using System.Collections.Immutable;
using System.Text.Json;
using StellaOps.Concelier.RawModels;
using StellaOps.Concelier.WebService.Contracts;

namespace StellaOps.Concelier.WebService.Extensions;

internal static class AdvisoryRawRequestMapper
{
    internal static AdvisoryRawDocument Map(AdvisoryIngestRequest request, string tenant, TimeProvider timeProvider)
    {
        ArgumentNullException.ThrowIfNull(request);
        ArgumentException.ThrowIfNullOrWhiteSpace(tenant);
        ArgumentNullException.ThrowIfNull(timeProvider);

        var sourceRequest = request.Source ?? throw new ArgumentException("source section is required.", nameof(request));
        var upstreamRequest = request.Upstream ?? throw new ArgumentException("upstream section is required.", nameof(request));
        var contentRequest = request.Content ?? throw new ArgumentException("content section is required.", nameof(request));
        var identifiersRequest = request.Identifiers ?? throw new ArgumentException("identifiers section is required.", nameof(request));

        var source = new RawSourceMetadata(
            sourceRequest.Vendor,
            sourceRequest.Connector,
            sourceRequest.Version,
            string.IsNullOrWhiteSpace(sourceRequest.Stream) ? null : sourceRequest.Stream);

        var signatureRequest = upstreamRequest.Signature ?? new AdvisorySignatureRequest(false, null, null, null, null, null);
        var signature = new RawSignatureMetadata(
            signatureRequest.Present,
            string.IsNullOrWhiteSpace(signatureRequest.Format) ? null : signatureRequest.Format,
            string.IsNullOrWhiteSpace(signatureRequest.KeyId) ? null : signatureRequest.KeyId,
            string.IsNullOrWhiteSpace(signatureRequest.Signature) ? null : signatureRequest.Signature,
            string.IsNullOrWhiteSpace(signatureRequest.Certificate) ? null : signatureRequest.Certificate,
            string.IsNullOrWhiteSpace(signatureRequest.Digest) ? null : signatureRequest.Digest);

        var retrievedAt = upstreamRequest.RetrievedAt ?? timeProvider.GetUtcNow();

        var upstream = new RawUpstreamMetadata(
            upstreamRequest.UpstreamId,
            string.IsNullOrWhiteSpace(upstreamRequest.DocumentVersion) ? null : upstreamRequest.DocumentVersion,
            retrievedAt,
            upstreamRequest.ContentHash,
            signature,
            NormalizeDictionary(upstreamRequest.Provenance));

        var rawContent = NormalizeRawContent(contentRequest.Raw);
        var content = new RawContent(
            contentRequest.Format,
            string.IsNullOrWhiteSpace(contentRequest.SpecVersion) ? null : contentRequest.SpecVersion,
            rawContent,
            string.IsNullOrWhiteSpace(contentRequest.Encoding) ? null : contentRequest.Encoding);

        var aliases = NormalizeStrings(identifiersRequest.Aliases);
        if (aliases.IsDefault)
        {
            aliases = ImmutableArray<string>.Empty;
        }

        var identifiers = new RawIdentifiers(
            aliases,
            identifiersRequest.Primary);

        var linksetRequest = request.Linkset;
        var linkset = new RawLinkset
        {
            Aliases = NormalizeStrings(linksetRequest?.Aliases),
            PackageUrls = NormalizeStrings(linksetRequest?.PackageUrls),
            Cpes = NormalizeStrings(linksetRequest?.Cpes),
            References = NormalizeReferences(linksetRequest?.References),
            ReconciledFrom = NormalizeStrings(linksetRequest?.ReconciledFrom),
            Notes = NormalizeDictionary(linksetRequest?.Notes)
        };

        return new AdvisoryRawDocument(
            tenant.Trim().ToLowerInvariant(),
            source,
            upstream,
            content,
            identifiers,
            linkset,
            AdvisoryKey: string.Empty,
            Links: ImmutableArray<RawLink>.Empty);
    }

    internal static ImmutableArray<string> NormalizeStrings(IEnumerable<string>? values)
    {
        if (values is null)
        {
            return ImmutableArray<string>.Empty;
        }

        var builder = ImmutableArray.CreateBuilder<string>();
        foreach (var value in values)
        {
            if (string.IsNullOrWhiteSpace(value))
            {
                continue;
            }

            builder.Add(value.Trim());
        }

        return builder.Count == 0 ? ImmutableArray<string>.Empty : builder.ToImmutable();
    }

    internal static ImmutableDictionary<string, string> NormalizeDictionary(IDictionary<string, string>? values)
    {
        if (values is null || values.Count == 0)
        {
            return ImmutableDictionary<string, string>.Empty;
        }

        var builder = ImmutableDictionary.CreateBuilder<string, string>(StringComparer.Ordinal);
        foreach (var kv in values)
        {
            if (string.IsNullOrWhiteSpace(kv.Key))
            {
                continue;
            }

            builder[kv.Key.Trim()] = kv.Value?.Trim() ?? string.Empty;
        }

        return builder.ToImmutable();
    }

    private static ImmutableArray<RawReference> NormalizeReferences(IEnumerable<AdvisoryLinksetReferenceRequest>? references)
    {
        if (references is null)
        {
            return ImmutableArray<RawReference>.Empty;
        }

        var builder = ImmutableArray.CreateBuilder<RawReference>();
        foreach (var reference in references)
        {
            if (reference is null)
            {
                continue;
            }

            if (string.IsNullOrWhiteSpace(reference.Type) || string.IsNullOrWhiteSpace(reference.Url))
            {
                continue;
            }

            builder.Add(new RawReference(reference.Type.Trim(), reference.Url.Trim(), string.IsNullOrWhiteSpace(reference.Source) ? null : reference.Source.Trim()));
        }

        return builder.Count == 0 ? ImmutableArray<RawReference>.Empty : builder.ToImmutable();
    }

    private static JsonElement NormalizeRawContent(JsonElement element)
    {
        var json = element.ValueKind == JsonValueKind.Undefined ? "{}" : element.GetRawText();
        using var document = JsonDocument.Parse(string.IsNullOrWhiteSpace(json) ? "{}" : json);
        return document.RootElement.Clone();
    }
}