package sync

import (
	"testing"
)

func TestTick_StrictlyMonotonic(t *testing.T) {
	// Reset global state.
	clock.mu.Lock()
	clock.last = 0
	clock.mu.Unlock()

	prev := int64(0)
	for i := 0; i < 1000; i++ {
		v := Tick(0)
		if v <= prev {
			t.Fatalf("iteration %d: Tick() = %d, want > %d", i, v, prev)
		}
		prev = v
	}
}

func TestTick_CausalOrdering(t *testing.T) {
	clock.mu.Lock()
	clock.last = 0
	clock.mu.Unlock()

	// Simulate a client HLC far in the future.
	future := int64(9_999_999_999) << counterBits
	v := Tick(future)
	if !After(v, future) {
		t.Fatalf("Tick(future) = %d, want > %d", v, future)
	}
}

func TestTick_NoDuplicates(t *testing.T) {
	clock.mu.Lock()
	clock.last = 0
	clock.mu.Unlock()

	seen := make(map[int64]bool)
	for i := 0; i < 10_000; i++ {
		v := Tick(0)
		if seen[v] {
			t.Fatalf("duplicate HLC value %d at iteration %d", v, i)
		}
		seen[v] = true
	}
}

func TestAfter(t *testing.T) {
	if !After(2, 1) {
		t.Fatal("After(2,1) must be true")
	}
	if After(1, 2) {
		t.Fatal("After(1,2) must be false")
	}
	if After(1, 1) {
		t.Fatal("After(1,1) must be false")
	}
}