package main

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

type EventsRow struct {
	description sql.NullString
	timestamp   sql.NullInt64
	interval    sql.NullString
	period      sql.NullString
	yearknown   sql.NullBool
	monthknown  sql.NullBool
	dayknown    sql.NullBool
	hourknown   sql.NullBool
	minuteknown sql.NullBool
	secondknown sql.NullBool
}

type TimelineDB struct {
	*sql.DB
}

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

func (db *TimelineDB) closestEvent(t int64) (EventsRow, error) {
	var event EventsRow
	query := `
	select description, timestamp, yearknown, monthknown, dayknown, hourknown, minuteknown, secondknown
	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, &event.yearknown, &event.monthknown, &event.dayknown, &event.hourknown, &event.minuteknown, &event.secondknown)
	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)

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

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

	timestamp, err := event.timestamp.Value()
	if err != nil {
		log.Fatal(err)
	}

	desc, err := event.description.Value()
	if err != nil {
		log.Fatal(err)
	}

	date := time.Unix(timestamp.(int64), 0)
	fmt.Printf("%v\t%v\t%v\n", timestamp, date, desc)
}