package generatedtext

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
)

func decodeGeneratedText[T any](data []byte, name string) (T, error) {
	var value T
	decoder := json.NewDecoder(bytes.NewReader(data))
	decoder.DisallowUnknownFields()
	if err := decoder.Decode(&value); err != nil {
		return value, fmt.Errorf("decode %s generated text: %w", name, err)
	}
	var extra any
	if err := decoder.Decode(&extra); err != nil {
		if err != io.EOF {
			return value, fmt.Errorf("decode %s generated text: %w", name, err)
		}
		return value, nil
	}
	return value, fmt.Errorf("decode %s generated text: multiple JSON values", name)
}

func normalizeGeneratedText[T any](value T, name string) ([]byte, error) {
	normalized, err := json.Marshal(value)
	if err != nil {
		return nil, fmt.Errorf("normalize %s generated text: %w", name, err)
	}
	return normalized, nil
}