/*
 * %CopyrightBegin%
 * 
 * Copyright Ericsson AB 2003-2009. All Rights Reserved.
 * 
 * The contents of this file are subject to the Erlang Public License,
 * Version 1.1, (the "License"); you may not use this file except in
 * compliance with the License. You should have received a copy of the
 * Erlang Public License along with this software. If not, it can be
 * retrieved online at http://www.erlang.org/.
 * 
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 * 
 * %CopyrightEnd%
 */
#pragma comment(linker,"/manifestdependency:\"type='win32' "\
		"name='Microsoft.Windows.Common-Controls' "\
		"version='6.0.0.0' processorArchitecture='*' "\
		"publicKeyToken='6595b64144ccf1df' language='*'\"")
#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include "init_file.h"

typedef int ErlexecFunction(int, char **, HANDLE, int); 

#define INI_FILENAME "erl.ini"
#define INI_SECTION "erlang"
#define ERLEXEC_BASENAME "erlexec.dll"

static void get_parameters(void);
static void error(char* format, ...);

static char *erlexec_name;
static char *erlexec_dir;

#ifdef WIN32_WERL
#define WERL 1
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
		    PSTR szCmdLine, int iCmdShow)
{
    int argc = __argc;
    char **argv = __argv;
#else
#define WERL 0
int main(int argc, char **argv)
{
#endif
  HANDLE erlexec_handle; /* Instance */
  ErlexecFunction *win_erlexec;
  char *path = malloc(100);
  char *npath;
  int pathlen;

  get_parameters();

  if ((pathlen = GetEnvironmentVariable("PATH",path,100)) == 0) {
    error("No PATH variable (!)");
  } else if (pathlen > 100) {
    path = realloc(path,pathlen);
    GetEnvironmentVariable("PATH",path,pathlen);
  }
  npath = malloc(strlen(path) + strlen(erlexec_dir) + 2);
  sprintf(npath,"%s;%s",erlexec_dir,path);
  SetEnvironmentVariable("PATH",npath);

  if ((erlexec_handle = LoadLibrary(erlexec_name)) == NULL) {
    error("Could not load module %s.",erlexec_name);
  }

  if ((win_erlexec = (ErlexecFunction *) 
       GetProcAddress(erlexec_handle,"win_erlexec")) == NULL) {
    error("Could not find entry point \"win_erlexec\" in %s.", erlexec_name);
  }

  return (*win_erlexec)(argc,argv,erlexec_handle,WERL);
  
} 


static char *replace_filename(char *path, char *new_base) 
{
    int plen = strlen(path);
    char *res = malloc((plen+strlen(new_base)+1)*sizeof(char));
    char *p;

    strcpy(res,path);
    for (p = res+plen-1 ;p >= res && *p != '\\'; --p)
        ;
    *(p+1) ='\0';
    strcat(res,new_base);
    return res;
}

static char *do_lookup_in_section(InitSection *inis, char *name, 
				  char *section, char *filename)
{
    char *p = lookup_init_entry(inis, name);

    if (p == NULL) {
	error("Could not find key %s in section %s of file %s",
	      name,section,filename);
    }
    return _strdup(p);
}

static void copy_latest_vsn(char *latest_vsn, char *next_vsn) 
{
    /* Copy */
    char *lp;
    char *np;
    /* Find vsn */
    for (lp = next_vsn+strlen(next_vsn)-1 ;lp >= next_vsn && *lp != '\\'; --lp)
        ;
    /* lp =+ length("erts-"); */
    for (np = next_vsn+strlen(next_vsn)-1 ;np >= next_vsn && *np != '\\'; --np)
        ;
    /* np =+ length("erts-"); */
    
    for (; lp && np; ++lp, ++np) {
	if (*lp == *np) {
	    continue;
	}	
	if (*np == '.' || *np == '\0' || *np <= *lp) {
	/* */
	    return;
	}
	if (*lp == '.' || *lp == '\0') {
	    strcpy(latest_vsn, next_vsn);
	    return;
	}
    }
    return;
}

static char *find_erlexec_dir2(char *install_dir) 
{
    /* List install dir and look for latest erts-vsn */

    HANDLE dir_handle;	        /* Handle to directory. */
    char wildcard[MAX_PATH];	/* Wildcard to search for. */
    WIN32_FIND_DATA find_data;	/* Data found by FindFirstFile() or FindNext(). */
    char latest_vsn[MAX_PATH];

    /* Setup wildcard */
    int length = strlen(install_dir);
    char *p;

    if (length+3 >= MAX_PATH) {
	error("Cannot find erlexec.exe");
    }

    strcpy(wildcard, install_dir);
    p = wildcard+length-1;
    if (*p != '/' && *p != '\\')
	*++p = '\\';
    strcpy(++p, "erts-*");

    /* Find first dir */
    dir_handle = FindFirstFile(wildcard, &find_data);
    if (dir_handle == INVALID_HANDLE_VALUE) {
	/* No erts-vsn found*/
	return NULL;
    }	
    strcpy(latest_vsn, find_data.cFileName);

    /* Find the rest */
    while(FindNextFile(dir_handle, &find_data)) {
	copy_latest_vsn(latest_vsn, find_data.cFileName);
    }
    
    FindClose(dir_handle);

    p = malloc((strlen(install_dir)+1+strlen(latest_vsn)+4+1)*sizeof(char));

    strcpy(p,install_dir);
    strcat(p,"\\");
    strcat(p,latest_vsn);
    strcat(p,"\\bin");
    return p;
}

static char *find_erlexec_dir(char *erlpath) 
{
    /* Assume that the path to erl is absolute and
     * that it is not a symbolic link*/
    
    char *dir =_strdup(erlpath);
    char *p;
    char *p2;
    
    /* Chop of base name*/
    for (p = dir+strlen(dir)-1 ;p >= dir && *p != '\\'; --p)
        ;
    *p ='\0';
    p--;

    /* Check if dir path is like ...\install_dir\erts-vsn\bin */
    for (;p >= dir && *p != '\\'; --p)
        ;
    p--;
    for (p2 = p;p2 >= dir && *p2 != '\\'; --p2)
        ;
    p2++;
    if (strncmp(p2, "erts-", strlen("erts-")) == 0) {
	p = _strdup(dir);
	free(dir);
	return p;
    }

    /* Assume that dir path is like ...\install_dir\bin */
    *++p ='\0'; /* chop off bin dir */

    p = find_erlexec_dir2(dir);
    free(dir);
    if (p == NULL) {
	error("Cannot find erlexec.exe");
    } else {
	return p;
    }
}

static void get_parameters(void)
{
    char buffer[MAX_PATH];
    char *ini_filename;
    HANDLE module = GetModuleHandle(NULL);
    InitFile *inif;
    InitSection *inis;
    char *bindir;

    if (module = NULL) {
        error("Cannot GetModuleHandle()");
    }

    if (GetModuleFileName(module,buffer,MAX_PATH) == 0) {
        error("Could not GetModuleFileName");
    }

    ini_filename = replace_filename(buffer,INI_FILENAME);

    if ((inif = load_init_file(ini_filename)) == NULL) {
	erlexec_dir = find_erlexec_dir(ini_filename);
	SetEnvironmentVariable("ERLEXEC_DIR", erlexec_dir);
    } else {

      if ((inis = lookup_init_section(inif,INI_SECTION)) == NULL) {
	error("Could not find section %s in init file %s",
	      INI_SECTION, ini_filename);
      }
      
      erlexec_dir = do_lookup_in_section(inis, "Bindir", INI_SECTION, ini_filename);
      free_init_file(inif);      
    }
    
    erlexec_name = malloc(strlen(erlexec_dir) + strlen(ERLEXEC_BASENAME) + 2);
    strcpy(erlexec_name,erlexec_dir);
    strcat(erlexec_name, "\\" ERLEXEC_BASENAME);
    
    free(ini_filename);
}


static void error(char* format, ...)
{
    char sbuf[2048];
    va_list ap;

    va_start(ap, format);
    vsprintf(sbuf, format, ap);
    va_end(ap);

#ifndef WIN32_WERL 
	fprintf(stderr, "%s\n", sbuf);
#else
	MessageBox(NULL, sbuf, "Werl", MB_OK|MB_ICONERROR);
#endif
    exit(1);
}