# -*- coding: utf-8 -*-
"""
Created on Tue Apr  2 18:41:27 2013

@author: pietro

@code

>>> import grass.pygrass.modules as pymod
>>> import copy
>>> region = pymod.Module("g.region")
>>> region.flags["p"].value = True
>>> region.flags["3"].value = True
>>> region.get_bash()
'g.region -p -3'
>>> new_region = copy.deepcopy(region)
>>> new_region.inputs["res"].value = "10"
>>> new_region.get_bash()
'g.region res=10 -p -3'

>>> neighbors = pymod.Module("r.neighbors")
>>> neighbors.inputs["input"].value = "mapA"
>>> neighbors.outputs["output"].value = "mapB"
>>> neighbors.inputs["size"].value = 5
>>> neighbors.get_bash()
'r.neighbors input=mapA method=average size=5 quantile=0.5 output=mapB'

>>> new_neighbors1 = copy.deepcopy(neighbors)
>>> new_neighbors1.inputs["input"].value = "mapD"
>>> new_neighbors1.inputs["size"].value = 3
>>> new_neighbors1.get_bash()
'r.neighbors input=mapD method=average size=3 quantile=0.5 output=mapB'

>>> new_neighbors2 = copy.deepcopy(neighbors)
>>> new_neighbors2(input="mapD", size=3, run_=False)
>>> new_neighbors2.get_bash()
'r.neighbors input=mapD method=average size=3 quantile=0.5 output=mapB'

>>> neighbors = pymod.Module("r.neighbors")
>>> neighbors.get_bash()
'r.neighbors method=average size=3 quantile=0.5'

>>> new_neighbors3 = copy.deepcopy(neighbors)
>>> new_neighbors3(input="mapA", size=3, output="mapB", run_=False)
>>> new_neighbors3.get_bash()
'r.neighbors input=mapA method=average size=3 quantile=0.5 output=mapB'

@endcode
"""

from __future__ import print_function
import subprocess
from itertools import izip_longest
from xml.etree.ElementTree import fromstring


from grass.pygrass.errors import GrassError, ParameterError
from parameter import Parameter
from flag import Flag
from typedict import TypeDict
from read import GETFROMTAG, DOC

class ParallelModuleQueue(object):
    """!This class is designed to run an arbitrary number of pygrass Module
       processes in parallel.

       Objects of type grass.pygrass.modules.Module can be put into the
       queue using put() method. When the queue is full with the maximum
       number of parallel processes it will wait for all processes to finish,
       sets the stdout and stderr of the Module object and removes it
       from the queue when its finished.

       This class will raise a GrassError in case a Module process exits
       with a return code other than 0.

       Usage:

       @code

       >>> import copy
       >>> import grass.pygrass.modules as pymod
       >>> mapcalc_list = []
       >>> mapcalc = pymod.Module("r.mapcalc",
       ...                        overwrite=True,
       ...                        run_=False,
       ...                        finish_=False)
       >>> queue = pymod.ParallelModuleQueue(max_num_procs=3)
       >>> for i in xrange(5):
       ...     new_mapcalc = copy.deepcopy(mapcalc)
       ...     mapcalc_list.append(new_mapcalc)
       ...     new_mapcalc(expression="test_pygrass_%i = %i"%(i, i))
       ...     queue.put(new_mapcalc)
       >>> queue.wait()
       >>> for mapcalc in mapcalc_list:
       ...     print(mapcalc.popen.returncode)
       0
       0
       0
       0
       0

       @endcode

    """
    def __init__(self, max_num_procs=1):
        """!Constructor

           @param max_num_procs The maximum number of Module processes that
                                can be run in parallel
        """
        self._num_procs = int(max_num_procs)
        self._list = int(max_num_procs) * [None]
        self._proc_count = 0

    def put(self, module):
        """!Put the next Module object in the queue

           To run the Module objects in parallel the run_ and finish_ options
           of the Module must be set to False.

           @param module A preconfigured Module object with run_ and finish_
                         set to False
        """
        self._list[self._proc_count] = module
        self._list[self._proc_count].run()
        self._proc_count += 1

        if self._proc_count == self._num_procs:
            self.wait()

    def get(self, num):
        """!Get a Module object from the queue

           @param num The number of the object in queue
           @return The Module object or None if num is not in the queue
        """
        if num < self._num_procs:
            return self._list[num]
        return None

    def get_num_run_procs(self):
        """!Get the number of Module processes that are in the queue running
           or finished

           @return The maximum number fo Module processes running/finished in
                   the queue
        """
        return len(self._list)

    def get_max_num_procs(self):
        """!Return the maximum number of parallel Module processes
        """
        return self._num_procs

    def set_max_num_procs(self, max_num_procs):
        """!Set the maximum number of Module processes that should run
           in parallel
        """
        self._num_procs = int(max_num_procs)
        self.wait()

    def wait(self):
        """!Wait for all Module processes that are in the list to finish
           and set the modules stdout and stderr output options
        """
        for proc in self._list:
            if proc:
                stdout, stderr = proc.popen.communicate(input=proc.stdin)
                proc.outputs['stdout'].value = stdout if stdout else ''
                proc.outputs['stderr'].value = stderr if stderr else ''

                if proc.popen.returncode != 0:
                    GrassError(("Error running module %s")%(proc.name))

        self._list = self._num_procs * [None]
        self._proc_count = 0

class Module(object):
    """

    Python allow developers to not specify all the arguments and
    keyword arguments of a method or function.

    ::

        def f(*args):
            for arg in args:
                print arg

    therefore if we call the function like: ::

        >>> f('grass', 'gis', 'modules')
        grass
        gis
        modules

    or we can define a new list: ::

        >>> words = ['grass', 'gis', 'modules']
        >>> f(*words)
        grass
        gis
        modules

    we can do the same with keyword arguments, rewrite the above function: ::

        def f(*args, **kargs):
            for arg in args:
                print arg
            for key, value in kargs.items():
                print "%s = %r" % (key, value)

    now we can use the new function, with: ::

        >>> f('grass', 'gis', 'modules', os = 'linux', language = 'python')
        grass
        gis
        modules
        os = 'linux'
        language = 'python'

    or, as before we can, define a dictionary and give the dictionary to
    the function, like: ::

        >>> keywords = {'os' : 'linux', 'language' : 'python'}
        >>> f(*words, **keywords)
        grass
        gis
        modules
        os = 'linux'
        language = 'python'

    In the Module class we heavily use this language feature to pass arguments
    and keyword arguments to the grass module.
    """
    def __init__(self, cmd, *args, **kargs):
        self.name = cmd
        try:
            # call the command with --interface-description
            get_cmd_xml = subprocess.Popen([cmd, "--interface-description"],
                                           stdout=subprocess.PIPE)
        except OSError:
            str_err = "Module %r not found, please check that the module exist"
            raise GrassError(str_err % self.name)
        # get the xml of the module
        self.xml = get_cmd_xml.communicate()[0]
        # transform and parse the xml into an Element class:
        # http://docs.python.org/library/xml.etree.elementtree.html
        tree = fromstring(self.xml)

        for e in tree:
            if e.tag not in ('parameter', 'flag'):
                self.__setattr__(e.tag, GETFROMTAG[e.tag](e))

        #
        # extract parameters from the xml
        #
        self.params_list = [Parameter(p) for p in tree.findall("parameter")]
        self.inputs = TypeDict(Parameter)
        self.outputs = TypeDict(Parameter)
        self.required = []

        # Insert parameters into input/output and required
        for par in self.params_list:
            if par.input:
                self.inputs[par.name] = par
            else:
                self.outputs[par.name] = par
            if par.required:
                self.required.append(par.name)

        #
        # extract flags from the xml
        #
        flags_list = [Flag(f) for f in tree.findall("flag")]
        self.flags = TypeDict(Flag)
        for flag in flags_list:
            self.flags[flag.name] = flag

        #
        # Add new attributes to the class
        #
        self.run_ = True
        self.finish_ = True
        self.env_ = None
        self.stdin_ = None
        self.stdin = None
        self.stdout_ = None
        self.stderr_ = None
        diz = {'name': 'stdin', 'required': False,
               'multiple': False, 'type': 'all',
               'value': None}
        self.inputs['stdin'] = Parameter(diz=diz)
        diz['name'] = 'stdout'
        self.outputs['stdout'] = Parameter(diz=diz)
        diz['name'] = 'stderr'
        self.outputs['stderr'] = Parameter(diz=diz)
        self.popen = None

        if args or kargs:
            self.__call__(*args, **kargs)

    def __call__(self, *args, **kargs):
        if not args and not kargs:
            self.run()
            return
        #
        # check for extra kargs, set attribute and remove from dictionary
        #
        if 'flags' in kargs:
            for flg in kargs['flags']:
                self.flags[flg].value = True
            del(kargs['flags'])
        if 'run_' in kargs:
            self.run_ = kargs['run_']
            del(kargs['run_'])
        if 'stdin_' in kargs:
            self.inputs['stdin'].value = kargs['stdin_']
            del(kargs['stdin_'])
        if 'stdout_' in kargs:
            self.outputs['stdout'].value = kargs['stdout_']
            del(kargs['stdout_'])
        if 'stderr_' in kargs:
            self.outputs['stderr'].value = kargs['stderr_']
            del(kargs['stderr_'])
        if 'env_' in kargs:
            self.env_ = kargs['env_']
            del(kargs['env_'])
        if 'finish_' in kargs:
            self.finish_ = kargs['finish_']
            del(kargs['finish_'])

        #
        # check args
        #
        for param, arg in zip(self.params_list, args):
            param.value = arg
        for key, val in kargs.items():
            if key in self.inputs:
                self.inputs[key].value = val
            elif key in self.outputs:
                self.outputs[key].value = val
            elif key in self.flags:
                # we need to add this, because some parameters (overwrite,
                # verbose and quiet) work like parameters
                self.flags[key].value = val
            else:
                raise ParameterError('%s is not a valid parameter.' % key)

        #
        # check reqire parameters
        #
        for key in self.required:
            if ((key in self.inputs and self.inputs[key].value is None) or
                    (key in self.outputs and self.outputs[key].value is None)):
                raise ParameterError(
                    "Required parameter <%s> not set." % key)

        #
        # check if execute
        #
        if self.run_:
            self.run()

    def get_bash(self):
        return ' '.join(self.make_cmd())

    def get_python(self):
        prefix = self.name.split('.')[0]
        name = '_'.join(self.name.split('.')[1:])
        params = ', '.join([par.get_python() for par in self.params_list
                           if par.get_python() != ''])
        special = ', '.join([flg.get_python()
                             for flg in self.flags.values()
                             if flg.special and flg.get_python() != ''])
        #     pre name par flg special
        if self.flags and special:
            return "%s.%s(%s, flags=%r, %s)" % (prefix, name, params,
                                                self.flags, special)
        elif self.flags:
            return "%s.%s(%s, flags=%r)" % (prefix, name, params, self.flags)
        elif special:
            return "%s.%s(%s, %s)" % (prefix, name, params, special)
        else:
            return "%s.%s(%s)" % (prefix, name, params)

    def __str__(self):
        """!Return the command string that can be executed in a shell
        """
        return ' '.join(self.make_cmd())

    def __repr__(self):
        return "Module(%r)" % self.name

    @property
    def __doc__(self):
        """{cmd_name}({cmd_params})
        """
        head = DOC['head'].format(cmd_name=self.name,
             cmd_params=('\n' +  # go to a new line
             # give space under the function name
             (' ' * (len(self.name) + 1))).join([', '.join(
             # transform each parameter in string
             [str(param) for param in line if param is not None])
             # make a list of parameters with only 3 param per line
             for line in izip_longest(*[iter(self.params_list)] * 3)]),)
        params = '\n'.join([par.__doc__ for par in self.params_list])
        flags = self.flags.__doc__
        return '\n'.join([head, params, DOC['flag_head'], flags, DOC['foot']])

    def get_dict(self):
        """!Return a dictionary that includes the name, all valid
            inputs, outputs and flags
        """
        dic = {}
        dic['name'] = self.name
        dic['inputs'] = [(k, v.value) for k, v in self.inputs.items()
                         if v.value]
        dic['outputs'] = [(k, v.value) for k, v in self.outputs.items()
                          if v.value]
        dic['flags'] = [flg for flg in self.flags if self.flags[flg].value]
        return dic

    def make_cmd(self):
        """!Create the command string that can be executed in a shell

           @return The command string
        """
        skip = ['stdin', 'stdout', 'stderr']
        args = [self.name, ]
        for key in self.inputs:
            if key not in skip and self.inputs[key].value:
                args.append(self.inputs[key].get_bash())
        for key in self.outputs:
            if key not in skip and self.outputs[key].value:
                args.append(self.outputs[key].get_bash())
        for flg in self.flags:
            if self.flags[flg].value:
                args.append(str(self.flags[flg]))
        return args

    def run(self, node=None):
        """!Run the module

           This function will wait for the process to terminate
           in case finish_==True and sets up stdout and stderr.
           If finish_==False this function will return after starting
           the process. Use self.popen.communicate() of self.popen.wait()
           to wait for the process termination. The handling
           of stdout and stderr must then be done outside of this
           function.
        """
        if self.inputs['stdin'].value:
            self.stdin = self.inputs['stdin'].value
            self.stdin_ = subprocess.PIPE
        if self.outputs['stdout'].value:
            self.stdout_ = self.outputs['stdout'].value
        if self.outputs['stderr'].value:
            self.stderr_ = self.outputs['stderr'].value
        cmd = self.make_cmd()
        self.popen = subprocess.Popen(cmd,
                                      stdin=self.stdin_,
                                      stdout=self.stdout_,
                                      stderr=self.stderr_,
                                      env=self.env_)
        if self.finish_:
            stdout, stderr = self.popen.communicate(input=self.stdin)
            self.outputs['stdout'].value = stdout if stdout else ''
            self.outputs['stderr'].value = stderr if stderr else ''

###############################################################################

if __name__ == "__main__":
    import doctest
    doctest.testmod()