// 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 Roslyn.Utilities;
using Xunit;
 
namespace Microsoft.CodeAnalysis.Differencing.UnitTests;
 
public sealed class MatchTests
{
    [Fact]
    public void KnownMatches()
    {
        TestNode x1, x2;
 
        var oldRoot = new TestNode(0, 1,
            x1 = new TestNode(1, 1));
 
        var newRoot = new TestNode(0, 1,
            x2 = new TestNode(1, 2));
 
        var m = TestTreeComparer.Instance.ComputeMatch(oldRoot, newRoot,
            [KeyValuePairUtil.Create(x1, x2), KeyValuePairUtil.Create(x1, x2)]);
        Assert.True(m.TryGetNewNode(x1, out var n));
        Assert.Equal(n, x2);
 
        Assert.Throws<ArgumentException>(() => TestTreeComparer.Instance.ComputeMatch(oldRoot, newRoot, [KeyValuePairUtil.Create(x1, x1)]));
 
        Assert.Throws<ArgumentException>(() => TestTreeComparer.Instance.ComputeMatch(oldRoot, newRoot, [KeyValuePairUtil.Create(x1, x2), KeyValuePairUtil.Create(x1, new TestNode(0, 0))]));
    }
 
    [Fact]
    public void KnownMatchesDups()
    {
        TestNode x1, x2, y1, y2;
 
        var oldRoot = new TestNode(0, 1,
            x1 = new TestNode(1, 1),
            y1 = new TestNode(1, 4));
 
        var newRoot = new TestNode(0, 1,
            x2 = new TestNode(1, 2),
            y2 = new TestNode(1, 3));
 
        var m = TestTreeComparer.Instance.ComputeMatch(oldRoot, newRoot,
        [
            KeyValuePairUtil.Create(x1, x2),
            KeyValuePairUtil.Create(y1, x2),
        ]);
 
        // the first one wins:
        Assert.True(m.TryGetNewNode(x1, out var n));
        Assert.Equal(x2, n);
        Assert.True(m.TryGetOldNode(x2, out n));
        Assert.Equal(x1, n);
        Assert.True(m.TryGetNewNode(y1, out n)); // matched
        Assert.Equal(y2, n);
    }
 
    [Fact]
    public void KnownMatchesRootMatch()
    {
        TestNode x1, x2;
 
        var oldRoot = new TestNode(0, 1,
            x1 = new TestNode(0, 1));
 
        var newRoot = new TestNode(0, 1,
            x2 = new TestNode(0, 2));
 
        var m = TestTreeComparer.Instance.ComputeMatch(oldRoot, newRoot,
        [
            KeyValuePairUtil.Create(x1, newRoot),
        ]);
 
        // the root wins:
        Assert.True(m.TryGetNewNode(x1, out var n)); // matched
        Assert.Equal(x2, n);
        Assert.True(m.TryGetOldNode(newRoot, out n));
        Assert.Equal(oldRoot, n);
        Assert.True(m.TryGetNewNode(oldRoot, out n));
        Assert.Equal(newRoot, n);
    }
}