using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

using MongoDB.Bson;
using MongoDB.Driver;
using MongoDB.Driver.GridFS;
using System.IO;

namespace TestCSharp326 {
    public static class Program {
        public static void Main(string[] args) {
            try {
                var server = MongoServer.Create("mongodb://localhost/?safe=true");
                var database = server["csharp326"];
                var grid = database.GridFS;

                var fileCount = 10000;
                var fileSize = 50;

                // create the files in parallel
                Console.WriteLine("Uploading the files");
                var parallelOptions = new ParallelOptions { MaxDegreeOfParallelism = 20 };
                Parallel.ForEach(Enumerable.Range(0, fileCount), parallelOptions, n => {
                    var filename = string.Format("/tmp/parallel/file{0}", n);
                    var fileInfo = TouchFile(grid, filename);
                    using (var stream = fileInfo.OpenWrite()) {
                        var bytes = Enumerable.Range(0, fileSize).Select(b => (byte) b).ToArray();
                        stream.Write(bytes, 0, bytes.Length);
                    }
                    //Console.WriteLine("Uploaded {0}", filename);
                });
                Console.WriteLine();

                // test the files in parallel
                Console.WriteLine("Downloading the files");
                Parallel.ForEach(Enumerable.Range(0, fileCount), parallelOptions, n => {
                    var filename = string.Format("/tmp/parallel/file{0}", n);
                    var fileInfo = new MongoGridFSFileInfo(database.GridFS, filename);
                    using (var stream = fileInfo.OpenRead()) {
                        var bytes = new byte[stream.Length];
                        var read = stream.Read(bytes, 0, bytes.Length);
                        if (read != bytes.Length) {
                            Console.WriteLine("{0} read={1}", filename, read);
                        }
                        var expected = Enumerable.Range(0, fileSize).Select(b => (byte) b).ToArray();
                        if (!expected.SequenceEqual(bytes)) {
                            Console.WriteLine("{0} contents don't match", filename);
                        }
                    }
                    //Console.WriteLine("Downloaded {0}", filename);
                });
                Console.WriteLine();

                Console.WriteLine("Dropping database csharp326");
                database.Drop();
            } catch (Exception ex) {
                Console.WriteLine("Unhandled exception:");
                Console.WriteLine(ex);
            }

            Console.WriteLine("Press Enter to continue");
            Console.ReadLine();
        }

        private static MongoGridFSFileInfo TouchFile(MongoGridFS grid, string path) {
            var dir = Path.GetDirectoryName(path);
            // Uploads an empty file into the system marked as 
            // a 'directory'
            var info = grid.Upload(
                new System.IO.MemoryStream(new byte[0]), path,
                new MongoGridFSCreateOptions() {
                    Metadata = new BsonDocument() { { "dirpath", BsonValue.Create(dir) } }
                });
            return info;
        }
    }
}