import { browser } from '$app/environment';
import type { AnalyticsInstance } from 'analytics';
export let analytics: AnalyticsInstance | undefined;

export const initAnalytics = async (): Promise<void> => {
  if (browser && !analytics) {
    try {
      const [{ Analytics }, { default: plausible }] = await Promise.all([
        import('analytics'),
        import('analytics-plugin-plausible')
      ]);
      analytics = Analytics({
        app: 'mermaid-live-editor',
        plugins: [
          plausible({
            domain: 'mermaid.live',
            hashMode: false,
            trackLocalhost: false, // By default 'false'
            apiHost: 'https://plausible.io'
          })
        ]
      });
    } catch (e) {
      console.log(e);
      console.info('Analytics blocked ;)');
    }
  }
};

export const detectType = (text: string): string | undefined => {
  const possibleDiagramTypes = [
    'classDiagram',
    'erDiagram',
    'flowChart',
    'gantt',
    'gitGraph',
    'graph',
    'journey',
    'pie',
    'stateDiagram'
  ];
  const firstLine = text
    .replace(/^\s*%%.*\n/g, '\n')
    .trimStart()
    .split(' ')[0]
    .toLowerCase();
  const detectedDiagram = possibleDiagramTypes.find((d) => firstLine.includes(d.toLowerCase()));
  return detectedDiagram;
};

export const countLines = (code: string): number => {
  return (code.match(/\n/g)?.length ?? 0) + 1;
};

export const saveStatistics = (graph: string): void => {
  const graphType = detectType(graph);
  if (!graphType) {
    return;
  }
  const length = countLines(graph);
  logEvent('render', { graphType, length });
};

const minutesToMilliSeconds = (minutes: number): number => {
  return minutes * 60_000;
};

const defaultDelay = minutesToMilliSeconds(1);
const delaysPerEvent = {
  render: minutesToMilliSeconds(5),
  panZoom: minutesToMilliSeconds(10),
  copyClipboard: defaultDelay,
  download: defaultDelay,
  copyMarkdown: defaultDelay,
  loadGist: defaultDelay,
  loadSampleDiagram: defaultDelay,
  renderDiagram: defaultDelay,
  history: defaultDelay,
  migration: defaultDelay,
  themeChange: defaultDelay
};
export type AnalyticsEvent = keyof typeof delaysPerEvent;
const timeouts: Map<string, number> = new Map<string, number>();
// manual debounce to reduce the number of events sent to analytics
export const logEvent = (name: AnalyticsEvent, data?: unknown): void => {
  if (!analytics) {
    return;
  }
  const key = data ? JSON.stringify({ name, data }) : name;
  if (!timeouts.has(key)) {
    void analytics.track(name, data);
  } else {
    clearTimeout(timeouts.get(key));
  }
  timeouts.set(
    key,
    window.setTimeout(() => timeouts.delete(key), delaysPerEvent[name])
  );
};