package service

import (
	"errors"
	"testing"

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

// =============================================================================
// ClassifiedError Tests
// =============================================================================

func TestClassifiedError_Error_WithMessage(t *testing.T) {
	err := newValidationError("custom validation message")
	assert.EqualError(t, err, "custom validation message")
}

func TestClassifiedError_Error_WithEmptyMessage(t *testing.T) {
	// Create error with only cause
	err := &classifiedError{cause: ErrValidationFailed}
	assert.EqualError(t, err, "validation failed")
}

func TestClassifiedError_Error_WithNoMessageOrCause(t *testing.T) {
	// Create error with neither message nor cause
	err := &classifiedError{}
	assert.Equal(t, "", err.Error())
}

func TestClassifiedError_Unwrap(t *testing.T) {
	err := newRateLimitError("too many requests")
	
	// Unwrap should return the cause
	unwrapped := errors.Unwrap(err)
	assert.Equal(t, ErrRateLimitExceeded, unwrapped)
}

func TestErrRateLimitExceeded(t *testing.T) {
	assert.EqualError(t, ErrRateLimitExceeded, "rate limit exceeded")
}

func TestErrValidationFailed(t *testing.T) {
	assert.EqualError(t, ErrValidationFailed, "validation failed")
}

func TestErrors_Is_RateLimit(t *testing.T) {
	// Test that wrapped errors can be identified using errors.Is
	err := newRateLimitError("too many requests")
	
	assert.True(t, errors.Is(err, ErrRateLimitExceeded))
	assert.False(t, errors.Is(err, ErrValidationFailed))
}

func TestErrors_Is_Validation(t *testing.T) {
	err := newValidationError("invalid input")
	
	assert.True(t, errors.Is(err, ErrValidationFailed))
	assert.False(t, errors.Is(err, ErrRateLimitExceeded))
}

func TestNewRateLimitError(t *testing.T) {
	err := newRateLimitError("rate limited")
	
	assert.EqualError(t, err, "rate limited")
	assert.True(t, errors.Is(err, ErrRateLimitExceeded))
}

func TestNewValidationError(t *testing.T) {
	err := newValidationError("validation failed")
	
	assert.EqualError(t, err, "validation failed")
	assert.True(t, errors.Is(err, ErrValidationFailed))
}