feat: add SendCloud.net SMS Sender (#43)

* feat:add SendCloud SMS Sender

* feat:add SendCloud SMS Sender

sendcloud.go

@@ -0,0 +1,191 @@
+package go_sms_sender
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// ResponseData structure holds the response from SendCloud API.
+type ResponseData struct {
+	Result     bool   `json:"result"`
+	StatusCode int    `json:"statusCode"`
+	Message    string `json:"message"`
+	Info       string `json:"info"`
+}
+
+// Config holds the configuration for the SMS sending service.
+type Config struct {
+	CharSet      string
+	Server       string
+	SendSMSAPI   string
+	SmsUser      string
+	SmsKey       string
+	MaxReceivers int
+}
+
+// NewConfig creates a new configuration with the provided user and key.
+func NewConfig(smsUser, smsKey string) (*Config, error) {
+	if smsUser == "" {
+		return nil, errors.New("smsUser cannot be empty")
+	}
+	if smsKey == "" {
+		return nil, errors.New("smsKey cannot be empty")
+	}
+
+	return &Config{
+		CharSet:      "utf-8",
+		Server:       "https://api.sendcloud.net",
+		SendSMSAPI:   "/smsapi/send",
+		MaxReceivers: 100,
+		SmsUser:      smsUser,
+		SmsKey:       smsKey,
+	}, nil
+}
+
+// SendCloudSms represents the data required to send an SMS message.
+type SendCloudSms struct {
+	TemplateId int
+	MsgType    int
+	Phone      []string
+	Vars       map[string]string
+}
+
+// NewSendCloudSms creates a new SendCloudSms instance with the provided parameters.
+func NewSendCloudSms(templateId, msgType int, phone []string, vars map[string]string) (*SendCloudSms, error) {
+	if templateId <= 0 {
+		return nil, errors.New("templateId must be greater than zero")
+	}
+	if msgType < 0 {
+		return nil, errors.New("msgType cannot be negative")
+	}
+	if len(phone) == 0 {
+		return nil, errors.New("phone cannot be empty")
+	}
+	return &SendCloudSms{
+		TemplateId: templateId,
+		MsgType:    msgType,
+		Phone:      phone,
+		Vars:       vars,
+	}, nil
+}
+
+// SendMessage sends an SMS using SendCloud API.
+func SendMessage(sms SendCloudSms, config Config) error {
+	if err := validateSendCloudSms(sms); err != nil {
+		return fmt.Errorf("failed to send message: %w", err)
+	}
+	if err := validateConfig(config); err != nil {
+		return fmt.Errorf("failed to send message: %w", err)
+	}
+
+	params, err := prepareParams(sms, config)
+	if err != nil {
+		return fmt.Errorf("failed to send message: %w", err)
+	}
+
+	signature := calculateSignature(params, config.SmsKey)
+	params.Set("signature", signature)
+
+	resp, err := http.PostForm(config.SendSMSAPI, params)
+	if err != nil {
+		return fmt.Errorf("failed to send HTTP POST request: %w", err)
+	}
+	defer func() {
+		err := resp.Body.Close()
+		if err != nil {
+			fmt.Println(err)
+			return
+		}
+	}()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("HTTP POST request failed with status code %d", resp.StatusCode)
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return fmt.Errorf("failed to read response body: %w", err)
+	}
+
+	var responseData ResponseData
+	if err := json.Unmarshal(body, &responseData); err != nil {
+		return fmt.Errorf("failed to unmarshal response body: %w", err)
+	}
+
+	if !responseData.Result {
+		return fmt.Errorf("SMS sending failed: %s", responseData.Message)
+	}
+
+	return nil
+}
+
+// prepareParams prepares parameters for sending SMS.
+func prepareParams(sms SendCloudSms, config Config) (url.Values, error) {
+	params := url.Values{}
+	params.Set("smsUser", config.SmsUser)
+	params.Set("msgType", strconv.Itoa(sms.MsgType))
+	params.Set("phone", strings.Join(sms.Phone, ","))
+	params.Set("templateId", strconv.Itoa(sms.TemplateId))
+	params.Set("timestamp", strconv.FormatInt(time.Now().UnixNano()/int64(time.Millisecond), 10))
+
+	if len(sms.Vars) > 0 {
+		varsJSON, err := json.Marshal(sms.Vars)
+		if err != nil {
+			return nil, fmt.Errorf("failed to marshal vars: %v", err)
+		}
+		params.Set("vars", string(varsJSON))
+	}
+
+	return params, nil
+}
+
+// validateConfig validates the SMS sending configuration.
+func validateConfig(config Config) error {
+	switch {
+	case config.CharSet == "":
+		return errors.New("charSet cannot be empty")
+	case config.Server == "":
+		return errors.New("server cannot be empty")
+	case config.SendSMSAPI == "":
+		return errors.New("sendSMSAPI cannot be empty")
+	case config.SmsUser == "":
+		return errors.New("smsUser cannot be empty")
+	case config.SmsKey == "":
+		return errors.New("smsKey cannot be empty")
+	case config.MaxReceivers <= 0:
+		return errors.New("maxReceivers must be greater than zero")
+	}
+
+	return nil
+}
+
+// validateSendCloudSms validates the SendCloudSms data.
+func validateSendCloudSms(sms SendCloudSms) error {
+	switch {
+	case sms.TemplateId == 0:
+		return errors.New("templateId cannot be zero")
+	case sms.MsgType < 0:
+		return errors.New("msgType cannot be negative")
+	case len(sms.Phone) == 0:
+		return errors.New("phone cannot be empty")
+	}
+	return nil
+}
+
+// calculateSignature calculates the signature for the request.
+func calculateSignature(params url.Values, key string) string {
+	sortedParams := params.Encode()
+	signStr := sortedParams + "&key=" + key
+	hasher := sha256.New()
+	hasher.Write([]byte(signStr))
+	return hex.EncodeToString(hasher.Sum(nil))
+}