"""Utilities for using pyvista with sphinx-gallery."""

from __future__ import annotations

from pathlib import Path
import shutil
from typing import TYPE_CHECKING

import pyvista as pv
from pyvista._deprecate_positional_args import _deprecate_positional_args

if TYPE_CHECKING:
    from collections.abc import Iterator

BUILDING_GALLERY_ERROR_MSG = (
    'pyvista.BUILDING_GALLERY must be set to True in your conf.py to capture '
    'images within sphinx_gallery or when building documentation using the '
    'pyvista-plot directive.'
)


def _get_sg_image_scraper():
    """Return the callable scraper to be used by Sphinx-Gallery.

    It allows PyVista users to just use strings as they already can for
    'matplotlib' and 'mayavi'. Details on this implementation can be found in
    `sphinx-gallery/sphinx-gallery/494`_

    This must be imported into the top level namespace of PyVista.

    .. _sphinx-gallery/sphinx-gallery/494: https://github.com/sphinx-gallery/sphinx-gallery/pull/494
    """
    return Scraper()


def html_rst(
    figure_list,
    sources_dir,
    srcsetpaths=None,
):  # pragma: no cover  # numpydoc ignore=PR01,RT01
    """Generate reST for viewer with exported scene."""
    from sphinx_gallery.scrapers import _get_srcset_st  # noqa: PLC0415
    from sphinx_gallery.scrapers import figure_rst  # noqa: PLC0415

    if srcsetpaths is None:
        # this should never happen, but figure_rst is public, so
        # this has to be a kwarg...
        srcsetpaths = [{0: fl} for fl in figure_list]

    images_rst = ''
    for i, hinnames in enumerate(srcsetpaths):
        srcset = _get_srcset_st(sources_dir, hinnames)
        if srcset[-5:] == 'vtksz':
            png_file = figure_list[i][:-5] + 'png'

            indented_firgure_rst = '\n'.join(
                ' ' * 5 + line for line in figure_rst([png_file], sources_dir).split('\n')
            )
            images_rst += f"""
\n
\n
.. tab-set::\n
\n
   .. tab-item:: Static Scene\n
\n
       {indented_firgure_rst}
\n
   .. tab-item:: Interactive Scene\n
\n
       .. offlineviewer:: {figure_list[i]}\n\n"""

        else:
            images_rst += '\n' + figure_rst([figure_list[i]], sources_dir) + '\n\n'

    return images_rst


def _process_events_before_scraping(plotter):
    """Process events such as changing the camera or an object before scraping."""
    if plotter.iren is not None and plotter.iren.initialized:
        # check for pyvistaqt app which can be specifically bound to pyvista plotter
        # objects in order to interact with qt, then process the events from qt
        if hasattr(plotter, 'app') and plotter.app is not None:
            plotter.app.processEvents()
        plotter.update()


@_deprecate_positional_args(allowed=['image_path_iterator'])
def generate_images(image_path_iterator: Iterator[str], dynamic: bool = False) -> list[str]:  # noqa: FBT001, FBT002
    """Generate images from the current plotters.

    The file names are taken from the ``image_path_iterator`` iterator.

    A gif will be created if a plotter has a ``_gif_filename`` attribute.
    Otherwise, depending on the value of ``dynamic``, either a ``.png`` static image
    or a ``.vtksz`` file will be created.

    Parameters
    ----------
    image_path_iterator : Iterator[str]
        An iterator that yields the path to the next image to be saved.

    dynamic : bool, default: False
        Whether to save a static ``.png`` image or a ``.vtksz`` (interactive)
        file.

    Returns
    -------
    list[str]
        A list of the names of the images that were created.

    """
    image_names = []
    figures = pv.plotting.plotter._ALL_PLOTTERS
    for plotter in figures.values():
        _process_events_before_scraping(plotter)
        fname = next(image_path_iterator)
        # Make sure the extension is "png"
        path = Path(fname)
        fname_withoutextension = str(path.parent / path.stem)
        fname = fname_withoutextension + '.png'

        if (gif_filename := plotter._gif_filename) is not None:
            # move gif to fname
            fname = fname[:-3] + 'gif'
            shutil.move(gif_filename, fname)
            image_names.append(fname)
        else:
            plotter.screenshot(fname)
            if not dynamic or plotter.last_vtksz is None:
                image_names.append(fname)
            else:  # pragma: no cover
                fname = fname[:-3] + 'vtksz'
                with Path(fname).open('wb') as f:
                    f.write(plotter.last_vtksz)  # type: ignore[arg-type]
                    image_names.append(fname)

    pv.close_all()  # close and clear all plotters
    return image_names


class Scraper:
    """Save ``pyvista.Plotter`` objects.

    Used by sphinx-gallery to generate the plots from the code in the examples.

    Pass an instance of this class to ``sphinx_gallery_conf`` in your
    ``conf.py`` as the ``"image_scrapers"`` argument.

    Be sure to set ``pyvista.BUILDING_GALLERY = True`` in your ``conf.py``.

    """

    def __repr__(self) -> str:
        """Return a stable representation of the class instance."""
        return f'<{type(self).__name__} object>'

    def __call__(self, block, block_vars, gallery_conf):  # noqa: ARG002
        """Save the figures generated after running example code.

        Called by sphinx-gallery.

        """
        from sphinx_gallery.scrapers import figure_rst  # noqa: PLC0415

        if not pv.BUILDING_GALLERY:
            raise RuntimeError(BUILDING_GALLERY_ERROR_MSG)

        image_path_iterator = block_vars['image_path_iterator']
        image_names = generate_images(image_path_iterator, dynamic=False)
        return figure_rst(image_names, gallery_conf['src_dir'])


class DynamicScraper:  # pragma: no cover
    """Save ``pyvista.Plotter`` objects dynamically.

    Used by sphinx-gallery to generate the plots from the code in the examples.

    Pass an instance of this class to ``sphinx_gallery_conf`` in your
    ``conf.py`` as the ``"image_scrapers"`` argument.

    Be sure to set ``pyvista.BUILDING_GALLERY = True`` in your ``conf.py``.

    If the boolean variable ``PYVISTA_GALLERY_FORCE_STATIC_IN_DOCUMENT = True/False``
    is set as a global variable in the document then its value will be used as default for the
    force_static argument of the pyvista-plot command. see also the notes at :func:plot_directive

    To alter the global value behavior just for some plots you may set the
    boolean variable ``PYVISTA_GALLERY_FORCE_STATIC = True``/
    ``PYVISTA_GALLERY_FORCE_STATIC = False`` just before the appropriate ``plot`` command.

    The default behavior of this scraper is to create interactive plots.

    """

    def __repr__(self) -> str:
        """Return a stable representation of the class instance."""
        return f'<{type(self).__name__} object>'

    def __call__(self, block, block_vars, gallery_conf):  # pragma: no cover
        """Save the figures generated after running example code.

        Called by sphinx-gallery.

        """
        if not pv.BUILDING_GALLERY:
            raise RuntimeError(BUILDING_GALLERY_ERROR_MSG)

        # read global option  if it exists
        force_static = block_vars['example_globals'].get(
            'PYVISTA_GALLERY_FORCE_STATIC_IN_DOCUMENT',
            False,
        )
        # override with block specific value if it exists
        if 'PYVISTA_GALLERY_FORCE_STATIC = True' in block[1].split('\n'):
            force_static = True
        elif 'PYVISTA_GALLERY_FORCE_STATIC = False' in block[1].split('\n'):
            force_static = False

        if force_static is None:
            # Just in case force_static is None at this point
            force_static = False

        dynamic = not force_static

        image_path_iterator = block_vars['image_path_iterator']
        image_names = generate_images(image_path_iterator, dynamic=dynamic)

        return html_rst(image_names, gallery_conf['src_dir'])
