package testkit

import (
	"errors"
	"strings"

	"galaxy/authsession/internal/ports"
)

// FixedCodeGenerator is a deterministic CodeGenerator double that always
// returns the same code or error.
type FixedCodeGenerator struct {
	// Code stores the fixed code returned by Generate when Err is nil.
	Code string

	// Err is returned directly from Generate when set.
	Err error
}

// Generate returns the configured fixed code.
func (g FixedCodeGenerator) Generate() (string, error) {
	if g.Err != nil {
		return "", g.Err
	}
	switch {
	case strings.TrimSpace(g.Code) == "":
		return "", errors.New("fixed code generator code must not be empty")
	case strings.TrimSpace(g.Code) != g.Code:
		return "", errors.New("fixed code generator code must not contain surrounding whitespace")
	default:
		return g.Code, nil
	}
}

var _ ports.CodeGenerator = FixedCodeGenerator{}