package device

import (
	"encoding/gob"
	"encoding/json"
	"os"
)

func init() {
	gob.Register(LoginPolicy{})
	gob.Register(FieldPolicy{})
}

type LoginPolicy struct {
	Username FieldPolicy `json:"username"`
	Password FieldPolicy `json:"password"`
}

type FieldPolicy struct {
	MinLength   int  `json:"min_len"`
	MaxLength   int  `json:"max_len"`
	NumericOnly bool `json:"num_only"`
}

func GetLoginPolicy() (LoginPolicy, error) {
	policyJSON := getLoginPolicyJSON()

	var devicePolicy LoginPolicy
	err := json.Unmarshal([]byte(policyJSON), &devicePolicy)
	if err != nil {
		return LoginPolicy{}, err
	}

	return devicePolicy, nil
}

func getLoginPolicyJSON() string {
	defaultPolicy := `{"username":{"min_len":1,"max_len":12,"num_only":false}, "password":{"min_len":1,"max_len":12,"num_only":false}}`

	fromEnv, exist := os.LookupEnv("IAM_DEVICE_POLICY")
	if !exist {
		return defaultPolicy
	}

	return fromEnv
}