using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Linq;
using System.Text.Json;
using StellaOps.Scanner.Core.Contracts;
using StellaOps.Scanner.Emit.Composition;
using Xunit;

namespace StellaOps.Scanner.Emit.Tests.Composition;

public sealed class SpdxComposerTests
{
    [Fact]
    public void Compose_ProducesJsonLdArtifact()
    {
        var request = BuildRequest();
        var composer = new SpdxComposer();

        var result = composer.Compose(request, new SpdxCompositionOptions());

        Assert.Equal("application/spdx+json; version=3.0.1", result.JsonMediaType);
        Assert.Equal(result.JsonSha256, result.ContentHash);
        Assert.Equal(64, result.JsonSha256.Length);
        Assert.Null(result.TagValueBytes);

        using var document = JsonDocument.Parse(result.JsonBytes);
        var root = document.RootElement;
        Assert.Equal("https://spdx.org/rdf/3.0.1/spdx-context.jsonld", root.GetProperty("@context").GetString());

        var graph = root.GetProperty("@graph").EnumerateArray().ToArray();
        Assert.NotEmpty(graph);

        var docNode = graph.Single(node => node.GetProperty("type").GetString() == "SpdxDocument");
        var rootElement = docNode.GetProperty("rootElement").EnumerateArray().Select(element => element.GetString()).ToArray();
        Assert.Single(rootElement);

        var packages = graph
            .Where(node => node.GetProperty("type").GetString() == "software_Package")
            .ToArray();
        Assert.Equal(3, packages.Length);

        var lodash = packages.Single(node => node.GetProperty("name").GetString() == "component-b");
        Assert.Equal("pkg:npm/b@2.0.0", lodash.GetProperty("software_packageUrl").GetString());
    }

    [Fact]
    public void Compose_WithTagValue_IncludesLegacyOutput()
    {
        var request = BuildRequest();
        var composer = new SpdxComposer();

        var result = composer.Compose(request, new SpdxCompositionOptions { IncludeTagValue = true });

        Assert.NotNull(result.TagValueBytes);
        var tagValue = System.Text.Encoding.UTF8.GetString(result.TagValueBytes!);
        Assert.Contains("SPDXVersion: SPDX-2.3", tagValue, StringComparison.Ordinal);
        Assert.Contains("DocumentNamespace:", tagValue, StringComparison.Ordinal);
    }

    [Fact]
    public void Compose_IsDeterministic()
    {
        var request = BuildRequest();
        var composer = new SpdxComposer();

        var first = composer.Compose(request, new SpdxCompositionOptions());
        var second = composer.Compose(request, new SpdxCompositionOptions());

        Assert.Equal(first.JsonSha256, second.JsonSha256);
    }

    private static SbomCompositionRequest BuildRequest()
    {
        var fragments = new[]
        {
            LayerComponentFragment.Create("sha256:layer1", new[]
            {
                new ComponentRecord
                {
                    Identity = ComponentIdentity.Create("pkg:npm/a", "component-a", "1.0.0", "pkg:npm/a@1.0.0", "library"),
                    LayerDigest = "sha256:layer1",
                    Evidence = ImmutableArray.Create(ComponentEvidence.FromPath("/app/node_modules/a/package.json")),
                    Dependencies = ImmutableArray.Create("pkg:npm/b"),
                    Usage = ComponentUsage.Create(true, new[] { "/app/start.sh" }),
                    Metadata = new ComponentMetadata
                    {
                        Scope = "runtime",
                        Licenses = new[] { "MIT" },
                        Properties = new Dictionary<string, string>
                        {
                            ["stellaops:source"] = "package-lock.json",
                        },
                        BuildId = "ABCDEF1234567890ABCDEF1234567890ABCDEF12",
                    },
                }
            }),
            LayerComponentFragment.Create("sha256:layer2", new[]
            {
                new ComponentRecord
                {
                    Identity = ComponentIdentity.Create("pkg:npm/b", "component-b", "2.0.0", "pkg:npm/b@2.0.0", "library"),
                    LayerDigest = "sha256:layer2",
                    Evidence = ImmutableArray.Create(ComponentEvidence.FromPath("/app/node_modules/b/package.json")),
                    Usage = ComponentUsage.Create(false),
                    Metadata = new ComponentMetadata
                    {
                        Scope = "development",
                        Licenses = new[] { "Apache-2.0" },
                        Properties = new Dictionary<string, string>
                        {
                            ["stellaops.os.analyzer"] = "language-node",
                        },
                    },
                }
            })
        };

        var image = new ImageArtifactDescriptor
        {
            ImageDigest = "sha256:1234567890abcdef",
            ImageReference = "registry.example.com/app/service:1.2.3",
            Repository = "registry.example.com/app/service",
            Tag = "1.2.3",
            Architecture = "amd64",
        };

        return SbomCompositionRequest.Create(
            image,
            fragments,
            new DateTimeOffset(2025, 10, 19, 12, 0, 0, TimeSpan.Zero),
            generatorName: "StellaOps.Scanner",
            generatorVersion: "0.10.0",
            properties: new Dictionary<string, string>
            {
                ["stellaops:scanId"] = "scan-1234",
            });
    }
}