analytics.ts

import { JsonStore } from './store/json-store'

interface UrlInfo {
  hits: number
}

const ignoreRoutes = ['/data/flushall']

export class Analytics {
  tempKeyCount = 0
  temp: { [key: string]: UrlInfo | undefined } = {}
  storing = false

  recordUrlVisit(url: string) {
    if (ignoreRoutes.find((r) => url.startsWith(r))) {
      return // ignore this route
    }
    if (this.temp[url] === undefined) {
      this.tempKeyCount++
      if (this.tempKeyCount > 1_000) {
        // this might likely be an attack, so stop analytics
        return
      }
      this.temp[url] = { hits: 0 }
    }
    this.temp[url]!.hits += 1
  }

  async storeTemp() {
    if (this.storing) return

    this.storing = true
    const store = new JsonStore(`data/_analytics/${date()}.json`, true)

    const entries = Object.entries(this.temp)
    this.temp = {}
    const resultArray: (UrlInfo | undefined)[] = await store._getMultiple<UrlInfo>(
      entries.map((e) => e[0])
    )

    for (let i = 0; i < resultArray.length; i++) {
      const result = resultArray[i]
      const key = entries[i][0]
      const value = entries[i][1]!
      if (result === undefined) {
        resultArray[i] = value
        await store.set(key, value)
      } else {
        // merge data
        result.hits += value.hits
      }
    }

    await store._setMultiple(
      entries.map((entry, i) => ({ key: entry[0], value: resultArray[i] }))
    )
    this.storing = false
  }
}

export function date() {
  const d = new Date()
  return `${d.getFullYear()}-${d.getMonth()}-${d.getDate()}`
}