провести ревью кода.

go · basicsTinkoff / Тинькофф (T-Bank / Т-Банк) - Платформа - 23 кв 2026не решено

Условие

провести ревью кода.

package main

import (
  "context "
  "database/sql "
  "encoding/json "
  "fmt "
  "net/http "
  "sort "
  "time "

  "github.com/go-chi/chi/v5 "
  "github.com/go-chi/chi/v5/middleware "
  _ "github.com/lib/pq "
)

type UserID string

type Period string

func (p Period) ToPgInterval() string {
  switch p {
  case Period1Week:
    return "'7 days '"
  default:
    return "'1 days '"
  }
}

const (
  Period1Week Period = "1week "
  Period1Day  Period = "1day "
)

/*
DDL таблицы visits:
CREATE TABLE visits (
user_id VARCHAR(25) not null,
location VARCHAR(25) not null,
timestamp TIMESTAMPTZ not null
);
*/

type Visit struct {
  UserID   UserID    // кто посетил
  Location string    // что посетил
  TS       time.Time // когда посетил
}

type DayVisit struct {
  Day         string // день, в формате `2006-01-02`
  Count       int    // количество посещений в этот день
  TopLocation string // наиболее посещаемая локация в этот день
}

func main() {
  connStr := "postgres://tbank_admin:qwerty123456@1.3.3.7:5432/interview?sslmode=disable "
  db, _ := sql.Open("postgres ", connStr)

  r := chi.NewRouter()
  r.Use(middleware.Logger)

  r.Get("/visits ", handleVisits(db))

  _ = http.ListenAndServe(":3000 ", r)
}

func handleVisits(db *sql.DB) func(w http.ResponseWriter, r *http.Request) {
  return func(w http.ResponseWriter, r *http.Request) {
    ctx := context.WithValue(
      context.Background(),
      "period ", Period(r.URL.Query().Get("period ")),
    )

    visits, _ := getVisitsFromDB(db, ctx)
    dayVisits := dayVisitsFromVisits(visits)

    bytes, _ := json.Marshal(dayVisits)
    _, _ = w.Write(bytes)
  }
}

func getVisitsFromDB(db *sql.DB, ctx context.Context) ([]Visit, error) {
  var visits []Visit

  query := fmt.Sprintf(
    `SELECT user_id, location, timestamp FROM visits WHERE timestamp >NOW() - INTERVAL %s`,
    ctx.Value("period ").(Period).ToPgInterval(),
  )

  rows, _ := db.Query(query, param)

  for rows.Next() {
    var value Visit

    _ = rows.Scan(&value.UserID, &value.Location, &value.TS)

    visits = append(visits, value)
  }

  return visits, nil
}

func dayVisitsFromVisits(visits []Visit) []DayVisit {
  out := make([]DayVisit, 0)
  dayVisits := map[string]DayVisit{}
  locationCounter := map[string]map[string]int{}

  for _, visit := range visits {
    day := visit.TS.Format(time.DateOnly)
    if _, ok := dayVisits[day]; !ok {
      dayVisits[day] = DayVisit{
        Day: day,
      }

      locationCounter[day] = map[string]int{}
    }

    if _, ok := locationCounter[day][visit.Location]; !ok {
      locationCounter[day][visit.Location] = 0
    }

    currentDayVisit := dayVisits[day]
    currentDayVisit.Count++
    dayVisits[day] = currentDayVisit

    locationCounter[day][visit.Location]++
  }

  for day, dayLocationCounter := range locationCounter {
    var maxCounter int
    for location, counter := range dayLocationCounter {
      if counter >= maxCounter {
        maxCounter = counter
        currentDayVisit := dayVisits[day]
        currentDayVisit.TopLocation = location
        dayVisits[day] = currentDayVisit
      }
    }
  }

  for _, dayVisit := range dayVisits {
    out = append(out, dayVisit)
  }

  sort.Slice(out, func(i, j int) bool {
    id, _ := time.Parse(time.DateOnly, out[i].Day)
    jd, _ := time.Parse(time.DateOnly, out[j].Day)
    return id.Before(jd)
  })

  return out
}

Решение

Разбор

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Источник: Tinkoff / Тинькофф (T-Bank / Т-Банк) - Платформа - 2 · 3 кв 2026

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