Implement and migrate to NominatimGeocoder

Fixes #159

Sources/D2Commands/CAU/UnivIS/CampusCommand.swift

@@ -20,7 +20,7 @@ public class CampusCommand: StringCommand {
         presented: true,
         requiredPermissionLevel: .basic
     )
-    let geocoder = MapQuestGeocoder()
+    let geocoder = NominatimGeocoder()
 
     public init() {}
 

Sources/D2Commands/Misc/GeocodeCommand.swift

@@ -9,7 +9,7 @@ public class GeocodeCommand: StringCommand {
         requiredPermissionLevel: .basic
     )
     public let outputValueType: RichValueType = .geoCoordinates
-    private let geocoder = MapQuestGeocoder()
+    private let geocoder = NominatimGeocoder()
 
     public init() {}
 

Sources/D2NetAPIs/Nominatim/NominatimGeocoder.swift

@@ -0,0 +1,29 @@
+import Foundation
+import Utils
+
+public struct NominatimGeocoder {
+    public init() {}
+
+    public func geocode(location: String) async throws -> GeoCoordinates {
+        let request = try HTTPRequest(
+            scheme: "https",
+            host: "nominatim.openstreetmap.org",
+            path: "/search",
+            query: [
+                "q": location,
+                "format": "jsonv2",
+            ],
+            headers: [
+                "User-Agent": "D2",
+            ]
+        )
+        let results = try await request.fetchJSON(as: [NominatimGeocodingResult].self)
+        guard let result = results.first else {
+            throw NominatimGeocodingError.noResults
+        }
+        guard let coords = result.geoCoordinates else {
+            throw NominatimGeocodingError.noGeoCoordinates
+        }
+        return coords
+    }
+}

Sources/D2NetAPIs/Nominatim/NominatimGeocodingError.swift

@@ -0,0 +1,4 @@
+public enum NominatimGeocodingError: Error {
+    case noResults
+    case noGeoCoordinates
+}

Sources/D2NetAPIs/Nominatim/NominatimGeocodingResult.swift

@@ -0,0 +1,44 @@
+import Utils
+
+struct NominatimGeocodingResult: Codable {
+    enum CodingKeys: String, CodingKey {
+        case placeId = "place_id"
+        case license
+        case osmType = "osm_type"
+        case osmId = "osm_id"
+        case lat
+        case lon
+        case category
+        case type
+        case placeRank = "place_rank"
+        case importance
+        case addressType = "addresstype"
+        case name
+        case displayName = "display_name"
+        case boundingBox = "boundingbox"
+    }
+
+    var placeId: Int?
+    var license: String?
+    var osmType: String?
+    var osmId: Int?
+    var lat: String?
+    var lon: String?
+    var category: String?
+    var type: String?
+    var placeRank: Int?
+    var importance: Double?
+    var addressType: String?
+    var name: String?
+    var displayName: String?
+    var boundingBox: [String]?
+
+    var geoCoordinates: GeoCoordinates? {
+        guard let lat = lat.flatMap(Double.init),
+              let lon = lon.flatMap(Double.init) else { return nil }
+        return .init(
+            latitude: lat,
+            longitude: lon
+        )
+    }
+}