using Microsoft.Extensions.Caching.Memory;
using NSubstitute;
using ScadaLink.CentralUI.ScriptAnalysis;

namespace ScadaLink.CentralUI.Tests.ScriptAnalysis;

public class ScriptAnalysisServiceTests
{
    private readonly ISharedScriptCatalog _catalog = Substitute.For<ISharedScriptCatalog>();
    private readonly IMemoryCache _cache = new MemoryCache(new MemoryCacheOptions { SizeLimit = 100 });
    private readonly ScriptAnalysisService _svc;

    public ScriptAnalysisServiceTests()
    {
        _catalog.GetNamesAsync().Returns(Array.Empty<string>());
        _svc = new ScriptAnalysisService(_catalog, _cache);
    }

    [Fact]
    public void EmptyCode_NoMarkers()
    {
        var resp = _svc.Diagnose(new DiagnoseRequest(""));
        Assert.Empty(resp.Markers);
    }

    [Fact]
    public void CleanScript_NoMarkers()
    {
        var resp = _svc.Diagnose(new DiagnoseRequest("var x = 1 + 2; return x;"));
        Assert.Empty(resp.Markers);
    }

    [Fact]
    public void MissingSemicolon_ReportsRoslynDiagnostic()
    {
        var resp = _svc.Diagnose(new DiagnoseRequest("var x = 1\n"));
        Assert.Contains(resp.Markers, m => m.Code.StartsWith("CS"));
    }

    [Fact]
    public void ForbiddenUsingDirective_RaisesSCADA001()
    {
        var resp = _svc.Diagnose(new DiagnoseRequest("using System.IO;"));
        Assert.Contains(resp.Markers, m => m.Code == "SCADA001" && m.Message.Contains("System.IO"));
    }

    [Theory]
    [InlineData("System.Diagnostics")]
    [InlineData("System.Reflection")]
    [InlineData("System.Net")]
    public void ForbiddenUsing_AllBannedNamespaces(string ns)
    {
        var resp = _svc.Diagnose(new DiagnoseRequest($"using {ns};"));
        Assert.Contains(resp.Markers, m => m.Code == "SCADA001" && m.Message.Contains(ns));
    }

    [Fact]
    public void ForbiddenTypeUsage_ResolvesViaSemanticModel()
    {
        var resp = _svc.Diagnose(new DiagnoseRequest(
            "using System.IO; var s = File.ReadAllText(\"x\");"));
        Assert.Contains(resp.Markers, m => m.Code == "SCADA002" && m.Message.Contains("File"));
    }

    [Fact]
    public void UserIdentifierNamedFile_DoesNotFalsePositive()
    {
        // No System.IO import; user defines their own 'File' local.
        var resp = _svc.Diagnose(new DiagnoseRequest(
            "var File = \"hello\"; return File.Length;"));
        Assert.DoesNotContain(resp.Markers, m => m.Code == "SCADA002");
    }

    [Fact]
    public void UserIdentifierNamedThread_DoesNotFalsePositive()
    {
        var resp = _svc.Diagnose(new DiagnoseRequest(
            "var Thread = 42; return Thread;"));
        Assert.DoesNotContain(resp.Markers, m => m.Code == "SCADA002");
    }

    [Fact]
    public void DiagnosticsAreCached_SecondCallSkipsRecompile()
    {
        var req = new DiagnoseRequest("using System.IO;");
        var first = _svc.Diagnose(req);
        var second = _svc.Diagnose(req);

        // Same instance reference indicates the cache returned the prior result.
        Assert.Same(first, second);
    }

    [Fact]
    public void DifferentCode_GetsDifferentCacheEntries()
    {
        var a = _svc.Diagnose(new DiagnoseRequest("var x = 1;"));
        var b = _svc.Diagnose(new DiagnoseRequest("var y = 2;"));
        Assert.NotSame(a, b);
    }

    [Fact]
    public async Task ParametersStringLiteral_ReturnsDeclaredParameterNames()
    {
        var req = new CompletionsRequest(
            CodeText: "var x = Parameters[\"",
            Line: 1,
            Column: 21,
            DeclaredParameters: new[] { "name", "temperature" });

        var resp = await _svc.CompleteAsync(req);

        Assert.Contains(resp.Items, i => i.Label == "name" && i.Detail == "declared parameter");
        Assert.Contains(resp.Items, i => i.Label == "temperature");
    }

    [Fact]
    public async Task CallScriptStringLiteral_ReturnsSiblingNames()
    {
        var req = new CompletionsRequest(
            CodeText: "var x = CallScript(\"",
            Line: 1,
            Column: 21,
            SiblingScripts: new[] { "SiblingA", "SiblingB" });

        var resp = await _svc.CompleteAsync(req);

        Assert.Contains(resp.Items, i => i.Label == "SiblingA" && i.Detail == "sibling script");
        Assert.Contains(resp.Items, i => i.Label == "SiblingB");
    }

    [Fact]
    public async Task CallSharedStringLiteral_ResolvesViaCatalog()
    {
        _catalog.GetNamesAsync().Returns(new[] { "GetWeather", "Greet" });

        var req = new CompletionsRequest(
            CodeText: "var x = CallShared(\"",
            Line: 1,
            Column: 21);

        var resp = await _svc.CompleteAsync(req);

        Assert.Contains(resp.Items, i => i.Label == "GetWeather" && i.Detail == "shared script");
        Assert.Contains(resp.Items, i => i.Label == "Greet");
    }

    [Fact]
    public async Task GeneralCompletion_ReturnsInScopeSymbols()
    {
        // At file scope of a script, ScriptHost members + the System namespace are visible.
        var req = new CompletionsRequest("var x = ", 1, 9);
        var resp = await _svc.CompleteAsync(req);
        Assert.Contains(resp.Items, i => i.Label == "Parameters");
        Assert.Contains(resp.Items, i => i.Label == "CallShared");
    }
}