package schema

import (
	"encoding/json"

	"github.com/pkg/errors"
)

func Extend(base []byte, schema []byte) ([]byte, error) {
	var (
		extension map[string]any
		extended  map[string]any
	)

	if err := json.Unmarshal(base, &extended); err != nil {
		return nil, errors.WithStack(err)
	}

	if err := json.Unmarshal(schema, &extension); err != nil {
		return nil, errors.WithStack(err)
	}

	extended["$id"] = extension["$id"]
	extended["title"] = extension["title"]

	props := extension["properties"].(map[string]any)
	extendedProps := extended["properties"].(map[string]any)
	for key, val := range props {
		extendedProps[key] = val
	}
	extended["properties"] = extendedProps

	data, err := json.MarshalIndent(extended, "", " ")
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return data, nil
}