NdoleStudio / smobilpay-go

package smobilpay

import (

	"bytes"

	"context"

	"crypto/hmac"

	"crypto/sha1"

	"encoding/base64"

	"encoding/json"

	"fmt"

	"io"

	"io/ioutil"

	"net/http"

	"net/url"

	"sort"

	"strings"

)

type service struct {

	client *Client

}

// Client is the smobilpay API client.

// Do not instantiate this client with Client{}. Use the New method instead.

type Client struct {

	httpClient   *http.Client

	common       service

	baseURL      string

	accessToken  string

	accessSecret string

	Topup *topupService

}

// New creates and returns a new *Client from a slice of Option.

func New(options ...Option) *Client {

	config := defaultClientConfig()

	for _, option := range options {

		option.apply(config)

	}

	client := &Client{

		httpClient:   config.httpClient,

		accessToken:  config.accessToken,

		accessSecret: config.accessSecret,

		baseURL:      config.baseURL,

	}

	client.common.client = client

	client.Topup = (*topupService)(&client.common)

	return client

}

// Ping checks if the API is available

//

// https://apidocs.smobilpay.com/s3papi/API-Reference.2066448558.html

func (client *Client) Ping(ctx context.Context, options ...RequestOption) (*PingStatus, *Response, error) {

	request, err := client.newRequest(ctx, options, http.MethodGet, "/ping", nil)

	if err != nil {

		return nil, nil, err

	}

	response, err := client.do(request)

	if err != nil {

		return nil, response, err

	}

	status := new(PingStatus)

	if err = json.Unmarshal(*response.Body, status); err != nil {

		return nil, response, err

	}

	return status, response, nil

}

func (client *Client) makeRequestConfig(options []RequestOption) *requestConfig {

	config := defaultRequestConfig()

	for _, option := range options {

		option.apply(config)

	}

	return config

}

// newRequest creates an API request. A relative URL can be provided in uri,

// in which case it is resolved relative to the BaseURL of the Client.

// URI's should always be specified without a preceding slash.

func (client *Client) newRequest(ctx context.Context, options []RequestOption, method, uri string, body map[string]string) (*http.Request, error) {

	config := client.makeRequestConfig(options)

	var buf io.ReadWriter

	if body != nil {

		buf = &bytes.Buffer{}

		enc := json.NewEncoder(buf)

		enc.SetEscapeHTML(false)

		err := enc.Encode(body)

		if err != nil {

			return nil, err

		}

	}

	req, err := http.NewRequestWithContext(ctx, method, client.baseURL+uri, buf)

	if err != nil {

		return nil, err

	}

	req.Header.Set("Content-Type", "application/json")

	req.Header.Set("Accept", "application/json")

	req.Header.Set("Authorization", client.getAuthHeader(req, config, client.authPayload(req, body)))

	return req, nil

}

func (client *Client) authPayload(request *http.Request, body map[string]string) map[string]string {

	payload := map[string]string{}

	for key, value := range request.URL.Query() {

		payload[key] = value[0]

	}

	for key, value := range body {

		payload[key] = value

	}

	return payload

}

func (client *Client) getBaseHmacAuthString(request *http.Request) string {

	return fmt.Sprintf(

		"%s&%s",

		strings.ToUpper(request.Method),

		url.QueryEscape(

			fmt.Sprintf("%s://%s%s", request.URL.Scheme, request.URL.Host, request.URL.Path),

		),

	)

}

func (client *Client) getPayloadHmacAuthString(config *requestConfig, payload map[string]string) string {

	params := url.Values{}

	params.Add("s3pAuth_nonce", config.nonce)

	params.Add("s3pAuth_signature_method", "HMAC-SHA1")

	params.Add("s3pAuth_timestamp", config.timestampString())

	params.Add("s3pAuth_token", client.accessToken)

	for key, value := range payload {

		params.Add(key, strings.TrimSpace(value))

	}

	keys := make([]string, 0, len(params))

	for k := range params {

		keys = append(keys, k)

	}

	sort.Strings(keys)

	var buf strings.Builder

	for _, k := range keys {

		if buf.Len() > 0 {

			buf.WriteByte('&')

		}

		buf.WriteString(k)

		buf.WriteByte('=')

		buf.WriteString(params[k][0])

	}

	return buf.String()

}

func (client *Client) getAuthHeader(request *http.Request, config *requestConfig, payload map[string]string) string {

	return fmt.Sprintf(

		"s3pAuth,s3pAuth_nonce=\"%s\",s3pAuth_signature=\"%s\",s3pAuth_signature_method=\"HMAC-SHA1\",s3pAuth_timestamp=\"%s\",s3pAuth_token=\"%s\"",

		config.nonce,

		client.computeHmac(client.getBaseHmacAuthString(request)+"&"+url.QueryEscape(client.getPayloadHmacAuthString(config, payload))),

		config.timestampString(),

		client.accessToken,

	)

}

func (client *Client) computeHmac(message string) string {

	key := []byte(client.accessSecret)

	h := hmac.New(sha1.New, key)

	_, _ = h.Write([]byte(message))

	return base64.StdEncoding.EncodeToString(h.Sum(nil))

}

// do carries out an HTTP request and returns a Response

func (client *Client) do(req *http.Request) (*Response, error) {

	if req == nil {

		return nil, fmt.Errorf("%T cannot be nil", req)

	}

	httpResponse, err := client.httpClient.Do(req)

	if err != nil {

		return nil, err

	}

	defer func() { _ = httpResponse.Body.Close() }()

	resp, err := client.newResponse(httpResponse)

	if err != nil {

		return resp, err

	}

	_, err = io.Copy(ioutil.Discard, httpResponse.Body)

	if err != nil {

		return resp, err

	}

	return resp, nil

}

// newResponse converts an *http.Response to *Response

func (client *Client) newResponse(httpResponse *http.Response) (*Response, error) {

	if httpResponse == nil {

		return nil, fmt.Errorf("%T cannot be nil", httpResponse)

	}

	resp := new(Response)

	resp.HTTPResponse = httpResponse

	buf, err := ioutil.ReadAll(resp.HTTPResponse.Body)

	if err != nil {

		return nil, err

	}

	resp.Body = &buf

	return resp, resp.Error()

}