#include <cstdarg>
#include <cstdio>
#include <cstdlib>
#include <windows.h>
#include <stdint.h>
#include <Xinput.h>
#include <dsound.h>
#include <math.h>

#define internal static // for functions
#define local_persist static // for static variables in a scope
#define global static // for global variables

typedef uint8_t uint8;
typedef uint16_t uint16;
typedef uint32_t uint32;
typedef uint64_t uint64;

typedef int8_t int8;
typedef int16_t int16;
typedef int32_t int32;
typedef int64_t int64;

typedef float real32;
typedef double real64;

typedef int32_t bool32;

struct Win32OffscreenBuffer {
    BITMAPINFO info;
    void *memory;
    int width;
    int height;
    int bytesPerPixel;
};

struct Win32WindowDimensions {
    int width;
    int height;
};

#define PI32 3.141592653589f

global ATOM HH_CTRLW;
global bool running;
global Win32OffscreenBuffer globalBackBuffer;
global LPDIRECTSOUNDBUFFER globalSecondaryBuffer;

void debug_printf(char* format, ...) { 
    int bufsize = strlen(format)*10;
    char *output = (char*)malloc(bufsize);
    va_list list;
    va_start(list, format);
    vsprintf_s(output, bufsize, format, list);
    OutputDebugStringA(output);
    free(output);
}

// XInputGetState
#define X_INPUT_GET_STATE(name) DWORD WINAPI name(DWORD dwUserIndex, XINPUT_STATE *pState)
typedef X_INPUT_GET_STATE(XInputGetStateFn);
X_INPUT_GET_STATE(XInputGetStateStub) { return ERROR_DEVICE_NOT_CONNECTED; }
global XInputGetStateFn *XInputGetStateDyn = XInputGetStateStub;
#define XInputGetState XInputGetStateDyn

// XInputSetState
#define X_INPUT_SET_STATE(name) DWORD WINAPI name(DWORD dwUserIndex, XINPUT_VIBRATION *pVibration)
typedef X_INPUT_SET_STATE(XInputSetStateFn);
X_INPUT_SET_STATE(XInputSetStateStub) { return ERROR_DEVICE_NOT_CONNECTED; }
global XInputSetStateFn *XInputSetStateDyn = XInputSetStateStub;
#define XInputSetState XInputSetStateDyn

typedef HRESULT WINAPI DirectSoundCreateFn(LPCGUID pcGuidDevice, LPDIRECTSOUND *ppDS, LPUNKNOWN pUnkOuter);

internal void renderWeirdGradient(Win32OffscreenBuffer *buffer, int xOffset, int yOffset) {
    int bytesPerPixel = 4;
    int pitch = buffer->width*bytesPerPixel;
    uint8 *row = (uint8 *)buffer->memory;
    for (int y = 0; y < buffer->height; y++) {
        uint32 *pixel = (uint32*)row;
        for (int x = 0; x < buffer->width; x++) {
            uint8 blue = x + xOffset;
            uint8 green = y + yOffset;
            *pixel++ = (green << 8) | blue;
        }
        row += pitch;
    }
}

internal void resizeDIBSection(Win32OffscreenBuffer *buffer, int width, int height) {
    if (buffer->memory) {
        VirtualFree(buffer->memory, NULL, MEM_RELEASE);
    }

    buffer->width = width;
    buffer->height = height;
    buffer->bytesPerPixel = 4;

    buffer->info.bmiHeader.biSize = sizeof(buffer->info.bmiHeader);
    buffer->info.bmiHeader.biWidth = buffer->width;
    buffer->info.bmiHeader.biHeight = -buffer->height;
    buffer->info.bmiHeader.biPlanes = 1;
    buffer->info.bmiHeader.biBitCount = 32;
    buffer->info.bmiHeader.biCompression = BI_RGB;

    int bitmapSize = buffer->width*buffer->height*buffer->bytesPerPixel;
    buffer->memory = VirtualAlloc(NULL, bitmapSize, MEM_COMMIT, PAGE_READWRITE);
}

internal Win32WindowDimensions win32GetWindowDimensions(HWND window) {
    Win32WindowDimensions result;
    RECT clientRect;
    GetClientRect(window, &clientRect);
    result.width = clientRect.right - clientRect.left;
    result.height = clientRect.bottom - clientRect.top;
    return result;
}

internal void win32DrawBufferInWindow(Win32OffscreenBuffer *buffer, HWND window) {
    Win32WindowDimensions winDims = win32GetWindowDimensions(window);
    StretchDIBits(
        GetDC(window),
        0, 0, winDims.width, winDims.height,
        0, 0, buffer->width, buffer->height,
        buffer->memory,
        &buffer->info, 
        DIB_RGB_COLORS,
        SRCCOPY
    );
}

internal void win32LoadXInput() {
    HMODULE xInputLib = LoadLibrary("xinput1_4.dll");
    if (!xInputLib) {
        xInputLib = LoadLibrary("xinput1_3.dll");
    }

    if (xInputLib) {
        XInputGetState = (XInputGetStateFn *)GetProcAddress(xInputLib, "XInputGetState");
        XInputSetState = (XInputSetStateFn *)GetProcAddress(xInputLib, "XInputSetState");
    }
}

internal void win32InitSound(HWND window, int32 samplesPerSec, int bufferSize) {
    HMODULE dSoundLibrary = LoadLibraryA("dsound.dll");
    if (dSoundLibrary) {
        DirectSoundCreateFn *DirectSoundCreate = (DirectSoundCreateFn*)GetProcAddress(dSoundLibrary, "DirectSoundCreate");
        LPDIRECTSOUND DirectSound;
        if (DirectSoundCreate && SUCCEEDED(DirectSoundCreate(0, &DirectSound, 0))) {
            WAVEFORMATEX waveFormat = {};
            waveFormat.wFormatTag = WAVE_FORMAT_PCM;
            waveFormat.nChannels = 2;
            waveFormat.nSamplesPerSec = samplesPerSec;
            waveFormat.wBitsPerSample = 16;
            waveFormat.nBlockAlign = (waveFormat.nChannels*waveFormat.wBitsPerSample) / 8;
            waveFormat.nAvgBytesPerSec = waveFormat.nSamplesPerSec*waveFormat.nBlockAlign;
            waveFormat.cbSize = 0;

            if (SUCCEEDED(DirectSound->SetCooperativeLevel(window, DSSCL_PRIORITY))) {
                DSBUFFERDESC bufferDescription = {};
                bufferDescription.dwSize = sizeof(bufferDescription);
                bufferDescription.dwFlags = DSBCAPS_PRIMARYBUFFER;

                LPDIRECTSOUNDBUFFER primaryBuffer;
                if (SUCCEEDED(DirectSound->CreateSoundBuffer(&bufferDescription, &primaryBuffer, 0))) {
                    if (SUCCEEDED(primaryBuffer->SetFormat(&waveFormat))) {
                        OutputDebugStringA("Primary buffer format was set.\n");
                    } else {
                        //No sound! (?)
                    }
                }
            } else {
                // No sound! (?)
            }

            DSBUFFERDESC bufferDescription = {};
            bufferDescription.dwSize = sizeof(bufferDescription);
            bufferDescription.dwFlags = 0;
            bufferDescription.dwBufferBytes = bufferSize;
            bufferDescription.lpwfxFormat = &waveFormat;

            if (SUCCEEDED(DirectSound->CreateSoundBuffer(&bufferDescription, &globalSecondaryBuffer, 0))) {
                OutputDebugStringA("Secondary buffer created successfully!\n");
            }
        } else {
            // No sound! (?)
        }
    }
}

LRESULT mainWindowCallback(
  HWND window,
  UINT message,
  WPARAM wParam,
  LPARAM lParam
) {
    LRESULT result = 0;
    switch (message) {
        case WM_SIZE: {
        } break;

        case WM_DESTROY: {
            OutputDebugStringA("WM_DESTROY\n");
        } break;

        case WM_CLOSE: {
            running = false;
        } break;

        case WM_PAINT: {
            PAINTSTRUCT paint = {};
            HDC deviceContext = BeginPaint(window, &paint);
            int x = paint.rcPaint.left;
            int y = paint.rcPaint.top;
            int width = paint.rcPaint.right - paint.rcPaint.left;
            int height = paint.rcPaint.bottom - paint.rcPaint.top;
            win32DrawBufferInWindow(&globalBackBuffer, window);
            EndPaint(window, &paint);
        } break;

        case WM_ACTIVATEAPP: {
        } break;

        case WM_HOTKEY: {
            if (wParam == HH_CTRLW) {
                running = false;
            }
        } break;

        case WM_SYSKEYDOWN:
        case WM_SYSKEYUP:
        case WM_KEYUP:
        case WM_KEYDOWN: {
            uint32 VKCode = wParam;
            bool wasDown = (lParam & (1 << 30)) != 0;
            bool isDown = (lParam & (1 << 31)) == 0;
            if (wasDown != isDown) {
                if (VKCode == 'W') {
                } else if (VKCode == 'A') {
                } else if (VKCode == 'S') {
                } else if (VKCode == 'D') {
                } else if (VKCode == 'Q') {
                } else if (VKCode == 'E') {
                } else if (VKCode == VK_ESCAPE) {
                } else if (VKCode == VK_UP) {
                } else if (VKCode == VK_LEFT) {
                } else if (VKCode == VK_DOWN) {
                } else if (VKCode == VK_RIGHT) {
                } else if (VKCode == VK_SPACE) {
                }
            }

            bool32 altKeyWasDown = lParam & (1 << 29);
            if (altKeyWasDown && VKCode == VK_F4) {
                running = false;
            }
        } break;

        default: {
            result = DefWindowProcA(window, message, wParam, lParam);
        } break;
    }
    return result;
}

struct Win32SoundOutput {
    int samplesPerSecond;
    int toneHz; 
    int wavePeriod;
    int16 toneVolume;
    uint32 runningSampleIndex;
    int bytesPerSample;
    int secondaryBufferSize;
};

internal void win32FillSoundBuffer(Win32SoundOutput *soundOutput, DWORD byteToLock, DWORD bytesToWrite) {
    VOID *region1;
    DWORD region1Size;
    VOID *region2;
    DWORD region2Size;
    HRESULT lock = globalSecondaryBuffer->Lock(byteToLock, bytesToWrite, &region1, &region1Size, &region2, &region2Size, 0);
    if (SUCCEEDED(lock)) {
        DWORD region1SampleCount = region1Size/soundOutput->bytesPerSample;
        int16 *sampleOut = (int16*)region1;
        for (DWORD sampleIndex = 0; sampleIndex < region1SampleCount; sampleIndex++) {
            real32 t = 2.0f * PI32 * (real32)soundOutput->runningSampleIndex / (real32)soundOutput->wavePeriod;
            int16 sampleValue =  (int16)(sin(t) * (real32)soundOutput->toneVolume);
            *sampleOut++ = sampleValue;
            *sampleOut++ = sampleValue;
            soundOutput->runningSampleIndex++;
        }
        DWORD region2SampleCount = region2Size/soundOutput->bytesPerSample;
        sampleOut = (int16*)region2;
        for (DWORD sampleIndex = 0; sampleIndex < region2SampleCount; sampleIndex++) {
            real32 t = 2.0f * PI32 * (real32)soundOutput->runningSampleIndex / (real32)soundOutput->wavePeriod;
            int16 sampleValue =  (int16)(sin(t) * soundOutput->toneVolume);
            *sampleOut++ = sampleValue;
            *sampleOut++ = sampleValue;
            soundOutput->runningSampleIndex++;
        }
        globalSecondaryBuffer->Unlock(region1, region1Size, region2, region2Size);
    } else {
        OutputDebugStringA("No lock!\n");
    }
}

int APIENTRY WinMain(
	HINSTANCE instance, 
	HINSTANCE prevInstance, 
	PSTR commandLine, 
	int commandShow
) {
    win32LoadXInput();

    WNDCLASSA windowClass = {};
    windowClass.style = CS_VREDRAW | CS_HREDRAW;
    windowClass.lpfnWndProc = &mainWindowCallback;
    windowClass.hInstance = instance;
    windowClass.lpszClassName = "HandmadeHeroWindowClass";

    resizeDIBSection(&globalBackBuffer, 1280, 720);

    if (RegisterClass(&windowClass)) {
        HWND window = CreateWindowExA(
            NULL,
            windowClass.lpszClassName,
            "Handmade Hero",
            WS_OVERLAPPEDWINDOW | WS_VISIBLE,
            CW_USEDEFAULT,
            CW_USEDEFAULT,
            CW_USEDEFAULT,
            CW_USEDEFAULT,
            NULL,
            NULL,
            instance,
            NULL
        );
        if (window) {
            HH_CTRLW = GlobalAddAtomA("HH_CTRLW");
            RegisterHotKey(window, HH_CTRLW, MOD_CONTROL, 'W');

            MSG message;
            running = true;

            // graphics test
            int xOffset = 0;
            int yOffset = 0;

            // sound test
            Win32SoundOutput soundOutput = {};
            soundOutput.samplesPerSecond = 48000;
            soundOutput.toneHz = 440; // A above middle C
            soundOutput.wavePeriod = soundOutput.samplesPerSecond / soundOutput.toneHz;
            soundOutput.toneVolume = 6000;
            soundOutput.runningSampleIndex = 0;
            soundOutput.bytesPerSample = sizeof(int16)*2;
            soundOutput.secondaryBufferSize = soundOutput.samplesPerSecond*soundOutput.bytesPerSample;

            win32InitSound(window, soundOutput.samplesPerSecond, soundOutput.secondaryBufferSize);
            win32FillSoundBuffer(&soundOutput, 0, soundOutput.secondaryBufferSize);
            globalSecondaryBuffer->Play(0, 0, DSBPLAY_LOOPING);

            while (running) {
                while (PeekMessageA(&message, NULL, NULL, NULL, PM_REMOVE)) {
                    if (message.message == WM_QUIT) {
                        running = false;
                    }
                    TranslateMessage(&message);
                    DispatchMessage(&message);
                }

                XINPUT_STATE controllerState;
                for (DWORD controllerIndex = 0; controllerIndex < XUSER_MAX_COUNT; controllerIndex++) {
                    if (XInputGetState(controllerIndex, &controllerState) == ERROR_SUCCESS) {
                        break;
                    } else {
                        // controller not available
                    }
                }
                XINPUT_GAMEPAD *Pad = &controllerState.Gamepad;
                bool up = (Pad->wButtons & XINPUT_GAMEPAD_DPAD_UP);
                bool down = (Pad->wButtons & XINPUT_GAMEPAD_DPAD_DOWN);
                bool left = (Pad->wButtons & XINPUT_GAMEPAD_DPAD_LEFT);
                bool right = (Pad->wButtons & XINPUT_GAMEPAD_DPAD_RIGHT);
                bool start = (Pad->wButtons & XINPUT_GAMEPAD_START);
                bool back = (Pad->wButtons & XINPUT_GAMEPAD_BACK);
                bool leftShoulder = (Pad->wButtons & XINPUT_GAMEPAD_LEFT_SHOULDER);
                bool rightShoulder = (Pad->wButtons & XINPUT_GAMEPAD_RIGHT_SHOULDER);
                bool aButton = (Pad->wButtons & XINPUT_GAMEPAD_A);
                bool bButton = (Pad->wButtons & XINPUT_GAMEPAD_B);
                bool xButton = (Pad->wButtons & XINPUT_GAMEPAD_X);
                bool yButton = (Pad->wButtons & XINPUT_GAMEPAD_Y);
                int16 stickX = Pad->sThumbLX;
                int16 stickY = Pad->sThumbLY;

                float stickYNorm = 0;
                float stickXNorm = 0;
                if (stickY != 0 && abs(stickY) > XINPUT_GAMEPAD_LEFT_THUMB_DEADZONE) {
                    stickYNorm = stickY / 32767.0;
                }
                if (stickX != 0 && abs(stickX) > XINPUT_GAMEPAD_LEFT_THUMB_DEADZONE) {
                    stickXNorm = stickX / 32767.0;
                }

                yOffset += stickY/5000;
                xOffset -= stickX/5000;

                renderWeirdGradient(&globalBackBuffer, xOffset, yOffset);

                // Sound test
                DWORD playCursor;
                DWORD writeCursor;
                if (SUCCEEDED(globalSecondaryBuffer->GetCurrentPosition(&playCursor, &writeCursor))) {
                    DWORD byteToLock = (soundOutput.runningSampleIndex*soundOutput.bytesPerSample) % soundOutput.secondaryBufferSize;
                    DWORD bytesToWrite;
                    if (byteToLock == playCursor) {
                        bytesToWrite = 0;
                    } else if (byteToLock > playCursor) {
                        bytesToWrite = soundOutput.secondaryBufferSize - byteToLock + playCursor;
                    } else {
                        bytesToWrite = playCursor - byteToLock;
                    }
                    win32FillSoundBuffer(&soundOutput, byteToLock, bytesToWrite);
                }

                win32DrawBufferInWindow(&globalBackBuffer, window);
            }
        } else {
            // failed
        }
    } else {
        // failed
    }
    return(0);
}