// Package models provides the models for the KermaGo application
package models

import (
	"errors"
	"regexp"

	"github.com/docker/go/canonical/json"
)

/*
A Hello represents a struct that has a type, a version and a user agent
*/
type Hello struct {
	Type    string `json:"type" binding:"required"`
	Version string `json:"version" binding:"required"`
	Agent   string `json:"agent"`
}

/*
Construct creates a new Hello object for this instance
*/
func (h *Hello) Construct() {
	h.Type = "hello"
	h.Version = "0.8.0"
	h.Agent = "BadKerma Go Client 0.8.x"
}

/*
MarshalJson returns the canonical json of the hello object
*/
func (h *Hello) MarshalJson() ([]byte, error) {
	return json.MarshalCanonical(h)
}

/*
UnmarshalJSON returns a new Hello request from a byte array
*/
func (h *Hello) UnmarshalJSON(data []byte) error {
	if len(data) == 0 {
		return nil
	}

	type tmp Hello
	err := json.Unmarshal(data, (*tmp)(h))
	if err != nil {
		return err
	}

	if !h.verify() {
		return errors.New("hello request not valid")
	}

	return nil
}

func (h *Hello) verify() bool {
	if h.Type == "hello" && h.isValidVersion() {
		return true
	}

	return false
}

func (h *Hello) isValidVersion() bool {
	RegExp := regexp.MustCompile(`^0\.8\.[0-9]$`)

	return RegExp.MatchString(h.Version)
}