feat(dashboard): add metering data overview endpoint for user dashboard

eeg_backend/src/main/java/at/mueller/eeg/backend/dashboard/api/DashboardController.java

@@ -4,12 +4,15 @@ import at.mueller.eeg.backend.common.security.CurrentUserId;
 import at.mueller.eeg.backend.dashboard.api.dto.DashboardStatsDto;
 import at.mueller.eeg.backend.dashboard.service.DashboardService;
 import lombok.RequiredArgsConstructor;
+import org.springframework.format.annotation.DateTimeFormat;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.access.prepost.PreAuthorize;
 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.LocalDateTime;
 import java.util.UUID;
 
 @RestController
@@ -30,4 +33,14 @@ public class DashboardController {
     public ResponseEntity<DashboardStatsDto.UserStats> getUserDashboard(@CurrentUserId String userId) {
         return ResponseEntity.ok(dashboardService.getUserStats(UUID.fromString(userId)));
     }
+
+    @GetMapping("/user/metering-data/overview")
+    @PreAuthorize("hasRole('MEMBER')")
+    public ResponseEntity<DashboardStatsDto.MeteringDataOverview> getMeteringDataOverview(
+            @CurrentUserId String userId,
+            @RequestParam @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) LocalDateTime from,
+            @RequestParam @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME) LocalDateTime to) {
+        return ResponseEntity.ok(dashboardService.getMeteringDataOverview(
+                UUID.fromString(userId), from, to));
+    }
 }

eeg_backend/src/main/java/at/mueller/eeg/backend/dashboard/api/dto/DashboardStatsDto.java

@@ -1,5 +1,12 @@
 package at.mueller.eeg.backend.dashboard.api.dto;
 
+import at.mueller.eeg.backend.community.domain.PointType;
+
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+
 public interface DashboardStatsDto {
     record AdminStats(
             long totalCommunities,
@@ -13,4 +20,21 @@ public interface DashboardStatsDto {
             long activeMemberships,
             long pendingMemberships
     ) {}
+
+    record MeteringDataOverview(
+            List<MeteringPointSummary> meteringPoints,
+            List<TimeSeriesEntry> timeSeries
+    ) {}
+
+    record MeteringPointSummary(
+            UUID id,
+            String atNumber,
+            PointType type,
+            double totalKwh
+    ) {}
+
+    record TimeSeriesEntry(
+            LocalDateTime timestamp,
+            Map<String, Double> values
+    ) {}
 }

eeg_backend/src/main/java/at/mueller/eeg/backend/dashboard/service/DashboardService.java

@@ -1,7 +1,10 @@
 package at.mueller.eeg.backend.dashboard.service;
 
+import at.mueller.eeg.backend.community.domain.MeteringData;
+import at.mueller.eeg.backend.community.domain.MeteringPoint;
 import at.mueller.eeg.backend.community.domain.MembershipStatus;
 import at.mueller.eeg.backend.community.repository.EnergyCommunityRepository;
+import at.mueller.eeg.backend.community.repository.MeteringDataRepository;
 import at.mueller.eeg.backend.community.repository.MembershipRepository;
 import at.mueller.eeg.backend.community.repository.MeteringPointRepository;
 import at.mueller.eeg.backend.dashboard.api.dto.DashboardStatsDto;
@@ -11,7 +14,12 @@ import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
-import java.util.UUID;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.LocalTime;
+import java.time.format.DateTimeFormatter;
+import java.util.*;
+import java.util.stream.Collectors;
 
 @Service
 @RequiredArgsConstructor
@@ -22,6 +30,7 @@ public class DashboardService {
     private final UserRepository userRepository;
     private final MembershipRepository membershipRepository;
     private final MeteringPointRepository meteringPointRepository;
+    private final MeteringDataRepository meteringDataRepository;
 
     public DashboardStatsDto.AdminStats getAdminStats() {
         long communities = energyCommunityRepository.count();
@@ -39,4 +48,47 @@ public class DashboardService {
 
         return new DashboardStatsDto.UserStats(meteringPoints, activeMemberships, pendingMemberships);
     }
+
+    public DashboardStatsDto.MeteringDataOverview getMeteringDataOverview(UUID userId, LocalDateTime from, LocalDateTime to) {
+        List<MeteringPoint> meteringPoints = meteringPointRepository.findAllByUserId(userId);
+
+        List<DashboardStatsDto.MeteringPointSummary> summaries = new ArrayList<>();
+        Map<String, Map<LocalDate, Double>> dailyData = new LinkedHashMap<>();
+
+        for (MeteringPoint mp : meteringPoints) {
+            List<MeteringData> data = meteringDataRepository.findByMeteringPointIdAndIntervalStartBetween(mp.getId(), from, to);
+
+            double totalKwh = data.stream().mapToDouble(MeteringData::getKwh).sum();
+            summaries.add(new DashboardStatsDto.MeteringPointSummary(
+                    mp.getId(),
+                    mp.getAtNumber(),
+                    mp.getType(),
+                    totalKwh
+            ));
+
+            for (MeteringData d : data) {
+                LocalDate day = d.getIntervalStart().toLocalDate();
+                dailyData.computeIfAbsent(mp.getAtNumber(), k -> new LinkedHashMap<>())
+                        .merge(day, d.getKwh(), Double::sum);
+            }
+        }
+
+        Set<LocalDate> allDays = dailyData.values().stream()
+                .flatMap(m -> m.keySet().stream())
+                .collect(Collectors.toCollection(TreeSet::new));
+
+        List<DashboardStatsDto.TimeSeriesEntry> timeSeries = allDays.stream()
+                .map(day -> {
+                    Map<String, Double> values = new LinkedHashMap<>();
+                    for (MeteringPoint mp : meteringPoints) {
+                        values.put(mp.getAtNumber(),
+                                dailyData.getOrDefault(mp.getAtNumber(), Collections.emptyMap())
+                                        .getOrDefault(day, 0.0));
+                    }
+                    return new DashboardStatsDto.TimeSeriesEntry(day.atStartOfDay(), values);
+                })
+                .toList();
+
+        return new DashboardStatsDto.MeteringDataOverview(summaries, timeSeries);
+    }
 }