// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System;
using System.IO;
using Microsoft.ML.Internal.Utilities;
using Microsoft.ML.Runtime;
using Microsoft.ML.TestFrameworkCommon;
 
namespace Microsoft.ML.PerformanceTests
{
    public class BenchmarkBase
    {
        // Make sure DataDir is initialized before benchmark running.
        static BenchmarkBase()
        {
            RootDir = TestCommon.GetRepoRoot();
            DataDir = Path.Combine(RootDir, "test", "data");
        }
 
        protected static string RootDir { get; }
        protected static string DataDir { get; }
 
        // Don't use BaseTestClass's GetDataPath method instead for benchmark.
        // BaseTestClass's static constructor is not guaranteed to be called before
        // benchmark running (depending on CLR version this has different behaviour).
        // The problem with executing BaseTestClass's static constructor when benchmark
        // is running is it sometime cause process hanging when the constructor trying 
        // to load MKL, this is related to below issue:
        // https://github.com/dotnet/machinelearning/issues/1073
        public static string GetBenchmarkDataPathAndEnsureData(string name, string path = "")
        {
            if (string.IsNullOrWhiteSpace(name))
                return null;
 
            var filePath = path == "" ?
                Path.GetFullPath(Path.Combine(DataDir, name)) :
                Path.GetFullPath(Path.Combine(DataDir, path, name));
 
            if (File.Exists(filePath))
                return filePath;
 
            var mlContext = new MLContext(1);
            int timeout = 10 * 60 * 1000;
            string url = $"benchmarks/{name}";
            var localPath = path == "" ?
                Path.GetFullPath(DataDir) :
                Path.GetFullPath(Path.Combine(DataDir, path));
 
            using (var ch = (mlContext as IHostEnvironment).Start("Ensuring dataset files are present."))
            {
                var ensureModel = ResourceManagerUtils.Instance.EnsureResourceAsync(
                    mlContext, ch, url, name, localPath, timeout);
                ensureModel.Wait();
                var errorResult = ResourceManagerUtils.GetErrorMessage(out var errorMessage, ensureModel.Result);
                if (errorResult != null)
                {
                    throw ch.Except($"{errorMessage}\n{name} could not be downloaded!");
                }
            }
 
            return filePath;
        }
    }
 
    public class RandomFile
    {
        public static string CreateRandomFile(string path, int numRows, int numColumns, int maxWordLength)
        {
            // Create file with random strings
            // to use as dataset of the benchmark
 
            Random random = new Random(1);
 
            using (StreamWriter file = new StreamWriter(path))
            {
                for (int i = 0; i < numRows; i++)
                    file.WriteLine(CreateRandomLine(numColumns, maxWordLength, random));
            }
            return path;
        }
 
        public static string CreateRandomLine(int columns, int maxWordLength, Random random)
        {
            var lineSB = new System.Text.StringBuilder();
            for (int i = 0; i < columns; i++)
            {
                lineSB.Append(CreateRandomColumn(random.Next(100), maxWordLength, random));
                lineSB.Append(",");
            }
            return lineSB.ToString();
        }
 
        public static string CreateRandomColumn(int numwords, int maxWordLength, Random random)
        {
            const string characters =
                "01234567890" +
                "abcdefghijklmnopqrstuvwxyz" +
                "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 
            var columnSB = new System.Text.StringBuilder();
            int wordLength;
 
            bool quoted = false;
            if (random.NextDouble() > 0.5)
            {
                quoted = true;
                columnSB.Append('"');
            }
 
            for (int i = 0; i < numwords; i++)
            {
                wordLength = random.Next(1, maxWordLength);
                for (int j = 0; j < wordLength; j++)
                    columnSB.Append(characters[random.Next(characters.Length)]);
 
                columnSB.Append(" ");
            }
 
            if (quoted)
                columnSB.Append('"');
 
            if (random.Next(2) == 0) // sometimes return the column as lowercase
                return columnSB.ToString().ToLower();
 
            return columnSB.ToString();
        }
    }
}