#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <math.h>
#include <windows.h>

#pragma once

/* 
 * ---------------
 *  Global flags: 
 * ---------------
 *
 * HANDMADE_SLOW
 * 0 - No slow code allowed
 * 1 - Slow code welcome
 *
 * HANDMADE_INTERNAL
 * 0 - Build for public release
 * 1 - Build for developer only
 *
 * HANDMADE_WIN32
 * 0 - Not a windows build
 * 1 - This is a windows build
 *
 */

#if HANDMADE_SLOW
#define Assert(Expression) if (!(Expression)) {*(volatile int *)0 = 0;}
#else
#define Assert(Expression) 
#endif

#define Kilobytes(Value) (Value*1024)
#define Megabytes(Value) (Kilobytes(Value)*1024)
#define Gigabytes(Value) (Megabytes(Value)*1024)
#define Terabytes(Value) (Gigabytes(Value)*1024)

#define ArrayCount(Array) (sizeof(Array) / sizeof((Array)[0]))

#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;

#define MAX_SAFE_UINT32 0xFFFFFFFF

inline uint32 safeTruncateUInt64(uint64 val) {
    Assert(val <= MAX_SAFE_UINT32);
    return (uint32)val;
}

// === Platform to game services ===
#if HANDMADE_INTERNAL

struct DebugReadFileResult {
    uint32 contentsSize;
    void *contents;
};

#define DEBUG_PLATFORM_READ_ENTIRE_FILE(name) DebugReadFileResult name(char *filename)
typedef DEBUG_PLATFORM_READ_ENTIRE_FILE(DebugPlatformReadEntireFileFn);

#define DEBUG_PLATFORM_FREE_FILE_MEMORY(name) void name(void *fileMemory)
typedef DEBUG_PLATFORM_FREE_FILE_MEMORY(DebugPlatformFreeFileMemoryFn);

#define DEBUG_PLATFORM_WRITE_ENTIRE_FILE(name) bool32 name(char *filename, uint32 memorySize, void *memory)
typedef DEBUG_PLATFORM_WRITE_ENTIRE_FILE(DebugPlatformWriteEntireFileFn);

#define DEBUG_PLATFORM_PRINTF(name) void name(wchar_t* format, ...)
typedef DEBUG_PLATFORM_PRINTF(DebugPrintfFn);

#endif

// Game to platform layer services
struct GameSoundOutputBuffer {
    int samplesPerSecond;
    int sampleCount;
    int16 *samples;
};

struct GameOffscreenBuffer {
    void *memory;
    int width;
    int height;
    int bytesPerPixel;
    int pitch; // Bytes per row
};

struct GameButtonState {
    int halfTransitionCount;
    bool32 endedDown;
};

struct GameControllerInput {
    bool32 isAnalog;

    real32 stickAvgY;
    real32 stickAvgX;

    union {
        GameButtonState buttons[6];
        struct {
            GameButtonState stickUp;
            GameButtonState stickDown;
            GameButtonState stickLeft;
            GameButtonState stickRight;
            GameButtonState btnUp;
            GameButtonState btnDown;
            GameButtonState btnLeft;
            GameButtonState btnRight;
            GameButtonState leftShoulder;
            GameButtonState rightShoulder;
        };
    };
}; 

struct GameInput {
    GameControllerInput controllers[5];
};

struct GameMemory {
    bool32 isInitialised;

    uint64 permanentStorageSize;
    void *permanentStorage; // required to be initialised to zero at startup 

    uint64 transientStorageSize;
    void *transientStorage; // required to be initialised to zero at startup 

    DebugPlatformReadEntireFileFn *debugReadEntireFile;
    DebugPlatformFreeFileMemoryFn *debugFreeFileMemory;
    DebugPlatformWriteEntireFileFn *debugWriteEntireFile;
    DebugPrintfFn *debug_printf;
};

struct GameState {
    int toneHz;
    int greenOffset;
    int blueOffset;
    real32 tSine;
    int playerY;
    int playerX;
};

// === Game to platform services ===

#define GAME_UPDATE_AND_RENDER(name) void name(GameMemory *memory, GameOffscreenBuffer *videoBuf, GameInput *input)
typedef GAME_UPDATE_AND_RENDER(GameUpdateAndRenderFn);
GAME_UPDATE_AND_RENDER(gameUpdateAndRenderStub) {}

#define GAME_GET_SOUND_SAMPLES(name) void name(GameMemory *memory, GameSoundOutputBuffer *soundBuf)
typedef GAME_GET_SOUND_SAMPLES(GameGetSoundSamplesFn);
GAME_GET_SOUND_SAMPLES(gameGetSoundSamplesStub) {}