# Source code for sphinx_gallery.notebook

    r"""Parser for Jupyter notebooks.

    Class that holds the Jupyter notebook information
    """

    # Author: Óscar Nájera
    # License: 3-clause BSD

    import argparse
    import base64
    import copy
    import json
    import mimetypes
    import os
    import re
    import sys
    import textwrap
    from collections import defaultdict
    from functools import partial
    from itertools import count
    from pathlib import Path

    import sphinx.util
    from sphinx.errors import ExtensionError

    from .py_source_parser import split_code_and_text_blocks

    logger = sphinx.util.logging.getLogger("sphinx-gallery")

    def jupyter_notebook_skeleton():
        """Returns a dictionary with the elements of a Jupyter notebook."""
        py_version = sys.version_info
        notebook_skeleton = {
            "cells": [],
            "metadata": {
                "kernelspec": {
                    "display_name": "Python " + str(py_version[0]),
                    "language": "python",
                    "name": "python" + str(py_version[0]),
                },
                "language_info": {
                    "codemirror_mode": {"name": "ipython", "version": py_version[0]},
                    "file_extension": ".py",
                    "mimetype": "text/x-python",
                    "name": "python",
                    "nbconvert_exporter": "python",
                    "pygments_lexer": "ipython" + str(py_version[0]),
                    "version": "{}.{}.{}".format(*sys.version_info[:3]),
                },
            },
            "nbformat": 4,
            "nbformat_minor": 0,
        }
        return notebook_skeleton

    def directive_fun(match, directive):
        """Helper to fill in directives."""
        directive_to_alert = dict(note="info", warning="danger")
        return '<div class="alert alert-{}"><h4>{}</h4><p>{}</p></div>'.format(
            directive_to_alert[directive], directive.capitalize(), match.group(1).strip()
        )

    def convert_code_to_md(text):
        """Rewrite code blocks to use Markdown's preferred backtick notation.

        Backtick notation preserves syntax highlighting.

        Parameters
        ----------
        text: str
            A mostly converted string of markdown text. May contain zero, one,
            or multiple code blocks in code-block format.
        """
        code_regex = r"[ \t]*\.\. code-block::[ \t]*(\S*)\n[ \t]*\n([ \t]+)"
        while True:
            code_block = re.search(code_regex, text)
            if not code_block:
                break
            indent = code_block.group(2)
            start_index = code_block.span()[1] - len(indent)

            # Find first non-empty, non-indented line
            end = re.compile(rf"^(?!{re.escape(indent)})[ \t]*\S+", re.MULTILINE)
            code_end_match = end.search(text, start_index)
            end_index = code_end_match.start() if code_end_match else len(text)

            contents = textwrap.dedent(text[start_index:end_index]).rstrip()
            new_code = f"```{code_block.group(1)}\n{contents}\n```\n"
            text = text[: code_block.span()[0]] + new_code + text[end_index:]
        return text

    def rst2md(text, gallery_conf, target_dir, heading_levels):
        """Converts reST from docstrings and text blocks to markdown for Jupyter notebooks.

        Parameters
        ----------
        text: str
            reST input to be converted to MD
        gallery_conf : dict
            The sphinx-gallery configuration dictionary.
        target_dir : str
            Path that notebook is intended for. Used where relative paths
            may be required.
        heading_levels: dict
            Mapping of heading style ``(over_char, under_char)`` to heading level.
            Note that ``over_char`` is `None` when only underline is present.
        """
        # Characters recommended for use with headings
        # https://docutils.readthedocs.io/en/sphinx-docs/user/rst/quickstart.html#sections
        adornment_characters = "=`:.'\"~^_*+#<>-"
        headings = re.compile(
            # Start of string or blank line
            r"(?P<pre>\A|^[ \t]*\n)"
            # Optional over characters, allowing leading space on heading text
            r"(?:(?P<over>[{0}])(?P=over)*\n[ \t]*)?"
            # The heading itself, with at least one non-white space character
            r"(?P<heading>\S[^\n]*)\n"
            # Under character, setting to same character if over present.
            r"(?P<under>(?(over)(?P=over)|[{0}]))(?P=under)*$"
            r"".format(adornment_characters),
            flags=re.M,
        )

        text = re.sub(
            headings,
            lambda match: "{1}{0} {2}".format(
                "#" * heading_levels[match.group("over", "under")],
                *match.group("pre", "heading"),
            ),
            text,
        )

        math_eq = re.compile(r"^\.\. math::((?:.+)?(?:\n+^  .+)*)", flags=re.M)
        text = re.sub(
            math_eq,
            lambda match: r"\begin{{align}}{0}\end{{align}}".format(match.group(1).strip()),
            text,
        )
        inline_math = re.compile(r":math:`(.+?)`", re.DOTALL)
        text = re.sub(inline_math, r"$\1$", text)

        directives = ("warning", "note")
        for directive in directives:
            directive_re = re.compile(
                r"^\.\. %s::((?:.+)?(?:\n+^  .+)*)" % directive, flags=re.M
            )
            text = re.sub(directive_re, partial(directive_fun, directive=directive), text)

        footnote_links = re.compile(r"^ *\.\. _.*:.*$\n", flags=re.M)
        text = re.sub(footnote_links, "", text)

        embedded_uris = re.compile(r"`([^`]*?)\s*<([^`]*)>`_")
        text = re.sub(embedded_uris, r"[\1](\2)", text)

        refs = re.compile(r":ref:`")
        text = re.sub(refs, "`", text)

        contents = re.compile(r"^\s*\.\. contents::.*$(\n +:\S+: *$)*\n", flags=re.M)
        text = re.sub(contents, "", text)

        images = re.compile(r"^\.\. image::(.*$)((?:\n +:\S+:.*$)*)\n", flags=re.M)
        image_opts = re.compile(r"\n +:(\S+): +(.*)$", flags=re.M)
        text = re.sub(
            images,
            lambda match: '<img src="{}"{}>\n'.format(
                generate_image_src(match.group(1).strip(), gallery_conf, target_dir),
                re.sub(image_opts, r' \1="\2"', match.group(2) or ""),
            ),
            text,
        )

        text = convert_code_to_md(text)

        return text

    def generate_image_src(image_path, gallery_conf, target_dir):
        """Modify image path for notebook, according to "notebook_images" config.

        URLs are unchanged.
        If "notebook_images" config is a str, it is used as a prefix to image path, relative
        to "src_dir". If "notebook_images" is `True`, image is embedded as URI. If
        "notebook_images" is `False`, "file://" is prepended.
        """
        if re.match(r"https?://", image_path):
            return image_path

        if not gallery_conf["notebook_images"]:
            return "file://" + image_path.lstrip("/")

        # If absolute path from source directory given
        if image_path.startswith("/"):
            # Path should now be relative to source dir, not target dir
            target_dir = gallery_conf["src_dir"]
            image_path = image_path.lstrip("/")
        full_path = os.path.join(target_dir, image_path.replace("/", os.sep))

        if isinstance(gallery_conf["notebook_images"], str):
            # Use as prefix e.g. URL
            prefix = gallery_conf["notebook_images"]
            rel_path = os.path.relpath(full_path, gallery_conf["src_dir"])
            return prefix + rel_path.replace(os.sep, "/")
        else:
            # True, but not string. Embed as data URI.
            try:
                with open(full_path, "rb") as image_file:
                    data = base64.b64encode(image_file.read())
            except OSError:
                raise ExtensionError(
                    f"Unable to open {full_path} to generate notebook data URI"
                )
            mime_type = mimetypes.guess_type(full_path)
            return f"data:{mime_type[0]};base64,{data.decode('ascii')}"

    def jupyter_notebook(script_blocks, gallery_conf, target_dir):
        """Generate a Jupyter notebook file cell-by-cell.

        Parameters
        ----------
        script_blocks : list
            Script execution cells.
        gallery_conf : dict
            The sphinx-gallery configuration dictionary.
        target_dir : str
            Path that notebook is intended for. Used where relative paths
            may be required.
        """
        first_cell = gallery_conf["first_notebook_cell"]
        last_cell = gallery_conf["last_notebook_cell"]
        work_notebook = jupyter_notebook_skeleton()
        if first_cell is not None:
            add_code_cell(work_notebook, first_cell)
        fill_notebook(work_notebook, script_blocks, gallery_conf, target_dir)
        if last_cell is not None:
            add_code_cell(work_notebook, last_cell)

        return work_notebook

    def add_code_cell(work_notebook, code):
        """Add a code cell to the notebook.

        Parameters
        ----------
        code : str
            Cell content
        """
        code_cell = {
            "cell_type": "code",
            "execution_count": None,
            "metadata": {"collapsed": False},
            "outputs": [],
            "source": [code.strip()],
        }
        work_notebook["cells"].append(code_cell)

    def add_markdown_cell(work_notebook, markdown):
        """Add a markdown cell to the notebook.

        Parameters
        ----------
        markdown : str
            Markdown cell content.
        """
        markdown_cell = {"cell_type": "markdown", "metadata": {}, "source": [markdown]}
        work_notebook["cells"].append(markdown_cell)

    def promote_jupyter_cell_magic(work_notebook, markdown):
        """Promote Jupyter cell magic in text blocks to code block in notebooks.

        Parses a block of markdown text looking for code blocks starting with a
        Jupyter cell magic (e.g. %%bash). Whenever one is found, the text before it
        and the code (as a runnable code block) are added to work_notebook. Any
        remaining text is returned.

        Parameters
        ----------
        markdown : str
            Markdown cell content.
        """
        # Regex detects all code blocks that use %% Jupyter cell magic
        cell_magic_regex = r"\n?```\s*[a-z]*\n(%%(?:[\s\S]*?))\n?```\n?"

        text_cell_start = 0
        for magic_cell in re.finditer(cell_magic_regex, markdown):
            # Extract the preceding text block, and add it if non-empty
            text_block = markdown[text_cell_start : magic_cell.span()[0]]
            if text_block and not text_block.isspace():
                add_markdown_cell(work_notebook, text_block)
            text_cell_start = magic_cell.span()[1]

            code_block = magic_cell.group(1)
            add_code_cell(work_notebook, code_block)

        # Return remaining text (which equals markdown if no magic cells exist)
        return markdown[text_cell_start:]

    def fill_notebook(work_notebook, script_blocks, gallery_conf, target_dir):
        """Writes the Jupyter notebook cells.

        If available, uses pypandoc to convert rst to markdown.

        Parameters
        ----------
        script_blocks : list
            Each list element should be a tuple of (label, content, lineno).
        """
        heading_level_counter = count(start=1)
        heading_levels = defaultdict(lambda: next(heading_level_counter))
        for blabel, bcontent, lineno in script_blocks:
            if blabel == "code":
                add_code_cell(work_notebook, bcontent)
            else:
                if gallery_conf["pypandoc"] is False:
                    markdown = rst2md(
                        bcontent + "\n", gallery_conf, target_dir, heading_levels
                    )
                else:
                    import pypandoc

                    # pandoc automatically adds \n to the end
                    markdown = pypandoc.convert_text(
                        bcontent, to="md", format="rst", **gallery_conf["pypandoc"]
                    )

                if gallery_conf["promote_jupyter_magic"]:
                    remaining = promote_jupyter_cell_magic(work_notebook, markdown)
                    if remaining and not remaining.isspace():
                        add_markdown_cell(work_notebook, remaining)
                else:
                    add_markdown_cell(work_notebook, markdown)

    def save_notebook(work_notebook, write_file):
        """Saves the Jupyter work_notebook to write_file."""
        with open(write_file, "w") as out_nb:
            json.dump(work_notebook, out_nb, indent=2)

    ###############################################################################
    # Notebook shell utility

    def python_to_jupyter_cli(args=None, namespace=None, sphinx_gallery_conf=None):
        """Exposes the jupyter notebook renderer to the command line.

        Takes the same arguments as ArgumentParser.parse_args.
        `sphinx_gallery_conf` functions same as in `conf.py`.
        """
        from . import gen_gallery  # To avoid circular import

        parser = argparse.ArgumentParser(description="Sphinx-Gallery Notebook converter")
        parser.add_argument(
            "python_src_file",
            nargs="+",
            help="Input Python file script to convert. "
            "Supports multiple files and shell wildcards"
            " (e.g. *.py)",
        )
        args = parser.parse_args(args, namespace)

        # handle `sphinx_gallery_conf`
        gallery_conf = copy.deepcopy(gen_gallery.DEFAULT_GALLERY_CONF)
        if sphinx_gallery_conf is not None:
            gallery_conf.update(sphinx_gallery_conf)

        # run script
        for src_file in args.python_src_file:
            file_conf, blocks = split_code_and_text_blocks(src_file)
            print(f"Converting {src_file}")
            target_dir = os.path.dirname(src_file)
            example_nb = jupyter_notebook(blocks, copy.deepcopy(gallery_conf), target_dir)
            save_notebook(example_nb, Path(src_file).with_suffix(".ipynb"))