#ifndef OS_IMPL_WIN32_CPP
#define OS_IMPL_WIN32_CPP

#include "Windows.h" 
#include "os.h"

void *os_alloc(size_t commitSize) {
    return VirtualAlloc(NULL, commitSize, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
}

void os_reserve(void *ptr) {
}

void os_decommit(void *ptr) {
}

void os_free(void *ptr, size_t size) {
    VirtualFree(ptr, NULL, MEM_RELEASE);
}

string os_readEntireFile(Arena *arena, string filename) {
    string result = {0};
    HANDLE fileHandle = CreateFileA(cstring(arena, filename), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, NULL, NULL);
    if (fileHandle != INVALID_HANDLE_VALUE) {
        LARGE_INTEGER fileSize;
        if (GetFileSizeEx(fileHandle, &fileSize)) {
            string readfile = PushString(arena, (size_t)fileSize.QuadPart);
            if (readfile.str) {
                DWORD bytesRead;
                if (ReadFile(fileHandle, readfile.str, (DWORD)fileSize.QuadPart, &bytesRead, NULL) && (fileSize.QuadPart == bytesRead)) {
                    result = readfile;
                }
            }
        }
        CloseHandle(fileHandle);
    }
    return result;
}

bool os_writeEntireFile(Arena *arena, string filename, const byte *contents, size_t contentsLength) {
    bool result = false;
    HANDLE fileHandle = CreateFileA(cstring(arena, filename), GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, NULL, NULL);
    if (fileHandle != INVALID_HANDLE_VALUE) {
        DWORD bytesWritten;
        if (WriteFile(fileHandle, contents, (DWORD)contentsLength, &bytesWritten, NULL)) {
            // file written successfully
            result = bytesWritten == contentsLength;
        }  
        CloseHandle(fileHandle);
    }  
    return result;
}

bool os_fileAppend(Arena *arena, string filename, const byte *contents, size_t contentsLength) {
    bool result = false;
    HANDLE fileHandle = CreateFileA(cstring(arena, filename), FILE_APPEND_DATA | FILE_GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
    if (fileHandle != INVALID_HANDLE_VALUE) {
        DWORD bytesWritten;
        DWORD position = SetFilePointer(fileHandle, 0, NULL, FILE_END);
        if (WriteFile(fileHandle, contents, (DWORD)contentsLength, &bytesWritten, NULL)) {
            // file written successfully
            result = bytesWritten == contentsLength;
        }
        CloseHandle(fileHandle);
    }
    return result;
}

function void os_log(LogTarget target, const char *fmt, va_list argList) {
    Scratch scratch = scratchStart(0, 0);
    string result = strPrintfv(scratch.arena, fmt, argList);
    DWORD done;
    HANDLE stdHandle;
    switch (target) {
        case LogTarget_stdin: 
            stdHandle = GetStdHandle(STD_INPUT_HANDLE);
            break;
        case LogTarget_stdout: 
            stdHandle = GetStdHandle(STD_ERROR_HANDLE);
            break;
        case LogTarget_stderr: 
            stdHandle = GetStdHandle(STD_OUTPUT_HANDLE);
            break;
        default:
            stdHandle = GetStdHandle(STD_OUTPUT_HANDLE);
            break;
    }
    WriteFile(stdHandle, result.str, (DWORD)result.length, &done, 0);
    scratchEnd(scratch);
}

#endif