package api

import "time"
import "net/http"

func (api *Client) ExchangeAuth() (*TokenPair, error) {
	result := &OAuthTokenResponse{}
	request := map[string] string {
		"client_id": api.options.ClientId,
		"client_secret": api.options.ClientSecret,
		"grant_type": "authorization_code",
		"code": api.options.AuthCode,
		"redirect_uri": api.options.RedirectURL,
	}

	err := api.doRequest("/oauth2/access_token", RequestOptions{
		Method: http.MethodPost,
		Body: request,
		Headers: makeHeaders(""),
	}, result)
	if err != nil {
		return nil, err
	}

	ret := &TokenPair{
		Access: result.AccessToken,
		Refresh: result.RefreshToken,
	}

	api.options.AccessToken = result.AccessToken
	api.options.RefreshToken = result.RefreshToken
	now := time.Now()
	api.options.ExpirationAt = now.Add(
		time.Second*time.Duration(result.ExpiresIn),
	)
	err = api.writeSecret()
	if err != nil {
		return nil, err
	}
	return ret, nil
}

func (api *Client) RefreshTokenIfExpired() error {
	if api.options.RefreshToken == "" {
		return nil
	}

	now := time.Now()
	if now.After(api.options.ExpirationAt) || now.Equal(api.options.ExpirationAt){
		_, err := api.RefreshToken()
		if err != nil {
			return err
		}
	}
	return nil
}

func (api *Client) RefreshToken() (*OAuthTokenResponse, error) {
	result := new(OAuthTokenResponse)
	request := map[string]string{
		"client_id": api.options.ClientId,
		"client_secret": api.options.ClientSecret,
		"grant_type": "refresh_token",
		"refresh_token": api.options.RefreshToken,
		"redirect_uri": api.options.RedirectURL,
	}

	err := api.doRequest(
		"/oauth2/access_token",
		RequestOptions{
			Method: http.MethodPost,
			Body: request,
			Headers: makeHeaders(""),
		},
		result,
	)
	if err != nil {
		return nil, err
	}

	api.options.AccessToken = result.AccessToken
	api.options.RefreshToken = result.RefreshToken
	now := time.Now()
	api.options.ExpirationAt = now.Add(
		time.Second*time.Duration(result.ExpiresIn),
	)
	err = api.writeSecret()
	if err != nil {
		return nil, err
	}

	return result, nil
}