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 IServiceProvider _services = Substitute.For<IServiceProvider>();
    private readonly ScriptAnalysisService _svc;

    private static ScriptShape Shape(string name, params ParameterShape[] ps) =>
        new(name, ps, null);

    private static ParameterShape Param(string name, string type = "String", bool required = true) =>
        new(name, type, required);

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

    // ── Diagnose ──────────────────────────────────────────────────────────

    [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()
    {
        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);
        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 void UnknownParameterKey_RaisesSCADA003()
    {
        var resp = _svc.Diagnose(new DiagnoseRequest(
            Code: "var x = Parameters[\"typo\"];",
            DeclaredParameters: new[] { "name", "temperature" }));
        Assert.Contains(resp.Markers, m => m.Code == "SCADA003" && m.Message.Contains("'typo'"));
    }

    [Fact]
    public void DeclaredParameterKey_NoMarker()
    {
        var resp = _svc.Diagnose(new DiagnoseRequest(
            Code: "var x = Parameters[\"name\"];",
            DeclaredParameters: new[] { "name", "temperature" }));
        Assert.DoesNotContain(resp.Markers, m => m.Code == "SCADA003");
    }

    // ── Completions ───────────────────────────────────────────────────────

    [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_ReturnsSiblingNamesWithSnippet()
    {
        var siblings = new[] { Shape("SiblingA", Param("x")) };
        var req = new CompletionsRequest(
            CodeText: "var x = Instance.CallScript(\"",
            Line: 1,
            Column: 30,
            SiblingScripts: siblings);

        var resp = await _svc.CompleteAsync(req);

        var item = Assert.Single(resp.Items, i => i.Label == "SiblingA");
        Assert.Equal(4, item.InsertTextRules);
        // The runtime call API takes args as an anonymous object — the snippet
        // emits one member per declared parameter.
        Assert.Contains("new { x = ${1:x} }", item.InsertText);
        Assert.Contains("sibling script", item.Detail);
    }

    [Fact]
    public async Task CallSharedStringLiteral_ResolvesViaCatalogWithShapes()
    {
        _catalog.GetShapesAsync().Returns(new[]
        {
            Shape("GetWeather"),
            Shape("Greet", Param("name"))
        });

        var req = new CompletionsRequest(
            CodeText: "var x = Scripts.CallShared(\"",
            Line: 1,
            Column: 29);

        var resp = await _svc.CompleteAsync(req);

        // No-parameter shape: snippet just closes the call.
        var weather = Assert.Single(resp.Items, i => i.Label == "GetWeather");
        Assert.Equal("GetWeather\")", weather.InsertText);
        // Parameterized shape: anonymous-object member per parameter.
        var greet = Assert.Single(resp.Items, i => i.Label == "Greet");
        Assert.Contains("new { name = ${1:name} }", greet.InsertText);
        Assert.Contains("shared script", greet.Detail);
    }

    [Fact]
    public async Task GeneralCompletion_ReturnsInScopeSymbols()
    {
        var req = new CompletionsRequest("var x = ", 1, 9);
        var resp = await _svc.CompleteAsync(req);
        // SandboxScriptHost globals are surfaced as in-scope symbols. The
        // runtime call API is member-access — Scripts.CallShared / Instance.*
        // — so the top-level globals are Parameters, Scripts, and Instance.
        Assert.Contains(resp.Items, i => i.Label == "Parameters");
        Assert.Contains(resp.Items, i => i.Label == "Scripts");
        Assert.Contains(resp.Items, i => i.Label == "Instance");
    }

    // ── Hover ─────────────────────────────────────────────────────────────

    [Fact]
    public async Task Hover_OnSiblingName_ReturnsSignature()
    {
        var siblings = new[] { Shape("Calc", Param("x", "Integer"), Param("y", "Float")) };
        // Cursor inside the "Calc" name literal of Instance.CallScript("Calc", ...).
        var resp = await _svc.Hover(new HoverRequest(
            CodeText: "var r = Instance.CallScript(\"Calc\", 1, 2);",
            Line: 1,
            Column: 32,
            SiblingScripts: siblings));
        Assert.NotNull(resp.Markdown);
        Assert.Contains("sibling script", resp.Markdown);
        Assert.Contains("Calc(x: Integer, y: Float): void", resp.Markdown);
    }

    [Fact]
    public async Task Hover_OnUnrelatedToken_ReturnsNull()
    {
        var resp = await _svc.Hover(new HoverRequest(
            CodeText: "var r = 1 + 2;",
            Line: 1,
            Column: 5));
        Assert.Null(resp.Markdown);
    }

    // ── Signature help ────────────────────────────────────────────────────

    [Fact]
    public async Task SignatureHelp_InsideCallScript_ReturnsParameterStrip()
    {
        var siblings = new[] { Shape("Calc", Param("x", "Integer"), Param("y", "Float")) };
        var resp = await _svc.SignatureHelp(new SignatureHelpRequest(
            CodeText: "var r = Instance.CallScript(\"Calc\", 1, ",
            Line: 1,
            Column: 40,
            SiblingScripts: siblings));
        Assert.Equal("Instance.CallScript(\"Calc\", x: Integer, y: Float)", resp.Label);
        Assert.Equal(2, resp.Parameters!.Count);
        Assert.Equal("x: Integer", resp.Parameters[0].Label);
        Assert.Equal("y: Float", resp.Parameters[1].Label);
        Assert.Equal(1, resp.ActiveParameter);
    }

    [Fact]
    public async Task SignatureHelp_OutsideCall_ReturnsNull()
    {
        var resp = await _svc.SignatureHelp(new SignatureHelpRequest(
            CodeText: "var r = 1 + 2;",
            Line: 1,
            Column: 5));
        Assert.Null(resp.Label);
    }

    // ── Format ────────────────────────────────────────────────────────────

    [Fact]
    public void Format_ScrambledCode_ReturnsPrettyPrinted()
    {
        var resp = _svc.Format(new FormatRequest("if(x){return 1;}else{return 2;}"));
        // Roslyn's default formatter adds spaces around keywords/braces.
        Assert.Contains("if (x)", resp.Code);
        Assert.NotEqual("if(x){return 1;}else{return 2;}", resp.Code);
    }

    [Fact]
    public void Format_EmptyCode_ReturnsEmpty()
    {
        Assert.Equal("", _svc.Format(new FormatRequest("")).Code);
    }

    // ── Self / Children / Parent attribute completions ────────────────────

    private static AttributeShape Attr(string name, string type = "String") => new(name, type);
    private static CompositionContext Comp(string name, AttributeShape[]? attrs = null, ScriptShape[]? scripts = null)
        => new(name, attrs ?? Array.Empty<AttributeShape>(), scripts ?? Array.Empty<ScriptShape>());

    [Fact]
    public async Task SelfAttribute_Literal_ReturnsSelfAttributeNames()
    {
        var req = new CompletionsRequest(
            CodeText: "var x = Attributes[\"",
            Line: 1,
            Column: 21,
            SelfAttributes: new[] { Attr("Temperature"), Attr("Setpoint", "Float") });
        var resp = await _svc.CompleteAsync(req);
        Assert.Contains(resp.Items, i => i.Label == "Temperature");
        Assert.Contains(resp.Items, i => i.Label == "Setpoint" && i.Detail.Contains("Float"));
    }

    [Fact]
    public async Task ChildAttribute_Literal_ReturnsChildAttributeNames()
    {
        var req = new CompletionsRequest(
            CodeText: "var x = Children[\"TempSensor\"].Attributes[\"",
            Line: 1,
            Column: 44,
            Children: new[] { Comp("TempSensor", attrs: new[] { Attr("Temperature"), Attr("Humidity") }) });
        var resp = await _svc.CompleteAsync(req);
        Assert.Contains(resp.Items, i => i.Label == "Temperature");
        Assert.Contains(resp.Items, i => i.Label == "Humidity");
    }

    [Fact]
    public async Task ParentAttribute_Literal_ReturnsParentAttributeNames()
    {
        var req = new CompletionsRequest(
            CodeText: "var x = Parent.Attributes[\"",
            Line: 1,
            Column: 28,
            Parent: Comp("Motor", attrs: new[] { Attr("SpeedRPM") }));
        var resp = await _svc.CompleteAsync(req);
        Assert.Contains(resp.Items, i => i.Label == "SpeedRPM");
    }

    [Fact]
    public async Task ChildrenLiteral_ReturnsCompositionNames()
    {
        var req = new CompletionsRequest(
            CodeText: "var x = Children[\"",
            Line: 1,
            Column: 19,
            Children: new[] { Comp("TempSensor"), Comp("PressureSensor") });
        var resp = await _svc.CompleteAsync(req);
        Assert.Contains(resp.Items, i => i.Label == "TempSensor" && i.Detail == "composition");
        Assert.Contains(resp.Items, i => i.Label == "PressureSensor");
    }

    [Fact]
    public void UnknownSelfAttribute_RaisesSCADA006()
    {
        var resp = _svc.Diagnose(new DiagnoseRequest(
            Code: "var x = Attributes[\"Typo\"];",
            SelfAttributes: new[] { Attr("Temperature") }));
        Assert.Contains(resp.Markers, m => m.Code == "SCADA006" && m.Message.Contains("Typo"));
    }

    [Fact]
    public void KnownSelfAttribute_NoMarker()
    {
        var resp = _svc.Diagnose(new DiagnoseRequest(
            Code: "var x = Attributes[\"Temperature\"];",
            SelfAttributes: new[] { Attr("Temperature") }));
        Assert.DoesNotContain(resp.Markers, m => m.Code == "SCADA006");
    }

    [Fact]
    public void UnknownChildAttribute_RaisesSCADA006()
    {
        var resp = _svc.Diagnose(new DiagnoseRequest(
            Code: "var x = Children[\"TempSensor\"].Attributes[\"Typo\"];",
            Children: new[] { Comp("TempSensor", attrs: new[] { Attr("Temperature") }) }));
        Assert.Contains(resp.Markers, m => m.Code == "SCADA006" && m.Message.Contains("TempSensor"));
    }

    [Fact]
    public void UnknownComposition_RaisesSCADA007()
    {
        var resp = _svc.Diagnose(new DiagnoseRequest(
            Code: "var x = Children[\"Unknown\"].Attributes[\"X\"];",
            Children: new[] { Comp("TempSensor") }));
        Assert.Contains(resp.Markers, m => m.Code == "SCADA007" && m.Message.Contains("Unknown"));
    }

    [Fact]
    public async Task ChildrenCallScript_ReturnsChildScripts()
    {
        var req = new CompletionsRequest(
            CodeText: "var x = Children[\"TempSensor\"].CallScript(\"",
            Line: 1,
            Column: 44,
            Children: new[]
            {
                Comp("TempSensor", scripts: new[] { Shape("Sample", Param("count", "Integer")) })
            });
        var resp = await _svc.CompleteAsync(req);
        var sample = Assert.Single(resp.Items, i => i.Label == "Sample");
        Assert.Contains("script on TempSensor", sample.Detail);
        Assert.Contains("${1:count}", sample.InsertText);
    }

    [Fact]
    public async Task ParentCallScript_ReturnsParentScripts()
    {
        var req = new CompletionsRequest(
            CodeText: "var x = Parent.CallScript(\"",
            Line: 1,
            Column: 28,
            Parent: Comp("Motor", scripts: new[] { Shape("Trip") }));
        var resp = await _svc.CompleteAsync(req);
        Assert.Contains(resp.Items, i => i.Label == "Trip" && i.Detail.Contains("parent script"));
    }

    // ── Hover on Parameters["name"] ───────────────────────────────────────

    [Fact]
    public async Task Hover_OnParametersKey_ShowsDeclaredType()
    {
        var resp = await _svc.Hover(new HoverRequest(
            CodeText: "var x = Parameters[\"name\"];",
            Line: 1,
            Column: 22,
            DeclaredParameters: new[] { new ParameterShape("name", "String", true) }));
        Assert.NotNull(resp.Markdown);
        Assert.Contains("name", resp.Markdown);
        Assert.Contains("String", resp.Markdown);
    }

    // ── CentralUI-001: trust-model gate before sandbox execution ──────────

    [Fact]
    public void Diagnose_FullyQualifiedForbiddenCall_RaisesSCADA002()
    {
        // A forbidden API reached by fully-qualified name (no `using`, no bare
        // type identifier) must still be flagged — the pre-fix semantic check
        // only inspected the leftmost identifier and missed this shape.
        var resp = _svc.Diagnose(new DiagnoseRequest(
            "var d = System.IO.Directory.GetCurrentDirectory(); return d;"));
        Assert.Contains(resp.Markers, m => m.Code == "SCADA002");
    }

    [Fact]
    public async Task RunInSandbox_FullyQualifiedForbiddenApi_IsBlockedBeforeExecution()
    {
        // Regression test for CentralUI-001. RunInSandboxAsync used to execute any
        // script that compiled, with no trust-model enforcement — so fully-qualified
        // forbidden API code ran in the central host process. The fix gates execution
        // on the forbidden-API analysis.
        var result = await _svc.RunInSandboxAsync(
            new SandboxRunRequest(
                "var d = System.IO.Directory.GetCurrentDirectory(); return d;",
                Parameters: null,
                TimeoutSeconds: null),
            CancellationToken.None);

        Assert.False(result.Success);
        Assert.Equal(SandboxErrorKind.CompileError, result.ErrorKind);
        Assert.Contains("trust model", result.Error);
        Assert.NotNull(result.Markers);
        Assert.Contains(result.Markers!, m => m.Code is "SCADA001" or "SCADA002");
    }

    [Fact]
    public async Task RunInSandbox_ForbiddenUsingDirective_IsBlockedBeforeExecution()
    {
        var result = await _svc.RunInSandboxAsync(
            new SandboxRunRequest(
                "using System.Diagnostics; var p = Process.GetCurrentProcess().Id; return p;",
                Parameters: null,
                TimeoutSeconds: null),
            CancellationToken.None);

        Assert.False(result.Success);
        Assert.Equal(SandboxErrorKind.CompileError, result.ErrorKind);
    }

    [Fact]
    public async Task RunInSandbox_CleanScript_StillRuns()
    {
        // The gate must not block a script that stays within the allowed surface.
        var result = await _svc.RunInSandboxAsync(
            new SandboxRunRequest("return 21 * 2;", Parameters: null, TimeoutSeconds: null),
            CancellationToken.None);

        Assert.True(result.Success);
        Assert.Equal("42", result.ReturnValueJson);
    }

    [Fact]
    public async Task RunInSandbox_CapturesConsoleOutput()
    {
        var result = await _svc.RunInSandboxAsync(
            new SandboxRunRequest(
                "System.Console.WriteLine(\"hello-sandbox\"); return 1;",
                Parameters: null,
                TimeoutSeconds: null),
            CancellationToken.None);

        Assert.True(result.Success);
        Assert.Contains("hello-sandbox", result.ConsoleOutput);
    }

    [Fact]
    public async Task RunInSandbox_ConcurrentRuns_DoNotCrossContaminateConsoleOutput()
    {
        // Regression test for CentralUI-003. RunInSandboxAsync used to redirect the
        // process-global Console.Out/Error to a per-call StringWriter. While one run
        // is mid-flight, any concurrent run's `finally` restores Console.Out to the
        // ORIGINAL writer — so the long run loses every Console.WriteLine it makes
        // after that point, and short runs cross-contaminate each other. The fix
        // routes capture per-call via an AsyncLocal writer without mutating
        // process-global Console state.

        // A long-running script: writes its tag, then burns CPU, then writes again,
        // repeatedly. While it spins, many short runs start and finish around it.
        async Task<string> RunLong()
        {
            var code = @"
                for (int i = 0; i < 40; i++)
                {
                    System.Console.WriteLine(""LONG"");
                    long acc = 0;
                    for (long j = 0; j < 2_000_000; j++) acc += j;
                    System.Console.WriteLine(""LONG"" + acc);
                }
                return 0;";
            var r = await _svc.RunInSandboxAsync(
                new SandboxRunRequest(code, Parameters: null, TimeoutSeconds: 30),
                CancellationToken.None);
            Assert.True(r.Success, r.Error);
            return r.ConsoleOutput;
        }

        async Task<string> RunShort(int id)
        {
            var code = $"for (int i = 0; i < 30; i++) System.Console.WriteLine(\"S{id}\"); return 0;";
            var r = await _svc.RunInSandboxAsync(
                new SandboxRunRequest(code, Parameters: null, TimeoutSeconds: 30),
                CancellationToken.None);
            Assert.True(r.Success, r.Error);
            return r.ConsoleOutput;
        }

        var longTask = RunLong();
        var shortTasks = new List<Task<string>>();
        for (var round = 0; round < 12; round++)
        {
            for (var k = 0; k < 4; k++)
                shortTasks.Add(RunShort(round * 4 + k));
            await Task.Yield();
        }

        var longOut = await longTask;
        var shortOuts = await Task.WhenAll(shortTasks);

        // The long run must have captured ALL 80 of its own writes (40 plain + 40 acc).
        var longLines = longOut.Split('\n', StringSplitOptions.RemoveEmptyEntries)
            .Count(l => l.StartsWith("LONG"));
        Assert.Equal(80, longLines);

        // No short run's output must have leaked into the long run's capture.
        for (var i = 0; i < shortOuts.Length; i++)
            Assert.DoesNotContain($"S{i}", longOut);

        // Each short run captured exactly its own 30 lines and nothing else.
        for (var i = 0; i < shortOuts.Length; i++)
        {
            var lines = shortOuts[i].Split('\n', StringSplitOptions.RemoveEmptyEntries);
            Assert.Equal(30, lines.Length);
            Assert.All(lines, l => Assert.Equal($"S{i}", l.Trim()));
        }
    }
}
