# -*- coding: utf-8 -*-
"""
===========
octavemagic
===========

Magics for interacting with Octave via oct2py.

.. note::

  The ``oct2py`` module needs to be installed separately and
  can be obtained using ``easy_install`` or ``pip``.

  You will also need a working copy of GNU Octave.

Usage
=====

To enable the magics below, execute ``%load_ext octavemagic``.

``%octave``

{OCTAVE_DOC}

``%octave_push``

{OCTAVE_PUSH_DOC}

``%octave_pull``

{OCTAVE_PULL_DOC}

"""

#-----------------------------------------------------------------------------
#  Copyright (C) 2012 The IPython Development Team
#
#  Distributed under the terms of the BSD License.  The full license is in
#  the file COPYING, distributed as part of this software.
#-----------------------------------------------------------------------------

import os
import shutil

import oct2py

from IPython.display import publish_display_data, display
from IPython.core.magic import (Magics, magics_class, line_magic,
                                line_cell_magic, needs_local_scope)
from IPython.testing.skipdoctest import skip_doctest
from IPython.core.magic_arguments import (
    argument, magic_arguments, parse_argstring
)
from IPython.utils.py3compat import unicode_to_str
from IPython.utils.text import dedent


@magics_class
class OctaveMagics(Magics):

    """A set of magics useful for interactive work with Octave via oct2py.
    """

    def __init__(self, shell):
        """
        Parameters
        ----------
        shell : IPython shell

        """
        super(OctaveMagics, self).__init__(shell)
        self._oct = oct2py.octave

        # Allow display to be overridden for
        # testing purposes.
        self._display = display

    @skip_doctest
    @line_magic
    def octave_push(self, line):
        '''
        Line-level magic that pushes a variable to Octave.

        `line` should be made up of whitespace separated variable names in the
        IPython namespace::

            In [7]: import numpy as np

            In [8]: X = np.arange(5)

            In [9]: X.mean()
            Out[9]: 2.0

            In [10]: %octave_push X

            In [11]: %octave mean(X)
            Out[11]: 2.0

        '''
        inputs = line.split(' ')
        for input in inputs:
            input = unicode_to_str(input)
            self._oct.push(input, self.shell.user_ns[input])

    @skip_doctest
    @line_magic
    def octave_pull(self, line):
        '''
        Line-level magic that pulls a variable from Octave.

        ::

            In [18]: _ = %octave x = [1 2; 3 4]; y = 'hello'

            In [19]: %octave_pull x y

            In [20]: x
            Out[20]:
            array([[ 1.,  2.],
                   [ 3.,  4.]])

            In [21]: y
            Out[21]: 'hello'

        '''
        outputs = line.split(' ')
        for output in outputs:
            output = unicode_to_str(output)
            self.shell.push({output: self._oct.pull(output)})

    @skip_doctest
    @magic_arguments()
    @argument(
        '-i', '--input', action='append',
        help='Names of input variables to be pushed to Octave. Multiple names '
             'can be passed, separated by commas with no whitespace.'
    )
    @argument(
        '-o', '--output', action='append',
        help='Names of variables to be pulled from Octave after executing cell '
             'body. Multiple names can be passed, separated by commas with no '
             'whitespace.'
    )
    @argument(
        '-s', '--size', action='store',
        help='Pixel size of plots, "width,height".'
    )
    @argument(
        '-f', '--format', action='store',
        help='Plot format (png, svg or jpg).'
    )
    @argument(
        '-w', '--width', type=int, action='store',
        help='The width of the plot in pixels'
    )
    @argument(
        '-h', '--height', type=int, action='store',
        help='The height of the plot in pixels'
    )
    @argument(
        '-r', '--resolution', type=int, action='store',
        help='The resolution of the plot in pixels per inch'
    )
    @argument(
        '-t', '--temp_dir', type=str, action='store',
        help='The directory to write variables for conversion between Octave and Python'
    )
    @needs_local_scope
    @argument(
        'code',
        nargs='*',
    )
    @line_cell_magic
    def octave(self, line, cell=None, local_ns=None):
        '''
        Execute code in Octave, and pull some of the results back into the
        Python namespace::

            In [9]: %octave X = [1 2; 3 4]; mean(X)
            Out[9]: array([[ 2., 3.]])

        As a cell, this will run a block of Octave code, without returning any
        value::

            In [10]: %%octave
               ....: p = [-2, -1, 0, 1, 2]
               ....: polyout(p, 'x')

            -2*x^4 - 1*x^3 + 0*x^2 + 1*x^1 + 2

        In the notebook, plots are published as the output of the cell, e.g.::

            %octave plot([1 2 3], [4 5 6])

        will create a line plot.

        Objects can be passed back and forth between Octave and IPython via the
        -i and -o flags in line::

            In [14]: Z = np.array([1, 4, 5, 10])

            In [15]: %octave -i Z mean(Z)
            Out[15]: array([ 5.])


            In [16]: %octave -o W W = Z * mean(Z)
            Out[16]: array([  5.,  20.,  25.,  50.])

            In [17]: W
            Out[17]: array([  5.,  20.,  25.,  50.])

        The size and format of output plots can be specified::

            In [18]: %%octave -s 600,800 -f svg
                ...: plot([1, 2, 3]);

        '''
        args = parse_argstring(self.octave, line)

        # arguments 'code' in line are prepended to the cell lines
        if cell is None:
            code = ''
            return_output = True
        else:
            code = cell
            return_output = False

        code = ' '.join(args.code) + code

        # if there is no local namespace then default to an empty dict
        if local_ns is None:
            local_ns = {}

        if args.input:
            for input in ','.join(args.input).split(','):
                input = unicode_to_str(input)
                try:
                    val = local_ns[input]
                except KeyError:
                    val = self.shell.user_ns[input]
                self._oct.push(input, val)

        width = args.width
        height = args.height

        if args.size is not None:
            width, height = [int(s) for s in args.size.split(',')]

        # Handle the temporary directory, defaulting to the Oct2Py instance's
        # temp dir.
        temp_dir = args.temp_dir
        if temp_dir and not os.path.isdir(temp_dir):
            temp_dir = None
        temp_dir = temp_dir or self._oct.temp_dir

        # Put the plots in the temp directory so we don't have to make another
        # temporary directory.
        plot_dir = os.path.join(temp_dir, 'plots')
        if os.path.exists(plot_dir):
            shutil.rmtree(plot_dir)
        os.makedirs(plot_dir)

        # Match current working directory.
        self._oct.cd(os.getcwd().replace(os.path.sep, '/'))
        value = self._oct.eval(code, stream_handler=self._publish,
            plot_dir=plot_dir, plot_width=width, plot_height=height,
            plot_format=args.format, plot_name='__ipy_oct_fig_',
            resolution=args.resolution, temp_dir=temp_dir)

        # Publish output
        if args.output:
            for output in ','.join(args.output).split(','):
                output = unicode_to_str(output)
                self.shell.push({output: self._oct.pull(output)})

        # Publish images
        if plot_dir:
            for img in self._oct.extract_figures(plot_dir, True):
                self._display(img)

        if return_output:
            return value

    def _publish(self, line):
        publish_display_data({'text/plain': line})


__doc__ = __doc__.format(
    OCTAVE_DOC=dedent(OctaveMagics.octave.__doc__),
    OCTAVE_PUSH_DOC=dedent(OctaveMagics.octave_push.__doc__),
    OCTAVE_PULL_DOC=dedent(OctaveMagics.octave_pull.__doc__)
)


def load_ipython_extension(ip):
    """Load the extension in IPython."""
    ip.register_magics(OctaveMagics)
