package promptkit

import (
	"context"
	"errors"
	"fmt"

	"gitea.maximumdirect.net/eric/promptkit/internal/domain"
	"gitea.maximumdirect.net/eric/promptkit/internal/llm"
)

type publicLLMClientAdapter struct {
	client LLMClient
}

func (a publicLLMClientAdapter) Generate(ctx context.Context, req domain.GenerateRequest) (*domain.GenerateResponse, error) {
	resp, err := a.client.Generate(ctx, fromDomainGenerateRequest(req))
	if err == nil && resp == nil {
		err = fmt.Errorf("%w: %w: llm client returned nil response", ErrLLMGenerate, ErrMalformedResponse)
	}
	if err != nil {
		switch {
		case errors.Is(err, ErrTransport):
			return nil, classifiedClientError{cause: err, category: llm.ErrTransport}
		case errors.Is(err, ErrMalformedResponse):
			return nil, classifiedClientError{cause: err, category: llm.ErrMalformedResponse}
		}
		return nil, err
	}
	return toDomainGenerateResponse(resp), nil
}

// classifiedClientError makes an explicit public category available internally
// without replacing the client's diagnostic or original error chain.
type classifiedClientError struct {
	cause    error
	category error
}

func (e classifiedClientError) Error() string        { return e.cause.Error() }
func (e classifiedClientError) Unwrap() error        { return e.cause }
func (e classifiedClientError) Is(target error) bool { return target == e.category }