using System.Security.Cryptography;
using System.Text;
using ScadaLink.Commons.Types.Transport;
using ScadaLink.Transport.Serialization;

namespace ScadaLink.Transport.Tests.Serialization;

public sealed class ManifestBuilderTests
{
    private static BundleSummary EmptySummary => new(0, 0, 0, 0, 0, 0, 0, 0, 0);
    private static IReadOnlyList<ManifestContentEntry> NoContents => Array.Empty<ManifestContentEntry>();

    [Fact]
    public void Build_populates_summary_from_contents()
    {
        var sut = new ManifestBuilder();
        var summary = new BundleSummary(2, 1, 0, 0, 0, 0, 0, 0, 0);
        var contents = new[]
        {
            new ManifestContentEntry("Template", "T1", 1, Array.Empty<string>()),
            new ManifestContentEntry("Template", "T2", 1, new[] { "T1" }),
            new ManifestContentEntry("TemplateFolder", "F1", 1, Array.Empty<string>()),
        };

        var manifest = sut.Build("env", "user", "1.0.0", encryption: null, summary, contents, contentBytes: new byte[] { 1, 2, 3 });

        Assert.Equal(summary, manifest.Summary);
        Assert.Equal(contents, manifest.Contents);
        Assert.Equal("env", manifest.SourceEnvironment);
        Assert.Equal("user", manifest.ExportedBy);
        Assert.Equal("1.0.0", manifest.ScadaLinkVersion);
        Assert.Equal(1, manifest.BundleFormatVersion);
        Assert.Equal("1.0", manifest.SchemaVersion);
        Assert.Null(manifest.Encryption);
    }

    [Fact]
    public void Build_computes_content_hash_with_sha256_prefix()
    {
        var sut = new ManifestBuilder();
        var bytes = Encoding.UTF8.GetBytes("known-content");
        var expectedHashHex = Convert.ToHexString(SHA256.HashData(bytes)).ToLowerInvariant();

        var manifest = sut.Build("env", "user", "v", encryption: null, EmptySummary, NoContents, bytes);

        Assert.Equal("sha256:" + expectedHashHex, manifest.ContentHash);
    }

    [Fact]
    public void Validate_rejects_unsupported_bundleFormatVersion()
    {
        var bytes = new byte[] { 1, 2, 3 };
        var hash = "sha256:" + Convert.ToHexString(SHA256.HashData(bytes)).ToLowerInvariant();
        var manifest = new BundleManifest(
            BundleFormatVersion: 999,
            SchemaVersion: "1.0",
            CreatedAtUtc: DateTimeOffset.UtcNow,
            SourceEnvironment: "env",
            ExportedBy: "u",
            ScadaLinkVersion: "v",
            ContentHash: hash,
            Encryption: null,
            Summary: EmptySummary,
            Contents: NoContents);

        var result = new ManifestValidator().Validate(manifest, bytes);

        Assert.Equal(ManifestValidationResult.UnsupportedFormatVersion, result);
    }

    [Fact]
    public void Validate_rejects_when_contentHash_mismatch()
    {
        var bytes = new byte[] { 1, 2, 3 };
        var manifest = new BundleManifest(
            BundleFormatVersion: 1,
            SchemaVersion: "1.0",
            CreatedAtUtc: DateTimeOffset.UtcNow,
            SourceEnvironment: "env",
            ExportedBy: "u",
            ScadaLinkVersion: "v",
            ContentHash: "sha256:deadbeef",
            Encryption: null,
            Summary: EmptySummary,
            Contents: NoContents);

        var result = new ManifestValidator().Validate(manifest, bytes);

        Assert.Equal(ManifestValidationResult.ContentHashMismatch, result);
    }

    [Fact]
    public void Validate_accepts_well_formed_v1_manifest()
    {
        var sut = new ManifestBuilder();
        var bytes = Encoding.UTF8.GetBytes("hello");
        var manifest = sut.Build("env", "u", "v", encryption: null, EmptySummary, NoContents, bytes);

        var result = new ManifestValidator().Validate(manifest, bytes);

        Assert.Equal(ManifestValidationResult.Ok, result);
    }
}