#import <Cocoa/Cocoa.h>
#import <MetalKit/MetalKit.h>
#import <Foundation/Foundation.h>
#include <GameController/GameController.h>
#include <mach/mach_time.h>
#include <gfx_metal.hpp>
#include <engine.hpp>
#include <map>
#include <file.hpp>

#include <@APP_INCLUDE@>

uint64_t last_time = 0;
bool is_qutting = false;

static std::map<InputButton, int> inputToKeyCode = { {
    {InputButton::C, 8},
    {InputButton::V, 9},
    {InputButton::X, 7},
    {InputButton::Q, 12},
    {InputButton::Y, 16},
    {InputButton::Z, 6},
    {InputButton::Backspace, 51},
    {InputButton::Enter, 36},
    {InputButton::Space, 49},
    {InputButton::Ctrl, 17},
    {InputButton::Shift, 10},
    {InputButton::A, 0},
    {InputButton::W, 13},
    {InputButton::S, 1},
    {InputButton::D, 2},
    {InputButton::Escape, 53},
    {InputButton::Tab, 48},
    {InputButton::LeftArrow, 123},
    {InputButton::RightArrow, 124}
}};

struct NativeWindow;

const char* platform::get_name() {
    return "macOS";
}

int platform::get_keycode(InputButton key) {
    if(inputToKeyCode.count(key))
        return inputToKeyCode[key];
    else
        return -1;
}

GFX* interface = nullptr;

@APP_CLASS@* app = nullptr;

float scrollX = 0.0f, scrollY = 0.0f;

std::array<bool, 8> inputKeys;

float rightX = 0.0f, rightY = 0.0f;
float leftX = 0.0f, leftY = 0.0f;

@interface GameView : NSObject<NSWindowDelegate>

@property NativeWindow *native;

@end

struct NativeWindow {
    int index = 0;
    NSWindow* window;
    GameView* delegate;
    CAMetalLayer* layer;
    bool willCaptureMouse = false;
    
    int currentWidth = 0, currentHeight = 0;
    int timeout = 0;
    
    NSPoint currentMousePos;
    bool showingCursor = true;
    bool inFocus = true;
};

std::vector<NativeWindow*> windows;

NativeWindow* get_window(const int index) {
    for(auto& window : windows) {
        if(window->index == index)
            return window;
    }
    
    return nullptr;
}

@implementation GameView

- (void)gameQuit {
    engine->prepare_quit();
}
- (void)gameFocus {
    if(![self native]->showingCursor)
        [NSCursor hide];
        
    [self native]->inFocus = true;
}
- (void)gameLostFocus {
    if(![self native]->showingCursor)
        [NSCursor unhide];
        
    [self native]->inFocus = false;
}

const double NANOSECONDS_TO_MILLISECONDS = 1.0 / 1000000000.0;

- (void)update {
    const bool is_main_window = [self native]->index == 0;
    
    if(is_main_window) {
        if([self native]->willCaptureMouse && [self native]->timeout > 5 && [self native]->inFocus) {
            NSPoint point;
            point.x = [self native]->window.frame.origin.x + ([self native]->currentWidth / 2);
            point.y = [NSScreen mainScreen].frame.size.height - ([self native]->window.frame.origin.y + ([self native]->currentHeight / 2));

            CGWarpMouseCursorPosition(point);
            CGAssociateMouseAndMouseCursorPosition(true);

            [self native]->currentMousePos.x = [self native]->currentWidth / 2;
            [self native]->currentMousePos.y = [self native]->currentHeight / 2;
                        
            [self native]->timeout = 0;
        }

        [self native]->timeout++;
    }
}

- (void)render {
    engine->render([self native]->index);
}

- (void)windowDidResize:(NSNotification *)notification {
    [self native]->currentWidth = [self native]->window.contentView.frame.size.width;
    [self native]->currentHeight = [self native]->window.contentView.frame.size.height;
    
    NSRect bounds = [[self native]->layer bounds];
    bounds = [[self native]->window convertRectToBacking:bounds];
    
    [self native]->layer.drawableSize = NSSizeToCGSize(bounds.size);;
    
    engine->resize([self native]->index, {static_cast<uint32_t>([self native]->currentWidth), static_cast<uint32_t>([self native]->currentHeight)});
}

-(void)windowWillClose:(NSNotification *)notification {
    if([self native]->index == 0)
        is_qutting = app->should_quit();
}

- (void) controllerConnected {
    GCController* controller = [GCController controllers][0];
    [[controller extendedGamepad] setValueChangedHandler:^(GCExtendedGamepad * _Nonnull gamepad, GCControllerElement * _Nonnull element) {
        const auto& handle_element = [element](int index, GCControllerElement* e) {
            if(element == e)
                inputKeys[index] = [(GCControllerButtonInput*)e value] == 1.0f;
        };
        
        handle_element(0, [[controller extendedGamepad] buttonA]);
        handle_element(1, [[controller extendedGamepad] buttonB]);
        handle_element(2, [[controller extendedGamepad] buttonX]);
        handle_element(3, [[controller extendedGamepad] buttonY]);
        
        if(element == [[controller extendedGamepad] dpad]) {
            inputKeys[4] = [[[[controller extendedGamepad] dpad] up] value] == 1.0f;
            inputKeys[5] = [[[[controller extendedGamepad] dpad] down] value] == 1.0f;
            inputKeys[6] = [[[[controller extendedGamepad] dpad] left] value] == 1.0f;
            inputKeys[7] = [[[[controller extendedGamepad] dpad] right] value] == 1.0f;
        }
        
        if(element == [[controller extendedGamepad] leftThumbstick]) {
            leftX = [[[[controller extendedGamepad] leftThumbstick] xAxis] value];
            leftY = [[[[controller extendedGamepad] leftThumbstick] yAxis] value];
        }

        if(element == [[controller extendedGamepad] rightThumbstick]) {
            rightX = [[[[controller extendedGamepad] rightThumbstick] xAxis] value];
            rightY = [[[[controller extendedGamepad] rightThumbstick] yAxis] value];
        }
    }];
}

@end

std::map<int, bool> pressed;
NSString* currentCharString = nil;

bool platform::supports_feature(const PlatformFeature feature) {
    switch(feature) {
        case PlatformFeature::Windowing:
            return true;
    }
    
    return false;
}

bool platform::get_key_down(const InputButton key) {
    if(key == InputButton::ButtonA)
        return inputKeys[0];
    
    if(key == InputButton::ButtonB)
        return inputKeys[1];
    
    if(key == InputButton::ButtonX)
        return inputKeys[2];
    
    if(key == InputButton::ButtonY)
        return inputKeys[3];
    
    if(key == InputButton::DPadUp)
        return inputKeys[4];
    
    if(key == InputButton::DPadDown)
        return inputKeys[5];
    
    if(key == InputButton::DPadLeft)
        return inputKeys[6];
    
    if(key == InputButton::DPadRight)
        return inputKeys[7];
        
    if(inputToKeyCode.count(key))
        return pressed[inputToKeyCode[key]];
    else
        return false;
}

char* platform::translate_keycode(const unsigned int keycode) {
    return const_cast<char*>([currentCharString UTF8String]);
}

inline std::string clean_path(const std::string_view path) {
    auto p = replace_substring(path, "%20", " ");
    
    // this is a path returned by an editor, so skip it
    // TODO: find a better way to do this!! NOO!!
    if(p.find("file:///") != std::string::npos)
        return p.substr(7, p.length());
    else
        return p;
}

void platform::open_dialog(const bool existing, std::function<void(std::string)> returnFunction, bool openDirectory) {
    NSOpenPanel* openDlg = [NSOpenPanel openPanel];

    [openDlg setCanChooseFiles:YES];

    [openDlg setAllowsMultipleSelection:NO];

    [openDlg setCanChooseDirectories:openDirectory];
    
    [openDlg setCanChooseFiles:!openDirectory];

    if([openDlg runModal] == NSModalResponseOK)
        returnFunction(clean_path([openDlg.URLs[0].absoluteString UTF8String]));
}

void platform::save_dialog(std::function<void(std::string)> returnFunction) {
    NSSavePanel* openDlg = [NSSavePanel savePanel];

    if ([openDlg runModal] == NSModalResponseOK)
        returnFunction(clean_path([openDlg.URL.absoluteString UTF8String]));
}

void platform::capture_mouse(const bool capture) {
    windows[0]->willCaptureMouse = capture;

    if(windows[0]->showingCursor && capture) {
        [NSCursor hide];
        windows[0]->showingCursor = false;
    } else if(!windows[0]->showingCursor && !capture) {
        [NSCursor unhide];
        windows[0]->showingCursor = true;
    }
}

float platform::get_window_dpi(const int index) {
    auto window = get_window(index);
    return [window->window backingScaleFactor];
}

float platform::get_monitor_dpi() {
    return [[NSScreen mainScreen] backingScaleFactor];
}

CGRect toTopLeftSpace(NSRect frame) {
    frame.origin.y = NSMaxY([[NSScreen mainScreen] frame]) - NSMaxY(frame);
    return NSRectToCGRect(frame);
}

prism::Rectangle platform::get_monitor_resolution() {
    auto frame = toTopLeftSpace([[NSScreen mainScreen] frame]);
    
    return {static_cast<int32_t>(frame.origin.x), static_cast<int32_t>(frame.origin.y), static_cast<uint32_t>(frame.size.width), static_cast<uint32_t>(frame.size.height)};
}

prism::Rectangle platform::get_monitor_work_area() {
    auto frame = toTopLeftSpace([[NSScreen mainScreen] visibleFrame]);
    
    return {static_cast<int32_t>(frame.origin.x), static_cast<int32_t>(frame.origin.y), static_cast<uint32_t>(frame.size.width), static_cast<uint32_t>(frame.size.height)};
}

NSPoint get_fixed_cursor_point(NSPoint point) {
    return {point.x, std::max(windows[0]->currentHeight - point.y, 0.0)};
}

prism::Offset platform::get_cursor_position() {
    return {static_cast<int32_t>(windows[0]->currentMousePos.x), static_cast<int32_t>(windows[0]->currentMousePos.y)};
}

prism::Offset platform::get_screen_cursor_position() {
    return {static_cast<int32_t>([NSEvent mouseLocation].x), static_cast<int32_t>([[NSScreen mainScreen] frame].size.height - [NSEvent mouseLocation].y)};
}

std::tuple<float, float> platform::get_wheel_delta() {
    return {scrollX, scrollY};
}

std::tuple<float, float> platform::get_left_stick_position() {
    return {leftX, leftY};
}

std::tuple<float, float> platform::get_right_stick_position() {
    return {rightX, rightY};
}

prism::Extent platform::get_window_size(const int index) {
    auto window = get_window(index);
    return {static_cast<uint32_t>(window->currentWidth), static_cast<uint32_t>(window->currentHeight)};
}

prism::Extent platform::get_window_drawable_size(const int index) {
    auto window = get_window(index);
    return {static_cast<uint32_t>(window->currentWidth * window->window.backingScaleFactor), static_cast<uint32_t>(window->currentHeight * window->window.backingScaleFactor)};
}

prism::Offset platform::get_window_position(const int index) {
    auto window = get_window(index);

    auto frame = toTopLeftSpace([window->window contentRectForFrameRect:[window->window frame]]);
    
    return {static_cast<int32_t>(frame.origin.x), static_cast<int32_t>(frame.origin.y)};
}

bool platform::is_window_focused(const int index) {
    auto window = get_window(index);

    return [window->window isKeyWindow];
}

void platform::set_window_focused(const int index) {
    auto window = get_window(index);
    [window->window makeKeyWindow];
}

bool platform::get_mouse_button_down(const int button) {
    return (button + 1) & [NSEvent pressedMouseButtons];
}

void platform::set_window_position(const int index, const prism::Offset offset) {
    auto window = get_window(index);

    NSPoint p;
    p.x = offset.x;
    p.y = [[NSScreen mainScreen] frame].size.height - offset.y;
    
    [window->window setFrameTopLeftPoint:p];
}

void platform::set_window_size(const int index, const prism::Extent extent) {
    auto window = get_window(index);

    NSSize size;
    size.width = extent.width;
    size.height = extent.height;
    
    [window->window setContentSize:size];
}

void platform::set_window_title(const int index, const std::string_view title) {
    auto window = get_window(index);
    [window->window setTitle:[NSString stringWithUTF8String:title.data()]];
}

void platform::mute_output() {}
void platform::unmute_output() {}

int platform::open_window(const std::string_view title, const prism::Rectangle rect, const WindowFlags flags) {
    NativeWindow* native = new NativeWindow();
    native->index = windows.size();
    GameView* del = [[GameView alloc] init];
    native->delegate = del;
    windows.push_back(native);

    NSRect nrect = NSMakeRect(rect.offset.x, rect.offset.y, rect.extent.width, rect.extent.height);
    
    NSWindowStyleMask windowStyle = NSWindowStyleMaskTitled
    | NSWindowStyleMaskClosable
    | NSWindowStyleMaskMiniaturizable;
    
    if(flags == WindowFlags::Resizable)
        windowStyle |= NSWindowStyleMaskResizable;
    else if(flags == WindowFlags::Borderless)
        windowStyle = NSWindowStyleMaskBorderless;
    
    native->window = [[NSWindow alloc]
                        initWithContentRect: nrect
                        styleMask:windowStyle
                        backing: NSBackingStoreBuffered
                        defer: NO];
                        
    native->currentWidth = rect.extent.width;
    native->currentHeight = rect.extent.height;
    
    native->layer = [CAMetalLayer layer];
        
    NSView* view = [[NSView alloc] init];
    view.wantsLayer = YES;
    view.layer = native->layer;
        
    native->layer.contentsScale = [native->window backingScaleFactor];
        
    engine->add_window(view.layer, native->index, rect.extent);

    [native->window setContentView:view];

    if(native->index == 0)
        app->initialize_render();
        
    [native->window setTitle:[NSString stringWithUTF8String:title.data()]];
    
    [del setNative:native];
    
    [native->window setDelegate:del];
    [native->window orderFrontRegardless];
    
    if(native->index == 0) {
        NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
        [nc addObserver:del
            selector:@selector(gameQuit)
            name:NSApplicationWillTerminateNotification
            object:nil];
            
        [nc addObserver:del
            selector:@selector(gameFocus)
            name:NSApplicationDidBecomeActiveNotification
            object:nil];
            
        [nc addObserver:del
            selector:@selector(gameLostFocus)
            name:NSApplicationDidResignActiveNotification
            object:nil];
            
        [nc addObserver:del
            selector:@selector(controllerConnected)
            name:GCControllerDidConnectNotification
            object:nil];
    }
                
    return native->index;
}

void platform::close_window(const int index) {
    auto window = get_window(index);

    engine->remove_window(window->index);

    [window->window close];

    utility::erase(windows, window);
}

void platform::force_quit() {
    [NSApp terminate:nil];
}

int main(int argc, char* argv[]) {
    NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
    
    NSApp = [NSApplication sharedApplication];
    
    engine = new Engine(argc, argv);
    
    app = new @APP_CLASS@();
    engine->set_app(app);
    
    GFXCreateInfo createInfo = {};
    createInfo.api_validation_enabled = true;
    
    interface = new GFXMetal();
    if(interface->initialize(createInfo)) {
        engine->set_gfx(interface);
    } else {
        NSLog(@"Failed to create Metal context!");
        
        return -1;
    }
    
    app_main(engine);
    
    [NSEvent addLocalMonitorForEventsMatchingMask:NSEventMaskKeyDown handler:^(NSEvent *event) {
        pressed[event.keyCode] = true;
        currentCharString = event.characters;
        
        engine->process_key_down(event.keyCode);
        
        return (NSEvent*)nil;
    }];
    
    [NSEvent addLocalMonitorForEventsMatchingMask:NSEventMaskKeyUp handler:^(NSEvent *event) {
         pressed[event.keyCode] = false;
         
         engine->process_key_up(event.keyCode);
         
         return (NSEvent*)nil;
     }];
     
     [NSEvent addLocalMonitorForEventsMatchingMask:NSEventMaskMouseMoved handler:^(NSEvent *event) {
         windows[0]->currentMousePos = get_fixed_cursor_point(event.locationInWindow);
                 
         return event;
     }];

    [NSEvent addLocalMonitorForEventsMatchingMask:NSEventMaskLeftMouseDown handler:^(NSEvent *event) {
        auto point = get_fixed_cursor_point(event.locationInWindow);
        engine->process_mouse_down(0, {static_cast<int32_t>(point.x), static_cast<int32_t>(point.y)});
        
        return event;
    }];

    [NSEvent addLocalMonitorForEventsMatchingMask:NSEventMaskRightMouseDown handler:^(NSEvent *event) {
        auto point = get_fixed_cursor_point(event.locationInWindow);
        engine->process_mouse_down(1, {static_cast<int32_t>(point.x), static_cast<int32_t>(point.y)});
        
        return event;
    }];
    
    [NSEvent addLocalMonitorForEventsMatchingMask:NSEventMaskRightMouseDragged handler:^(NSEvent *event) {
        windows[0]->currentMousePos = get_fixed_cursor_point(event.locationInWindow);

        return event;
    }];

    [NSEvent addLocalMonitorForEventsMatchingMask:NSEventMaskLeftMouseDragged handler:^(NSEvent *event) {
        windows[0]->currentMousePos = get_fixed_cursor_point(event.locationInWindow);
        
        return event;
    }];
    
    [NSEvent addLocalMonitorForEventsMatchingMask:NSEventMaskScrollWheel handler:^(NSEvent *event) {
          double wheel_dx = 0.0;
          double wheel_dy = 0.0;

          wheel_dx = [event scrollingDeltaX];
          wheel_dy = [event scrollingDeltaY];
          if ([event hasPreciseScrollingDeltas])
          {
              wheel_dx *= 0.1;
              wheel_dy *= 0.1;
          }
      
          scrollX += wheel_dx * 0.1f;
          scrollY +=  wheel_dy * 0.1f;
          
          return event;
    }];
    
    last_time = clock_gettime_nsec_np(CLOCK_UPTIME_RAW);
      
    while (!is_qutting) {
        @autoreleasepool {
            NSEvent* event = nullptr;
            do {
                event = [NSApp nextEventMatchingMask: NSEventMaskAny
                                        untilDate: nil
                                           inMode: NSDefaultRunLoopMode
                                          dequeue: YES];
                if(event)
                    [NSApp sendEvent: event];
            } while(event);
            
            const uint64_t current = clock_gettime_nsec_np(CLOCK_UPTIME_RAW);
            const uint64_t elapsed = current - last_time;
            
            for(auto& window : windows) {
                if(window != nullptr)
                    [window->delegate update];
            }
            
            engine->update(elapsed * NANOSECONDS_TO_MILLISECONDS);
            
            engine->begin_frame(elapsed * NANOSECONDS_TO_MILLISECONDS);
            
            for(auto& window : windows) {
                if(window != nullptr)
                    [window->delegate render];
            }
            
            scrollX = 0.0f;
            scrollY = 0.0f;
            
            last_time = current;
        }
    }
    
    app->prepare_quit();
    
    [NSApp release];
    [pool release];
    
    return 0;
}