using System.Text.Json;
using System.Text.Json.Serialization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using StellaOps.Scanner.WebService.Constants;
using StellaOps.Scanner.WebService.Domain;
using StellaOps.Scanner.WebService.Infrastructure;
using StellaOps.Scanner.WebService.Security;
using StellaOps.Scanner.WebService.Services;

namespace StellaOps.Scanner.WebService.Endpoints;

internal static class ExportEndpoints
{
    private static readonly JsonSerializerOptions SerializerOptions = new(JsonSerializerDefaults.Web)
    {
        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
        Converters = { new JsonStringEnumConverter() },
        WriteIndented = true
    };

    public static void MapExportEndpoints(this RouteGroupBuilder scansGroup)
    {
        ArgumentNullException.ThrowIfNull(scansGroup);

        // GET /scans/{scanId}/exports/sarif
        scansGroup.MapGet("/{scanId}/exports/sarif", HandleExportSarifAsync)
            .WithName("scanner.scans.exports.sarif")
            .WithTags("Exports")
            .Produces(StatusCodes.Status200OK, contentType: "application/sarif+json")
            .Produces(StatusCodes.Status404NotFound)
            .RequireAuthorization(ScannerPolicies.ScansRead);

        // GET /scans/{scanId}/exports/cdxr
        scansGroup.MapGet("/{scanId}/exports/cdxr", HandleExportCycloneDxRAsync)
            .WithName("scanner.scans.exports.cdxr")
            .WithTags("Exports")
            .Produces(StatusCodes.Status200OK, contentType: "application/vnd.cyclonedx+json; version=1.7")
            .Produces(StatusCodes.Status404NotFound)
            .RequireAuthorization(ScannerPolicies.ScansRead);

        // GET /scans/{scanId}/exports/openvex
        scansGroup.MapGet("/{scanId}/exports/openvex", HandleExportOpenVexAsync)
            .WithName("scanner.scans.exports.openvex")
            .WithTags("Exports")
            .Produces(StatusCodes.Status200OK, contentType: "application/json")
            .Produces(StatusCodes.Status404NotFound)
            .RequireAuthorization(ScannerPolicies.ScansRead);
    }

    private static async Task<IResult> HandleExportSarifAsync(
        string scanId,
        IScanCoordinator coordinator,
        ISarifExportService exportService,
        HttpContext context,
        CancellationToken cancellationToken)
    {
        ArgumentNullException.ThrowIfNull(coordinator);
        ArgumentNullException.ThrowIfNull(exportService);

        if (!ScanId.TryParse(scanId, out var parsed))
        {
            return ProblemResultFactory.Create(
                context,
                ProblemTypes.Validation,
                "Invalid scan identifier",
                StatusCodes.Status400BadRequest,
                detail: "Scan identifier is required.");
        }

        var snapshot = await coordinator.GetAsync(parsed, cancellationToken).ConfigureAwait(false);
        if (snapshot is null)
        {
            return ProblemResultFactory.Create(
                context,
                ProblemTypes.NotFound,
                "Scan not found",
                StatusCodes.Status404NotFound,
                detail: "Requested scan could not be located.");
        }

        var sarifDocument = await exportService.ExportAsync(parsed, cancellationToken).ConfigureAwait(false);
        if (sarifDocument is null)
        {
            return ProblemResultFactory.Create(
                context,
                ProblemTypes.NotFound,
                "No findings available",
                StatusCodes.Status404NotFound,
                detail: "No findings available for SARIF export.");
        }

        var json = JsonSerializer.Serialize(sarifDocument, SerializerOptions);
        return Results.Content(json, "application/sarif+json", System.Text.Encoding.UTF8, StatusCodes.Status200OK);
    }

    private static async Task<IResult> HandleExportCycloneDxRAsync(
        string scanId,
        IScanCoordinator coordinator,
        ICycloneDxExportService exportService,
        HttpContext context,
        CancellationToken cancellationToken)
    {
        ArgumentNullException.ThrowIfNull(coordinator);
        ArgumentNullException.ThrowIfNull(exportService);

        if (!ScanId.TryParse(scanId, out var parsed))
        {
            return ProblemResultFactory.Create(
                context,
                ProblemTypes.Validation,
                "Invalid scan identifier",
                StatusCodes.Status400BadRequest,
                detail: "Scan identifier is required.");
        }

        var snapshot = await coordinator.GetAsync(parsed, cancellationToken).ConfigureAwait(false);
        if (snapshot is null)
        {
            return ProblemResultFactory.Create(
                context,
                ProblemTypes.NotFound,
                "Scan not found",
                StatusCodes.Status404NotFound,
                detail: "Requested scan could not be located.");
        }

        var cdxDocument = await exportService.ExportWithReachabilityAsync(parsed, cancellationToken).ConfigureAwait(false);
        if (cdxDocument is null)
        {
            return ProblemResultFactory.Create(
                context,
                ProblemTypes.NotFound,
                "No findings available",
                StatusCodes.Status404NotFound,
                detail: "No findings available for CycloneDX export.");
        }

        var json = JsonSerializer.Serialize(cdxDocument, SerializerOptions);
        return Results.Content(json, "application/vnd.cyclonedx+json; version=1.7", System.Text.Encoding.UTF8, StatusCodes.Status200OK);
    }

    private static async Task<IResult> HandleExportOpenVexAsync(
        string scanId,
        IScanCoordinator coordinator,
        IOpenVexExportService exportService,
        HttpContext context,
        CancellationToken cancellationToken)
    {
        ArgumentNullException.ThrowIfNull(coordinator);
        ArgumentNullException.ThrowIfNull(exportService);

        if (!ScanId.TryParse(scanId, out var parsed))
        {
            return ProblemResultFactory.Create(
                context,
                ProblemTypes.Validation,
                "Invalid scan identifier",
                StatusCodes.Status400BadRequest,
                detail: "Scan identifier is required.");
        }

        var snapshot = await coordinator.GetAsync(parsed, cancellationToken).ConfigureAwait(false);
        if (snapshot is null)
        {
            return ProblemResultFactory.Create(
                context,
                ProblemTypes.NotFound,
                "Scan not found",
                StatusCodes.Status404NotFound,
                detail: "Requested scan could not be located.");
        }

        var vexDocument = await exportService.ExportAsync(parsed, cancellationToken).ConfigureAwait(false);
        if (vexDocument is null)
        {
            return ProblemResultFactory.Create(
                context,
                ProblemTypes.NotFound,
                "No VEX data available",
                StatusCodes.Status404NotFound,
                detail: "No VEX data available for export.");
        }

        var json = JsonSerializer.Serialize(vexDocument, SerializerOptions);
        return Results.Content(json, "application/json", System.Text.Encoding.UTF8, StatusCodes.Status200OK);
    }
}