#! /bin/bash /home/russ/bin/dscript

import std.stdio;
import std.c.process;
import std.file;
import std.c.stdio;
import std.string;
import std.c.stdlib;
import std.system;

extern(C) FILE *popen(char*,char*);
extern(C) int wait(int*);
extern(C) int waitpid(int,int*,int);

int WEXITSTATUS(int status) { return (status & 0x0FF00) >> 8; }
const int WNOHANG = 1;



FILE *popen_d(char[] cmd,char[] mode) {
  return popen(toStringz(cmd),toStringz(mode));
}
FILE *fopen_d(char[] file,char[] mode) {
  return fopen(toStringz(file),toStringz(mode));
}
int system_d(char[] cmd) {
  return system(toStringz(cmd));
}

void dump(FILE *from,FILE *to) {
  char c = fgetc(from);
  while(!feof(from)) {
    fputc(c, to);
    c = fgetc(from);
  };
}
void flush_pending_child_stati()
{
  int status;
  while(waitpid(-1, &status, WNOHANG) > 0) { ; }
  return;
}
char[] implode_args(char[][] args) {
  if(args.length == 0)
    return "";

  char[] ret = "\""~args[0]~"\"";
  foreach(char[] arg; args[1..length]) {
    ret ~= " \""~arg~"\"";
  }
  return ret;
}



if(argv.length < 2 || argv[1].length == 0) {
  fwritefln(stderr, "dscript ERROR: No command given.");
  fwritefln(stderr, "dscript SYNTAX: ",argv[0]," <script> <args>");
  return 1;
}
/* Skipped this, since it is sort of hard to implement in D.
if(!readable(argv[1])) {
  fwritefln(stderr, "dscript ERROR: Cannot read ",argv[1]);
  return 2;
}
*/

char[] cmd = argv[1];
argv = argv[0..1]~argv[2..length];

char[] temp_dir = format("/tmp/dscript_in_dscript.",getenv("USER")[0..strlen(getenv("USER"))],".",getpid());
char[] cur_dir  = getcwd();
mkdir(temp_dir);

FILE *script_file = fopen_d(format(temp_dir,"/dscript_script.d"), "w");

FILE *input_imports    = popen_d(format("grep  -E \"(^import |^extern\\()\" ",cmd," | grep -vE \"^#! \""), "r");
FILE *input_no_imports = popen_d(format("grep -vE \"(^import |^extern\\()\" ",cmd," | grep -vE \"^#! \""), "r");

dump(input_imports, script_file);
fwritefln(script_file, "int main(char[][] argv) {");
dump(input_no_imports, script_file);
fwritefln(script_file, "  return 0;");
fwritefln(script_file, "}");
fclose(script_file);

chdir(temp_dir);
flush_pending_child_stati(); FILE *dmd_output = popen("dmd dscript_script","r");
int dmd_status; wait(&dmd_status);
system("sleep 2"); // there's a bug in my kernel that will break this if I don't sleep here
chdir(cur_dir);
if(WEXITSTATUS(dmd_status) != 0) {
  dump(dmd_output, stdout);
  writefln("dscript ERROR: Compilation failed.");
  writefln("DUMP OF SCRIPT:");
  fflush(null); system_d("cat "~temp_dir~"/dscript_script.d");
  writefln("END DUMP");
  system_d("rm -r "~temp_dir);
  return WEXITSTATUS(dmd_status);
}

int script_status = system_d(temp_dir~"/dscript_script "~implode_args(argv[1..length]));

system_d("rm -r "~temp_dir);

return WEXITSTATUS(script_status);