feat: Add metrics API with request and response DTOs for revenue, orders, and user statistics

Author: gustaavik

src/main/java/com/zenfulcode/commercify/api/system/MetricsController.java

@@ -0,0 +1,61 @@
+package com.zenfulcode.commercify.api.system;
+
+import com.zenfulcode.commercify.api.system.dto.MetricsRequest;
+import com.zenfulcode.commercify.api.system.dto.MetricsResponse;
+import com.zenfulcode.commercify.metrics.application.MetricsApplicationService;
+import com.zenfulcode.commercify.metrics.application.dto.MetricsQuery;
+import com.zenfulcode.commercify.shared.interfaces.ApiResponse;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.format.annotation.DateTimeFormat;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.validation.annotation.Validated;
+import org.springframework.web.bind.annotation.*;
+
+import java.time.LocalDate;
+
+@Slf4j
+@RestController
+@RequestMapping("/api/v2/metrics")
+@RequiredArgsConstructor
+public class MetricsController {
+
+    private final MetricsApplicationService metricsService;
+
+    @GetMapping
+    @PreAuthorize("hasRole('ADMIN')")
+    public ResponseEntity<ApiResponse<MetricsResponse>> getMetrics(
+            @RequestParam(required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate startDate,
+            @RequestParam(required = false) @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate endDate,
+            @RequestParam(required = false) Integer lastDays) {
+
+        log.info("Getting metrics");
+
+        MetricsRequest request = new MetricsRequest(startDate, endDate, lastDays);
+
+        // Handle either date range or "last X days"
+        if (lastDays != null) {
+            request.setLastDays(lastDays);
+        } else {
+            request.setStartDate(startDate);
+            request.setEndDate(endDate);
+        }
+
+        final MetricsQuery metricsQuery = MetricsQuery.of(request);
+
+        MetricsResponse metrics = metricsService.getMetrics(metricsQuery);
+        return ResponseEntity.ok(ApiResponse.success(metrics));
+    }
+
+    @PostMapping
+    @PreAuthorize("hasRole('ADMIN')")
+    public ResponseEntity<ApiResponse<MetricsResponse>> getMetricsWithFilters(
+            @Validated @RequestBody MetricsRequest request) {
+
+        final MetricsQuery metricsQuery = MetricsQuery.of(request);
+
+        MetricsResponse metrics = metricsService.getMetrics(metricsQuery);
+        return ResponseEntity.ok(ApiResponse.success(metrics));
+    }
+}

src/main/java/com/zenfulcode/commercify/api/system/dto/MetricsRequest.java

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+package com.zenfulcode.commercify.api.system.dto;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import jakarta.validation.constraints.Min;
+import lombok.Data;
+import org.springframework.format.annotation.DateTimeFormat;
+
+import java.time.LocalDate;
+
+@Data
+public class MetricsRequest {
+    private LocalDate startDate;
+    private LocalDate endDate;
+
+    @Min(1)
+    private Integer lastDays;
+
+    public MetricsRequest(@DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate startDate,
+                          @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate endDate,
+                          Integer lastDays) {
+        this.startDate = startDate;
+        this.endDate = endDate;
+        this.lastDays = lastDays;
+    }
+
+    // Optional filters
+    private String productCategory;
+    private String region;
+
+    @JsonIgnore
+    public LocalDate getEffectiveStartDate() {
+        if (lastDays != null) {
+            return LocalDate.now().minusDays(lastDays);
+        }
+        return startDate != null ? startDate : LocalDate.now().minusDays(30); // Default 30 days
+    }
+
+    @JsonIgnore
+    public LocalDate getEffectiveEndDate() {
+        return endDate != null ? endDate : LocalDate.now();
+    }
+}

src/main/java/com/zenfulcode/commercify/api/system/dto/MetricsResponse.java

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+package com.zenfulcode.commercify.api.system.dto;
+
+import com.fasterxml.jackson.annotation.JsonFormat;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import java.math.BigDecimal;
+import java.time.LocalDate;
+
+@Data
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+public class MetricsResponse {
+    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd")
+    private LocalDate startDate;
+
+    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd")
+    private LocalDate endDate;
+
+    private BigDecimal totalRevenue;
+    private int totalOrders;
+    private int newProductsAdded;
+    private int activeUsers;
+
+    // Optional: include trend data
+    private BigDecimal revenueChangePercent;
+    private int orderChangePercent;
+}