general cleanup - removed old comments, enforced naming conventions etc

backend/internal/notifications/slack.go

@@ -0,0 +1,128 @@
+package notifications
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/http"
+	"time"
+)
+
+// SlackNotifier sends alert notifications via a Slack webhook.
+type SlackNotifier struct {
+	WebhookURL string
+}
+
+// Send implements Notifier for Slack.
+func (s *SlackNotifier) Send(_ context.Context, message string, meta AlertMetadata) error {
+	_, err := SendSlackNotification(s.WebhookURL, message, meta)
+	return err
+}
+
+const slackHTTPTimeoutSeconds = 10
+
+var slackHTTPClient = &http.Client{ //nolint:gochecknoglobals
+	Timeout: slackHTTPTimeoutSeconds * time.Second,
+}
+
+type slackAttachment struct {
+	Color  string        `json:"color"`
+	Title  string        `json:"title"`
+	Text   string        `json:"text"`
+	Fields []slackField  `json:"fields"`
+	Footer string        `json:"footer"`
+	Ts     int64         `json:"ts"`
+}
+
+type slackField struct {
+	Title string `json:"title"`
+	Value string `json:"value"`
+	Short bool   `json:"short"`
+}
+
+type slackPayload struct {
+	Text        string            `json:"text,omitempty"`
+	Attachments []slackAttachment `json:"attachments,omitempty"`
+}
+
+func SendSlackNotification(webhookURL, message string, meta AlertMetadata) (bool, error) {
+	fields := []slackField{
+		{Title: "Address", Value: meta.AddressLabel, Short: true},
+		{Title: "Blockchain Address", Value: fmt.Sprintf("`%s`", meta.Address), Short: false},
+	}
+
+	if meta.TxHash != "" {
+		fields = append(fields, slackField{
+			Title: "Transaction",
+			Value: fmt.Sprintf("<https://etherscan.io/tx/%s|View on Etherscan>", meta.TxHash),
+			Short: false,
+		})
+	}
+
+	payload := slackPayload{
+		Attachments: []slackAttachment{
+			{
+				Color:  slackColorForAlertType(meta.AlertType),
+				Title:  "Koin Ping Alert",
+				Text:   message,
+				Fields: fields,
+				Footer: "Koin Ping",
+				Ts:     time.Now().Unix(),
+			},
+		},
+	}
+
+	body, err := json.Marshal(payload)
+	if err != nil {
+		return false, fmt.Errorf("marshal slack payload: %w", err)
+	}
+
+	resp, err := slackHTTPClient.Post(webhookURL, "application/json", bytes.NewReader(body))
+	if err != nil {
+		log.Printf("Failed to send Slack notification: %v", err)
+		return false, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		log.Printf("Slack webhook failed: HTTP %d", resp.StatusCode)
+		return false, fmt.Errorf("slack webhook failed: HTTP %d", resp.StatusCode)
+	}
+
+	return true, nil
+}
+
+func TestSlackWebhook(webhookURL string) (bool, error) {
+	payload := slackPayload{
+		Text: "Koin Ping test notification — Your Slack alerts are configured correctly!",
+	}
+
+	body, err := json.Marshal(payload)
+	if err != nil {
+		return false, err
+	}
+
+	resp, err := slackHTTPClient.Post(webhookURL, "application/json", bytes.NewReader(body))
+	if err != nil {
+		log.Printf("Slack webhook test failed: %v", err)
+		return false, err
+	}
+	defer resp.Body.Close()
+
+	return resp.StatusCode >= 200 && resp.StatusCode < 300, nil
+}
+
+func slackColorForAlertType(alertType string) string {
+	switch alertType {
+	case "incoming_tx":
+		return "#00ff00"
+	case "outgoing_tx":
+		return "#ff9900"
+	case "large_transfer", "balance_below":
+		return "#ff0000"
+	default:
+		return "#0099ff"
+	}
+}