#!/usr/bin/env python 
# -*- coding: utf-8 -*-

# Copyright (C) 2010 Modelon AB
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, version 3 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
""" 
Module containing optimization, simulation and initialization algorithms.
"""

#from abc import ABCMeta, abstractmethod
import logging
import time
import numpy as N

from .xmlparser import XMLException

default_int = int
int = N.int32
N.int = N.int32

class AlgorithmBase(object):
    """ 
    Abstract class which all algorithms that are to be used in
    simulating/optimization/initialization with Model classes extending
    common.core.BaseModel must implement.
    """
#    __metaclass__=ABCMeta
    
#    @abstractmethod
    def __init__(self, model, alg_args): pass
    
#    @abstractmethod
    def solve(self): pass
    
#   @abstractmethod
    def get_result(self): pass
    
    @classmethod
    def get_default_options(self): pass
    
class ResultBase(object):
    """ 
    Base class for an algorithm result. All algorithms used in any of the 
    high-level functions should return an object which extends this class.
    """
    
    def __init__(self, model=None, result_file_name=None, solver=None, 
        result_data=None, options=None):
        """ 
        Create a result object containing the model used in the algorithm, the 
        name of the result file, the solver used in the algorithm, the result 
        data object and the object (dict) holding the options used in the 
        algorithm run.
                       
        Parameters::
        
            model -- 
                The Model (extending common.BaseModel) object for the model used
                in the algorithm.
                
            result_file_name --
                Name of the file containing the algorithm result created on the 
                file system.
                
            solver --
                The solver object used in the algorithm.
                
            result_data --
                The result data object created when running the algorithm. Holds 
                the whole result data matrix.
                
            options --
                The options object with the options that the algorithm was run 
                with.
        """
        self._model = model
        self._result_file_name = result_file_name
        self._solver = solver
        self._result_data = result_data
        self._options = options
    
    def _get_model(self):
        if self._model is not None:
            return self._model
        raise Exception("model has not been set")
        
    def _set_model(self, model):
        self._model = model
        
    model = property(fget=_get_model, fset=_set_model, doc = 
    """
    Property for accessing the model that was used in the algorithm.
    """)
        
    def _get_result_file(self):
        if self._result_file_name is not None:
            return self._result_file_name
        raise Exception("result file name has not been set")
    
    def _set_result_file(self, file_name):
        self._result_file_name = result_file_name
        
    result_file = property(fget=_get_result_file, fset=_set_result_file, doc = 
    """
    Property for accessing the name of the result file created in the algorithm.
    """)
        
    def _get_solver(self):
        if self._solver is not None:
            return self._solver
        raise Exception("solver has not been set")

    def _set_solver(self, solver):
        self._solver = solver
        
    solver = property(fget=_get_solver, fset=_set_solver, doc = 
    """
    Property for accessing the solver that was used in the algorithm.
    """)
        
    def _get_result_data(self):
        if self._result_data is not None:
            return self._result_data
        raise Exception("result data has not been set")
        
    def _set_result_data(self, result_data):
        self._result_data = result_data
        
    result_data = property(fget=_get_result_data, fset=_set_result_data, doc = 
    """
    Property for accessing the result data matrix that was created in the 
    algorithm.
    """)
    
    def _get_options(self):
        if self._options is not None:
            return self._options
        raise Exception("options has not been set")
        
    def _set_options(self, options):
        self._options = options
        
    options = property(fget=_get_options, fset=_set_options, doc = 
    """
    Property for accessing he options object holding the options used in the 
    algorithm.
    """)

class JMResultBase(ResultBase):
    
    def keys(self):
        """
        Returns the variable names in the result file.
        """
        return self.result_data.name
    
    def __getitem__(self, key):
        """
        Returns vector with result trajectory for a variable, parameter 
        or constant that has the same length as the time vector.
        
        Parameters::
        
            key --
                Name of the variable/parameter/constant.
        """
        val_x = self.result_data.get_variable_data(key).x
        
        if self.result_data.is_variable(key):
            return val_x
            
        time = self.result_data.get_variable_data('time')
        return val_x[0].repeat(len(time.t))
        
    def final(self, key):
        """
        Returns the final value of a variable result trajectory.

        Parameters::
        
            key --
                Name of the variable/parameter/constant.
        """
        val_x = self.result_data.get_variable_data(key).x
        return val_x[-1]
        
    def initial(self, key):
        """
        Returns the initial value of a variable result trajectory.

        Parameters::
        
            key --
                Name of the variable/parameter/constant.
        """
        val_x = self.result_data.get_variable_data(key).x
        return val_x[0]
        
    def is_variable(self, name):
        """
        Returns True if the given name corresponds to a time-varying variable.
        
        Parameters::
        
            name --
                Name of the variable/parameter/constant.
                
        Returns::
        
            True if the variable is time-varying.
        """
        return self.result_data.is_variable(name)
    
    def is_negated(self, name):
        return self.result_data.is_negated(name)
    
    def _get_data_matrix(self):
        return self.result_data.get_data_matrix()
        
    data_matrix = property(fget=_get_data_matrix, doc = 
    """
    Property for accessing the result matrix.
    """)

    def get_column(self, name):
        """
        Returns the column number in the data matrix where the values of the 
        variable are stored.
        
        Parameters::
        
            name --
                Name of the variable/parameter/constant.
            
        Returns::
        
            The column number.
        """
        return self.result_data.get_column(name)

class AssimuloSimResult(JMResultBase):
    pass

class OptionBase(dict):
    """ 
    Base class for an algorithm option class. 
    
    All algorithm option classes should extend this class. 
    
    This class extends the dict class overriding __init__, __setitem__, update 
    and setdefault methods with the purpose of offering a key check for the 
    extending classes.
    
    The extending class can define a set of keys and default values by 
    overriding __init__ or when instantiating the extended class and thereby not 
    allow any other keys to be added to the dict.
    
     * Example overriding __init__:
    
    class MyOptionsClass(OptionBase):
        def __init__(self, *args, **kw):
            mydefaults = {'def1':1, 'def2':2}
            super(MyOptionsClass,self).__init__(mydefaults)
        
            self.update(*args, **kw)
            
    >> opts = MyOptionsClass()
    >> opts['def1'] = 3   // ok
    >> opts.update({'def2':4})   // ok
    >> opts['def3']= 5   // not ok
    
            
     * Example setting defaults in constructor:
     
     class MyOptionsClass(OptionBase):pass
     
    >> opts = MyOptionsClass(def1=1, def2=2)
    >> opts['def1'] = 3   // ok
    >> opts.update({'def2':4})   // ok
    >> opts['def3']= 5   // not ok
    
    >> opts2 = MyOptionsClass()   // this class has no restrictions on keys
    >> opts2['def5'] = 'hello'   //ok
    """
    
    def __init__(self, *args, **kw):
        # create dict
        super(OptionBase,self).__init__(*args, **kw)
        # save keys - these are now the set of allowed keys
        self._keys = super(OptionBase,self).keys()

    def __setitem__(self, key, value):
        if self._keys:
            if not key in self._keys:
                raise UnrecognizedOptionError(
                    "The key: %s, is not a valid algorithm option" %str(key))
            
        super(OptionBase,self).__setitem__(key, value)
    
    def update(self, *args, **kw):
        if args:
            if len(args) > 1:
                raise TypeError(
                    "update expected at most 1 arguments, got %d" % len(args))
            other = dict(args[0])
            for key in other:
                self[key] = other[key]
        for key in kw:
            self[key] = kw[key]

    def setdefault(self, key, value=None):
        if key not in self:
            self[key] = value
        return self[key]
        
    def _update_keep_dict_defaults(self, *args, **kw):
        """ 
        Go through args/kw and for each value in a key-value-set that is a dict 
        - update the current dict with the new dict (don't overwrite).
        """
        if args:
            if len(args) > 1:
                raise TypeError(
                    "update expected at most 1 arguments, got %d" % len(args))
            other = dict(args[0])
            for key in other:
                if not key in self._keys:
                    raise UnrecognizedOptionError(
                        "The key: %s, is not a valid algorithm option" %str(key))
                if isinstance(self[key], dict):
                    self[key].update(other[key])
                else:
                    self[key] = other[key]
            
        for key in kw:
            if not key in self._keys:
                raise UnrecognizedOptionError(
                    "The key: %s, is not a valid algorithm option" %str(key))
            if isinstance(self[key], dict):
                self[key].update(kw[key])
            else:
                self[key] = kw[key]
    
class InvalidAlgorithmOptionException(Exception):
    """ 
    Exception raised when an algorithm options argument is encountered that is 
    not valid.
    """
    def __init__(self, arg):
        self.msg='Invalid algorithm options object: '+str(arg)
        
    def __str__(self):
        return repr(self.msg)

class InvalidSolverArgumentException(Exception):
    """ 
    Exception raised when a solver argument is encountered that does not exist.
    """
    def __init__(self, arg):
        self.msg='Invalid solver argument: '+str(arg)
        
    def __str__(self):
        return repr(self.msg)
    
class UnrecognizedOptionError(Exception): pass
