package moslice

import (
	"testing"

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

func TestBatch(t *testing.T) {
	t.Run("empty slice", func(t *testing.T) {
		result := Batch([]int{}, 3)
		assert.Nil(t, result)
	})

	t.Run("zero or negative size", func(t *testing.T) {
		result := Batch([]int{1, 2, 3}, 0)
		assert.Nil(t, result)

		result = Batch([]int{1, 2, 3}, -1)
		assert.Nil(t, result)
	})

	t.Run("slice smaller than batch size", func(t *testing.T) {
		result := Batch([]int{1, 2}, 5)
		assert.Equal(t, [][]int{{1, 2}}, result)
	})

	t.Run("slice equal to batch size", func(t *testing.T) {
		result := Batch([]int{1, 2, 3}, 3)
		assert.Equal(t, [][]int{{1, 2, 3}}, result)
	})

	t.Run("slice evenly divisible by batch size", func(t *testing.T) {
		result := Batch([]int{1, 2, 3, 4, 5, 6}, 2)
		assert.Equal(t, [][]int{{1, 2}, {3, 4}, {5, 6}}, result)
	})

	t.Run("slice not evenly divisible by batch size", func(t *testing.T) {
		result := Batch([]int{1, 2, 3, 4, 5}, 2)
		assert.Equal(t, [][]int{{1, 2}, {3, 4}, {5}}, result)
	})

	t.Run("batch size of 1", func(t *testing.T) {
		result := Batch([]int{1, 2, 3}, 1)
		assert.Equal(t, [][]int{{1}, {2}, {3}}, result)
	})

	t.Run("string slice", func(t *testing.T) {
		result := Batch([]string{"a", "b", "c", "d", "e"}, 2)
		assert.Equal(t, [][]string{{"a", "b"}, {"c", "d"}, {"e"}}, result)
	})
}