package main

import (
	"database/sql"
	"flag"
	"fmt"
	_ "github.com/mattn/go-sqlite3"
	"log"
	"math"
	"time"
)

type Event struct {
	description string
	timestamp   int64
}

func formula(p float64) int64 {
	yearsAgo := math.Exp(20.3444*math.Pow(p, 3)+3) - math.Exp(3)
	return int64(yearsAgo * 31556926)
}

func closestEvent(t int64, db *sql.DB) (Event, error) {
	var event Event
	query := `
	select description, timestamp
	from events
	where timestamp is not null
	order by abs(? - timestamp) asc
	limit 1
	`

	stmt, err := db.Prepare(query)
	if err != nil {
		return event, err
	}
	defer stmt.Close()

	err = stmt.QueryRow(t).Scan(&event.description, &event.timestamp)
	return event, err
}

func main() {
	percent := flag.Float64("p", -1, "percentage")
	flag.Parse()

	if *percent < 0 || *percent > 1 {
		log.Fatal("invalid percentage")
	}

	t := time.Now().Unix() - formula(*percent)

	db, err := sql.Open("sqlite3", "./timeline.db")
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	event, err := closestEvent(t, db)
	if err != nil {
		log.Fatal(err)
	}

	date := time.Unix(event.timestamp, 0)
	fmt.Printf("%v\t%v\t%v\n", event.timestamp, date, event.description)
}