优化目录结构

backend/src/main/java/com/openisle/controller/StatController.java

@@ -0,0 +1,41 @@
+package com.openisle.controller;
+
+import com.openisle.service.UserVisitService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.format.annotation.DateTimeFormat;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.time.LocalDate;
+import java.util.List;
+import java.util.Map;
+
+@RestController
+@RequestMapping("/api/stats")
+@RequiredArgsConstructor
+public class StatController {
+    private final UserVisitService userVisitService;
+
+    @GetMapping("/dau")
+    public Map<String, Long> dau(@RequestParam(value = "date", required = false)
+                                 @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate date) {
+        long count = userVisitService.countDau(date);
+        return Map.of("dau", count);
+    }
+
+    @GetMapping("/dau-range")
+    public List<Map<String, Object>> dauRange(@RequestParam(value = "days", defaultValue = "30") int days) {
+        if (days < 1) days = 1;
+        LocalDate end = LocalDate.now();
+        LocalDate start = end.minusDays(days - 1L);
+        var data = userVisitService.countDauRange(start, end);
+        return data.entrySet().stream()
+                .map(e -> Map.<String,Object>of(
+                        "date",  e.getKey().toString(),
+                        "value", e.getValue()
+                ))
+                .toList();
+    }
+}