using System;
using System.Collections.Generic;

using MongoDB.Bson;
using MongoDB.Driver;

namespace MongoDBApp_CSharpCore
{
    class Program
    {
        static void Main(string[] args)
        {
            MongoDBTest();

            Console.WriteLine("Exiting main");

            Console.ReadKey();  // Pause
        }

        private static async void MongoDBTest()
        {
            MongoClient client = new MongoClient();

            IMongoDatabase database = client.GetDatabase("mydb");
            IMongoCollection<BsonDocument> collection = database.GetCollection<BsonDocument>("test");

            Create("1","buy something","BASE",collection);
            Create("2","sell","BASE",collection);
            Create("3","close down","BASE",collection);
            Console.WriteLine("Reading all the documents");
            await collection.Find(new BsonDocument()).ForEachAsync(d => Console.WriteLine(d));
            Read("1",collection);
            Update("2","sold out",collection);
            Delete("1",collection);  
            DeleteAll(collection);
        }

        private static async void Create(String id, String info, String comp, IMongoCollection<BsonDocument> collection)
        {
            String time = DateTime.Now.ToString();
            BsonDocument doc = new BsonDocument
            {
                { "event_id", id },
                { "event_time", time },
                { "event_info", info },
                { "event_company", comp }
            };

            Console.WriteLine("----CREATE SUCCESS!----");

            await collection.InsertOneAsync(doc);
        }

        private static async void Read(String id, IMongoCollection<BsonDocument> collection)
        {
            BsonDocument doc = await collection.Find(Builders<BsonDocument>.Filter.Eq("event_id", id)).FirstOrDefaultAsync();
            if (doc == null)
            {
                Console.WriteLine("No document found for {0}", id);
            }
            else if (doc.Contains("event_info"))   
            {
                Console.WriteLine("----READ SUCCESS!----");
                Console.WriteLine("Finding document: {0} ", doc);
            }
            else
            {
                Console.WriteLine("Error: info field did not exist in document");
            }
        }

        private static async void Update(String id, String newinfo, IMongoCollection<BsonDocument> collection)
        {
            BsonDocument doc = await collection.Find(Builders<BsonDocument>.Filter.Eq("event_id", id)).FirstOrDefaultAsync();
            if (doc == null)
            {
                Console.WriteLine("No document found for {0}", id);
            }
            else if (doc.Contains("event_info"))  
            {
                Console.WriteLine("(The document is ready for updating)");
            }
            else
            {
                Console.WriteLine("Error: info field did not exist in document");
            }

            UpdateResult updated;
            updated = await collection.UpdateOneAsync(Builders<BsonDocument>.Filter.Eq("_id", doc["_id"]), 
                                    Builders<BsonDocument>.Update
                                    .Set("event_info", newinfo));

            doc = await collection.Find(Builders<BsonDocument>.Filter.Eq("event_id", id)).FirstOrDefaultAsync();
            Console.WriteLine("----UPDATE SUCCESS!----");
            Console.Write("Changed document now contains {0}\n", doc);
        }

        private static async void Delete(String id, IMongoCollection<BsonDocument> collection)
        {
            DeleteResult deleted;

            deleted = await collection.DeleteOneAsync(Builders<BsonDocument>.Filter.Eq("event_id", id));
            if (deleted.IsAcknowledged)
            {
                Console.WriteLine("----DELETE SUCCESS!----");
                Console.WriteLine("Deleted {0} documents",deleted.DeletedCount);
            }
        }

        private static async void DeleteAll(IMongoCollection<BsonDocument> collection)
        {
            long countBefore = collection.CountDocuments(new BsonDocument());
            DeleteResult deleted = await collection.DeleteManyAsync(new BsonDocument());       
            if (deleted.IsAcknowledged)
            {
                Console.WriteLine("Deleting all documents in the collection, deleted {0} documents, before:{1} after:{2}\n",
                    deleted.DeletedCount,
                    countBefore,
                    collection.CountDocuments(new BsonDocument()));

                await collection.Find(new BsonDocument()).ForEachAsync(d => Console.WriteLine(d)); // Display all
            }
        }
    }
}