/***************************************************************************
                          Task.h  -  class Task
                             -------------------
    begin                : Tue Nov 27 16:40:42 CET 2001
    copyright            : (C) 2001 by Sebastian Stein
    email                : seb.kde@hpfsc.de

    copyright            : (C) 2008 by Tiago Porangaba, tiago.porangaba@ltia.fc.unesp.br
    copyright            : (C) 2008 by Tadeu Araujo, tadeu.araujo@ltia.fc.unesp.br
    copyright            : (C) 2008 by Danilo Balzaque, danilo.balzaque@ltia.fc.unesp.br
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#ifndef TASK_H
#define TASK_H

#include "Ratio.h"
#include "PrimeNumber.h"

#include <vector>
#include <QTextStream>

/** important for add_sub and mul_div */
#define YES 1
#define NO  0

/** important for op_vector */
#define ADD 0
#define SUB 1
#define MUL 2
#define DIV 3

/** to mark a prime factor as used or unused */
#define UNUSED 0
#define USED    1

/** Structure represents a prime factor.
 *  Structure stores a prime factor and its usage status. The factor is marked
 *  as used or unused.
 **/
typedef struct PRIME_FACTOR {
    /** the prime factor */
    int factor;

    /** the status of the prime factor (used or unused) */
    short flag;
}
Tprime_factor;

/** we use the vector template class to create 3 dynamic types */
typedef QVector<Ratio> RatioArray;
typedef QVector<short> ShortArray;
typedef QVector<Tprime_factor> PrimeFactorArray;

/*! class to handle mathematical tasks with ratios
 *  naming:
 *  - a task has at least 2 ratios
 *  - a task has at least 1 operation
 *
 *  \author Sebastian Stein */
class Task
{
public:
    /** constructor */
    Task();

    /** destructor */
    ~Task();

    /** automatically generate a new task with the given parameters */
    void create_task(unsigned int pmax_md = 10, short pnr_ratios = 2,
                     short padd_add = YES, short padd_div = NO, short padd_mult = NO, short padd_sub = NO);

    /** set ratio n */
    void set_ratio_n(unsigned short number = 0, int numerator = 0,
                     int denominator = 1);

    /** set ratio n */
    void set_ratio_n(unsigned short number, const Ratio &fraction);

    /** returns ration n */
    Ratio get_ratio_n(unsigned short number = 0) const;

    /** set operation n */
    void set_op_n(unsigned short number = 0, short operation = ADD);

    /** return operation n */
    short get_op_n(unsigned short number = 0) const;

    /** add a ratio to the end of the task */
    void add_ratio(const Ratio &new_ratio);

    /** add a ratio to the end of the task */
    void add_ratio(int numerator = 0, int denominator = 1);

    /** add an operation at the end of the task */
    void add_operation(short operation = ADD);

    /** display the whole task, mainly for debug */
    QTextStream & display(QTextStream & str);

    /** solves the task and returns the result as ratio */
    Ratio solve();

    /** returns the number of ratios in the vector */
    int getNumberOfRatios() const;

    /** returns the number of operations in the vector */
    int getNumberOfOperations() const;

    /** removes all ratios and operations from the given task */
    void clean();

private:
    /** the ratio vector */
    RatioArray ratio_vector;

    /** the operation vector, smaller by one than ratio_vector */
    ShortArray op_vector;

    /** the prime factor vector is used to store all prime factors of the
     * main denominator */
    PrimeFactorArray prim_fac_vector;

    /** this function is needed by solve() */
    Ratio product(RatioArray::iterator & ratio_pointer,
                  ShortArray::iterator & op_pointer);

    /** generate the operations randomly; return how many mul or div
     * are in one block */
    unsigned short make_operation(short padd_add = YES, short padd_div = NO,
                                  short padd_mult = NO, short padd_sub = NO,
                                  short pnr_ratios = 0);

    /** find a denominator for the task */
    int make_main_dn(unsigned int pmax_md, unsigned short max_product_length);

    /** returns the count number's prime factors  */
    unsigned short prim_factor_nr(int number = 1);

    /** set the numerators randomly */
    void make_numerators(int main_denominator, short pnr_ratios);

    /** create the ratios' denominators */
    void make_denominators(int main_denominator = 0, short pmax_md = 0,
                           short padd_div = NO, short padd_mult = NO);
};


/* ------ some prototypes of non class functions ------ */

/** it is possible to code: cout << task_object << endl; */
QTextStream & operator<< (QTextStream & str, Task & ptask);

#endif
