package magna

import (
	"testing"

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

func TestBufferOverflowError(t *testing.T) {
	tests := []struct {
		name     string
		length   int
		offset   int
		expected string
	}{
		{"PositiveOffset", 10, 15, "buffer overflow: attempted to read past buffer length 10 at offset 15"},
		{"ZeroLengthBuffer", 0, 5, "buffer overflow: attempted to read past buffer length 0 at offset 5"},
		{"NegativeOffset", 10, -1, "buffer overflow: attempted to read past buffer length 10 at offset -1"},
		{"EqualOffset", 10, 10, "buffer overflow: attempted to read past buffer length 10 at offset 10"},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := &BufferOverflowError{Length: tt.length, Offset: tt.offset}
			assert.Equal(t, tt.expected, err.Error())
		})
	}
}

func TestInvalidLabelError(t *testing.T) {
	tests := []struct {
		name     string
		length   int
		expected string
	}{
		{"LengthTooLarge", 64, "invalid domain label: length 64 exceeds maximum 63"},
		{"LengthZero", 0, "invalid domain label: zero length label encountered"},
		{"ValidLength", 30, "invalid domain label: unexpected length 30"},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := &InvalidLabelError{Length: tt.length}
			assert.Equal(t, tt.expected, err.Error())
		})
	}
}

func TestDomainCompressionError(t *testing.T) {
	t.Run("Standard", func(t *testing.T) {
		err := &DomainCompressionError{}
		expected := "invalid domain compression: pointer loop detected"
		assert.Equal(t, expected, err.Error(), "Error() output mismatch")
	})
}