using System.Text.Json;
using Recordingtest.DiffReporter;
using Xunit;

namespace Recordingtest.DiffReporter.Tests;

public class DifferTests
{
    private static string TempDir()
    {
        var d = Path.Combine(Path.GetTempPath(), "diffrep-" + Guid.NewGuid().ToString("N"));
        Directory.CreateDirectory(d);
        return d;
    }

    [Fact]
    public void Identical_JsonFiles_ReturnsIdentical()
    {
        var dir = TempDir();
        var a = Path.Combine(dir, "a.json");
        var b = Path.Combine(dir, "b.json");
        File.WriteAllText(a, "{\"x\":1,\"y\":\"hi\"}");
        File.WriteAllText(b, "{\"x\":1,\"y\":\"hi\"}");
        var r = Differ.Compare(a, b);
        Assert.True(r.Identical);
        Assert.Empty(r.Hunks);
    }

    [Fact]
    public void OneFieldChanged_JsonFiles_OneHunk()
    {
        var dir = TempDir();
        var a = Path.Combine(dir, "a.json");
        var b = Path.Combine(dir, "b.json");
        File.WriteAllText(a, "{\"x\":1,\"y\":\"hi\"}");
        File.WriteAllText(b, "{\"x\":2,\"y\":\"hi\"}");
        var r = Differ.Compare(a, b);
        Assert.False(r.Identical);
        Assert.Single(r.Hunks);
        Assert.Equal("changed", r.Hunks[0].Kind);
    }

    [Fact]
    public void BinaryDiff_ReturnsHexSummary()
    {
        var dir = TempDir();
        var a = Path.Combine(dir, "a.bin");
        var b = Path.Combine(dir, "b.bin");
        File.WriteAllBytes(a, new byte[] { 0x00, 0x01, 0x02, 0xFF, 0x80 });
        File.WriteAllBytes(b, new byte[] { 0x00, 0x01, 0x03, 0xFE, 0x80 });
        var r = Differ.Compare(a, b);
        Assert.False(r.Identical);
        Assert.NotEmpty(r.Hunks);
        foreach (var h in r.Hunks)
        {
            // hex strings only
            Assert.Matches("^[0-9A-F]*$", h.Before);
            Assert.Matches("^[0-9A-F]*$", h.After);
        }
    }

    [Fact]
    public void Cli_IdenticalFiles_ExitZero_And_DiffJsonExists()
    {
        var dir = TempDir();
        var a = Path.Combine(dir, "a.json");
        var b = Path.Combine(dir, "b.json");
        File.WriteAllText(a, "{\"x\":1}");
        File.WriteAllText(b, "{\"x\":1}");
        var outDir = Path.Combine(dir, "out");
        var code = Cli.Program.Main(new[] { "--approved", a, "--received", b, "--out", outDir });
        Assert.Equal(0, code);
        Assert.True(File.Exists(Path.Combine(outDir, "diff.json")));
        Assert.True(File.Exists(Path.Combine(outDir, "diff.md")));
    }

    [Fact]
    public void TriageReadable_DiffJson_CanBeParsed()
    {
        var dir = TempDir();
        var a = Path.Combine(dir, "a.json");
        var b = Path.Combine(dir, "b.json");
        File.WriteAllText(a, "{\"x\":1}");
        File.WriteAllText(b, "{\"x\":2}");
        var outDir = Path.Combine(dir, "out");
        var code = Cli.Program.Main(new[] { "--approved", a, "--received", b, "--out", outDir });
        Assert.Equal(1, code);
        var json = File.ReadAllText(Path.Combine(outDir, "diff.json"));
        using var doc = JsonDocument.Parse(json);
        var root = doc.RootElement;
        Assert.True(root.TryGetProperty("file", out _));
        Assert.True(root.TryGetProperty("hunks", out _));
        Assert.True(root.TryGetProperty("summary", out var summary));
        Assert.True(summary.TryGetProperty("added", out _));
        Assert.True(summary.TryGetProperty("removed", out _));
        Assert.True(summary.TryGetProperty("changed", out _));
    }
}