package jsoninfo

import (

	"encoding/json"

	"fmt"

	"sort"

	"strings"

)

// UnsupportedPropertiesError is a helper for extensions that want to refuse

// unsupported JSON object properties.

//

// It produces a helpful error message.

type UnsupportedPropertiesError struct {

	Value                 interface{}

	UnsupportedProperties map[string]json.RawMessage

}

func NewUnsupportedPropertiesError(v interface{}, m map[string]json.RawMessage) error {

	return &UnsupportedPropertiesError{

		Value:                 v,

		UnsupportedProperties: m,

	}

}

func (err *UnsupportedPropertiesError) Error() string {

	m := err.UnsupportedProperties

	typeInfo := GetTypeInfoForValue(err.Value)

	if m == nil || typeInfo == nil {

		return "Invalid UnsupportedPropertiesError"

	}

	keys := make([]string, 0, len(m))

	for k := range m {

		keys = append(keys, k)

	}

	sort.Strings(keys)

	supported := typeInfo.FieldNames()

	if len(supported) == 0 {

		return fmt.Sprintf("Type '%T' doesn't take any properties. Unsupported properties: '%s'\n",

			err.Value, strings.Join(keys, "', '"))

	}

	return fmt.Sprintf("Unsupported properties: '%s'\nSupported properties are: '%s'",

		strings.Join(keys, "', '"),

		strings.Join(supported, "', '"))

}