package wechat

import (
	"crypto/sha1"
	"encoding/hex"
	"net/url"
	"sort"
	"strings"

	"github.com/imroc/req/v3"
	"github.com/pkg/errors"
)

const BaseURL = "https://api.weixin.qq.com/"

var DefaultClient = req.
	NewClient().
	SetBaseURL(BaseURL).
	SetCommonHeader("Content-Type", "application/json")

const (
	ScopeBase     = "snsapi_base"
	ScopeUserInfo = "snsapi_userinfo"
)

type AuthScope string

func (s AuthScope) String() string {
	return string(s)
}

type Client struct {
	client *req.Client

	appID     string
	appSecret string
	token     string
	aesKey    string
}

func New(options ...Options) *Client {
	we := &Client{
		client: DefaultClient,
	}

	for _, opt := range options {
		opt(we)
	}

	return we
}

func (we *Client) Verify(signature, timestamp, nonce string) error {
	params := []string{signature, timestamp, nonce, we.token}
	sort.Strings(params)
	str := strings.Join(params, "")
	hash := sha1.Sum([]byte(str))
	hashStr := hex.EncodeToString(hash[:])

	if hashStr == signature {
		return errors.New("Signature verification failed")
	}

	return nil
}

func (we *Client) wrapParams(params map[string]string) map[string]string {
	if params == nil {
		params = make(map[string]string)
	}

	params["appid"] = we.appID
	params["secret"] = we.appSecret

	return params
}

func (we *Client) GetAccessToken() (*AccessTokenResponse, error) {
	params := map[string]string{
		"grant_type": "client_credential",
	}

	var data AccessTokenResponse
	_, err := we.client.R().SetSuccessResult(&data).SetQueryParams(params).Get("/cgi-bin/token")
	if err != nil {
		return nil, errors.Wrap(err, "call /cgi-bin/token failed")
	}

	return &data, nil
}

// ScopeAuthorizeURL
func (we *Client) ScopeAuthorizeURL(opts ...ScopeAuthorizeURLOptions) (*url.URL, error) {
	params := url.Values{}
	params.Add("appid", we.appID)
	params.Add("response_type", "code")

	for _, opt := range opts {
		opt(params)
	}

	if params.Get("scope") == "" {
		params.Add("scope", ScopeBase)
	}

	u, err := url.Parse("https://open.weixin.qq.com/connect/oauth2/authorize")
	if err != nil {
		return nil, errors.Wrap(err, "parse url failed")
	}

	u.Fragment = "wechat_redirect"
	u.RawQuery = url.Values(params).Encode()

	return u, nil
}

type AuthorizeAccessToken struct {
	AccessToken    string `json:"access_token"`
	ExpiresIn      int64  `json:"expires_in"`
	IsSnapshotuser int64  `json:"is_snapshotuser"`
	Openid         string `json:"openid"`
	RefreshToken   string `json:"refresh_token"`
	Scope          string `json:"scope"`
	Unionid        string `json:"unionid"`
}

func (we *Client) AuthorizeCode2Token(code string) (*AuthorizeAccessToken, error) {
	params := we.wrapParams(map[string]string{
		"code":       code,
		"grant_type": "authorization_code",
	})

	var data AuthorizeAccessToken
	_, err := we.client.R().SetSuccessResult(&data).SetQueryParams(params).Get("/sns/oauth2/access_token")
	if err != nil {
		return nil, errors.Wrap(err, "call /sns/oauth2/access_token failed")
	}

	return &data, nil
}

func (we *Client) AuthorizeRefreshAccessToken(accessToken string) (*AuthorizeAccessToken, error) {
	params := we.wrapParams(map[string]string{
		"refresh_token": accessToken,
		"grant_type":    "refresh_token",
	})

	var data AuthorizeAccessToken
	_, err := we.client.R().SetSuccessResult(&data).SetQueryParams(params).Get("/sns/oauth2/refresh_token")
	if err != nil {
		return nil, errors.Wrap(err, "call /sns/oauth2/refresh_token failed")
	}

	return &data, nil
}

type AuthorizeUserInfo struct {
	City       string   `json:"city"`
	Country    string   `json:"country"`
	Headimgurl string   `json:"headimgurl"`
	Nickname   string   `json:"nickname"`
	Openid     string   `json:"openid"`
	Privilege  []string `json:"privilege"`
	Province   string   `json:"province"`
	Sex        int64    `json:"sex"`
	Unionid    string   `json:"unionid"`
}

func (we *Client) AuthorizeUserInfo(accessToken, openID string) (*AuthorizeUserInfo, error) {
	params := (map[string]string{
		"access_token": accessToken,
		"openid":       openID,
	})

	var data AuthorizeUserInfo
	_, err := we.client.R().SetSuccessResult(&data).SetQueryParams(params).Get("/sns/userinfo")
	if err != nil {
		return nil, errors.Wrap(err, "call /sns/userinfo failed")
	}

	return &data, nil
}