package lru

import (
	"fmt"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
)

func TestTtl(t *testing.T) {
	cache := New[int](1)

	cache.Set("first", 1, 500*time.Millisecond)

	value, ok := cache.Get("first")
	assert.True(t, ok)
	assert.Equal(t, 1, value)

	time.Sleep(600 * time.Millisecond)

	value, ok = cache.Get("first")
	assert.False(t, ok)
	assert.Equal(t, 0, value)
}

func TestEvictFirst(t *testing.T) {
	cache := New[int](2)

	assert.False(t, cache.Set("first", 1, 500*time.Millisecond))
	assert.False(t, cache.Set("second", 2, 500*time.Millisecond))
	assert.True(t, cache.Set("third", 3, 500*time.Millisecond))

	_, ok := cache.Get("first")
	assert.False(t, ok)
}

func TestEvictExpired(t *testing.T) {
	cache := New[int](2)

	assert.False(t, cache.Set("first", 1, 1000*time.Millisecond))
	assert.False(t, cache.Set("second", 2, 100*time.Millisecond))

	time.Sleep(200 * time.Millisecond)

	assert.True(t, cache.Set("third", 3, 1000*time.Millisecond))

	var ok bool
	_, ok = cache.Get("first")
	assert.True(t, ok)
	_, ok = cache.Get("third")
	assert.True(t, ok)
	_, ok = cache.Get("second")
	assert.False(t, ok)
}

func TestSetExisted(t *testing.T) {
	cache := New[int](2)

	assert.False(t, cache.Set("first", 1, 200*time.Millisecond))
	assert.False(t, cache.Set("second", 2, 500*time.Millisecond))

	time.Sleep(100 * time.Millisecond)

	assert.False(t, cache.Set("first", 11, 1000*time.Millisecond))
	assert.True(t, cache.Set("third", 3, 1000*time.Millisecond))

	value, ok := cache.Get("first") // exists with updated ttl
	assert.True(t, ok)
	assert.Equal(t, 11, value)
	_, ok = cache.Get("third")
	assert.True(t, ok)
	_, ok = cache.Get("second") // evicted
	assert.False(t, ok)
}

func TestDummy(t *testing.T) { // for coverage 100% coverage
	cache := New[int](0)
	cache.evict()
}

func Benchmark(b *testing.B) {
	cache := New[string](10)
	ttl := 1000 * time.Millisecond

	b.Run("Set", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			cache.Set(fmt.Sprintf("item:%d", i), fmt.Sprintf("item:%d", i), ttl)
		}
	})

	b.Run("Get", func(b *testing.B) {
		for i := 0; i < b.N; i++ {
			value, ok := cache.Get(fmt.Sprintf("item:%d", i))
			if ok {
				_ = value
			}
		}
	})
}