#ifdef USE_PCH
 #include "pch.h"
#else
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/ipc.h>
 #include <sys/sem.h>
 #include <errno.h>
 #include <iostream>
 #include <fstream>
 #include <cassert>
 #include "sitecing/sitecing_util.h"
#endif

namespace sitecing {

    /*
     * XXX: all of these utilities could be sheerly optimized.
     */

    string normalize_path(const string& path,int opts) {
	const char *s = path.c_str();
	string rv;
	string::size_type notslash = 0;
	if( (*s)=='.' && s[1]=='/' )
	    s+=2;
	if(opts&strip_leading_slash)
	    for(;(*s) && (*s)=='/';s++);
	for(;*s;s++) {
	    if( (*s)=='/' ) {
		if(s[1]=='/')
		    continue;
		if(s[1]=='.' && s[2]=='/') {
		    s+=2;
		    continue;
		}
	    }
	    if(opts&restrict_dotdot) {
		if(
			( rv.empty() && s[0]=='.' && s[1]=='.' && s[2]=='/' )	// "^../"
			|| ( s[0]=='/' && s[1]=='.' && s[2]=='.' && (s[3]==0 || s[3]=='/') ) // "/..(/|$)"
		  )
		    throw utility_restricted_sequence(CODEPOINT,"restricted updir sequence encountered");
	    }
	    rv += *s;
	    if( (*s) != '/' )
		notslash=rv.length();
	}
	if(!(opts&strip_trailing_slash))
	    notslash++;
	if(notslash<rv.length())
	    rv.erase(notslash); // XXX: check the logic of stripping/not strippling trailing slash
	return rv;
    }

    string strip_prefix(const string& str,const string& prefix) {
	if(str.compare(0,prefix.length(),prefix))
	    throw utility_no_prefix(CODEPOINT,"no such prefix");
	return str.substr(prefix.length());
    }

    string strip_suffix(const string& str,const string& suffix) {
	if(str.compare(str.length()-suffix.length(),suffix.length(),suffix))
	    throw utility_no_suffix(CODEPOINT,"no such suffix");
	return str.substr(0,str.length()-suffix.length());
    }

    string dir_name(const string& filename) {
	string::size_type sl = filename.find_last_of('/');
	if(sl==string::npos)
	    return ""; // no slashes -- no dir.
	string::size_type nosl = filename.find_last_not_of('/',sl);
	if(nosl==string::npos)
	    return ""; // only slashes -- no dir. XXX: only slashes after the last slash... does it mean no dir?
	return filename.substr(0,nosl+1);
    }

    void make_path(const string& path,mode_t mode) {
	struct stat st;
	for(string::size_type sl=0;sl!=string::npos;sl=path.find('/',sl+1)) {
	    if(!sl)
		continue;
	    string p = path.substr(0,sl);
	    if(stat(p.c_str(),&st) || !S_ISDIR(st.st_mode)) {
		if(mkdir(p.c_str(),mode))
		    throw konforka::exception(CODEPOINT,"failed to mkdir()");
	    }
	}
	if(stat(path.c_str(),&st) || !S_ISDIR(st.st_mode)) {
	    if(mkdir(path.c_str(),mode))
		throw konforka::exception(CODEPOINT,"failed to mkdir()");
	}
    }

    void file_lock::lock(const string& f) {
	unlock();
	fd = open(f.c_str(),O_CREAT|O_RDWR,S_IRUSR|S_IWUSR);
	if(fd<0)
	    throw konforka::exception(CODEPOINT,"failed to open/create lockfile");
	try {
	    lock();
	}catch(konforka::exception& ke) {
	    ke.see(CODEPOINT);
	    close(fd); fd=-1;
	    throw;
	}catch(...) {
	    close(fd); fd=-1;
	    throw;
	}
    }
    void file_lock::lock() {
	assert(fd>=0);
	struct flock fl;
	fl.l_type = F_WRLCK;
	fl.l_whence=SEEK_SET;
	fl.l_start=fl.l_len=0;
	for(int tries=3;tries;tries--) {
	    if(!fcntl(fd,F_SETLK,&fl))
		return;
	    sleep(8);
	}
	throw konforka::exception(CODEPOINT,"failed to obtain file lock");
    }
    void file_lock::unlock() {
	if(fd<0)
	    return;
	struct flock fl;
	fl.l_type = F_UNLCK;
	fl.l_whence=SEEK_SET;
	fl.l_start=fl.l_len=0;
	int rv = fcntl(fd,F_SETLK,&fl);
	close(fd);
	fd=-1;
	if(rv)
	    throw konforka::exception(CODEPOINT,"failed to release file lock");
    }

    void pid_file::set(const string& f,bool u) {
	ofstream of(f.c_str(),ios::trunc);
	if(!of)
	    throw konforka::exception(CODEPOINT,"failed to open file for writing pid");
	of << getpid() << endl;
	of.close();
	file_name = f;
	unlink_pid = u;
    }
    void pid_file::unlink() {
	if(!unlink_pid)
	    return;
	::unlink(file_name.c_str());
    }

    void semaphore::init() {
	deinit();
	semid = semget(IPC_PRIVATE,1,IPC_CREAT|0600);
	if(semid<0)
	    throw konforka::exception(CODEPOINT,"failed to semget()");
	if(semctl(semid,0,SETVAL,1))
	    throw konforka::exception(CODEPOINT,"failed to semctl()");
    }
    void semaphore::deinit() {
	if(semid<0)
	    return;
	semctl(semid,0,IPC_RMID,0);
    }
    void semaphore::on() {
	assert(semid>=0);
	struct sembuf sb;
	sb.sem_num=0;
	sb.sem_op=-1;
	sb.sem_flg = SEM_UNDO;
	while(semop(semid,&sb,1)<0) {
	    if(errno!=EINTR)
		throw konforka::exception(CODEPOINT,"failed to semop()");
	}
    }
    void semaphore::off() {
	assert(semid>=0);
	struct sembuf sb;
	sb.sem_num=0;
	sb.sem_op=1;
	sb.sem_flg = SEM_UNDO;
	while(semop(semid,&sb,1)<0) {
	    if(errno!=EINTR)
		throw konforka::exception(CODEPOINT,"failed to semop()");
	}
    }

    void semaphore_lock::lock() {
	assert(sem);
	if(locked)
	    return;
	sem->on();
	locked = true;
    }
    void semaphore_lock::unlock() {
	if(!sem)
	    return;
	if(!locked)
	    return;
	sem->off();
	locked=false;
    }

    string combine_path(const string& origin,const string& relative,int opts) {
	string r = normalize_path(relative,0);
	string rv;
	// XXX: what to do if relative is empty is a question, really.
	if(r.empty()) {
	    return normalize_path( (opts&origin_is_file)?dir_name(origin):origin ,strip_leading_slash|restrict_dotdot|strip_trailing_slash);
	}else{
	    if(r[0]=='/') {
		r.erase(0,1);
	    }else{
		rv = normalize_path((opts&origin_is_file)?dir_name(origin):origin,restrict_dotdot|strip_trailing_slash);
	    }
	}
	string::size_type lsl = rv.rfind('/');
	for(string::size_type sl=r.find('/');sl!=string::npos;sl=r.find('/')) {
	    assert(sl!=0);
	    if(sl==1 && r[0]=='.') {
		// it's a "./"
		r.erase(0,2);
	    }else if(sl==2 && r[0]=='.' && r[1]=='.') {
		// we have a "../"
		if(lsl==string::npos) {
		    if(rv.empty() && (opts&fail_beyond_root))
			throw utility_beyond_root(CODEPOINT,"went beyond root while combining path");
		    rv.clear();
		}else{
		    rv.erase(lsl);
		    lsl = rv.rfind('/');
		}
		r.erase(0,3);
	    }else{
		// we have a "something/"
		lsl = rv.length();
		rv += '/';
		rv += r.substr(0,sl);
		r.erase(0,sl+1);
	    }
	}
	if(r.empty())
	    return rv+'/';
	if(r.length()==2 && r[0]=='.' && r[0]=='.') {
	    if(lsl==string::npos) {
		if(rv.empty() & (opts&fail_beyond_root))
		    throw utility_beyond_root(CODEPOINT,"went beyond root while combining path");
		return "/";
	    }else{
		rv.erase(lsl+1);
		return rv;
	    }
	}
	rv += '/';
	rv += r;
	return rv;
    }

    void auto_chdir::pushdir(const string& td,bool ap) {
	/* TODO: make use of fchdir(2) instead */
	char *tmp = getcwd(0,0);
	assert(tmp);
	saved_pwd = tmp;
	free(tmp);
	autopop=ap;
	if(chdir(td.c_str()))
	    throw konforka::exception(CODEPOINT,"failed to chdir()");
    }
    void auto_chdir::popdir() {
	autopop=false;
	if(chdir(saved_pwd.c_str()))
	    throw konforka::exception(CODEPOINT,"failed to chdir()");
	// XXX: or should it be thrown? after all we call it from destructor...
    }

}