using System.Diagnostics;
using System.Linq;
using WhiteMagic;
using WhiteMagic.Native;
using WhiteMagic.ProcessDiscovery;
using Xunit;

namespace WhiteMagicTest.ProcessDiscovery;

/// <summary>
/// Tests for process discovery via <see cref="ApplicationFinder"/> and the matching
/// <see cref="Magic.Open"/> overloads.
/// </summary>
public sealed class ApplicationFinderTests
{
    [Fact]
    public void Enumerate_finds_current_process_by_name()
    {
        string currentName = Process.GetCurrentProcess().ProcessName;

        Process[] found = ApplicationFinder.Enumerate(currentName).ToArray();

        Assert.True(found.Length >= 1);
        Assert.Contains(found, p => p.Id == Process.GetCurrentProcess().Id);
    }

    [Fact]
    public void Open_by_name_returns_current_process_when_unique()
    {
        string currentName = Process.GetCurrentProcess().ProcessName;

        using Process process = ApplicationFinder.OpenProcess(currentName);

        Assert.Equal(Process.GetCurrentProcess().Id, process.Id);
    }

    [Fact]
    public void Open_throws_when_name_is_ambiguous()
    {
        // Look for a multi-instance system process; skip if the environment is not typical.
        Process[] candidates = Process.GetProcessesByName("svchost");
        if (candidates.Length <= 1)
        {
            return;
        }

        InvalidOperationException ex = Assert.Throws<InvalidOperationException>(
            () => ApplicationFinder.OpenProcess("svchost"));

        Assert.Contains("svchost", ex.Message);
        Assert.Contains("ambiguous", ex.Message, StringComparison.OrdinalIgnoreCase);
    }

    [Fact]
    public void Open_throws_when_no_process_matches()
    {
        InvalidOperationException ex = Assert.Throws<InvalidOperationException>(
            () => ApplicationFinder.OpenProcess("probably-not-loaded-xyz.exe"));

        Assert.Contains("No process", ex.Message);
    }

    [Fact]
    public void OpenByWindowHandle_returns_owning_process()
    {
        IntPtr handle = Process.GetCurrentProcess().MainWindowHandle;
        if (handle == IntPtr.Zero)
        {
            return;
        }

        using Process process = ApplicationFinder.OpenByWindowHandle(handle);
        Assert.Equal(Process.GetCurrentProcess().Id, process.Id);
    }

    [Fact]
    public void OpenByWindowHandle_throws_for_zero_handle()
    {
        Assert.Throws<ArgumentException>("handle", () => ApplicationFinder.OpenByWindowHandle(IntPtr.Zero));
    }

    [Fact]
    public void Magic_Open_by_name_attaches_to_current_process()
    {
        string currentName = Process.GetCurrentProcess().ProcessName;

        using var magic = Magic.Open(currentName);

        Assert.Equal(Process.GetCurrentProcess().Id, magic.Memory.ProcessId);
    }

    [Fact]
    public void Magic_OpenByWindowHandle_attaches_to_owning_process()
    {
        IntPtr handle = Process.GetCurrentProcess().MainWindowHandle;
        if (handle == IntPtr.Zero)
        {
            return;
        }

        using var magic = Magic.OpenByWindowHandle(handle);

        Assert.Equal(Process.GetCurrentProcess().Id, magic.Memory.ProcessId);
    }
}