); }

  static async login(server, email, password, device, fetchImpl) {
    const c = new Client(server, '', fetchImpl);
    const r = await c.post('/api/v1/mobile/login', { email, password, device });
    return { token: r.token, keyId: r.keyId, user: r.user };
  }

  alerts(status) { return this.get('/api/v1/alerts?limit=100' + (status ? '&status=' + status : '')); }
  ack(id) { return this.post('/api/v1/alerts/' + id + '/ack'); }
  snooze(id, minutes) { return this.post('/api/v1/alerts/' + id + '/snooze', { minutes }); }
  escalate(id) { return this.post('/api/v1/alerts/' + id + '/escalate'); }
  resolve(id) { return this.post('/api/v1/alerts/' + id + '/resolve'); }
  alert(id) { return this.get('/api/v1/alerts/' + id); }
  onCall() { return this.get('/api/v1/oncall'); }
  monitors() { return this.get('/api/v1/monitors'); }
  monitorStates() { return this.get('/api/v1/monitor-states'); }
  edges() { return this.get('/api/v1/hammerhead/edges'); }
  messages(topic, since) { return this.get('/api/v1/topics/' + encodeURIComponent(topic) + '/messages?since=' + (since || 0)); }
  publish(topic, message, title, priority) {
    const headers = { 'Content-Type': 'text/plain' };
    if (this.token) headers.Authorization = 'Bearer ' + this.token;
    if (title) headers.Title = title;
    if (priority) headers.Priority = String(priority);
    return this.fetch(this.server + '/' + encodeURIComponent(topic), { method: 'POST', headers, body: message });
  }
  pushKey() { return this.get('/api/v1/push/key'); }
  pushSubs() { return this.get('/api/v1/push/subscriptions'); }
  savePush(sub, topics, device) {
    const j = sub.toJSON ? sub.toJSON() : sub;
    return this.post('/api/v1/push/subscriptions', { endpoint: j.endpoint, keys: j.keys, topics, device });
  }
  deletePush(id) { return this.del('/api/v1/push/subscriptions/' + id); }
  testPush() { return this.post('/api/v1/push/test'); }
  logout(keyId) { return keyId ? this.del('/api/v1/apikeys/' + keyId) : Promise.resolve(); }

  // Streams a topic as newline-delimited JSON until the signal aborts, calling onMessage for each
  // message. Resolves when the stream ends, so the caller decides whether to reconnect.
  async stream(topic, since, onMessage, signal) {
    const headers = this.token ? { Authorization: 'Bearer ' + this.token } : {};
    const res = await this.fetch(this.server + '/' + encodeURIComponent(topic) + '/json?since=' + encodeURIComponent(since || 'all'), { headers, signal });
    if (!res.ok) throw new ApiError(res.status, 'Could not follow ' + topic + '.');
    const reader = res.body.getReader();
    const dec = new TextDecoder();
    let buf = '';
    for (;;) {
      const { done, value } = await reader.read();
      if (done) return;
      buf += dec.decode(value, { stream: true });
      let i;
      while ((i = buf.indexOf('\n')) >= 0) {
        const line = buf.slice(0, i).trim();
        buf = buf.slice(i + 1);
        if (!line) continue;
        try {
          const m = JSON.parse(line);
          if (m.event === 'message') onMessage(m);
        } catch { /* skip a bad line */ }
      }
    }
  }
}

export function urlBase64ToUint8Array(b64) {
  const pad = '='.repeat((4 - (b64.length % 4)) % 4);
  const raw = atob((b64 + pad).replace(/-/g, '+').replace(/_/g, '/'));
  return Uint8Array.from(raw, (c) => c.charCodeAt(0));
}

export function ago(sec, now = Date.now() / 1000) {
  const d = Math.max(0, Math.round(now - sec));
  if (d < 60) return 'just now';
  if (d < 3600) return Math.floor(d / 60) + ' min ago';
  if (d < 86400) return Math.floor(d / 3600) + ' h ago';
  return Math.floor(d / 86400) + ' d ago';
}