/*
* Copyright (C) 2008 Emweb bv, Herent, Belgium.
*
* See the LICENSE file for terms of use.
*/

#include <Wt/WApplication.h>
#include <Wt/WBreak.h>
#include <Wt/WContainerWidget.h>
#include <Wt/WLineEdit.h>
#include <Wt/WPushButton.h>
#include <Wt/WText.h>

/*
* A simple hello world application class which demonstrates how to react
* to events, read input, and give feed-back.
*/
class HelloApplication : public Wt::WApplication
{
public:
HelloApplication(const Wt::WEnvironment& env);

private:
Wt::WLineEdit *nameEdit_;
Wt::WText *greeting_;

void greet();
};

/*
* The env argument contains information about the new session, and
* the initial request. It must be passed to the WApplication
* constructor so it is typically also an argument for your custom
* application constructor.
*/
HelloApplication::HelloApplication(const Wt::WEnvironment& env)
: WApplication(env)
{
setTitle("Hello world"); // application title

root()->addWidget(std::make_unique<Wt::WText>("Your name, please ? ")); // show some text

nameEdit_ = root()->addWidget(std::make_unique<Wt::WLineEdit>()); // allow text input
nameEdit_->setFocus(); // give focus

auto button = root()->addWidget(std::make_unique<Wt::WPushButton>("Greet me."));
// create a button
button->setMargin(5, Wt::Side::Left); // add 5 pixels margin

root()->addWidget(std::make_unique<Wt::WBreak>()); // insert a line break
greeting_ = root()->addWidget(std::make_unique<Wt::WText>()); // empty text

/*
* Connect signals with slots
*
* - simple Wt-way: specify object and method
*/
button->clicked().connect(this, &HelloApplication::greet);

/*
* - using an arbitrary function object, e.g. useful to bind
* values with std::bind() to the resulting method call
*/
nameEdit_->enterPressed().connect(std::bind(&HelloApplication::greet, this));

/*
* - using a lambda:
*/
button->clicked().connect([=]() {
std::cerr << "Hello there, " << nameEdit_->text() << std::endl;
});
}

void HelloApplication::greet()
{
/*
* Update the text, using text input into the nameEdit_ field.
*/
greeting_->setText("Hello there, " + nameEdit_->text());
}

int main(int argc, char **argv)
{
/*
* Your main method may set up some shared resources, but should then
* start the server application (FastCGI or httpd) that starts listening
* for requests, and handles all of the application life cycles.
*
* The last argument to WRun specifies the function that will instantiate
* new application objects. That function is executed when a new user surfs
* to the Wt application, and after the library has negotiated browser
* support. The function should return a newly instantiated application
* object.
*/
return Wt::WRun(argc, argv, [](const Wt::WEnvironment &env) {
/*
* You could read information from the environment to decide whether
* the user has permission to start a new application
*/
return std::make_unique<HelloApplication>(env);
});
}