mapping _ntervals.go

package intervals

var names = map[string]string{
	"daily":   "daily",
	"weekly":  "weekly",
	"monthly": "monthly",
	"yearly":  "yearly",
}

var singular = map[string]string{
	"daily":   "day",
	"weekly":  "week",
	"monthly": "month",
	"yearly":  "year",
}

func Name(interval string) string {
	return names[interval]
}

func Singular(interval string) string {
	return singular[interval]
}

ranges.go

package ranges

import (
	"fmt"
	"time"
)

type Params struct {
	interval string
	Start    string `db:"start"`
	End      string `db:"end"`
}

func New(interval string) *Params {
	return &Params{interval: interval}
}

func (r *Params) AsRange() *Params {
	currentTime := time.Now()
	r.End = currentTime.Format("2006-01-02")
	previousTime := time.Now()

	switch r.interval {

	// daily - last 24 hours
	case "daily":
		previousTime = currentTime.Add(-time.Hour * 24)
		fmt.Println(previousTime)

	// weekly - last 7 days
	case "weekly":
		previousTime = currentTime.AddDate(0, 0, -7)

	// weekly - last 1 month
	case "monthly":
		currentYear, currentMonth, _ := currentTime.Date()
		currentLocation := currentTime.Location()
		firstOfMonth := time.Date(
			currentYear, currentMonth, 1, 0, 0, 0, 0, currentLocation,
		)

		previousTime = firstOfMonth

	// yearly - last 1 year
	case "yearly":
		currentYear, _, _ := currentTime.Date()
		currentLocation := currentTime.Location()

		firstOfYear := time.Date(
			currentYear, 1, 1, 0, 0, 0, 0, currentLocation,
		)

		previousTime = firstOfYear
	}

	r.Start = previousTime.Format("2006-01-02")

	return r
}

func (r *Params) AsHistogram() *Params {
	currentTime := time.Now()
	r.End = currentTime.Format("2006-01-02")
	previousTime := time.Now()

	switch r.interval {

	// daily - last 7 days
	case "daily":
		previousTime = currentTime.AddDate(0, 0, -7)

	// weekly - last 4 weeks
	case "weekly":
		previousTime = currentTime.AddDate(0, 0, -7*4)

	// monthly - last 4 months
	case "monthly":
		previousTime = currentTime.AddDate(0, -4, 0)

	// yearly - last 4 years
	case "yearly":
		previousTime = currentTime.AddDate(-4, 0, 0)
	}

	r.Start = previousTime.Format("2006-01-02")

	return r
}