/*
    Copyright 2016-2023 melonDS team

    This file is part of melonDS.

    melonDS is free software: you can redistribute it and/or modify it under
    the terms of the GNU General Public License as published by the Free
    Software Foundation, either version 3 of the License, or (at your option)
    any later version.

    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with melonDS. If not, see http://www.gnu.org/licenses/.
*/

#ifndef SCREEN_H
#define SCREEN_H

#include <optional>

#include "glad/glad.h"
#include "FrontendUtil.h"
#include "duckstation/gl/context.h"

#include <QWidget>
#include <QWindow>
#include <QMainWindow>
#include <QImage>
#include <QActionGroup>
#include <QTimer>
#include <QMutex>
#include <QScreen>
#include <QCloseEvent>


class EmuThread;


const struct { int id; float ratio; const char* label; } aspectRatios[] =
{
    { 0, 1,                       "4:3 (native)" },
    { 4, (5.f  / 3) / (4.f / 3), "5:3 (3DS)"},
    { 1, (16.f / 9) / (4.f / 3),  "16:9" },
    { 2, (21.f / 9) / (4.f / 3),  "21:9" },
    { 3, 0,                       "window" }
};
constexpr int AspectRatiosNum = sizeof(aspectRatios) / sizeof(aspectRatios[0]);


class ScreenHandler
{
    Q_GADGET

public:
    ScreenHandler(QWidget* widget);
    virtual ~ScreenHandler();
    QTimer* setupMouseTimer();
    void updateMouseTimer();
    QTimer* mouseTimer;
    QSize screenGetMinSize(int factor);

protected:
    void screenSetupLayout(int w, int h);

    void screenOnMousePress(QMouseEvent* event);
    void screenOnMouseRelease(QMouseEvent* event);
    void screenOnMouseMove(QMouseEvent* event);

    void screenHandleTablet(QTabletEvent* event);
    void screenHandleTouch(QTouchEvent* event);

    float screenMatrix[Frontend::MaxScreenTransforms][6];
    int screenKind[Frontend::MaxScreenTransforms];
    int numScreens;

    bool touching = false;

    void showCursor();
};


class ScreenPanelNative : public QWidget, public ScreenHandler
{
    Q_OBJECT

public:
    explicit ScreenPanelNative(QWidget* parent);
    virtual ~ScreenPanelNative();

protected:
    void paintEvent(QPaintEvent* event) override;

    void resizeEvent(QResizeEvent* event) override;

    void mousePressEvent(QMouseEvent* event) override;
    void mouseReleaseEvent(QMouseEvent* event) override;
    void mouseMoveEvent(QMouseEvent* event) override;

    void tabletEvent(QTabletEvent* event) override;
    bool event(QEvent* event) override;
private slots:
    void onScreenLayoutChanged();

private:
    void setupScreenLayout();

    QImage screen[2];
    QTransform screenTrans[Frontend::MaxScreenTransforms];
};


class ScreenPanelGL : public QWidget, public ScreenHandler
{
    Q_OBJECT

public:
    explicit ScreenPanelGL(QWidget* parent);
    virtual ~ScreenPanelGL();

    std::optional<WindowInfo> getWindowInfo();

    bool createContext();

    void setSwapInterval(int intv);

    void initOpenGL();
    void deinitOpenGL();
    void drawScreenGL();

    GL::Context* getContext() { return glContext.get(); }

    void transferLayout();
protected:

    qreal devicePixelRatioFromScreen() const;
    int scaledWindowWidth() const;
    int scaledWindowHeight() const;

    QPaintEngine* paintEngine() const override;

    void resizeEvent(QResizeEvent* event) override;

    void mousePressEvent(QMouseEvent* event) override;
    void mouseReleaseEvent(QMouseEvent* event) override;
    void mouseMoveEvent(QMouseEvent* event) override;

    void tabletEvent(QTabletEvent* event) override;
    bool event(QEvent* event) override;

private slots:
    void onScreenLayoutChanged();

private:
    void setupScreenLayout();

    std::unique_ptr<GL::Context> glContext;

    GLuint screenVertexBuffer, screenVertexArray;
    GLuint screenTexture;
    GLuint screenShaderProgram[3];
    GLuint screenShaderTransformULoc, screenShaderScreenSizeULoc;

    QMutex screenSettingsLock;
    WindowInfo windowInfo;
    bool filter;

    int lastScreenWidth = -1, lastScreenHeight = -1;
};

#endif // SCREEN_H