namespace Xilium.CefGlue
{
    using System;
    using System.Collections.Generic;
    using System.Diagnostics;
    using System.Runtime.InteropServices;
    using Xilium.CefGlue.Interop;

    /// <summary>
    /// Implement this interface to handle events related to browser requests. The
    /// methods of this class will be called on the IO thread unless otherwise
    /// indicated.
    /// </summary>
    public abstract unsafe partial class CefResourceRequestHandler
    {
        private cef_cookie_access_filter_t* get_cookie_access_filter(cef_resource_request_handler_t* self, cef_browser_t* browser, cef_frame_t* frame, cef_request_t* request)
        {
            CheckSelf(self);

            var m_browser = CefBrowser.FromNativeOrNull(browser);
            var m_frame = CefFrame.FromNativeOrNull(frame);
            var m_request = CefRequest.FromNative(request); // TODO dispose?

            var m_result = GetCookieAccessFilter(m_browser, m_frame, m_request);

            return m_result != null ? m_result.ToNative() : null;
        }

        /// <summary>
        /// Called on the IO thread before a resource request is loaded. The |browser|
        /// and |frame| values represent the source of the request, and may be NULL for
        /// requests originating from service workers or CefURLRequest. To optionally
        /// filter cookies for the request return a CefCookieAccessFilter object. The
        /// |request| object cannot not be modified in this callback.
        /// </summary>
        protected abstract CefCookieAccessFilter GetCookieAccessFilter(CefBrowser browser, CefFrame frame, CefRequest request);


        private CefReturnValue on_before_resource_load(cef_resource_request_handler_t* self, cef_browser_t* browser, cef_frame_t* frame, cef_request_t* request, cef_request_callback_t* callback)
        {
            CheckSelf(self);

            var m_browser = CefBrowser.FromNativeOrNull(browser);
            var m_frame = CefFrame.FromNativeOrNull(frame);
            var m_request = CefRequest.FromNative(request); 
            var m_callback = CefRequestCallback.FromNative(callback);

            var result = OnBeforeResourceLoad(m_browser, m_frame, m_request, m_callback);

            if (result != CefReturnValue.ContinueAsync)
            {
                m_browser.Dispose();
                m_frame.Dispose();
                m_request.Dispose();
                m_callback.Dispose();
            }

            return result;
        }

        /// <summary>
        /// Called on the IO thread before a resource request is loaded. The |browser|
        /// and |frame| values represent the source of the request, and may be NULL for
        /// requests originating from service workers or CefURLRequest. To redirect or
        /// change the resource load optionally modify |request|. Modification of the
        /// request URL will be treated as a redirect. Return RV_CONTINUE to continue
        /// the request immediately. Return RV_CONTINUE_ASYNC and call
        /// CefRequestCallback:: Continue() at a later time to continue or cancel the
        /// request asynchronously. Return RV_CANCEL to cancel the request immediately.
        /// </summary>
        protected virtual CefReturnValue OnBeforeResourceLoad(CefBrowser browser, CefFrame frame, CefRequest request, CefRequestCallback callback)
        {
            return CefReturnValue.Continue;
        }


        private cef_resource_handler_t* get_resource_handler(cef_resource_request_handler_t* self, cef_browser_t* browser, cef_frame_t* frame, cef_request_t* request)
        {
            CheckSelf(self);

            var m_browser = CefBrowser.FromNativeOrNull(browser);
            var m_frame = CefFrame.FromNativeOrNull(frame);
            using (var m_request = CefRequest.FromNative(request))
            {
                var handler = GetResourceHandler(m_browser, m_frame, m_request);

                return handler != null ? handler.ToNative() : null;
            }
        }

        /// <summary>
        /// Called on the IO thread before a resource is loaded. The |browser| and
        /// |frame| values represent the source of the request, and may be NULL for
        /// requests originating from service workers or CefURLRequest. To allow the
        /// resource to load using the default network loader return NULL. To specify a
        /// handler for the resource return a CefResourceHandler object. The |request|
        /// object cannot not be modified in this callback.
        /// </summary>
        protected virtual CefResourceHandler GetResourceHandler(CefBrowser browser, CefFrame frame, CefRequest request)
        {
            return null;
        }


        private void on_resource_redirect(cef_resource_request_handler_t* self, cef_browser_t* browser, cef_frame_t* frame, cef_request_t* request, cef_response_t* response, cef_string_t* new_url)
        {
            CheckSelf(self);

            var m_browser = CefBrowser.FromNativeOrNull(browser);
            var m_frame = CefFrame.FromNativeOrNull(frame);
            var m_request = CefRequest.FromNative(request); // TODO dispose?
            var m_response = CefResponse.FromNative(response); // TODO dispose?
            var m_newUrl = cef_string_t.ToString(new_url);

            var o_newUrl = m_newUrl;
            OnResourceRedirect(m_browser, m_frame, m_request, m_response, ref m_newUrl);

            if ((object)m_newUrl != (object)o_newUrl)
            {
                cef_string_t.Copy(m_newUrl, new_url);
            }
        }

        /// <summary>
        /// Called on the IO thread when a resource load is redirected. The |browser|
        /// and |frame| values represent the source of the request, and may be NULL for
        /// requests originating from service workers or CefURLRequest. The |request|
        /// parameter will contain the old URL and other request-related information.
        /// The |response| parameter will contain the response that resulted in the
        /// redirect. The |new_url| parameter will contain the new URL and can be
        /// changed if desired. The |request| and |response| objects cannot be modified
        /// in this callback.
        /// </summary>
        protected virtual void OnResourceRedirect(CefBrowser browser, CefFrame frame, CefRequest request, CefResponse response, ref string newUrl)
        {
        }


        private int on_resource_response(cef_resource_request_handler_t* self, cef_browser_t* browser, cef_frame_t* frame, cef_request_t* request, cef_response_t* response)
        {
            CheckSelf(self);

            var m_browser = CefBrowser.FromNativeOrNull(browser);
            var m_frame = CefFrame.FromNativeOrNull(frame);
            var m_request = CefRequest.FromNative(request); // TODO dispose?
            var m_response = CefResponse.FromNative(response); // TODO dispose?

            var m_result = OnResourceResponse(m_browser, m_frame, m_request, m_response);

            return m_result ? 1 : 0;
        }

        /// <summary>
        /// Called on the IO thread when a resource response is received. The |browser|
        /// and |frame| values represent the source of the request, and may be NULL for
        /// requests originating from service workers or CefURLRequest. To allow the
        /// resource load to proceed without modification return false. To redirect or
        /// retry the resource load optionally modify |request| and return true.
        /// Modification of the request URL will be treated as a redirect. Requests
        /// handled using the default network loader cannot be redirected in this
        /// callback. The |response| object cannot be modified in this callback.
        /// WARNING: Redirecting using this method is deprecated. Use
        /// OnBeforeResourceLoad or GetResourceHandler to perform redirects.
        /// </summary>
        protected virtual bool OnResourceResponse(CefBrowser browser, CefFrame frame, CefRequest request, CefResponse response)
        {
            return false;
        }


        private cef_response_filter_t* get_resource_response_filter(cef_resource_request_handler_t* self, cef_browser_t* browser, cef_frame_t* frame, cef_request_t* request, cef_response_t* response)
        {
            CheckSelf(self);

            var mBrowser = CefBrowser.FromNativeOrNull(browser);
            var mFrame = CefFrame.FromNativeOrNull(frame);
            var mRequest = CefRequest.FromNative(request); // TODO dispose?
            var mResponse = CefResponse.FromNative(response); // TODO dispose?

            var result = GetResourceResponseFilter(mBrowser, mFrame, mRequest, mResponse);

            if (result != null)
            {
                return result.ToNative();
            }

            return null;
        }

        /// <summary>
        /// Called on the IO thread to optionally filter resource response content. The
        /// |browser| and |frame| values represent the source of the request, and may
        /// be NULL for requests originating from service workers or CefURLRequest.
        /// |request| and |response| represent the request and response respectively
        /// and cannot be modified in this callback.
        /// </summary>
        protected virtual CefResponseFilter GetResourceResponseFilter(CefBrowser browser, CefFrame frame, CefRequest request, CefResponse response)
        {
            return null;
        }


        private void on_resource_load_complete(cef_resource_request_handler_t* self, cef_browser_t* browser, cef_frame_t* frame, cef_request_t* request, cef_response_t* response, CefUrlRequestStatus status, long received_content_length)
        {
            CheckSelf(self);

            var mBrowser = CefBrowser.FromNativeOrNull(browser);
            var mFrame = CefFrame.FromNativeOrNull(frame);
            var mRequest = CefRequest.FromNative(request); // TODO dispose?
            var mResponse = CefResponse.FromNative(response); // TODO dispose?

            OnResourceLoadComplete(mBrowser, mFrame, mRequest, mResponse, status, received_content_length);
        }

        /// <summary>
        /// Called on the IO thread when a resource load has completed. The |browser|
        /// and |frame| values represent the source of the request, and may be NULL for
        /// requests originating from service workers or CefURLRequest. |request| and
        /// |response| represent the request and response respectively and cannot be
        /// modified in this callback. |status| indicates the load completion status.
        /// |received_content_length| is the number of response bytes actually read.
        /// This method will be called for all requests, including requests that are
        /// aborted due to CEF shutdown or destruction of the associated browser. In
        /// cases where the associated browser is destroyed this callback may arrive
        /// after the CefLifeSpanHandler::OnBeforeClose callback for that browser. The
        /// CefFrame::IsValid method can be used to test for this situation, and care
        /// should be taken not to call |browser| or |frame| methods that modify state
        /// (like LoadURL, SendProcessMessage, etc.) if the frame is invalid.
        /// </summary>
        protected virtual void OnResourceLoadComplete(CefBrowser browser, CefFrame frame, CefRequest request, CefResponse response, CefUrlRequestStatus status, long receivedContentLength)
        {
        }


        private void on_protocol_execution(cef_resource_request_handler_t* self, cef_browser_t* browser, cef_frame_t* frame, cef_request_t* request, int* allow_os_execution)
        {
            CheckSelf(self);

            var m_browser = CefBrowser.FromNativeOrNull(browser);
            var m_frame = CefFrame.FromNativeOrNull(frame);
            var m_request = CefRequest.FromNative(request); // TODO dispose?
            var m_allow_os_execution = *allow_os_execution != 0;

            OnProtocolExecution(m_browser, m_frame, m_request, ref m_allow_os_execution);

            *allow_os_execution = m_allow_os_execution ? 1 : 0;
        }

        /// <summary>
        /// Called on the IO thread to handle requests for URLs with an unknown
        /// protocol component. The |browser| and |frame| values represent the source
        /// of the request, and may be NULL for requests originating from service
        /// workers or CefURLRequest. |request| cannot be modified in this callback.
        /// Set |allow_os_execution| to true to attempt execution via the registered OS
        /// protocol handler, if any.
        /// SECURITY WARNING: YOU SHOULD USE THIS METHOD TO ENFORCE RESTRICTIONS BASED
        /// ON SCHEME, HOST OR OTHER URL ANALYSIS BEFORE ALLOWING OS EXECUTION.
        /// </summary>
        protected virtual void OnProtocolExecution(CefBrowser browser, CefFrame frame, CefRequest request, ref bool allowOSExecution)
        {
        }
    }
}