optimise station database by stripping unused info

EDDB/API.cs

@@ -1,20 +1,29 @@
 using System;
 using System.IO;
 using System.Net;
+using System.Collections.Generic;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
 
 namespace NonaBGS.EDDB {
     public class API {
         private static readonly string EDDB_SYSTEMS_ARCHIVE = "https://eddb.io/archive/v6/systems_populated.json";
+        private static readonly string EDDB_STATIONS_ARCHIVE = "https://eddb.io/archive/v6/stations.json";
+
         private string cache_folder = null;
-        private readonly WebClient client = new WebClient();
 
         private string systems_file = null;
+        private string stations_file = null;
+        private string stations_file_short = null;
 
         public delegate void DatabaseAvailableDelegate();
 
         public event DatabaseAvailableDelegate SystemsAvailable;
+        public event DatabaseAvailableDelegate StationsAvailable;
 
         public string SystemsFile => systems_file;
+        public string StationsFile => stations_file;
+        public string StationsFileShort => stations_file_short;
 
         public string Cache {
             get => cache_folder;
@@ -28,19 +37,70 @@ namespace NonaBGS.EDDB {
         private void Initialise(string cache_folder) {
             this.cache_folder = cache_folder;
             systems_file = Path.Combine(this.cache_folder, "systems_populated.json");
-            client.DownloadDataCompleted += Client_DownloadDataCompleted;
+            stations_file = Path.Combine(this.cache_folder, "stations.json");
+            stations_file_short = Path.Combine(this.cache_folder, "stations_short.json");
         }
 
         private void DownloadFile(string url, string file, DatabaseAvailableDelegate notifier) {
+            WebClient client = new WebClient();
+            client.DownloadDataCompleted += Client_DownloadDataCompleted;
             client.DownloadFileAsync(new Uri(url), file, notifier);
         }
 
+        private void TranslateStations() {
+            if (!HaveStationsFile) {
+                return;
+            }
+
+            Dictionary<int, List<string>> systems = new Dictionary<int, List<string>>();
+
+            using (var str = new StreamReader(StationsFile)) {
+                using (var reader = new JsonTextReader(str)) {
+                    JArray obj = (JArray)JToken.ReadFrom(reader);
+                    
+
+                    foreach (JObject child in obj.Children<JObject>()) {
+                        int system_id = child.Value<int>("system_id");
+                        string name = child.Value<string>("name");
+
+                        if (!systems.ContainsKey(system_id)) {
+                            systems.Add(system_id, new List<string>());
+                        }
+
+                        systems[system_id].Add(name);
+                    }
+                }
+            }
+
+            JObject short_stations = new JObject();
+
+            foreach(int ids in systems.Keys) {
+                JArray station_names = new JArray();
+                foreach(string system in systems[ids]) {
+                    station_names.Add(system);
+                }
+                short_stations.Add(ids.ToString(), station_names);
+            }
+
+            using (var outstr = new StreamWriter(stations_file_short)) {
+                using (var jwriter = new JsonTextWriter(outstr)) {
+                    short_stations.WriteTo(jwriter);
+                }
+            }
+        }
+
         public void Download(bool force) {
             if (!HaveSystemsFile || force) {
                 DownloadFile(EDDB_SYSTEMS_ARCHIVE, systems_file, SystemsAvailable);
             } else if (HaveSystemsFile) {
                 SystemsAvailable?.Invoke();
             }
+
+            if (!HaveStationsFile || force) {
+                DownloadFile(EDDB_STATIONS_ARCHIVE, stations_file, StationsAvailable);
+            } else if (HaveStationsFile) {
+                StationsAvailable?.Invoke();
+            }
         }
 
         public void Download() {
@@ -51,6 +111,14 @@ namespace NonaBGS.EDDB {
             get { return systems_file != null && File.Exists(systems_file); }
         }
 
+        public bool HaveStationsFile {
+            get { return stations_file != null && File.Exists(stations_file); }
+        }
+
+        public bool HaveStationsFileShort {
+            get { return stations_file_short != null && File.Exists(stations_file_short); }
+        }
+
         public PopulatedSystems MakePopulatedSystems() {
             if (!HaveSystemsFile) {
                 throw new InvalidOperationException("no local systems file downloaded");
@@ -59,6 +127,18 @@ namespace NonaBGS.EDDB {
             return PopulatedSystems.FromFile(SystemsFile);
         }
 
+        public Stations MakeStations() {
+            if (!HaveStationsFile) {
+                throw new InvalidOperationException("no local systems file downloaded");
+            }
+
+            if (!HaveStationsFileShort) {
+                TranslateStations();
+            }
+
+            return Stations.FromFile(StationsFileShort);
+        }
+
         private void Client_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e) {
             DatabaseAvailableDelegate notifier = e.UserState as DatabaseAvailableDelegate;
             notifier?.Invoke();

EDDB/PopulatedSystems.cs

@@ -1,6 +1,6 @@
 using System.IO;
 using System.Linq;
-using System;
+using System.Collections.Generic;
 using System.Globalization;
 using Newtonsoft.Json.Linq;
 
@@ -9,6 +9,7 @@ namespace NonaBGS.EDDB {
         private string json_file = null;
         private JArray root = null;
         private string[] system_names = null;
+        private Dictionary<string, int> to_id;
 
         public static PopulatedSystems FromFile(string file) {
             PopulatedSystems pop = new PopulatedSystems();
@@ -16,10 +17,21 @@ namespace NonaBGS.EDDB {
 
             pop.json_file = file;
             pop.root = JArray.Parse(content);
+            pop.Initialise();
 
             return pop;
         }
 
+        private void Initialise() {
+            MakeSystemNames();
+
+            to_id = root.ToDictionary(x => x.Value<string>("name"), x => x.Value<int>("id"));
+        }
+
+        public int ToId(string name) {
+            return to_id.First(x => string.Compare(x.Key, name, true) == 0).Value;
+        }
+
         private void MakeSystemNames() {
             if (root == null) {
                 throw new InvalidDataException("no JSON loaded");

EDDB/Stations.cs

@@ -0,0 +1,51 @@
+using System.Globalization;
+using System.Collections.Generic;
+using System.Linq;
+using System.IO;
+using Newtonsoft.Json.Linq;
+
+namespace NonaBGS.EDDB {
+    public class Stations {
+        private JObject root = null;
+        private Dictionary<int, List<string>> by_system_id = null;
+
+        public JObject JSON => root;
+
+        private Stations() {
+        }
+
+        private void Initialise() {
+            by_system_id = new Dictionary<int, List<string>>();
+            foreach (var station in root.Properties()) {
+                int id = int.Parse(station.Name);
+                var names = root.Value<JArray>(id.ToString()).Values<string>().ToArray();
+
+                if (!by_system_id.ContainsKey(id)) {
+                    by_system_id[id] = new List<string>();
+                }
+
+                by_system_id[id].AddRange(names);
+            }
+        }
+
+        public static Stations FromFile(string filename) {
+            string alltext = File.ReadAllText(filename);
+            Stations stations = new Stations {
+                root = JObject.Parse(alltext),
+            };
+            stations.Initialise();
+
+            return stations;
+        }
+
+        public string[] StationNamesBySystemId(int systemid, string filter) {
+            if (!by_system_id.ContainsKey(systemid)) {
+                return new string[0];
+            }
+            return by_system_id[systemid]
+                .Where(x => CultureInfo.InvariantCulture.CompareInfo.IndexOf(x, filter, CompareOptions.IgnoreCase) > -1)
+                .ToArray()
+                ;
+        }
+    }
+}