promiscuity/microservices/LocationsApi/Services/LocationStore.cs

using LocationsApi.Models;
using MongoDB.Bson;
using MongoDB.Driver;

namespace LocationsApi.Services;

public class LocationStore
{
    private readonly IMongoCollection<Location> _col;

    public LocationStore(IConfiguration cfg)
    {
        var cs = cfg["MongoDB:ConnectionString"] ?? "mongodb://127.0.0.1:27017";
        var dbName = cfg["MongoDB:DatabaseName"] ?? "GameDb";
        var client = new MongoClient(cs);
        var db = client.GetDatabase(dbName);
        var collectionName = "Locations";
        EnsureLocationSchema(db, collectionName);
        _col = db.GetCollection<Location>(collectionName);

        var coordIndex = Builders<Location>.IndexKeys
            .Ascending(l => l.Coord.X)
            .Ascending(l => l.Coord.Y);
        var coordIndexOptions = new CreateIndexOptions { Unique = true };
        _col.Indexes.CreateOne(new CreateIndexModel<Location>(coordIndex, coordIndexOptions));

        EnsureOriginLocation();
    }

    private static void EnsureLocationSchema(IMongoDatabase db, string collectionName)
    {
        var validator = new BsonDocument
        {
            {
                "$jsonSchema", new BsonDocument
                {
                    { "bsonType", "object" },
                    { "required", new BsonArray { "name", "coord", "createdUtc" } },
                    {
                        "properties", new BsonDocument
                        {
                            { "name", new BsonDocument { { "bsonType", "string" } } },
                            {
                                "coord", new BsonDocument
                                {
                                    { "bsonType", "object" },
                                    { "required", new BsonArray { "x", "y" } },
                                    {
                                        "properties", new BsonDocument
                                        {
                                            { "x", new BsonDocument { { "bsonType", "int" } } },
                                            { "y", new BsonDocument { { "bsonType", "int" } } }
                                        }
                                    }
                                }
                            },
                            {
                                "characterIds", new BsonDocument
                                {
                                    { "bsonType", "array" },
                                    { "items", new BsonDocument { { "bsonType", "string" } } }
                                }
                            },
                            { "createdUtc", new BsonDocument { { "bsonType", "date" } } }
                        }
                    }
                }
            }
        };

        var collections = db.ListCollectionNames().ToList();
        if (!collections.Contains(collectionName))
        {
            var createCommand = new BsonDocument
            {
                { "create", collectionName },
                { "validator", validator },
                { "validationAction", "error" }
            };
            db.RunCommand<BsonDocument>(createCommand);
            return;
        }

        var command = new BsonDocument
        {
            { "collMod", collectionName },
            { "validator", validator },
            { "validationAction", "error" }
        };
        db.RunCommand<BsonDocument>(command);
    }

    public Task CreateAsync(Location location) => _col.InsertOneAsync(location);

    public Task<List<Location>> GetAllAsync() =>
        _col.Find(Builders<Location>.Filter.Empty).ToListAsync();

    public async Task<bool> DeleteAsync(string id)
    {
        var filter = Builders<Location>.Filter.Eq(l => l.Id, id);
        var result = await _col.DeleteOneAsync(filter);
        return result.DeletedCount > 0;
    }

    public async Task<bool> UpdateNameAsync(string id, string name)
    {
        var filter = Builders<Location>.Filter.Eq(l => l.Id, id);
        var update = Builders<Location>.Update.Set(l => l.Name, name);
        var result = await _col.UpdateOneAsync(filter, update);
        return result.ModifiedCount > 0;
    }

    public async Task<bool> UpdatePresenceAsync(string characterId, Coord coord)
    {
        if (string.IsNullOrWhiteSpace(characterId))
            return false;

        var pullFilter = Builders<Location>.Filter.AnyEq(l => l.CharacterIds, characterId);
        var pullUpdate = Builders<Location>.Update.Pull(l => l.CharacterIds, characterId);
        await _col.UpdateManyAsync(pullFilter, pullUpdate);

        var targetFilter = Builders<Location>.Filter.And(
            Builders<Location>.Filter.Eq(l => l.Coord.X, coord.X),
            Builders<Location>.Filter.Eq(l => l.Coord.Y, coord.Y)
        );
        var addUpdate = Builders<Location>.Update.AddToSet(l => l.CharacterIds, characterId);
        var result = await _col.UpdateOneAsync(targetFilter, addUpdate);
        return result.MatchedCount > 0;
    }

    private void EnsureOriginLocation()
    {
        var filter = Builders<Location>.Filter.And(
            Builders<Location>.Filter.Eq(l => l.Coord.X, 0),
            Builders<Location>.Filter.Eq(l => l.Coord.Y, 0)
        );
        var existing = _col.Find(filter).FirstOrDefault();
        if (existing is not null)
            return;

        var origin = new Location
        {
            Name = "Origin",
            Coord = new Coord { X = 0, Y = 0 },
            CharacterIds = new List<string>(),
            CreatedUtc = DateTime.UtcNow
        };

        try
        {
            _col.InsertOne(origin);
        }
        catch (MongoWriteException ex) when (ex.WriteError.Category == ServerErrorCategory.DuplicateKey)
        {
            // Another instance seeded it first.
        }
    }
}