package main

import (
	"time"
)

type Typed func(*Timer) string

type Timer struct {
	config Config
	From   time.Time
	Typed  Typed
	paused bool
	offset time.Duration
}

func NewTimer(config Config) (*Timer, error) {
	t := &Timer{From: time.Now().Add(time.Duration(-1) * config.Offset), config: config}
	return t, t.setTyped(config)
}

func (t *Timer) TogglePause() {
	if t.paused {
		t.Resume()
	} else {
		t.Pause()
	}
}

func (t *Timer) Resume() {
	t.paused = false
	t.From = time.Now().Add(time.Duration(-1) * t.offset)
	t.offset = 0
}

func (t *Timer) Pause() {
	t.paused = true
	t.offset = time.Since(t.From)
}

func (t *Timer) setTyped(config Config) error {
	if config.Stopwatch {
		t.Typed = NewBasicStopwatch
	} else {
		t.Typed = NewBasicTimer
	}

	if config.ETA {
		t.Typed = WithETA(t.Typed)
	}

	if config.Done {
		t.Typed = WithDone(t.Typed)
	}

	if config.TS {
		t.Typed = WithTS(t.Typed)
	}

	return nil
}

func (t *Timer) Remaining() time.Duration {
	return time.Until(t.Deadline()) + time.Second
}

func (t *Timer) Deadline() time.Time {
	from := t.From
	if t.paused {
		from = time.Now().Add(time.Duration(-1) * t.offset)
	}
	return from.Add(t.config.Duration)
}

func (t *Timer) Ack() {
	for t.Done() {
		t.From = t.From.Add(t.config.Duration)
	}
}

func (t *Timer) Reset() {
	t.From = time.Now()
}

func (t *Timer) Done() bool {
	return time.Now().After(t.From.Add(t.config.Duration))
}

func (t *Timer) String() string {
	return t.Typed(t)
}

func (t *Timer) Add(d time.Duration) {
	t.From = t.From.Add(d)
}

func (t *Timer) Sub(d time.Duration) {
	t.Add(time.Duration(-1) * d)
}