Reddit ranking algorithms by Go

main.go

package main

import (
	"fmt"
	"math"
	"time"
)

func epoch_seconds(date time.Time) (sec float64) {
	/* Returns the number of seconds from the epoch to date. */
	epoch := time.Date(1970, 1, 1, 0, 0, 0, 0, time.Local).Unix()
	td := date.Unix() - epoch
	sec = float64(td)
	return
}

func score(ups float64, downs float64) (score float64) {
	return ups - downs
}

func hot(ups float64, downs float64, date time.Time) (finalScore float64) {
	/* The hot formula. Should match the equivalent function in postgres. */
	s := score(ups, downs)
	order := math.Log10(math.Max(math.Abs(s), 1))

	var sign float64
	if s < 0 {
		sign = -1
	} else if s > 0 {
		sign = 1
	} else {
		sign = 0
	}

	seconds := epoch_seconds(date) - 1134028003
	finalScore = sign*order + seconds/45000
	return
}