package greeter_test

import (
	"testing"

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

// ── Service (unit tests) ──────────────────────────────────────────────────────

func TestGreet(t *testing.T) {
	svc := greeter.New(logger.NewNop())

	t.Run("returns personalized greeting", func(t *testing.T) {
		msg, err := svc.Greet("World").Unwrap()
		testutil.NoError(t, err)
		testutil.Equal(t, msg, "Hello, World!")
	})

	t.Run("rejects empty name", func(t *testing.T) {
		testutil.ErrorContains(t, svc.Greet("").Err(), "name must not be empty")
	})
}

// ── Manual fake example ───────────────────────────────────────────────────────
// For consumers that depend on the Greeter interface, write a manual fake.
// No code generation required — just implement the interface directly.

type fakeGreeter struct {
	greetFn func(name string) result.Expect[string]
}

func (f *fakeGreeter) Greet(name string) result.Expect[string] {
	return f.greetFn(name)
}

func TestFakeUsageExample(t *testing.T) {
	fake := &fakeGreeter{
		greetFn: func(name string) result.Expect[string] {
			return result.Ok("Hello, " + name + "!")
		},
	}

	msg, err := fake.Greet("Alice").Unwrap()
	testutil.NoError(t, err)
	testutil.Equal(t, msg, "Hello, Alice!")
}