namespace DTLib.Web.Routes;

public class ServeFilesRouteHandler(IOPath _publicDir, string _homePageUrl = "index.html") : IRouteHandler
{
    public async Task<HttpStatusCode> HandleRequest(HttpListenerContext ctx)
    {
        if (ctx.Request.HttpMethod != "GET")
            return HttpStatusCode.BadRequest;

        string requestPath = ctx.Request.Url?.AbsolutePath!;
        if (string.IsNullOrEmpty(requestPath) || requestPath == "/")
        {
            requestPath = _homePageUrl;
        }
        
        string ext = Path.Extension(requestPath).Str;
        IOPath filePath = Path.Concat(_publicDir, requestPath);
        if (!File.Exists(filePath))
            return HttpStatusCode.NotFound;

        List<(string key, string val)> headers = ext switch
        {
            "html" => [("Content-Type", "text/html")],
            "css" => [("Content-Type", "text/css")],
            "js" or "jsx" or "ts" or "tsx" or "map" => [("Content-Type", "text/javascript")],
            _ =>
            [
                ("Content-Type", "binary/octet-stream"),
                ("Content-Disposition", $"attachment filename={filePath.LastName()}")
            ]
        };
        foreach (var header in headers)
            ctx.Response.Headers.Set(header.key, header.val);

        var fileStream = File.OpenRead(filePath);
        ctx.Response.ContentLength64 = fileStream.Length;
        await fileStream.CopyToAsync(ctx.Response.OutputStream);
        return HttpStatusCode.OK;
    }
}