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using System;
using System.Linq;
using System.Net.WebSockets;
using System.Text.Json;
using Gremlin.Net.Driver;
using Gremlin.Net.Structure.IO.GraphSON;
using Newtonsoft.Json;

namespace GremlinNetSample
{
    // based on Azure sample: https://github.com/Azure-Samples/azure-cosmos-db-graph-gremlindotnet-getting-started
    class Program
    {
        static void Main(string[] args)
        {
            // Azure Cosmos Graph database configuration values:
            var host = "mycosmos-account.gremlin.cosmos.azure.com";
            var port = 443;
            var enableSsl = true;
            var databaseName = "mydatabase";
            var graphName = "mygraph";
            var username = $"/dbs/{databaseName}/colls/{graphName}";
            var password = Environment.GetEnvironmentVariable("GREMLIN_DB_PRIMARY_KEY");   // store primary key as a system environment variable.

            // create a gremlin server object:
            var gremlinServer = new GremlinServer(host, port, enableSsl, username, password);

            // configure connection pool:
            var connectionPoolSettings = new ConnectionPoolSettings()
            {
                MaxInProcessPerConnection = 10,
                PoolSize = 30,
                ReconnectionAttempts = 3,
                ReconnectionBaseDelay = TimeSpan.FromMilliseconds(500)
            };

            // create a websocket configuration object:
            var webSocketConfiguration =
                new Action<ClientWebSocketOptions>(options =>
                {
                    options.KeepAliveInterval = TimeSpan.FromSeconds(10);
                });

            // create a gremlin client:
            using var gremlinClient = new GremlinClient(
                gremlinServer,
                new GraphSON2Reader(),
                new GraphSON2Writer(),
                GremlinClient.GraphSON2MimeType,
                connectionPoolSettings,
                webSocketConfiguration);

            RunQueries(gremlinClient);
        }

        // Run your queries here.
        private static void RunQueries(GremlinClient gremlinClient)
        {
            string myQuery = null;

            // delete all graph vertices, edges, and properties (does not delete the graph):
            myQuery = "g.V().drop()";
            SendQuery(gremlinClient, myQuery);

            // add vertex (a person):
            myQuery = "g.addV('person').property('id', 'Juanita').property('firstName', 'Juanita').property('location', 'Los Angeles').property('pk', 'pk')";
            SendQuery(gremlinClient, myQuery);

            // add vertex (a person):
            myQuery = "g.addV('person').property('id', 'Sam').property('firstName', 'Sam').property('location', 'New Mexico').property('pk', 'pk')";
            SendQuery(gremlinClient, myQuery);

            // add vertex (a person):
            myQuery = "g.addV('person').property('id', 'Nikhil').property('firstName', 'Nikhil').property('location', 'New York').property('pk', 'pk')";
            SendQuery(gremlinClient, myQuery);

            // add vertex (a movie):
            myQuery = "g.addv('movie').property('id', 'I, robot').property('title', 'I, robot').property('year', 2004).property('pk', 'pk')";
            SendQuery(gremlinClient, myQuery);

            // add vertex (a movie):
            myQuery = "g.addv('movie').property('id', 'Fried green tomatoes').property('title', 'Fried green tomatoes').property('year', 1991).property('pk', 'pk')";
            SendQuery(gremlinClient, myQuery);

            // add vertex (a movie):
            myQuery = "g.addv('movie').property('id', 'David Copperfield').property('title', 'David Copperfield').property('year', 2019).property('pk', 'pk')";
            SendQuery(gremlinClient, myQuery);

            // add edge (a relationship):
            myQuery = "g.V('Juanita').addE('knows').to(g.V('Sam'))";
            SendQuery(gremlinClient, myQuery);

            // add edge (a relationship):
            myQuery = "g.V('Sam').addE('knows').to(g.V('Nikhil'))";
            SendQuery(gremlinClient, myQuery);

            // add edge (a relationship):
            myQuery = "g.V('Juanita').addE('likes').to(g.V('I, robot'))";
            SendQuery(gremlinClient, myQuery);

            // add edge (a relationship):
            myQuery = "g.V('Sam').addE('likes').to(g.V('Fried green tomatoes'))";
            SendQuery(gremlinClient, myQuery);

            // add edge (a relationship):
            myQuery = "g.V('Nikhil').addE('likes').to(g.V('David Copperfield'))";
            SendQuery(gremlinClient, myQuery);

            // count vertices:
            myQuery = "g.V().count()";
            SendQuery(gremlinClient, myQuery);

            // get graph contents:
            myQuery = "g.V()";
            SendQuery(gremlinClient, myQuery);

            // get the person that Juanita knows (Person A):
            myQuery = "g.V('Juanita').out('knows').hasLabel('person')";
            SendQuery(gremlinClient, myQuery);

            // get the movie that Person A likes:
            myQuery = "g.V('Juanita').out('knows').hasLabel('person').out('likes')";
            SendQuery(gremlinClient, myQuery);

            // get the person that Person A knows (Person B):
            myQuery = "g.V('Juanita').out('knows').hasLabel('person').out('knows').hasLabel('person')";
            SendQuery(gremlinClient, myQuery);

            // get the movie that Person B likes:
            myQuery = "g.V('Juanita').out('knows').hasLabel('person').out('knows').hasLabel('person').out('likes')";
            SendQuery(gremlinClient, myQuery);
        }

        // send gremlin query to cloud for execution and print result.
        private static void SendQuery(GremlinClient gremlinClient, string query)
        {
            try
            {
                var resultSet = gremlinClient.SubmitAsync<dynamic>(query).Result;
                
                Console.WriteLine(Environment.NewLine + $"Result set for query: {query}");
                var jsonStr = "[" + string.Join(",", resultSet.Select(x => JsonConvert.SerializeObject(x))) + "]";
                PrettyPrintJson(jsonStr);
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }

        // prettyprint JSON string.
        public static void PrettyPrintJson(string jsonString)
        {
            var options = new JsonSerializerOptions()
            {
                WriteIndented = true
            };

            var jsonElement = System.Text.Json.JsonSerializer.Deserialize<JsonElement>(jsonString);

            Console.WriteLine(System.Text.Json.JsonSerializer.Serialize(jsonElement, options));
        }
    }
}