"""Simple sphinx extension that executes code in jupyter and inserts output."""

from pathlib import Path

import docutils
import ipywidgets
from IPython.lib.lexers import IPython3Lexer, IPythonTracebackLexer
from sphinx.errors import ExtensionError
from sphinx.util import logging
from sphinx.util.fileutil import copy_asset

from ._version import __version__
from .ast import (
    WIDGET_VIEW_MIMETYPE,
    CellInput,
    CellInputNode,
    CellOutput,
    CellOutputNode,
    CombineCellInputOutput,
    JupyterCell,
    JupyterCellNode,
    JupyterDownloadRole,
    JupyterKernelNode,
    JupyterWidgetStateNode,
    JupyterWidgetViewNode,
    MimeBundleNode,
)
from .execute import ExecuteJupyterCells, JupyterKernel
from .thebelab import ThebeButton, ThebeButtonNode, ThebeOutputNode, ThebeSourceNode

REQUIRE_URL_DEFAULT = (
    "https://cdnjs.cloudflare.com/ajax/libs/require.js/2.3.4/require.min.js"
)
THEBELAB_URL_DEFAULT = "https://unpkg.com/thebelab@^0.4.0"

logger = logging.getLogger(__name__)

# Constants and functions we'll use later

# Used for nodes that do not need to be rendered


def skip(self, node):
    raise docutils.nodes.SkipNode


# Used for nodes that should be gone by rendering time (OutputMimeBundleNode)
def halt(self, node):
    raise ExtensionError(
        "Rendering encountered a node type that should "
        "have been removed before rendering: %s" % type(node)
    )


# Renders the children of a container
render_container = (
    lambda self, node: self.visit_container(node),
    lambda self, node: self.depart_container(node),
)


# Used to render the container and its children as HTML
def visit_container_html(self, node):
    self.body.append(node.visit_html())
    self.visit_container(node)


def depart_container_html(self, node):
    self.depart_container(node)
    self.body.append(node.depart_html())


# Used to render an element node as HTML
def visit_element_html(self, node):
    self.body.append(node.html())
    raise docutils.nodes.SkipNode


# Used to render the ThebeSourceNode conditionally for non-HTML builders
def visit_thebe_source(self, node):
    if node["hide_code"]:
        raise docutils.nodes.SkipNode
    else:
        self.visit_container(node)


render_thebe_source = (
    visit_thebe_source,
    lambda self, node: self.depart_container(node),
)


# Sphinx callback functions
def builder_inited(app):
    """
    2 cases
    case 1: ipywidgets 7, with require
    case 2: ipywidgets 7, no require
    """
    require_url = app.config.jupyter_sphinx_require_url
    if require_url:
        app.add_js_file(require_url)
        embed_url = (
            app.config.jupyter_sphinx_embed_url
            or ipywidgets.embed.DEFAULT_EMBED_REQUIREJS_URL
        )
    else:
        embed_url = (
            app.config.jupyter_sphinx_embed_url
            or ipywidgets.embed.DEFAULT_EMBED_SCRIPT_URL
        )
    if embed_url:
        app.add_js_file(embed_url)


def copy_file(src, dst):
    if not (dst / src.name).exists():
        copy_asset(str(src), str(dst))


def build_finished(app, env):
    if app.builder.format != "html":
        return

    module_dir = Path(__file__).parent
    static = Path(app.outdir) / "_static"

    # Copy stylesheet
    src = module_dir / "css" / "jupyter-sphinx.css"
    copy_file(src, static)

    thebe_config = app.config.jupyter_sphinx_thebelab_config
    if not thebe_config:
        return

    # Copy all thebelab related assets
    src_dir = module_dir / "thebelab"
    for fname in ["thebelab-helper.js", "thebelab.css"]:
        copy_file(src_dir / fname, static)


##############################################################################
# Main setup
def setup(app):
    """A temporary setup function so that we can use it here and in execute.

    This should be removed and converted into `setup` after a deprecation
    cycle.
    """
    # Configuration

    app.add_config_value(
        "jupyter_execute_kwargs",
        dict(timeout=-1, allow_errors=True, store_widget_state=True),
        "env",
    )
    app.add_config_value("jupyter_execute_default_kernel", "python3", "env")
    app.add_config_value(
        "render_priority_html",
        [
            WIDGET_VIEW_MIMETYPE,
            "application/javascript",
            "text/html",
            "image/svg+xml",
            "image/png",
            "image/jpeg",
            "text/latex",
            "text/plain",
        ],
        "env",
    )
    app.add_config_value(
        "render_priority_latex",
        [
            "image/svg+xml",
            "image/png",
            "image/jpeg",
            "text/latex",
            "text/plain",
        ],
        "env",
    )

    # ipywidgets config
    app.add_config_value("jupyter_sphinx_require_url", REQUIRE_URL_DEFAULT, "html")
    app.add_config_value("jupyter_sphinx_embed_url", None, "html")

    # thebelab config, can be either a filename or a dict
    app.add_config_value("jupyter_sphinx_thebelab_config", None, "html")
    app.add_config_value("jupyter_sphinx_thebelab_url", THEBELAB_URL_DEFAULT, "html")

    # linenos config
    app.add_config_value("jupyter_sphinx_linenos", False, "env")
    app.add_config_value("jupyter_sphinx_continue_linenos", False, "env")

    # JupyterKernelNode is just a doctree marker for the
    # ExecuteJupyterCells transform, so we don't actually render it.
    app.add_node(
        JupyterKernelNode,
        html=(skip, None),
        latex=(skip, None),
        textinfo=(skip, None),
        text=(skip, None),
        man=(skip, None),
    )

    # Register our container nodes, these should behave just like a regular container
    for node in [JupyterCellNode, CellInputNode, CellOutputNode, MimeBundleNode]:
        app.add_node(
            node,
            override=True,
            html=(render_container),
            latex=(render_container),
            textinfo=(render_container),
            text=(render_container),
            man=(render_container),
        )

    # JupyterWidgetViewNode holds widget view JSON,
    # but is only rendered properly in HTML documents.
    app.add_node(
        JupyterWidgetViewNode,
        html=(visit_element_html, None),
        latex=(skip, None),
        textinfo=(skip, None),
        text=(skip, None),
        man=(skip, None),
    )
    # JupyterWidgetStateNode holds the widget state JSON,
    # but is only rendered in HTML documents.
    app.add_node(
        JupyterWidgetStateNode,
        html=(visit_element_html, None),
        latex=(skip, None),
        textinfo=(skip, None),
        text=(skip, None),
        man=(skip, None),
    )

    # ThebeSourceNode holds the source code and is rendered if
    # hide-code is not specified. For HTML it is always rendered,
    # but hidden using the stylesheet
    app.add_node(
        ThebeSourceNode,
        html=(visit_container_html, depart_container_html),
        latex=render_thebe_source,
        textinfo=render_thebe_source,
        text=render_thebe_source,
        man=render_thebe_source,
    )

    # ThebeOutputNode holds the output of the Jupyter cells
    # and is rendered if hide-output is not specified.
    app.add_node(
        ThebeOutputNode,
        html=(visit_container_html, depart_container_html),
        latex=render_container,
        textinfo=render_container,
        text=render_container,
        man=render_container,
    )

    # ThebeButtonNode is the button that activates thebelab
    # and is only rendered for the HTML builder
    app.add_node(
        ThebeButtonNode,
        html=(visit_element_html, None),
        latex=(skip, None),
        textinfo=(skip, None),
        text=(skip, None),
        man=(skip, None),
    )

    app.add_directive("jupyter-execute", JupyterCell)
    app.add_directive("jupyter-kernel", JupyterKernel)
    app.add_directive("jupyter-input", CellInput)
    app.add_directive("jupyter-output", CellOutput)
    app.add_directive("thebe-button", ThebeButton)
    for sep in [":", "-"]:
        # Since Sphinx 4.0.0 using ":" inside of a role/directive does not work.
        # Therefore, we add "-" as separator to get e.g., jupyter-download-notebook
        # We leave the ":" syntax for backward compatibility reasons.
        app.add_role(f"jupyter-download{sep}notebook", JupyterDownloadRole())
        app.add_role(f"jupyter-download{sep}nb", JupyterDownloadRole())
        app.add_role(f"jupyter-download{sep}script", JupyterDownloadRole())
    app.add_transform(CombineCellInputOutput)
    app.add_transform(ExecuteJupyterCells)

    # For syntax highlighting
    app.add_lexer("ipythontb", IPythonTracebackLexer)
    app.add_lexer("ipython3", IPython3Lexer)

    app.connect("builder-inited", builder_inited)
    app.connect("build-finished", build_finished)

    # add jupyter-sphinx and thebelab js and css
    app.add_css_file("jupyter-sphinx.css")
    app.add_js_file("thebelab-helper.js")
    app.add_css_file("thebelab.css")

    return {"version": __version__, "parallel_read_safe": True}
