完成门店管理后端接口与任务

src/Infrastructure/TakeoutSaaS.Infrastructure/App/Services/DeliveryZoneService.cs

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+using System.Text.Json;
+using TakeoutSaaS.Application.App.Stores.Dto;
+using TakeoutSaaS.Application.App.Stores.Services;
+using TakeoutSaaS.Domain.Stores.Entities;
+
+namespace TakeoutSaaS.Infrastructure.App.Services;
+
+/// <summary>
+/// 配送范围检测服务实现。
+/// </summary>
+public sealed class DeliveryZoneService : IDeliveryZoneService
+{
+    /// <inheritdoc />
+    public StoreDeliveryCheckResultDto CheckPointInZones(
+        IReadOnlyList<StoreDeliveryZone> zones,
+        double longitude,
+        double latitude)
+    {
+        // 1. 无配送区域直接返回
+        if (zones is null || zones.Count == 0)
+        {
+            return new StoreDeliveryCheckResultDto { InRange = false };
+        }
+        // 2. (空行后) 逐个检测多边形命中
+        foreach (var zone in zones)
+        {
+            if (!TryReadPolygon(zone.PolygonGeoJson, out var polygon))
+            {
+                continue;
+            }
+            if (IsPointInPolygon(polygon, longitude, latitude))
+            {
+                return new StoreDeliveryCheckResultDto
+                {
+                    InRange = true,
+                    DeliveryZoneId = zone.Id,
+                    DeliveryZoneName = zone.ZoneName
+                };
+            }
+        }
+        // 3. (空行后) 未命中任何区域
+        return new StoreDeliveryCheckResultDto { InRange = false };
+    }
+
+    private static bool TryReadPolygon(string geoJson, out List<Point> polygon)
+    {
+        polygon = [];
+        if (string.IsNullOrWhiteSpace(geoJson))
+        {
+            return false;
+        }
+        try
+        {
+            using var document = JsonDocument.Parse(geoJson);
+            var root = document.RootElement;
+            if (root.ValueKind != JsonValueKind.Object)
+            {
+                return false;
+            }
+            if (!root.TryGetProperty("coordinates", out var coordinatesElement) || coordinatesElement.ValueKind != JsonValueKind.Array)
+            {
+                return false;
+            }
+            if (coordinatesElement.GetArrayLength() == 0)
+            {
+                return false;
+            }
+            var ringElement = coordinatesElement[0];
+            if (ringElement.ValueKind != JsonValueKind.Array)
+            {
+                return false;
+            }
+            foreach (var pointElement in ringElement.EnumerateArray())
+            {
+                if (pointElement.ValueKind != JsonValueKind.Array || pointElement.GetArrayLength() < 2)
+                {
+                    return false;
+                }
+                if (!pointElement[0].TryGetDouble(out var x) || !pointElement[1].TryGetDouble(out var y))
+                {
+                    return false;
+                }
+                polygon.Add(new Point(x, y));
+            }
+            if (polygon.Count >= 2 && AreSamePoint(polygon[0], polygon[^1]))
+            {
+                polygon.RemoveAt(polygon.Count - 1);
+            }
+            return polygon.Count >= 3;
+        }
+        catch (JsonException)
+        {
+            return false;
+        }
+    }
+
+    private static bool IsPointInPolygon(IReadOnlyList<Point> polygon, double x, double y)
+    {
+        var inside = false;
+        for (var i = 0; i < polygon.Count; i++)
+        {
+            var j = i == 0 ? polygon.Count - 1 : i - 1;
+            var xi = polygon[i].Longitude;
+            var yi = polygon[i].Latitude;
+            var xj = polygon[j].Longitude;
+            var yj = polygon[j].Latitude;
+            var intersect = ((yi > y) != (yj > y)) && (x < (xj - xi) * (y - yi) / (yj - yi + double.Epsilon) + xi);
+            if (intersect)
+            {
+                inside = !inside;
+            }
+        }
+        return inside;
+    }
+
+    private static bool AreSamePoint(Point first, Point second)
+        => Math.Abs(first.Longitude - second.Longitude) <= 1e-6
+           && Math.Abs(first.Latitude - second.Latitude) <= 1e-6;
+
+    private readonly record struct Point(double Longitude, double Latitude);
+}