// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only

/*!

    \example demos/coffee
    \title Coffee Machine
    \ingroup qtquickdemos
    \brief A Qt Quick application with a state-based custom user interface.
    \meta {tag} {quick,embedded,states,touch}
    \examplecategory {Application Examples}
    \examplecategory {Embedded}
    \examplecategory {Mobile}

    \borderedimage coffee_machine_overview.png

    \section1 Coffee Machine example overview

    This app demonstrates a cross platform, multi screen size and responsive way
    of implementing a typical user interface for product ordering.

    \section2 Selecting a recipe

    \image coffee_machine_selection.png
    \caption The coffee selection

    The coffee machine application lets you choose a type of coffee and indicates
    how many coffees of that type you have left to order.

    \section2 Coffee customization

    \borderedimage coffee_machine_modify.png

    Once a recipe is selected, the app displays what ratio the coffee blend
    will contain of:
    \list
        \li brewed coffee
        \li hot milk
        \li milk foam
        \li sugar
    \endlist
    This can be modified using sliders.

    \section2 Displaying the brewing status

    Once the user has acknowledged that the cup is in the machine the brew starts.

    When the brew has been started, the app shows an animated display of the
    brewing process.

    \section2 Coffee is ready

    Once the brewing process has ended, the app shows coffee cup with the desired
    coffee mix in it for a few seconds before returning to the starting page.

    \section1 How it works

    Here we discuss how these features are implemented.

    \section2 Adapting to screen sizes and orientation

    The application window root object has initial values for height
    and width, which will be used as the window size on desktop platforms.
    The default QWindow::AutomaticVisibility ensures that the window will
    be shown as maximized or fullscreen on platforms that require it,
    such as mobile platforms.

    \snippet demos/coffee/main.qml Set application window size

    From there child objects of the \c ApplicationWindow fetch the size of the
    \c ApplicationWindow to determine their own sizes accordingly.

    The app uses \l {GridLayout} throughout the application page components to
    easily adapt to changes in screen orientation.

    \section2 Navigating through the app pages

    The application uses \l {StackView} QML type to display different pages of
    the app. The \c StackView handling the different page components is
    implemented in \c ApplicationFlowForm.ui.qml.

    Navigating from one page to next triggers a state change in
    \c ApplicationFlow.qml where the needed property changes are handled by
    \l {PropertyChanges} QML type:

    \snippet demos/coffee/ApplicationFlow.qml States

    The animations happening during these state changes are implemented with
    \l {Transition} and \l {PropertyAnimation} inside the \c StackView component
    in \c ApplicationFLowForm.ui.qml.

    \section2 Implementing start page

    The application starts by showing the \c Home page to the user as the initial
    item in the \l {StackView}:

    \snippet demos/coffee/ApplicationFlowForm.ui.qml Stack view

    The \c Home component is structured by placing \l {Item} component as the
    root object with state machine and appropriate property aliases, followed by
    \l {GridLayout}. This same kind of structuring will be used in all of the app
    page components.

    The \c Home page displays an image of a coffee cup with
    Qt logo on top, Coffee Machine as a title, caption with some catchy briefing
    on what the user can expect and a \c getStartedButton button.

    The user can move forward by pressing the \c getStartedButton, the button
    \c onClicked function is implemented \c ApplicationFlow.qml:

    \snippet demos/coffee/ApplicationFlow.qml On clicked

    This will trigger the state change to "Coffee-selection" in
    \c ApplicationFlow.qml and push the \c choosingCoffee component on top of
    the \c Home component in \l{StackView}.

    \section2 Implementing coffee selection

    On the Coffee Selection page \c ChoosingCoffee.qml is displayed, here the
    user sees 4 different coffee options to choose from. These options are
    displayed as \c CoffeeCards which are located inside the \l{GridLayout} in
    \c ChoosingCoffee.qml:

    \snippet demos/coffee/ChoosingCoffeeForm.ui.qml Coffees

    The implementation of the \c CoffeeCard is located \c CoffeeCard.qml.

    These  cards may be displayed in either grid or in a row type of way
    depending on the available screen width and height properties that the
    \c ApplicationWindow root object follows and passes down to the
    \c ChoosingCoffee.qml and to the \l{GridLayout} in there through the state
    machine.

    \c CoffeeCards vary in their names, brewing times, ingredients and how many
    cups there are available at the moment.

    On this page the user can also change the application theme for the first time
    by pressing the little sun looking icon button from the upper right corner of
    the screen.
    Pressing the theme button calls \c themeButton function in \c ApplicationFlow.qml:

    \snippet demos/coffee/ApplicationFlow.qml Theme button

    The function changes the \c currentTheme property of \c Colors.qml and colors
    change throughout the app by property bindings automatically.
    All the colors used in app are located in \c Colors.qml.

    If theme is switched to light theme the theme changing icon button icon turns
    to represent a half moon.

    Pressing on any of the coffee cards triggers a state change inside
    \l{AbstractButton} in \c CoffeeCard.qml which then triggers \l{NumberAnimation}
    through \l{Transition}:

    \snippet demos/coffee/CoffeeCardForm.ui.qml AbstractButton

    This will scale the selected coffee card down to smaller size and
    turns the edges of the card to green giving user the expression that the
    coffee was indeed selected.

    Every coffee cards \c button property alias \c onClicked function binds to a
    function located in \c ApplicationFlow.qml. When user presses any of the
    coffee cards the function with a name correlating with the chosen coffee
    option gets called. The function will set the state of \c ApplicationFlow.qml
    to \c Settings , push a new component to the \l{StackView} and set the
    ingredient properties accordingly.

    \section2 Implementing coffee settings

    On this page the user can customize their coffee option to match their
    preference by adjusting custom \l {Slider} QML types. Changing the value of
    sliders will affect the liquid levels seen inside the coffee cup, this is
    made possible by binding the height of the liquid images inside \c Cup.qml to
    the values of corresponding sliders.

    The values of the sliders will be stored to property variables in
    \c ApplicationFLow.qml through \c onValueChanged function.

    \snippet demos/coffee/Settings.qml Value changed

    Clicking on Start button changes the state of \c ApplicationFlow.qml to
    "Insert", and the app displays the \c Insert.qml.

    \section2 Implementing insert cup

    On this page the user is instructed to insert their cup on to the machine
    before the brewing process can start.

    Pressing the \c Continue button will move app to \c Progress page.

    \section2 Implementing brewing coffee

    Progress page displays a coffee cup and progress bar that will both in their
    own way signal the brewing process in real time.

    The coffee cup here once filled will display the exact same configuration as
    the user selected on \c Settings page, this is made sure by binding the
    \c Cup property variables  to the saved corresponding values in
    \c ApplicationFlow.qml.

    The animation for filling the coffee cup happens with state engines
    \l {Transition} and \l {SmoothedAnimation}.

    \snippet demos/coffee/ProgressForm.ui.qml Cup

    The progress bar animation is implemented with \l {Behavior}.

    \snippet demos/coffee/Progress.qml Behavior

    \l {Timer} will take care of updating the application state once the brewing
    is done.

    \snippet demos/coffee/Progress.qml Timer

    \section2 Implementing coffee ready

    Ready page displays a coffee cup filled with whatever configuration the user
    selected with a "Your coffee is ready" text and a check icon.

    When this page is displayed a \l {Timer} starts running and once the interval
    set is reached user is directed back to \c Home.qml.

*/

