feat: Add analytics handler with dashboard, revenue analytics, and scheduled report endpoints

- Add AnalyticsHandler struct with service and logger dependencies and NewAnalyticsHandler constructor
- Add GetDashboard method with tenant ID extraction, date range filtering, and dashboard metrics retrieval
- Add GetRevenueAnalytics method with tenant filtering and group-by support
- Add CreateScheduledReport and ListScheduledReports methods for report management
- Add date parsing for start_date and end_date query

apps/carrier-connector/internal/handlers/analytics_handlers.go

@@ -0,0 +1,103 @@
+package handlers
+
+import (
+	"net/http"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/nutcas3/telecom-platform/apps/carrier-connector/internal/analytics"
+	"github.com/sirupsen/logrus"
+)
+
+// AnalyticsHandler handles analytics API requests
+type AnalyticsHandler struct {
+	service *analytics.Service
+	logger  *logrus.Logger
+}
+
+// NewAnalyticsHandler creates a new analytics handler
+func NewAnalyticsHandler(service *analytics.Service, logger *logrus.Logger) *AnalyticsHandler {
+	return &AnalyticsHandler{service: service, logger: logger}
+}
+
+// GetDashboard returns the main analytics dashboard
+func (h *AnalyticsHandler) GetDashboard(c *gin.Context) {
+	tenantID := c.GetHeader("X-Tenant-ID")
+	if tenantID == "" {
+		tenantID = c.Query("tenant_id")
+	}
+
+	filter := &analytics.AnalyticsFilter{
+		TenantID:  tenantID,
+		StartDate: time.Now().AddDate(0, -1, 0),
+		EndDate:   time.Now(),
+	}
+
+	if start := c.Query("start_date"); start != "" {
+		if t, err := time.Parse("2006-01-02", start); err == nil {
+			filter.StartDate = t
+		}
+	}
+	if end := c.Query("end_date"); end != "" {
+		if t, err := time.Parse("2006-01-02", end); err == nil {
+			filter.EndDate = t
+		}
+	}
+
+	dashboard, err := h.service.GetDashboard(c.Request.Context(), filter)
+	if err != nil {
+		h.logger.WithError(err).Error("Failed to get dashboard")
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, dashboard)
+}
+
+// GetRevenueAnalytics returns detailed revenue analytics
+func (h *AnalyticsHandler) GetRevenueAnalytics(c *gin.Context) {
+	tenantID := c.GetHeader("X-Tenant-ID")
+	filter := &analytics.AnalyticsFilter{
+		TenantID:  tenantID,
+		StartDate: time.Now().AddDate(0, -1, 0),
+		EndDate:   time.Now(),
+		GroupBy:   c.Query("group_by"),
+	}
+
+	revenue, err := h.service.GetRevenueAnalytics(c.Request.Context(), filter)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, revenue)
+}
+
+// CreateScheduledReport creates a scheduled report
+func (h *AnalyticsHandler) CreateScheduledReport(c *gin.Context) {
+	var report analytics.ScheduledReport
+	if err := c.ShouldBindJSON(&report); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	report.TenantID = c.GetHeader("X-Tenant-ID")
+	if err := h.service.CreateScheduledReport(c.Request.Context(), &report); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusCreated, report)
+}
+
+// ListScheduledReports lists scheduled reports
+func (h *AnalyticsHandler) ListScheduledReports(c *gin.Context) {
+	tenantID := c.GetHeader("X-Tenant-ID")
+	reports, err := h.service.ListScheduledReports(c.Request.Context(), tenantID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, reports)
+}