Implement fetching scheduled arrivals for stop

1 files changed, 194 insertions, 0 deletions

diff --git a/src/Costasdev.Busurbano.Backend/Controllers/TileController.cs b/src/Costasdev.Busurbano.Backend/Controllers/TileController.cs
new file mode 100644
index 0000000..fad18e7
--- /dev/null
+++ b/src/Costasdev.Busurbano.Backend/Controllers/TileController.cs
@@ -0,0 +1,194 @@
+using Costasdev.Busurbano.Backend.GraphClient;
+using Costasdev.Busurbano.Backend.GraphClient.App;
+
+using NetTopologySuite.Features;
+using NetTopologySuite.IO.VectorTiles;
+using NetTopologySuite.IO.VectorTiles.Mapbox;
+
+using Microsoft.AspNetCore.Mvc;
+
+using Microsoft.Extensions.Caching.Memory;
+using System.Text.Json;
+using Costasdev.Busurbano.Backend.Helpers;
+
+namespace Costasdev.Busurbano.Backend.Controllers;
+
+[ApiController]
+[Route("api/tiles")]
+public class TileController : ControllerBase
+{
+    private readonly ILogger<TileController> _logger;
+    private readonly IMemoryCache _cache;
+    private readonly HttpClient _httpClient;
+
+    public TileController(
+        ILogger<TileController> logger,
+        IMemoryCache cache,
+        HttpClient httpClient
+    )
+    {
+        _logger = logger;
+        _cache = cache;
+        _httpClient = httpClient;
+    }
+
+    private static readonly string[] HiddenStops =
+    [
+        "vitrasa:20223", // Castrelos (Pavillón - U1)
+        "vitrasa:20146", // García Barbón, 7 (A, 18A)
+        "vitrasa:20220", // COIA-SAMIL (15)
+        "vitrasa:20001", // Samil por Beiramar (15B)
+        "vitrasa:20002", // Samil por Torrecedeira (15C)
+        "vitrasa:20144", // Samil por Coia (C3d, C3i)
+        "vitrasa:20145"  // Samil por Bouzs (C3d, C3i)
+    ];
+
+    [HttpGet("stops/{z:int}/{x:int}/{y:int}")]
+    public async Task<IActionResult> Stops(int z, int x, int y)
+    {
+        if (z < 9 || z > 16)
+        {
+            return BadRequest("Zoom level out of range (9-16)");
+        }
+
+        var cacheHit = _cache.TryGetValue($"stops-tile-{z}-{x}-{y}", out byte[]? cachedTile);
+        if (cacheHit && cachedTile != null)
+        {
+            Response.Headers.Append("X-Cache-Hit", "true");
+            return File(cachedTile, "application/x-protobuf");
+        }
+
+        // Calculate bounding box in EPSG:4326
+        var n = Math.Pow(2, z);
+        var lonMin = x / n * 360.0 - 180.0;
+        var lonMax = (x + 1) / n * 360.0 - 180.0;
+
+        var latMaxRad = Math.Atan(Math.Sinh(Math.PI * (1 - 2 * y / n)));
+        var latMax = latMaxRad * 180.0 / Math.PI;
+
+        var latMinRad = Math.Atan(Math.Sinh(Math.PI * (1 - 2 * (y + 1) / n)));
+        var latMin = latMinRad * 180.0 / Math.PI;
+
+        var requestContent = StopTileRequestContent.Query(new StopTileRequestContent.Bbox(lonMin, latMin, lonMax, latMax));
+        var request = new HttpRequestMessage(HttpMethod.Post, "http://100.67.54.115:3957/otp/gtfs/v1");
+        request.Content = JsonContent.Create(new GraphClientRequest
+        {
+            Query = requestContent
+        });
+
+        var response = await _httpClient.SendAsync(request);
+        var responseBody = await response.Content.ReadFromJsonAsync<GraphClientResponse<StopTileResponse>>();
+
+        if (responseBody is not { IsSuccess: true })
+        {
+            _logger.LogError(
+                "Error fetching stop data, received {StatusCode} {ResponseBody}",
+                response.StatusCode,
+                await response.Content.ReadAsStringAsync()
+            );
+            return StatusCode(500, "Error fetching stop data");
+        }
+
+        var tileDef = new NetTopologySuite.IO.VectorTiles.Tiles.Tile(x, y, z);
+        VectorTile vt = new() { TileId = tileDef.Id };
+        var lyr = new Layer { Name = "stops" };
+
+        responseBody.Data?.StopsByBbox?.ForEach(stop =>
+        {
+            var idParts = stop.GtfsId.Split(':', 2);
+            string codeWithinFeed = stop.Code ?? string.Empty;
+
+            // TODO: Refactor this, maybe do it client-side or smth
+            if (idParts[0] == "vitrasa")
+            {
+                var digits = new string(codeWithinFeed.Where(char.IsDigit).ToArray());
+                if (int.TryParse(digits, out int code))
+                {
+                    codeWithinFeed = code.ToString();
+                }
+            }
+
+            if (HiddenStops.Contains($"{idParts[0]}:{codeWithinFeed}"))
+            {
+                return;
+            }
+
+            var fallbackColours = GetFallbackColourForFeed(idParts[0]);
+
+            Feature feature = new()
+            {
+                Geometry = new NetTopologySuite.Geometries.Point(stop.Lon, stop.Lat),
+                Attributes = new AttributesTable
+                {
+                    // The ID will be used to request the arrivals
+                    { "id", stop.GtfsId },
+                    // The feed is the first part of the GTFS ID, corresponding to the feed where the info comes from, used for icons probably
+                    { "feed", idParts[0] },
+                    // The public identifier, usually feed:code or feed:id, recognisable by users and in other systems
+                    { "code", $"{idParts[0]}:{codeWithinFeed}" },
+                    // The name of the stop
+                    { "name", stop.Name },
+                    // Routes
+                    { "routes", JsonSerializer.Serialize(stop.Routes?
+                    .DistinctBy(r => r.ShortName)
+                    .OrderBy(
+                        r => r.ShortName,
+                        Comparer<string?>.Create(SortingHelper.SortRouteShortNames)
+                    ).Select(r => {
+                        var colour = r.Color ?? fallbackColours.Color;
+                        string textColour;
+
+                        if (r.Color is null) // None is present, use fallback
+                        {
+                            textColour = fallbackColours.TextColor;
+                        }
+                        else if (r.TextColor is null || r.TextColor.EndsWith("000000"))
+                        {
+                            // Text colour not provided, or default-black; check the better contrasting
+                            textColour = ContrastHelper.GetBestTextColour(colour);
+                        }
+                        else
+                        {
+                            // Use provided text colour
+                            textColour = r.TextColor;
+                        }
+
+                        return new {
+                            shortName = r.ShortName,
+                            colour,
+                            textColour
+                        };
+                    })) }
+                }
+            };
+
+            lyr.Features.Add(feature);
+        });
+
+        vt.Layers.Add(lyr);
+
+        using var ms = new MemoryStream();
+        vt.Write(ms, minLinealExtent: 1, minPolygonalExtent: 2);
+
+        _cache.Set($"stops-tile-{z}-{x}-{y}", ms.ToArray(), TimeSpan.FromMinutes(15));
+        Response.Headers.Append("X-Cache-Hit", "false");
+
+        return File(ms.ToArray(), "application/x-protobuf");
+    }
+
+    private static (string Color, string TextColor) GetFallbackColourForFeed(string feed)
+    {
+        return feed switch
+        {
+            "vitrasa" => ("#95D516", "#000000"),
+            "santiago" => ("#508096", "#FFFFFF"),
+            "coruna" => ("#E61C29", "#FFFFFF"),
+            "xunta" => ("#007BC4", "#FFFFFF"),
+            "renfe" => ("#870164", "#FFFFFF"),
+            "feve" => ("#EE3D32", "#FFFFFF"),
+            _ => ("#000000", "#FFFFFF"),
+
+        };
+    }
+
+}