Wrote most of the client functions

Sources/AmtrakStatus/AmtrakClient.swift

@@ -14,6 +14,36 @@ struct AmtrakClient {
     let trainsBaseURL =  "https://api.amtraker.com/v3/trains"
     let staleBaseURL = "https://api.amtraker.com/v3/stale"
     
+    func fetchTrain(number trainid: String) async throws -> TrainResponse {
+        try await get("\(trainsBaseURL)/\(trainid)")
+    }
+    
+    func fetchAllTrains() async throws -> TrainResponse {
+        try await get(trainsBaseURL)
+    }
+    
+    func fetchStation(code stationid: String) async throws -> StationResponse {
+        try await get("\(stationBaseURL)/\(stationid)")
+    }
+    
+    func fetchAllStations() async throws -> StationResponse {
+        try await get(stationBaseURL)
+    }
+    
+    func trainNumber(fromTrainId trainId: String) -> String {
+        trainId.split(separator: "-").first.map(String.init) ?? trainId
+    }
+    
+    func fetchStationTrainNumbers(stationCode code: String) async throws -> [String] {
+        let reponse = try await fetchStation(code: code)
+        
+        guard let meta = reponse[code] else {
+            throw AmtrakError.stationNotFound(code)
+        }
+        
+        return Array(Set(meta.trains.map(trainNumber(fromTrainId:))))
+    }
+    
     func get<T: Decodable>(_ urlString: String) async throws -> T {
         
         guard let url = URL(string: urlString) else {