package eventbus

import (
	"sync"
	"testing"

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

func TestRingBuffer_PushPop(t *testing.T) {
	ring := NewRingBuffer[int](5)

	ring.Push(1)
	ring.Push(2)
	ring.Push(3)

	v, ok := ring.Pop()
	require.True(t, ok)
	assert.Equal(t, 1, v)

	v, ok = ring.Pop()
	require.True(t, ok)
	assert.Equal(t, 2, v)

	v, ok = ring.Pop()
	require.True(t, ok)
	assert.Equal(t, 3, v)
}

func TestRingBuffer_Empty(t *testing.T) {
	ring := NewRingBuffer[int](5)

	v, ok := ring.Pop()
	assert.False(t, ok)
	assert.Equal(t, 0, v)
}

func TestRingBuffer_OverwriteOldest(t *testing.T) {
	ring := NewRingBuffer[int](4)

	ring.Push(1)
	ring.Push(2)
	ring.Push(3)
	ring.Push(4)
	ring.Push(5)
	ring.Push(6)

	var values []int
	for {
		v, ok := ring.Pop()
		if !ok {
			break
		}
		values = append(values, v)
	}

	assert.Equal(t, []int{3, 4, 5, 6}, values)
}

func TestRingBuffer_Len(t *testing.T) {
	ring := NewRingBuffer[int](5)

	assert.Equal(t, 0, ring.Len())

	ring.Push(1)
	assert.Equal(t, 1, ring.Len())

	ring.Push(2)
	ring.Push(3)
	assert.Equal(t, 3, ring.Len())

	ring.Pop()
	assert.Equal(t, 2, ring.Len())

	ring.Push(4)
	ring.Push(5)
	ring.Push(6)
	ring.Push(7)
	assert.Equal(t, 5, ring.Len())

	ring.Push(8)
	assert.Equal(t, 5, ring.Len())
}

func TestRingBuffer_Concurrent(t *testing.T) {
	ring := NewRingBuffer[int](100)
	var wg sync.WaitGroup

	for i := 0; i < 10; i++ {
		wg.Add(1)
		go func(id int) {
			defer wg.Done()
			for j := 0; j < 100; j++ {
				ring.Push(id*100 + j)
			}
		}(i)
	}

	wg.Add(1)
	go func() {
		defer wg.Done()
		for i := 0; i < 500; i++ {
			ring.Pop()
		}
	}()

	wg.Wait()
}