package line

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"path"

	"git.trj.tw/golang/mtgbot/modules/apiact"
	"git.trj.tw/golang/mtgbot/modules/config"
	jsoniter "github.com/json-iterator/go"
)

var json = jsoniter.ConfigCompatibleWithStandardLibrary

// NullString -
type NullString *string

// String -
func String(s string) NullString {
	return &s
}

// NullInt -
type NullInt *int

// Int -
func Int(i int) NullInt {
	return &i
}

// Line -
type Line struct {
	URL         string
	APIVersion  string
	AccessToken string
}

// UserInfo -
type UserInfo struct {
	DisplayName string `json:"displayName"`
	UserID      string `json:"userId"`
}

type pushBody struct {
	To       string        `json:"to"`
	Messages []interface{} `json:"messages"`
}

type replyBody struct {
	ReplyToken string        `json:"replyToken"`
	Messages   []interface{} `json:"messages"`
}

// NewLineApi -
func NewLineApi(apiVersion string) (line *Line, err error) {
	if len(apiVersion) == 0 {
		apiVersion = "v2"
	}
	line = &Line{}
	line.URL = "https://api.line.me"
	line.APIVersion = apiVersion

	conf := config.GetConf()

	if len(conf.Line.Access) == 0 {
		return nil, errors.New("access token is empty")
	}

	line.AccessToken = conf.Line.Access
	return
}

func (p *Line) getAPIURL(urlPath string) (apiURL string, err error) {
	u, err := url.Parse(p.URL)
	if err != nil {
		return "", err
	}

	u.Path = path.Join(u.Path, p.APIVersion, urlPath)

	return u.String(), nil
}

func (p *Line) getHeader() (header map[string]string) {
	header = make(map[string]string)

	header["Content-Type"] = "application/json"
	header["Authorization"] = fmt.Sprintf("Bearer %s", p.AccessToken)

	return
}

func checkMessageStruct(msg interface{}) (valid bool) {
	switch msg.(type) {
	case TextMessage:
	case ImageMessage:
	case VideoMessage:
		return true
	}
	return false
}

// PushMessage -
func (p *Line) PushMessage(to string, msg interface{}) (err error) {
	if len(to) == 0 {
		return errors.New("target is empty")
	}
	apiURL, err := p.getAPIURL("/bot/message/push")
	if err != nil {
		return err
	}

	if !checkMessageStruct(msg) {
		return errors.New("message struct validate fail")
	}

	body := &pushBody{To: to}
	body.Messages = append(body.Messages, msg)

	dataByte, err := json.Marshal(body)
	if err != nil {
		return err
	}

	dataReader := bytes.NewReader(dataByte)

	resp, err := p.sendAPI(apiURL, "POST", dataReader)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	return
}

// ReplyMessage -
func (p *Line) ReplyMessage(token string, msg interface{}) (err error) {
	if len(token) == 0 {
		return errors.New("reply token is empty")
	}
	apiURL, err := p.getAPIURL("/bot/message/reply")
	if err != nil {
		return err
	}

	if !checkMessageStruct(msg) {
		return errors.New("message struct validate fail")
	}

	body := &replyBody{ReplyToken: token}
	body.Messages = append(body.Messages, msg)

	dataByte, err := json.Marshal(body)
	if err != nil {
		return err
	}

	dataReader := bytes.NewReader(dataByte)

	resp, err := p.sendAPI(apiURL, "POST", dataReader)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	return
}

func (p *Line) sendAPI(apiURL, method string, body io.Reader) (resp *http.Response, err error) {
	if len(apiURL) == 0 {
		return nil, errors.New("api url is empty")
	}

	reqObj := apiact.RequestObject{
		Method:  method,
		URL:     apiURL,
		Body:    body,
		Headers: p.getHeader(),
	}
	req, err := apiact.GetRequest(reqObj)
	if err != nil {
		return nil, err
	}

	resp, err = http.DefaultClient.Do(req)
	if err != nil {
		return nil, err
	}

	return
}