package manifest

import (
	"bytes"
	"encoding/json"
)

// Argument is a special struct that was made to handle a mixed-typed array
// of arguments in a manifest.
//
// An argument in a manifest could be:
//   - a single string
//   - an object consists of rules array field and a value field that could be
//     a single string or an array of strings.
type Argument struct {
	Rules []Rule   `json:"rules"`
	Value []string `json:"value"`
}

// CheckRules returns true if all rules passed and a feature set in a rule if
// applicable, a FeatureUnknown otherwise.
func (a Argument) CheckRules() (ok bool, feature Feature) {
	feature = FeatureUnknown
	for _, r := range a.Rules {
		ok, feature = r.Check()
		if !ok {
			return false, feature
		}
	}
	return true, feature
}

// UnmarshalJSON had to be implemented because of mixed-typed nature of an
// arguments array in a manifest.
func (a *Argument) UnmarshalJSON(data []byte) error {
	if data[0] == '"' {
		a.Value = append(a.Value, string(data[1:len(data)-1]))
	} else if data[0] == '{' && bytes.Contains(data, []byte("value\": \"")) {
		singleValArg := struct {
			Rules []Rule `json:"rules"`
			Value string `json:"value"`
		}{}
		if err := json.Unmarshal(data, &singleValArg); err != nil {
			return err
		}
		a.Rules = singleValArg.Rules
		a.Value = append(a.Value, singleValArg.Value)
	} else if data[0] == '{' {
		multiValArg := struct {
			Rules []Rule   `json:"rules"`
			Value []string `json:"value"`
		}{}
		if err := json.Unmarshal(data, &multiValArg); err != nil {
			return err
		}
		a.Rules = multiValArg.Rules
		a.Value = multiValArg.Value
	}
	return nil
}