#ifndef __SITECING_SITECING_UTIL_H
#define __SITECING_SITECING_UTIL_H

#include <sys/types.h>
#include <string>
#include <konforka/exception.h>

/**
 * @file
 * @brief utility classes and functions.
 */

namespace sitecing {
    using namespace std;

    /**
     * Base class for utility exceptions.
     */
    class utility_error : public konforka::exception {
	public:
	    utility_error(const string& fi,const string& fu,int l,const string& w)
		: konforka::exception(fi,fu,l,w) { }
    };
    /**
     * Restricted sequence encountered.
     */
    class utility_restricted_sequence : public utility_error {
	public:
	    utility_restricted_sequence(const string& fi,const string& fu,int l,const string& w)
		: utility_error(fi,fu,l,w) { }
    };
    /**
     * No prefix or suffix found to strip out.
     */
    class utility_no_affix : public utility_error {
	public:
	    utility_no_affix(const string& fi,const string& fu,int l,const string& w)
		: utility_error(fi,fu,l,w) { }
    };
    /**
     * No prefix to strip found.
     */
    class utility_no_prefix : public utility_no_affix {
	public:
	    utility_no_prefix(const string& fi,const string& fu,int l,const string& w)
		: utility_no_affix(fi,fu,l,w) { }
    };
    /**
     * No suffix to strip found.
     */
    class utility_no_suffix : public utility_no_affix {
	public:
	    utility_no_suffix(const string& fi,const string& fu,int l,const string& w)
		: utility_no_affix(fi,fu,l,w) { }
    };

    /**
     * Went up beyond root.
     * @todo TODO: wish I could remember the details -- document me.
     */
    class utility_beyond_root : public utility_error {
	public:
	    utility_beyond_root(const string& fi,const string& fu,int l,const string& w)
		: utility_error(fi,fu,l,w) { }
    };

    /**
     * The file lock object. Released at the object destruction.
     */
    class file_lock {
	public:
	    /**
	     * The file descriptor.
	     */
	    int fd;

	    file_lock()
		: fd(-1) { }
	    /**
	     * @param f file name.
	     */
	    file_lock(const string& f)
		: fd(-1) { lock(f); }
	    ~file_lock() { unlock(); }

	    /**
	     * Do lock.
	     * @param f file name.
	     */
	    void lock(const string& f);
	    /**
	     * @todo TODO: wish I could remember the details -- document me.
	     */
	    void lock();
	    /**
	     * Release the lock obtained.
	     */
	    void unlock();
    };

    /**
     * The pid file. Removed at object destruction.
     */
    class pid_file {
	public:
	    /**
	     * The file name.
	     */
	    string file_name;
	    /**
	     * Do we unlink the file after we're done?
	     */
	    bool unlink_pid;

	    pid_file()
		: unlink_pid(false) { }
	    ~pid_file() { unlink(); }

	    /**
	     * @param f file name.
	     * @param u whether we want to unlink the file.
	     */
	    void set(const string& f,bool u=true);
	    /**
	     * Unlink the file if we wanted to in the first place.
	     */
	    void unlink();
    };

    /**
     * The semaphore object.
     */
    class semaphore {
	public:
	    /**
	     * The semaphore id.
	     */
	    int semid;

	    semaphore()
		: semid(-1) { }
	    /**
	     * @param sid semaphore id.
	     */
	    semaphore(int sid)
		: semid(sid) { }
	    ~semaphore() {
		deinit();
	    }

	    /**
	     * Init semaphore.
	     */
	    void init();
	    /**
	     * Undo the init.
	     */
	    void deinit();

	    /**
	     * Semaphore on.
	     */
	    void on();
	    /**
	     * Semaphore off.
	     */
	    void off();
    };

    /**
     * The semaphor lock object, released at object destruction.
     */
    class semaphore_lock {
	public:
	    /**
	     * Pointer to the semaphore we're operating on.
	     */
	    semaphore* sem;
	    /**
	     * Whether it is locked.
	     */
	    bool locked;

	    semaphore_lock()
		: sem(NULL), locked(false) {}
	    /**
	     * @param s pointer to the semaphore.
	     * @param l lock at creation?
	     */
	    semaphore_lock(semaphore* s,bool l=true)
		: sem(s), locked(false) {
		    if(l) lock();
		}
	    /**
	     * @param s reference to the semaphore.
	     * @param l lock at creation?
	     */
	    semaphore_lock(semaphore& s,bool l=true)
		: sem(&s), locked(false) {
		    if(l) lock();
		}

	    ~semaphore_lock() {
		unlock();
	    }

	    /**
	     * Lock it.
	     */
	    void lock();
	    /**
	     * Unlock it.
	     */
	    void unlock();
    };

    /**
     * normalize_path options enumeration.
     * @see normalize_path()
     */
    enum normalize_path_options {
	/**
	 * Restrict the /../ sequence.
	 */
	restrict_dotdot = 1,
	/**
	 * Strip out the leading slash.
	 */
	strip_leading_slash = 2,
	/**
	 * Strip out the trailing slash.
	 */
	strip_trailing_slash = 4
    };
    /**
     * combine_path options enumeration.
     * @see combine_path()
     */
    enum combine_path_options {
	/**
	 * The origin is file. Otherwise it is directory.
	 */
	origin_is_file = 1,
	/**
	 * Fail if we've gone up beyond root.
	 */
	fail_beyond_root = 2
    };

    /**
     * Normalize pathname by stripping duplicate slashes, etc.
     * @param path the path name.
     * @param opts options.
     * @return the normalized path.
     * @see normalize_path_options
     * @todo TODO: document exceptions.
     */
    string normalize_path(const string& path,int opts=(restrict_dotdot|strip_trailing_slash));
    /**
     * Strip prefix from the string.
     * @param str the string.
     * @param prefix prefix to strip.
     * @return the string without prefix.
     * @todo TODO: document exceptions.
     */
    string strip_prefix(const string& str,const string& prefix);
    /**
     * Strip suffix from the string.
     * @param str the string.
     * @param suffix suffix to strip.
     * @return the string without suffix.
     * @todo TODO: document exceptions.
     */
    string strip_suffix(const string& str,const string& suffix);
    /**
     * Get the directory part of the filename.
     * @param filename the full file name.
     * @return the directory part.
     */
    string dir_name(const string& filename);
    /**
     * Combine path with the relative path.
     * @param origin the origin.
     * @param relative relative path to combine origin with.
     * @param opts options.
     * @return the pathc combined.
     * @see combine_path_options
     * @todo TODO: document exceptions.
     */
    string combine_path(const string& origin,const string& relative,int opts=origin_is_file);
   
    /**
     * Create directory and parent directories if needed.
     * @param path the pathname.
     * @param mode the mode for newly created directories.
     */
    void make_path(const string& path,mode_t mode);

    /**
     * Change to the directory and pop back at object's destruction (e.g. when
     * the object goes out of scope).
     */
    class auto_chdir {
	public:
	    /**
	     * Saved working directory.
	     */
	    string saved_pwd;
	    /**
	     * Whether we want to change back automatically.
	     */
	    bool autopop;

	    auto_chdir()
		: autopop(false) { }
	    /**
	     * @param td destination path.
	     * @param ap automatically come back?
	     */
	    auto_chdir(const string& td,bool ap=true)
		: autopop(false) { pushdir(td,ap); }
	    ~auto_chdir() {
		if(autopop)
		    popdir();
	    }

	    /**
	     * Change into directory.
	     * @param td the directory.
	     * @param ap automaticall pop back?
	     */
	    void pushdir(const string& td,bool ap=true);
	    /**
	     * Change to the saved directory.
	     */
	    void popdir();
    };

}

#endif /* __SITECING_SITECING_UTIL_H */