using Microsoft.Extensions.Options;
using System.Text.RegularExpressions;
using YarpGateway.Services;

namespace YarpGateway.Middleware;

public class TenantRoutingMiddleware
{
    private readonly RequestDelegate _next;
    private readonly IRouteCache _routeCache;
    private readonly ILogger<TenantRoutingMiddleware> _logger;

    public TenantRoutingMiddleware(
        RequestDelegate next,
        IRouteCache routeCache,
        ILogger<TenantRoutingMiddleware> logger)
    {
        _next = next;
        _routeCache = routeCache;
        _logger = logger;
    }

    public async Task InvokeAsync(HttpContext context)
    {
        var tenantId = context.Request.Headers["X-Tenant-Id"].FirstOrDefault();
        if (string.IsNullOrEmpty(tenantId))
        {
            await _next(context);
            return;
        }

        var path = context.Request.Path.Value ?? string.Empty;
        var serviceName = ExtractServiceName(path);

        if (string.IsNullOrEmpty(serviceName))
        {
            await _next(context);
            return;
        }

        var route = _routeCache.GetRoute(tenantId, serviceName);
        if (route == null)
        {
            _logger.LogWarning("Route not found - Tenant: {Tenant}, Service: {Service}", tenantId, serviceName);
            await _next(context);
            return;
        }

        context.Items["DynamicClusterId"] = route.ClusterId;

        var routeType = route.IsGlobal ? "global" : "tenant-specific";
        _logger.LogInformation("Tenant routing - Tenant: {Tenant}, Service: {Service}, Cluster: {Cluster}, Type: {Type}",
            tenantId, serviceName, route.ClusterId, routeType);

        await _next(context);
    }

    private string ExtractServiceName(string path)
    {
        var match = Regex.Match(path, @"/api/(\w+)/?");
        return match.Success ? match.Groups[1].Value : string.Empty;
    }
}