"""
Classes to create, solve, and make dinner for linear programs. Handles
integration with lp_solve.
"""

import os
import site
import sys

# Add LP_SOLVE_PATH to our path. There is no point to this variable
# other than to make the site.addsitedir() line fit within 80
# characters.
LP_SOLVE_PATH = '/../lib/lp_solve'
site.addsitedir(os.path.dirname(os.path.abspath(sys.argv[0])) + LP_SOLVE_PATH)

from lp_solve import *


# Constants denoting the three different types of (in)equalities.
# These are defined by lp_solve.
LEQ = -1 # Less than or equal to.
EQ  =  0 # Equal to
GEQ =  1 # Greater than or Equal to.


class LinearProgram(object):
    """
    Represents an instance of an lp_solve linear program.    
    """
    
    def __init__(self):
        self.objective_function_coefficients = []
        self.constraint_matrix = []
        self.rhs = []
        self.inequalities = []


    def solve(self):
        [v,x,duals] = lp_solve(self.objective_function_coefficients,
                               self.constraint_matrix,
                               self.rhs,
                               self.inequalities)
        return [v,x,duals]