package ddns

import (
	"context"
	"testing"
	"time"
)

func TestNewRunner_ZeroStatus(t *testing.T) {
	rn := NewRunner()
	s := rn.GetStatus()
	if s.Enabled {
		t.Error("new runner should have Enabled=false")
	}
	if s.CurrentIP != "" {
		t.Errorf("new runner should have empty CurrentIP, got %q", s.CurrentIP)
	}
	if !s.LastChecked.IsZero() {
		t.Error("new runner should have zero LastChecked")
	}
}

func TestTrigger_NonBlocking(t *testing.T) {
	rn := NewRunner()
	done := make(chan struct{})
	go func() {
		rn.Trigger()
		rn.Trigger()
		close(done)
	}()

	select {
	case <-done:
	case <-time.After(time.Second):
		t.Error("Trigger blocked unexpectedly")
	}
}

func staticParams(token string, records []string) ParamsFunc {
	return func() Params {
		return Params{APIToken: token, Records: records, IntervalMinutes: 5}
	}
}

func TestStart_SetsEnabledStatus(t *testing.T) {
	rn := NewRunner()
	started := make(chan struct{}, 1)
	rn.ipFetcher = func() (string, error) {
		select {
		case started <- struct{}{}:
		default:
		}
		return "1.2.3.4", nil
	}

	rn.Start(context.Background(), staticParams("tok", []string{"a.example.com"}))

	select {
	case <-started:
	case <-time.After(time.Second):
		t.Fatal("goroutine did not start in time")
	}

	if !rn.GetStatus().Enabled {
		t.Error("expected Enabled=true after Start with valid params")
	}

	rn.Stop()

	if rn.GetStatus().Enabled {
		t.Error("expected Enabled=false after Stop()")
	}
}

func TestStart_InvalidParams_SetsDisabled(t *testing.T) {
	for _, pfn := range []ParamsFunc{
		func() Params { return Params{} },
		func() Params { return Params{APIToken: ""} },
		func() Params { return Params{APIToken: "tok", Records: nil} },
	} {
		rn := NewRunner()
		rn.Start(context.Background(), pfn)
		if rn.GetStatus().Enabled {
			t.Errorf("expected Enabled=false for empty params")
		}
	}
}

func TestStart_Restart_KeepsEnabled(t *testing.T) {
	rn := NewRunner()
	reached := make(chan struct{}, 2)
	rn.ipFetcher = func() (string, error) {
		select {
		case reached <- struct{}{}:
		default:
		}
		return "1.2.3.4", nil
	}

	pfn := staticParams("tok", []string{"a.example.com"})
	rn.Start(context.Background(), pfn)

	select {
	case <-reached:
	case <-time.After(time.Second):
		t.Fatal("first goroutine did not start")
	}

	// Restart — old goroutine is cancelled, new one starts
	rn.Start(context.Background(), pfn)

	if !rn.GetStatus().Enabled {
		t.Error("expected Enabled=true after restart")
	}

	rn.Stop()
}

func TestStop_ClearsEnabled(t *testing.T) {
	rn := NewRunner()
	rn.mu.Lock()
	rn.status.Enabled = true
	rn.mu.Unlock()

	rn.Stop()

	if rn.GetStatus().Enabled {
		t.Error("expected Enabled=false after Stop()")
	}
}

func TestStart_CancelsAndRestarts(t *testing.T) {
	rn := NewRunner()

	block := make(chan struct{})
	firstReady := make(chan struct{}, 1)
	rn.ipFetcher = func() (string, error) {
		select {
		case firstReady <- struct{}{}:
		default:
		}
		<-block
		return "1.2.3.4", nil
	}

	pfn := staticParams("tok", []string{"a.example.com"})
	rn.Start(context.Background(), pfn)

	select {
	case <-firstReady:
	case <-time.After(time.Second):
		t.Fatal("first goroutine did not start")
	}

	close(block)

	// Second Start with disabled params must not deadlock
	done := make(chan struct{})
	go func() {
		rn.Start(context.Background(), func() Params { return Params{} })
		close(done)
	}()

	select {
	case <-done:
	case <-time.After(time.Second):
		t.Error("second Start blocked unexpectedly")
	}
}

func TestCheckAndUpdate_UpdatesCurrentIP(t *testing.T) {
	rn := NewRunner()
	rn.ipFetcher = func() (string, error) { return "5.6.7.8", nil }
	rn.paramsFn = staticParams("fake", []string{"a.example.com"})

	rn.checkAndUpdate()

	if rn.GetStatus().CurrentIP != "5.6.7.8" {
		t.Errorf("expected CurrentIP=5.6.7.8, got %q", rn.GetStatus().CurrentIP)
	}
}

func TestCheckAndUpdate_SkipsWhenNoParams(t *testing.T) {
	rn := NewRunner()
	rn.ipFetcher = func() (string, error) { return "1.2.3.4", nil }
	rn.paramsFn = func() Params { return Params{} }

	rn.checkAndUpdate()

	if rn.GetStatus().CurrentIP != "" {
		t.Error("expected empty CurrentIP when params have no token/records")
	}
}

func TestCheckAndUpdate_ParamsFuncCalledEachTime(t *testing.T) {
	rn := NewRunner()
	rn.ipFetcher = func() (string, error) { return "1.2.3.4", nil }

	calls := 0
	rn.paramsFn = func() Params {
		calls++
		return Params{APIToken: "fake", Records: []string{"a.example.com"}}
	}

	rn.checkAndUpdate()
	rn.checkAndUpdate()

	if calls != 2 {
		t.Errorf("expected paramsFn called 2 times, got %d", calls)
	}
}

func TestGetStatus_ReflectsManualUpdate(t *testing.T) {
	rn := NewRunner()
	rn.mu.Lock()
	rn.status.CurrentIP = "1.2.3.4"
	rn.status.LastChecked = time.Now()
	rn.status.Enabled = true
	rn.mu.Unlock()

	s := rn.GetStatus()
	if s.CurrentIP != "1.2.3.4" {
		t.Errorf("got CurrentIP %q, want 1.2.3.4", s.CurrentIP)
	}
	if !s.Enabled {
		t.Error("expected Enabled=true")
	}
}