package queue_test

import (
	"math/rand"
	"testing"

	"gogs.humancabbage.net/sam/priorityq/queue"
)

func TestRepeatPushPop(t *testing.T) {
	t.Parallel()
	q := queue.Make[int](4)
	if q.Capacity() != 4 {
		t.Errorf("wrong capacity")
	}
	for i := 0; i < 50; i++ {
		q.PushBack(1)
		q.PushBack(2)
		q.PushBack(3)
		q.PushBack(4)
		if q.Len() != 4 {
			t.Errorf("wrong length")
		}
		checkPop := func(n int) {
			if v := q.PopFront(); v != n {
				t.Errorf("popped %d, expected %d", v, n)
			}
		}
		checkPop(1)
		checkPop(2)
		checkPop(3)
		checkPop(4)
	}
}

func TestInterleavedPushPop(t *testing.T) {
	t.Parallel()
	q := queue.Make[int](4)
	checkPop := func(n int) {
		if v := q.PopFront(); v != n {
			t.Errorf("popped %d, expected %d", v, n)
		}
	}
	q.PushBack(1)
	q.PushBack(2)
	q.PushBack(3)
	checkPop(1)
	q.PushBack(4)
	q.PushBack(5)
	checkPop(2)
}

func TestEmptyPopPanic(t *testing.T) {
	defer func() {
		if r := recover(); r == nil {
			t.Errorf("popping empty buffer did not panic")
		}
	}()
	t.Parallel()
	q := queue.Make[int](4)
	q.PopFront()
}

func TestFullPushPanic(t *testing.T) {
	defer func() {
		if r := recover(); r == nil {
			t.Errorf("pushing full buffer did not panic")
		}
	}()
	t.Parallel()
	q := queue.Make[int](1)
	q.PushBack(1)
	q.PushBack(2)
}

func TestIter(t *testing.T) {
	q := queue.Make[int](4)
	q.PushBack(1)
	q.PushBack(2)
	q.PushBack(3)
	q.PushBack(4)
	i := 0
	for v := range q.Iter() {
		expected := i + 1
		if v != expected {
			t.Errorf("iter %d should have value %d, not %d",
				i, expected, v)
		}
		i++
	}
	if q.Len() != 4 {
		t.Errorf("wrong length")
	}
}

func TestIterPop(t *testing.T) {
	t.Parallel()
	q := queue.Make[int](4)
	q.PushBack(1)
	q.PushBack(2)
	q.PushBack(3)
	q.PushBack(4)
	i := 0
	for v := range q.IterPop() {
		expected := i + 1
		if v != expected {
			t.Errorf("iter %d should have value %d, not %d",
				i, expected, v)
		}
		i++
		// to test yield() returning false
		if i == 4 {
			break
		}
	}
	if q.Len() != 0 {
		t.Errorf("wrong length")
	}
}

func BenchmarkPush(b *testing.B) {
	q := queue.Make[int](b.N)
	rs := rand.NewSource(0)
	r := rand.New(rs)
	items := make([]int, b.N)
	for i := 0; i < b.N; i++ {
		items[i] = r.Int()
	}
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		q.PushBack(items[i])
	}
}

func BenchmarkPop(b *testing.B) {
	q := queue.Make[int](b.N)
	rs := rand.NewSource(0)
	r := rand.New(rs)
	for i := 0; i < b.N; i++ {
		q.PushBack(r.Int())
	}
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		q.PopFront()
	}
}