using Microsoft.Extensions.Configuration;
using StellaOps.Doctor.Models;
using StellaOps.Doctor.Plugins;
using StellaOps.Doctor.Plugins.Builders;
using StellaOps.Doctor.Plugins.Verification.Configuration;
using System.Text.Json;

namespace StellaOps.Doctor.Plugins.Verification.Checks;

/// <summary>
/// Verifies SBOM validation for test artifact.
/// </summary>
public sealed class SbomValidationCheck : VerificationCheckBase
{
    /// <inheritdoc />
    public override string CheckId => "check.verification.sbom.validation";

    /// <inheritdoc />
    public override string Name => "SBOM Validation";

    /// <inheritdoc />
    public override string Description => "Fetches and validates SBOM for test artifact (CycloneDX/SPDX)";

    /// <inheritdoc />
    public override IReadOnlyList<string> Tags => ["verification", "sbom", "cyclonedx", "spdx", "supply-chain"];

    /// <inheritdoc />
    public override TimeSpan EstimatedDuration => TimeSpan.FromSeconds(10);

    /// <inheritdoc />
    public override bool CanRun(DoctorPluginContext context)
    {
        if (!base.CanRun(context))
            return false;

        var options = VerificationPlugin.GetOptions(context);
        return HasTestArtifactConfigured(options);
    }

    /// <inheritdoc />
    protected override async Task<DoctorCheckResult> ExecuteCheckAsync(
        DoctorPluginContext context,
        VerificationPluginOptions options,
        CheckResultBuilder result,
        CancellationToken ct)
    {
        if (!HasTestArtifactConfigured(options))
        {
            return GetNoTestArtifactConfiguredResult(result, CheckId);
        }

        // Check offline bundle for SBOM
        if (!string.IsNullOrEmpty(options.TestArtifact.OfflineBundlePath))
        {
            return await ValidateFromOfflineBundle(options, result, ct);
        }

        // Online SBOM validation
        return await ValidateFromOnline(context, options, result, ct);
    }

    private static Task<DoctorCheckResult> ValidateFromOfflineBundle(
        VerificationPluginOptions options,
        CheckResultBuilder result,
        CancellationToken ct)
    {
        var bundlePath = options.TestArtifact.OfflineBundlePath!;

        if (!File.Exists(bundlePath))
        {
            return Task.FromResult(result
                .Fail($"Offline bundle not found: {bundlePath}")
                .WithEvidence("SBOM validation", e => e
                    .Add("Mode", "Offline")
                    .Add("BundlePath", bundlePath)
                    .Add("FileExists", "false"))
                .WithRemediation(r => r
                    .AddShellStep(1, "Export bundle", "stella verification bundle export --include-sbom --output " + bundlePath)
                    .WithRunbookUrl(""))
                .WithVerification($"stella doctor --check check.verification.sbom.validation")
                .Build());
        }

        try
        {
            var content = File.ReadAllText(bundlePath);

            // Detect SBOM format
            var (format, version, componentCount) = DetectSbomFormat(content);

            if (format == SbomFormat.None)
            {
                return Task.FromResult(result
                    .Fail("No valid SBOM found in offline bundle")
                    .WithEvidence("SBOM validation", e => e
                        .Add("Mode", "Offline")
                        .Add("BundlePath", bundlePath)
                        .Add("SbomFound", "false"))
                    .WithCauses(
                        "Bundle was exported without SBOM",
                        "Test artifact has no SBOM attached")
                    .WithRemediation(r => r
                        .AddShellStep(1, "Re-export with SBOM", "stella verification bundle export --include-sbom --output " + bundlePath)
                        .AddManualStep(2, "Generate SBOM", "Enable SBOM generation in your build pipeline")
                        .WithRunbookUrl(""))
                    .WithVerification($"stella doctor --check check.verification.sbom.validation")
                    .Build());
            }

            return Task.FromResult(result
                .Pass($"SBOM valid ({format} {version}, {componentCount} components)")
                .WithEvidence("SBOM validation", e => e
                    .Add("Mode", "Offline")
                    .Add("BundlePath", bundlePath)
                    .Add("Format", format.ToString())
                    .Add("Version", version ?? "(unknown)")
                    .Add("ComponentCount", componentCount.ToString()))
                .Build());
        }
        catch (Exception ex)
        {
            return Task.FromResult(result
                .Fail($"Cannot read offline bundle: {ex.Message}")
                .WithEvidence("SBOM validation", e => e
                    .Add("Mode", "Offline")
                    .Add("BundlePath", bundlePath)
                    .Add("Error", ex.Message))
                .Build());
        }
    }

    private static Task<DoctorCheckResult> ValidateFromOnline(
        DoctorPluginContext context,
        VerificationPluginOptions options,
        CheckResultBuilder result,
        CancellationToken ct)
    {
        var reference = options.TestArtifact.Reference!;

        // Note: Full SBOM validation requires the Scanner/Concelier service
        // For doctor check, we verify configuration is in place

        var sbomGenerationEnabled = context.Configuration.GetValue<bool>("Scanner:SbomGeneration:Enabled");
        var sbomAttestationEnabled = context.Configuration.GetValue<bool>("Attestor:SbomAttestation:Enabled");

        if (!sbomGenerationEnabled && !sbomAttestationEnabled)
        {
            return Task.FromResult(result
                .Warn("SBOM generation and attestation not enabled")
                .WithEvidence("SBOM validation", e => e
                    .Add("Mode", "Online")
                    .Add("Reference", reference)
                    .Add("SbomGenerationEnabled", sbomGenerationEnabled.ToString())
                    .Add("SbomAttestationEnabled", sbomAttestationEnabled.ToString())
                    .Add("Note", "Enable SBOM generation to attach SBOMs to artifacts"))
                .WithCauses(
                    "SBOM generation not configured",
                    "SBOM attestation not configured")
                .WithRemediation(r => r
                    .AddManualStep(1, "Enable SBOM generation", "Set Scanner:SbomGeneration:Enabled to true")
                    .AddManualStep(2, "Enable SBOM attestation", "Set Attestor:SbomAttestation:Enabled to true")
                    .WithRunbookUrl(""))
                .WithVerification($"stella doctor --check check.verification.sbom.validation")
                .Build());
        }

        return Task.FromResult(result
            .Pass("SBOM generation/attestation configured")
            .WithEvidence("SBOM validation", e => e
                .Add("Mode", "Online")
                .Add("Reference", reference)
                .Add("SbomGenerationEnabled", sbomGenerationEnabled.ToString())
                .Add("SbomAttestationEnabled", sbomAttestationEnabled.ToString())
                .Add("Note", "Full SBOM validation requires runtime scanner service"))
            .Build());
    }

    private static (SbomFormat Format, string? Version, int ComponentCount) DetectSbomFormat(string content)
    {
        try
        {
            using var doc = JsonDocument.Parse(content);
            var root = doc.RootElement;

            // Check for CycloneDX
            if (root.TryGetProperty("bomFormat", out var bomFormat) &&
                bomFormat.GetString()?.Equals("CycloneDX", StringComparison.OrdinalIgnoreCase) == true)
            {
                var version = root.TryGetProperty("specVersion", out var sv) ? sv.GetString() : null;
                var componentCount = root.TryGetProperty("components", out var c) && c.ValueKind == JsonValueKind.Array
                    ? c.GetArrayLength()
                    : 0;
                return (SbomFormat.CycloneDX, version, componentCount);
            }

            // Check for SPDX
            if (root.TryGetProperty("spdxVersion", out var spdxVersion))
            {
                var version = spdxVersion.GetString();
                var componentCount = root.TryGetProperty("packages", out var p) && p.ValueKind == JsonValueKind.Array
                    ? p.GetArrayLength()
                    : 0;
                return (SbomFormat.SPDX, version, componentCount);
            }

            // Check for embedded SBOM in bundle
            if (root.TryGetProperty("sbom", out var sbomElement))
            {
                var sbomContent = sbomElement.GetRawText();
                return DetectSbomFormat(sbomContent);
            }
        }
        catch
        {
            // Not valid JSON or parsing failed
        }

        return (SbomFormat.None, null, 0);
    }

    private enum SbomFormat
    {
        None,
        CycloneDX,
        SPDX
    }
}