// Package greeter is a minimal example domain package.
// It demonstrates how to:
//   - define an interface (satisfied by manual fakes in tests)
//   - inject dependencies (logger) through a constructor
//   - use the logger.WithField pattern
//
// Replace this package with your own domain logic.
package greeter

import (
	"errors"
	"fmt"

	"gitea.djmil.dev/go/template/internal/logger"
	"gitea.djmil.dev/go/template/pkg/result"
)

// Greeter produces a greeting for a given name.
// The interface is what other packages should depend on — never the concrete type.
type Greeter interface {
	Greet(name string) result.Expect[string]
}

// Service is the concrete implementation.
type Service struct {
	log *logger.Logger
}

// New creates a Greeter service with the provided logger.
func New(log *logger.Logger) *Service {
	return &Service{log: log}
}

// Greet returns a personalized greeting and logs the interaction.
func (s *Service) Greet(name string) result.Expect[string] {
	if name == "" {
		return result.Fail[string](errors.New("Greet: name must not be empty"))
	}

	msg := fmt.Sprintf("Hello, %s!", name)

	s.log.
		WithField("component", "greeter").
		WithField("name", name).
		Info("greeting generated")

	return result.Ok(msg)
}