package promptkit

import "fmt"

// GenerationError reports a non-2xx response from Promptkit's built-in
// OpenAI-compatible client during [Engine.Run] or [Engine.RunPrepared].
//
// Engine-produced values are immutable, caller-owned values. Use errors.Is to
// match [ErrLLMGenerate] and errors.As with a *GenerationError target to obtain
// this type. The four provider accessors expose untrusted provider-controlled
// values that can contain sensitive request or schema fragments. Applications
// must apply their own disclosure policy before logging, displaying, or
// returning them to another caller.
//
// Accessors, Error, GoString, and Unwrap are safe on a nil receiver and a zero
// value. Default and Go-syntax formatting deliberately redact provider details.
// GenerationError has no stable JSON representation.
type GenerationError struct {
	statusCode      int
	providerCode    string
	providerType    string
	providerMessage string
}

func newGenerationError(statusCode int, providerCode, providerType, providerMessage string) *GenerationError {
	return &GenerationError{
		statusCode:      statusCode,
		providerCode:    providerCode,
		providerType:    providerType,
		providerMessage: providerMessage,
	}
}

// StatusCode returns the received provider HTTP status code, or zero for a nil
// receiver or zero value.
func (e *GenerationError) StatusCode() int {
	if e == nil {
		return 0
	}
	return e.statusCode
}

// ProviderCode returns the normalized provider error code, if present. Its
// value is untrusted and may contain sensitive data.
func (e *GenerationError) ProviderCode() string {
	if e == nil {
		return ""
	}
	return e.providerCode
}

// ProviderType returns the normalized provider error type, if present. Its
// value is untrusted and may contain sensitive data.
func (e *GenerationError) ProviderType() string {
	if e == nil {
		return ""
	}
	return e.providerType
}

// ProviderMessage returns the bounded normalized provider diagnostic, if
// present. Its value is untrusted and may contain sensitive data.
func (e *GenerationError) ProviderMessage() string {
	if e == nil {
		return ""
	}
	return e.providerMessage
}

// Error returns a redacted diagnostic that is not a parsing contract.
func (e *GenerationError) Error() string {
	if e == nil || e.statusCode == 0 {
		return ErrLLMGenerate.Error()
	}
	return fmt.Sprintf("%s: provider returned HTTP status %d", ErrLLMGenerate, e.statusCode)
}

// GoString returns the same redacted diagnostic as Error.
func (e *GenerationError) GoString() string {
	return e.Error()
}

// Unwrap returns ErrLLMGenerate. It is safe to call on a nil receiver or zero
// value.
func (e *GenerationError) Unwrap() error {
	return ErrLLMGenerate
}