/// <summary>
/// EN: ASP.NET Core BFF (Backend for Frontend) with YARP Reverse Proxy.
/// VI: ASP.NET Core BFF (Backend for Frontend) với YARP Reverse Proxy.
/// </summary>

using Microsoft.AspNetCore.Rewrite;

var builder = WebApplication.CreateBuilder(args);

// ═══════════════════════════════════════════════════════════════════════════════
// EN: Add services to the container
// VI: Thêm các services vào container
// ═══════════════════════════════════════════════════════════════════════════════

// EN: Load YARP configuration from yarp.json
// VI: Load cấu hình YARP từ yarp.json
builder.Configuration.AddJsonFile("yarp.json", optional: false, reloadOnChange: true);

// EN: Override YARP cluster addresses from Docker environment variables
// VI: Override địa chỉ YARP cluster từ biến môi trường Docker
var iamBaseUrl = Environment.GetEnvironmentVariable("IamService__BaseUrl");
var gatewayUrl = Environment.GetEnvironmentVariable("ApiSettings__GatewayUrl");

if (!string.IsNullOrEmpty(iamBaseUrl))
{
    builder.Configuration["ReverseProxy:Clusters:iam-cluster:Destinations:destination1:Address"] = iamBaseUrl;
}

// EN: Merchant service — discover via env or construct from gateway naming convention
// VI: Merchant service — phát hiện qua env hoặc tạo từ naming convention gateway
var merchantBaseUrl = Environment.GetEnvironmentVariable("MerchantService__BaseUrl");
if (string.IsNullOrEmpty(merchantBaseUrl) && !string.IsNullOrEmpty(iamBaseUrl))
{
    // EN: If no explicit merchant URL, try to construct from Docker network naming
    // VI: Nếu không có URL merchant rõ ràng, thử tạo từ Docker network naming
    merchantBaseUrl = iamBaseUrl.Replace("iam-service-net", "merchant-service-net");
}
if (!string.IsNullOrEmpty(merchantBaseUrl))
{
    builder.Configuration["ReverseProxy:Clusters:merchant-cluster:Destinations:destination1:Address"] = merchantBaseUrl;
}

var catalogBaseUrl = Environment.GetEnvironmentVariable("CatalogService__BaseUrl");
if (string.IsNullOrEmpty(catalogBaseUrl) && !string.IsNullOrEmpty(iamBaseUrl))
{
    catalogBaseUrl = iamBaseUrl.Replace("iam-service-net", "catalog-service-net");
}
if (!string.IsNullOrEmpty(catalogBaseUrl))
{
    builder.Configuration["ReverseProxy:Clusters:catalog-cluster:Destinations:destination1:Address"] = catalogBaseUrl;
}

var orderBaseUrl = Environment.GetEnvironmentVariable("OrderService__BaseUrl");
if (string.IsNullOrEmpty(orderBaseUrl) && !string.IsNullOrEmpty(iamBaseUrl))
{
    orderBaseUrl = iamBaseUrl.Replace("iam-service-net", "order-service-net");
}
if (!string.IsNullOrEmpty(orderBaseUrl))
{
    builder.Configuration["ReverseProxy:Clusters:order-cluster:Destinations:destination1:Address"] = orderBaseUrl;
}

// EN: Add YARP Reverse Proxy
// VI: Thêm YARP Reverse Proxy
builder.Services.AddReverseProxy()
    .LoadFromConfig(builder.Configuration.GetSection("ReverseProxy"));

// EN: Add OpenAPI/Swagger support
// VI: Thêm hỗ trợ OpenAPI/Swagger
builder.Services.AddOpenApi();

// EN: Add CORS for Blazor WebAssembly client
// VI: Thêm CORS cho Blazor WebAssembly client
builder.Services.AddCors(options =>
{
    options.AddPolicy("BlazorClient", policy =>
    {
        policy.AllowAnyOrigin()
              .AllowAnyMethod()
              .AllowAnyHeader();
    });
});

// EN: Add health checks
// VI: Thêm health checks
builder.Services.AddHealthChecks();

// EN: Add MVC controllers for BFF data endpoints
// VI: Thêm MVC controllers cho BFF data endpoints
builder.Services.AddControllers();

var app = builder.Build();

// ═══════════════════════════════════════════════════════════════════════════════
// EN: Configure the HTTP request pipeline
// VI: Cấu hình HTTP request pipeline
// ═══════════════════════════════════════════════════════════════════════════════

if (app.Environment.IsDevelopment())
{
    app.MapOpenApi();
    app.UseDeveloperExceptionPage();
    app.UseWebAssemblyDebugging();
}

app.UseHttpsRedirection();

// EN: Redirect exact root "/" to "/home" before Blazor SPA catches it
// VI: Redirect chính xác "/" về "/home" trước khi Blazor SPA xử lý
app.Use(async (context, next) =>
{
    if (context.Request.Path == "/" && context.Request.Method == "GET"
        && !context.Request.Path.StartsWithSegments("/api")
        && !context.Request.Headers.Accept.ToString().Contains("application/json"))
    {
        context.Response.Redirect("/home");
        return;
    }
    await next();
});

// EN: Enable CORS
// VI: Kích hoạt CORS
app.UseCors("BlazorClient");

// EN: Rewrite localized framework/content requests to root
// VI: Viết lại các yêu cầu framework/content từ đường dẫn ngôn ngữ về root
var rewriteOptions = new RewriteOptions()
    .AddRewrite(@"^(en-US|vi-VN)/(_framework|_content)/(.*)", "$2/$3", skipRemainingRules: true);
app.UseRewriter(rewriteOptions);

// EN: Serve static files with fingerprinting support (.NET 10+)
// VI: Phục vụ static files với hỗ trợ fingerprinting (.NET 10+)
app.MapStaticAssets();

// EN: Map health check endpoint
// VI: Map endpoint health check
app.MapHealthChecks("/health");

// EN: Map YARP Reverse Proxy routes to microservices
// VI: Map các routes YARP Reverse Proxy đến microservices
app.MapReverseProxy();

// EN: Localization Support - Serve index.html with dynamic base tag for specific cultures
// VI: Hỗ trợ đa ngôn ngữ - Phục vụ index.html với base tag động cho các ngôn ngữ cụ thể
var supportedCultures = new[] { "en-US", "vi-VN" };
var localizationOptions = new RequestLocalizationOptions()
    .SetDefaultCulture("en-US")
    .AddSupportedCultures(supportedCultures)
    .AddSupportedUICultures(supportedCultures);

app.UseRequestLocalization(localizationOptions);

// Handle mapped culture routes (e.g. /en-US/home, /vi-VN/solutions)
app.Map("{culture:regex(^(en-US|vi-VN)$)}/{**slug}", async (string culture, HttpContext context, IWebHostEnvironment env) => 
{
    // Try to find index.html
    var fileInfo = env.WebRootFileProvider.GetFileInfo("index.html");
    if (!fileInfo.Exists)
    {
        // In Development with Hosted Blazor, index.html might not be in Server's wwwroot strictly directly depending on setup,
        // but typically it is served via StaticFiles/BlazorFrameworkFiles.
        // If we can't find it easily via IWebHostEnvironment in Dev, we might fail.
        // However, for this task let's assume standard structure or handle gracefully.
        return Results.NotFound("index.html not found in wwwroot. Ensure the Client project is built.");
    }

    using var stream = fileInfo.CreateReadStream();
    using var reader = new StreamReader(stream);
    var html = await reader.ReadToEndAsync();
    
    // Replace base tag: <base href="/" /> -> <base href="/vi-VN/" />
    // Be robust with spaces or standard format
    var modifiedHtml = html.Replace("<base href=\"/\" />", $"<base href=\"/{culture}/\" />")
                           .Replace("<base href=\"/\"/>", $"<base href=\"/{culture}/\" />");

    return Results.Content(modifiedHtml, "text/html");
});

// EN: Map BFF API controllers
// VI: Map BFF API controllers
app.MapControllers();

// EN: Fallback to index.html for SPA routing (default culture)
// VI: Fallback đến index.html cho SPA routing (ngôn ngữ mặc định)
app.MapFallbackToFile("index.html");

app.Run();