// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the Apache 2.0 License.
// See the LICENSE file in the project root for more information. 

<#@ template debug="false" hostspecific="false" language="C#" #>
<#@ assembly name="System.Core" #>
<#@ import namespace="System.Linq" #>
<#@ import namespace="System.Text" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ output extension=".cs" #>
<#
Func<bool, bool, bool, bool, string, string> getAsyncMethod = (then, desc, async, cancel, body) =>
{
    var mtd = (then ? "ThenBy" : "OrderBy") + (desc ? "Descending" : "");

    var arg = async ? (cancel ? "(x, ct) => " : "x => ") + "new ValueTask<int>(" + body + ")" : "x => " + body;

    if (async)
    {
        mtd += "Await";

        if (cancel)
        {
            mtd += "WithCancellation";
        }
    }

    return "." + mtd + "(" + arg + ")";
};

Func<bool, bool, int, string, string> getAsyncMethodWithVariant = (then, desc, variant, body) =>
{
    return getAsyncMethod(then, desc, variant > 0 ? true : false, variant == 2 ? true : false, body);
};

Func<bool, bool, string, string> getSyncMethod = (then, desc, body) =>
{
    var mtd = (then ? "ThenBy" : "OrderBy") + (desc ? "Descending" : "");

    var arg = "x => " + body;

    return "." + mtd + "(" + arg + ")";
};

Func<bool, bool, int, string> getVariantName = (then, desc, variant) =>
{
    var v = variant == 0 ? "" : (variant == 1 ? "Async" : "AsyncWithCancellation");
    return "_" + (then ? "ThenBy" : "OrderBy") + (desc ? "Descending" : "") + v;
};

Func<bool, string, List<Tuple<string, string, string>>> getAsyncMethodVariants = (then, body) =>
{
    var res = new List<Tuple<string, string, string>>();

    foreach (var desc in new[] { false, true })
    {
        foreach (var variant in new[] { 0, 1, 2 })
        {
            var v = getVariantName(then, desc, variant);
            var async = getAsyncMethodWithVariant(then, desc, variant, body);
            var sync = getSyncMethod(then, desc, body);

            res.Add(new Tuple<string, string, string>(v, async, sync));
        }
    }

    return res;
};

Func<int, List<Tuple<string, string, string>>> getVariants = null;

getVariants = depth =>
{
    if (depth == 1)
    {
        return getAsyncMethodVariants(false, "x % 2");
    }
    else
    {
        var res = new List<Tuple<string, string, string>>();

        var next = getVariants(depth - 1);

        foreach (var item in next)
        {
            foreach (var variant in getAsyncMethodVariants(true, "x % " + (depth + 1)))
            {
                res.Add(new Tuple<string, string, string>(item.Item1 + variant.Item1, item.Item2 + variant.Item2, item.Item3 + variant.Item3));
            }
        }

        return res;
    }
};
#>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Xunit;

namespace Tests
{
    partial class OrderBy
    {
<#
for (var i = 1; i <= 3; i++)
{
    foreach (var v in getVariants(i))
    {
        var variant = v.Item1;
        var asyncCall = v.Item2;
        var syncCall = v.Item3;
#>
        [Fact]
        public async Task OrderBy<#=variant#>()
        {
            var rand = new Random(42);
            var xs = Enumerable.Range(0, 100).Select(x => rand.Next(0, 100)).ToArray().Select(x => x);

            var asyncRes = xs.ToAsyncEnumerable()<#=asyncCall#>;
            var syncRes = xs<#=syncCall#>;

            await AssertSorted(asyncRes, syncRes);

            var asyncSegment = asyncRes.AsAsyncEnumerable();
            var syncSegment = syncRes.AsEnumerable();

            foreach (var skipCount in new[] { 3, 7, 2, 5 })
            {
                asyncSegment = asyncSegment.Skip(skipCount);
                syncSegment = syncSegment.Skip(skipCount);
            }

            foreach (var takeCount in new[] { 31, 29, 23 })
            {
                asyncSegment = asyncSegment.Take(takeCount);
                syncSegment = syncSegment.Take(takeCount);
            }

            await AssertSorted(asyncSegment, syncSegment);
        }

<#
    }
}
#>

        private async Task AssertSorted<T>(IAsyncEnumerable<T> asyncRes, IEnumerable<T> syncRes)
        {
            Assert.True(await syncRes.ToAsyncEnumerable().SequenceEqualAsync(asyncRes));
            Assert.True(syncRes.ToList().SequenceEqual(await asyncRes.ToListAsync()));
            Assert.True(syncRes.ToArray().SequenceEqual(await asyncRes.ToArrayAsync()));

            int syncCount = syncRes.Count();
            int asyncCount = await asyncRes.CountAsync();
            Assert.Equal(syncCount, asyncCount);

            Assert.Equal(syncRes.First(), await asyncRes.FirstAsync());
            Assert.Equal(syncRes.Last(), await asyncRes.LastAsync());

            for (var i = 0; i < syncCount; i++)
            {
                Assert.Equal(syncRes.ElementAt(i), await asyncRes.ElementAtAsync(i));
            }
        }
    }
}