/************************************************************/
/* Launch5j, by LoRd_MuldeR <MuldeR2@GMX.de>                */
/* Java JAR wrapper for creating Windows native executables */
/* https://github.com/lordmulder/                           */
/*                                                          */
/* This work has been released under the MIT license.       */
/* Please see LICENSE.TXT for details!                      */
/*                                                          */
/* ACKNOWLEDGEMENT                                          */
/* This project is partly inspired by the Launch4j project: */
/* https://sourceforge.net/p/launch4j/                      */
/************************************************************/

#define WIN32_LEAN_AND_MEAN 1

#include <Windows.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <direct.h>
#include "resource.h"

// Const
static const DWORD SPLASH_SCREEN_TIMEOUT = 30000U;
static const wchar_t *const JRE_RELATIVE_PATH = L"runtime\\bin\\javaw.exe";

// Options
#ifndef ENABLE_SPLASH
#define ENABLE_SPLASH 1
#endif
#ifndef JAR_FILE_WRAPPED
#define JAR_FILE_WRAPPED 0
#endif
#ifndef WAIT_FOR_WINDOW
#define WAIT_FOR_WINDOW 1
#endif
#ifndef STAY_ALIVE
#define STAY_ALIVE 1
#endif

/* ======================================================================== */
/* String routines                                                          */
/* ======================================================================== */

#define NOT_EMPTY(STR) ((STR) && ((STR)[0U]))

static wchar_t *awprintf(const wchar_t *const fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    
    const int str_len = _vscwprintf(fmt, ap);
    if (str_len < 1)
    {
        return NULL;
    }

    wchar_t *buffer = (wchar_t*) malloc(sizeof(wchar_t) * (((size_t)str_len) + 1U));
    if (!buffer)
    {
        return NULL;
    }

    const int result = vswprintf(buffer, ((size_t)str_len) + 1U, fmt, ap);
    if (result < 1)
    {
        free(buffer);
        buffer = NULL;
    }

    va_end(ap);
    return buffer;
}

static wchar_t *wcsndup (const wchar_t *const str, const size_t n)
{
    size_t str_len = wcslen(str);
    if (n < str_len)
    {
        str_len = n;
    }

    wchar_t *const result = (wchar_t*) malloc(sizeof(wchar_t) * (str_len + 1U));
    if (!result)
    {
        return NULL;
    }

    wcsncpy(result, str, str_len);
    result[str_len] = '\0';
    return result;
}

/* ======================================================================== */
/* File name routines                                                       */
/* ======================================================================== */

static wchar_t *get_directory_part(const wchar_t *const path)
{
    size_t lastsep = SIZE_MAX;

    if(NOT_EMPTY(path))
    {
        for (size_t i = 0; path[i]; ++i)
        {
            if ((path[i] == L'\\') || (path[i] == L'/'))
            {
                lastsep = i;
            }
        }
    }

    if (lastsep != SIZE_MAX)
    {
        return wcsndup(path, lastsep);
    }

    return wcsdup(L".");
}

static wchar_t *remove_file_extension(const wchar_t *const path)
{
    size_t lastsep = SIZE_MAX;
    size_t lastdot = SIZE_MAX;

    for (size_t i = 0; path[i]; ++i)
    {
        if ((path[i] == L'\\') || (path[i] == L'/'))
        {
            lastsep = i;
        }
        else if (path[i] == L'.')
        {
            lastdot = i;
        }
    }

    if (lastdot != SIZE_MAX)
    {
        if((lastsep == SIZE_MAX) || (lastdot > lastsep))
        {
            return wcsndup(path, lastdot);
        }
    }

    return wcsdup(path);
}

static BOOL file_exists(const wchar_t *const filename) {
    struct _stat buffer;
    if (_wstat(filename, &buffer) == 0)
    {
        return S_ISDIR(buffer.st_mode) ? FALSE : TRUE;
    }
    return FALSE;
}

/* ======================================================================== */
/* Path detection                                                           */
/* ======================================================================== */

static const wchar_t *const DEFAULT_JARFILE_NAME = L"application.jar";

static const wchar_t *get_executable_path(void)
{
    if (_wpgmptr && _wpgmptr[0U])
    {
        return wcsdup(_wpgmptr);
    }
    return NULL;
}

static const wchar_t *get_executable_directory(const wchar_t *const executable_path)
{
    const wchar_t *const directory_part = get_directory_part(executable_path);
    if (directory_part)
    {
        return directory_part;
    }

    free((void*)directory_part);
    return wcsdup(L".");
}

static const wchar_t *get_jarfile_path(const wchar_t *const executable_path, const wchar_t *const executable_directory)
{
#if JAR_FILE_WRAPPED
    return wcsdup(executable_path); /*JAR file is wrapped*/
#else
    const wchar_t *jarfile_path = NULL;

    const wchar_t *const path_prefix = remove_file_extension(executable_path);
    if (NOT_EMPTY(path_prefix))
    {
        const size_t len = wcslen(path_prefix);
        if (!((len > 0U) && ((path_prefix[len-1U] == L'\\') || (path_prefix[len-1U] == L'/'))))
        {
            jarfile_path = awprintf(L"%ls.jar", path_prefix);
        }
    }

    if (!jarfile_path)
    {
        jarfile_path = NOT_EMPTY(executable_directory) ? awprintf(L"%ls\\%ls", executable_directory, DEFAULT_JARFILE_NAME) : wcsdup(DEFAULT_JARFILE_NAME);
    }

    free((void*)path_prefix);
    return jarfile_path;
#endif
}

/* ======================================================================== */
/* Path manipulation                                                        */
/* ======================================================================== */

static const BOOL set_current_directory(const wchar_t *const path)
{
    if(NOT_EMPTY(path))
    {
        if(iswalpha(path[0U]) && (path[1U] == L':') && (path[2U] == L'\0'))
        {
            const wchar_t root_path[4U] = { path[0U], L':', L'\\', L'\0' };
            return SetCurrentDirectoryW(root_path);
        }
        else
        {
            return SetCurrentDirectoryW(path);
        }
    }
    else
    {
        return SetCurrentDirectoryW(L"\\");
    }
}

/* ======================================================================== */
/* Splash screen                                                            */
/* ======================================================================== */

static BOOL create_splash_screen(const HWND hwnd, const HANDLE splash_image)
{
    if (hwnd && splash_image)
    {
        RECT rect;
        SendMessageW(hwnd, STM_SETIMAGE, IMAGE_BITMAP, (LPARAM) splash_image);
        GetWindowRect(hwnd, &rect);
        const int x = (GetSystemMetrics(SM_CXSCREEN) - (rect.right - rect.left)) / 2;
        const int y = (GetSystemMetrics(SM_CYSCREEN) - (rect.bottom - rect.top)) / 2;
        SetWindowPos(hwnd, HWND_TOP, x, y, 0, 0, SWP_NOSIZE);
        ShowWindow(hwnd, SW_SHOW);
        return UpdateWindow(hwnd);
    }
    return FALSE;
}

static BOOL process_window_messages(const HWND hwnd)
{
    BOOL result = FALSE;
    if (hwnd != NULL)
    {
        MSG msg = {};
        for (DWORD k = 0U; k < MAXWORD; ++k)
        {
            if (PeekMessageW(&msg, hwnd, 0U, 0U, PM_REMOVE))
            {
                result = TRUE;
                TranslateMessage(&msg);
                DispatchMessageW(&msg);
            }
            else
            {
                break; /*no more messages!*/
            }
        }
    }
    return result;
}

/* ======================================================================== */
/* Find window functions                                                    */
/* ======================================================================== */

typedef struct
{
    DWORD process_id;
    HWND hwnd;
}
find_window_t;

static BOOL CALLBACK enum_windows_callback(const HWND hwnd, const LPARAM lparam)
{
    DWORD process_id = MAXDWORD;
    find_window_t *const ptr = (find_window_t*) lparam;
    if(IsWindowVisible(hwnd))
    {
        GetWindowThreadProcessId(hwnd, &process_id);
        if(process_id == ptr->process_id)
        {
            ptr->hwnd = hwnd;
            return FALSE;
        }
    }
    return TRUE;
}

static HWND find_window_by_process_id(const DWORD process_id)
{
    find_window_t find_window_data;
    find_window_data.process_id = process_id;
    find_window_data.hwnd = NULL;
    EnumWindows(enum_windows_callback, (LONG_PTR)&find_window_data);
    return find_window_data.hwnd;
}

/* ======================================================================== */
/* Wait for process                                                         */
/* ======================================================================== */

static BOOL signaled_or_failed(const DWORD wait_result)
{
    return (wait_result == WAIT_OBJECT_0) || (wait_result == WAIT_FAILED);
}

static BOOL wait_for_process_ready(const HWND hwnd, const HANDLE process_handle, const DWORD process_id)
{
    const DWORD ticks_start = GetTickCount();
    for (;;)
    {
        const HWND child_hwnd = find_window_by_process_id(process_id);
        if (child_hwnd)
        {
            SwitchToThisWindow(child_hwnd, TRUE);
            return TRUE;
        }
        if (signaled_or_failed(WaitForSingleObject(process_handle, 13U)))
        {
            break;
        }
        const DWORD ticks_delta = GetTickCount() - ticks_start;
        if(ticks_delta > SPLASH_SCREEN_TIMEOUT)
        {
            break;
        }
        process_window_messages(hwnd);
    }

    return FALSE;
}

/* ======================================================================== */
/* Message box                                                              */
/* ======================================================================== */

static const wchar_t *describe_system_error(const DWORD error_code)
{
    const wchar_t *error_test = NULL, *buffer = NULL;

    const DWORD len = FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER |FORMAT_MESSAGE_IGNORE_INSERTS, NULL, error_code, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPWSTR)&buffer, 0, NULL);
    if((len > 0U) && NOT_EMPTY(buffer))
    {
        error_test = wcsdup(buffer);
        LocalFree((HLOCAL)buffer);
    }

    return error_test;
}

#define show_message(HWND, FLAGS, TITLE, TEXT) \
{ \
    MessageBoxW((HWND), (TEXT), (TITLE), (FLAGS)); \
} \
while(0)

#define show_message_format(HWND, FLAGS, TITLE, FORMAT, ...) do \
{ \
    const wchar_t *const _text = awprintf((FORMAT), __VA_ARGS__); \
    if(_text) \
    { \
        MessageBoxW((HWND), _text, (TITLE), (FLAGS)); \
    } \
    free((void*)_text); \
} \
while(0)

/* ======================================================================== */
/* Utilities                                                                */
/* ======================================================================== */

static void close_handle(HANDLE *const handle)
{
    if(*handle)
    {
        CloseHandle(*handle);
        *handle = NULL;
    }
}

static void delete_object(HGDIOBJ *const handle)
{
    if(*handle)
    {
        DeleteObject(*handle);
        *handle = NULL;
    }
}

static void destroy_window(HWND *const hwnd)
{
    if(*hwnd)
    {
        DestroyWindow(*hwnd);
        *hwnd = NULL;
    }
}

/* ======================================================================== */
/* MAIN                                                                     */
/* ======================================================================== */

int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PWSTR pCmdLine, int nCmdShow)
{
    int result = -1;
    const wchar_t *executable_path = NULL, *executable_directory = NULL, *jarfile_path = NULL, *java_runtime_path = NULL, *command_line = NULL;
    HGDIOBJ splash_image = NULL;
    PROCESS_INFORMATION process_info;
    STARTUPINFOW startup_info;

    // Initialize
    SecureZeroMemory(&startup_info, sizeof(STARTUPINFOW));
    SecureZeroMemory(&process_info, sizeof(PROCESS_INFORMATION));

    // Create the window
    HWND hwnd = CreateWindowExW(WS_EX_TOOLWINDOW | WS_EX_TOPMOST, L"STATIC", L"", WS_POPUP | SS_BITMAP, 0, 0, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL);

    // Show the splash screen
#if ENABLE_SPLASH
    if(splash_image = LoadImage(hInstance, MAKEINTRESOURCE(ID_SPLASH_BITMAP), IMAGE_BITMAP, 0, 0, LR_DEFAULTSIZE))
    {
        if(create_splash_screen(hwnd, splash_image))
        {
            process_window_messages(hwnd);
        }
    }
#endif

    // Find executable path
    if(!(executable_path = get_executable_path()))
    {
        show_message(hwnd, MB_ICONERROR | MB_TOPMOST, L"System Error", L"The path of the executable could not be determined!");
        goto cleanup;
    }

    // Find executable directory
    if(!(executable_directory = get_executable_directory(executable_path)))
    {
        show_message(hwnd, MB_ICONERROR | MB_TOPMOST, L"System Error", L"The executable directory could not be determined!");
        goto cleanup;
    }

    // Set the current directory
    if(_wcsicmp(executable_directory, L".") != 0)
    {
        set_current_directory(executable_directory);
    }

    // Find the JAR file path
    if(!(jarfile_path = get_jarfile_path(executable_path, executable_directory)))
    {
        show_message(hwnd, MB_ICONERROR | MB_TOPMOST, L"System Error", L"The path of the JAR file could not be determined!");
        goto cleanup;
    }

    // Find the Java runtime executable path
    if(!(java_runtime_path = awprintf(L"%ls\\%ls", executable_directory, JRE_RELATIVE_PATH)))
    {
        show_message(hwnd, MB_ICONERROR | MB_TOPMOST, L"System Error", L"The path of the Java runtime could not be determined!");
        goto cleanup;
    }

    // Does the JAR file exist?
#if !JAR_FILE_WRAPPED
    if(!file_exists(jarfile_path))
    {
        show_message_format(hwnd, MB_ICONERROR | MB_TOPMOST, L"JAR not found", L"The required JAR file could not be found:\n\n%ls\n\n\nRe-installing the application may fix the problem!", jarfile_path);
        goto cleanup;
    }
#endif

    // Does the Java runtime executable exist?
    if(!file_exists(java_runtime_path))
    {
        show_message_format(hwnd, MB_ICONERROR | MB_TOPMOST, L"Java not found", L"The required Java runtime could not be found:\n\n%ls\n\n\nRe-installing the application may fix the problem!", java_runtime_path);
        goto cleanup;
    }

    // Build the command-line
    command_line = NOT_EMPTY(pCmdLine) ? awprintf(L"\"%ls\" -jar \"%ls\" %ls", java_runtime_path, jarfile_path, pCmdLine) : awprintf(L"\"%ls\" -jar \"%ls\"", java_runtime_path, jarfile_path);
    if(!command_line)
    {
        show_message(hwnd, MB_ICONERROR | MB_TOPMOST, L"System Error", L"The Java command-line could not be generated!");
        goto cleanup;
    }

    // Process pending window messages
#if ENABLE_SPLASH
    process_window_messages(hwnd);
#endif

    // Now actually start the process!
    if(!CreateProcessW(NULL, (LPWSTR)command_line, NULL, NULL, FALSE, 0U, NULL, executable_directory, &startup_info, &process_info))
    {
        const wchar_t *const error_text = describe_system_error(GetLastError());
        if(error_text)
        {
            show_message_format(hwnd, MB_ICONERROR | MB_TOPMOST, L"System Error", L"Failed to create the Java process:\n\n%ls\n\n\n%ls", command_line, error_text);
            free((void*)error_text);
        }
        else
        {
            show_message_format(hwnd, MB_ICONERROR | MB_TOPMOST, L"System Error", L"Failed to create the Java process:\n\n%ls", command_line);
        }
        goto cleanup;
    }

    // Process pending window messages
#if ENABLE_SPLASH
    process_window_messages(hwnd);
#if WAIT_FOR_WINDOW
    wait_for_process_ready(hwnd, process_info.hProcess, process_info.dwProcessId);
#endif
    destroy_window(&hwnd);
#endif

    // Wait for process to exit, then get exit code
#if STAY_ALIVE
    if(WaitForSingleObject(process_info.hProcess, INFINITE) == WAIT_OBJECT_0)
    {
        DWORD exit_code = 0U;
        if(GetExitCodeProcess(process_info.hProcess, &exit_code))
        {
            result = (int) exit_code;
        }
    }
#else
    result = 0;
#endif

cleanup:

    close_handle(&process_info.hThread);
    close_handle(&process_info.hProcess);

    destroy_window(&hwnd);
    delete_object(splash_image);

    free((void*)command_line);
    free((void*)java_runtime_path);
    free((void*)jarfile_path);
    free((void*)executable_directory);
    free((void*)executable_path);

    return result;
}