package main

import (
	"errors"
	"fmt"
	"time"
)

func GetRoundToDuration() time.Duration {
	var dur time.Duration
	var err error
	if dur, err = time.ParseDuration(cfg.Get("roundto")); err != nil {
		cfg.Set("roundto", DefRoundTo)
		dur, _ = time.ParseDuration(DefRoundTo)
	}
	return dur
}

func DurationToDecimal(dur time.Duration) float64 {
	mins := dur.Minutes() - (dur.Hours() * 60)
	return dur.Hours() + (mins / 60)
}

// pullRemoveTagsFromArgs takes a list of arguments, removes all 'remove tags' from them
// then returns the tags and the remaining args
func pullRemoveTagsFromArgs(args []string) ([]string, []string) {
	var tags, rem []string
	for _, opt := range args {
		if opt[0] == '-' {
			tags = append(tags, opt[1:])
		} else {
			rem = append(rem, opt)
		}
	}
	return tags, rem
}

// pullTagsFromArgs takes a list of arguments, removes all tags from them
// then returns the tags and the remaining args
func pullTagsFromArgs(args []string) ([]string, []string) {
	var tags, rem []string
	for _, opt := range args {
		if opt[0] == '+' {
			tags = append(tags, opt[1:])
		} else {
			rem = append(rem, opt)
		}
	}
	return tags, rem
}

func parseFuzzyTime(t string) (time.Time, error) {
	var ret time.Time
	var err error
	for i := range fuzzyFormats {
		ret, err = time.Parse(fuzzyFormats[i], t)
		if err == nil {
			// Make sure it's in the local timezone
			tz := time.Now().Format("Z07:00")
			t = ret.Format("2006-01-02T15:04:05") + tz
			if ret, err = time.Parse(time.RFC3339, t); err != nil {
				return ret, err
			}
			// Check for zero on year/mo/day
			if ret.Year() == 0 && ret.Month() == time.January && ret.Day() == 1 {
				ret = ret.AddDate(time.Now().Year(), int(time.Now().Month())-1, time.Now().Day()-1)
			}
			return ret, nil
		}
	}
	return time.Time{}, errors.New("Unable to parse time: " + t)
}

func friendlyFormatForTime(t time.Time) string {
	nowTime := time.Now()
	if t.Year() != nowTime.Year() || t.Month() != nowTime.Month() {
		return "2006-01-02 15:04"
	} else if t.Day() != nowTime.Day() {
		return "01/02 15:04"
	}
	return "15:04"
}

// timeToFriendlyString returns an easier to read version of the time
// giving enough details that the user should be fine inferring the rest
func timeToFriendlyString(t time.Time) string {
	return t.Format(friendlyFormatForTime(t))
}

func sinceToString(tm time.Time) string {
	return diffToString(tm, time.Now())
}

func diffToString(tm1, tm2 time.Time) string {
	ret := ""
	yr, mo, dy, hr, mn, sc := diff(tm1, tm2)
	higher := false

	if yr > 0 {
		ret += fmt.Sprintf("%4dy ", yr)
		higher = true
	}
	if mo > 0 || higher {
		ret += fmt.Sprintf("%2dm ", mo)
		higher = true
	}
	if dy > 0 || higher {
		ret += fmt.Sprintf("%2dd ", dy)
		higher = true
	}
	if hr > 0 || higher {
		ret += fmt.Sprintf("%2dh ", hr)
		higher = true
	}
	if mn > 0 || higher {
		ret += fmt.Sprintf("%2dm ", mn)
		higher = true
	}
	if sc > 0 || higher {
		ret += fmt.Sprintf("%2ds", sc)
	}
	return ret
}

func padRight(st string, l int) string {
	for len(st) < l {
		st = st + " "
	}
	return st
}

func padLeft(st string, l int) string {
	for len(st) < l {
		st = " " + st
	}
	return st
}

func diff(a, b time.Time) (year, month, day, hour, min, sec int) {
	if a.Location() != b.Location() {
		b = b.In(a.Location())
	}
	if a.After(b) {
		a, b = b, a
	}
	y1, M1, d1 := a.Date()
	y2, M2, d2 := b.Date()

	h1, m1, s1 := a.Clock()
	h2, m2, s2 := b.Clock()

	year = int(y2 - y1)
	month = int(M2 - M1)
	day = int(d2 - d1)
	hour = int(h2 - h1)
	min = int(m2 - m1)
	sec = int(s2 - s1)

	// Normalize negative values
	if sec < 0 {
		sec += 60
		min--
	}
	if min < 0 {
		min += 60
		hour--
	}
	if hour < 0 {
		hour += 24
		day--
	}
	if day < 0 {
		// days in month:
		t := time.Date(y1, M1, 32, 0, 0, 0, 0, time.UTC)
		day += 32 - t.Day()
		month--
	}
	if month < 0 {
		month += 12
		year--
	}

	return
}