package magna

import (
	"fmt"
	"testing"

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

func TestBufferOverflowError(t *testing.T) {
	tests := []struct {
		name     string
		length   int
		offset   int
		expected string
	}{
		{"PositiveOffset", 10, 15, "magna: offset 15 is past the buffer length 10"},
		{"ZeroLengthBuffer", 0, 5, "magna: offset 5 is past the buffer length 0"},
		{"NegativeOffset", 10, -1, "magna: offset -1 is past the buffer length 10"},
		{"EqualOffset", 10, 10, "magna: offset 10 is past the buffer length 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, "magna: received invalid label length 64"},
		{"LengthZero", 0, "magna: received invalid label length 0"},
		{"NegativeLength", -1, "magna: received invalid label length -1"},
	}

	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 := "magna: loop detected in domain compression"
		assert.Equal(t, expected, err.Error(), "Error() output mismatch")
	})
}

func TestMagnaError(t *testing.T) {
	tests := []struct {
		name     string
		message  string
		expected string
	}{
		{"EmptyMessage", "", "magna: "},
		{"SimpleMessage", "test error", "magna: test error"},
		{"MessageWithPunctuation", "error: invalid input!", "magna: error: invalid input!"},
	}

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