# -*- coding: utf-8 -*-
"""
    sphinx.ext.autosummary
    ~~~~~~~~~~~~~~~~~~~~~~

    Sphinx extension that adds an autosummary:: directive, which can be
    used to generate function/method/attribute/etc. summary lists, similar
    to those output eg. by Epydoc and other API doc generation tools.

    An :autolink: role is also provided.

    autosummary directive
    ---------------------

    The autosummary directive has the form::

        .. autosummary::
           :nosignatures:
           :toctree: generated/

           module.function_1
           module.function_2
           ...

    and it generates an output table (containing signatures, optionally)

        ========================  =============================================
        module.function_1(args)   Summary line from the docstring of function_1
        module.function_2(args)   Summary line from the docstring
        ...
        ========================  =============================================

    If the :toctree: option is specified, files matching the function names
    are inserted to the toctree with the given prefix:

        generated/module.function_1
        generated/module.function_2
        ...

    Note: The file names contain the module:: or currentmodule:: prefixes.

    .. seealso:: autosummary_generate.py


    autolink role
    -------------

    The autolink role functions as ``:obj:`` when the name referred can be
    resolved to a Python object, and otherwise it becomes simple emphasis.
    This can be used as the default role to make links 'smart'.

    :copyright: Copyright 2007-2011 by the Sphinx team, see AUTHORS.
    :license: BSD, see LICENSE for details.
"""

from __future__ import (absolute_import, division, print_function)

import os
import re
import sys
import inspect
import posixpath

from six import text_type
from docutils.parsers.rst import Directive, directives
from docutils.statemachine import ViewList
from docutils import nodes

import sphinx
from sphinx import addnodes


# -- autosummary_toc node -----------------------------------------------------

class autosummary_toc(nodes.comment):
    pass


def process_autosummary_toc(app, doctree):
    """Insert items described in autosummary:: to the TOC tree, but do
    not generate the toctree:: list.
    """
    env = app.builder.env
    crawled = {}

    def crawl_toc(node, depth=1):
        crawled[node] = True
        for j, subnode in enumerate(node):
            try:
                if (isinstance(subnode, autosummary_toc) and
                        isinstance(subnode[0], addnodes.toctree)):
                    env.note_toctree(env.docname, subnode[0])
                    continue
            except IndexError:
                continue
            if not isinstance(subnode, nodes.section):
                continue
            if subnode not in crawled:
                crawl_toc(subnode, depth + 1)
    crawl_toc(doctree)


def autosummary_toc_visit_html(self, node):
    """Hide autosummary toctree list in HTML output."""
    raise nodes.SkipNode


def autosummary_noop(self, node):
    pass


# -- autosummary_table node ---------------------------------------------------

class autosummary_table(nodes.comment):
    pass


def autosummary_table_visit_html(self, node):
    """Make the first column of the table non-breaking."""
    try:
        tbody = node[0][0][-1]
        for row in tbody:
            col1_entry = row[0]
            par = col1_entry[0]
            for j, subnode in enumerate(list(par)):
                if isinstance(subnode, nodes.Text):
                    new_text = text_type(subnode.astext())
                    new_text = new_text.replace(u" ", u"\u00a0")
                    par[j] = nodes.Text(new_text)
    except IndexError:
        pass


# -- autodoc integration ------------------------------------------------------

class FakeDirective:
    env = {}
    genopt = {}


def get_documenter(obj, parent):
    """Get an autodoc.Documenter class suitable for documenting the given
    object.

    *obj* is the Python object to be documented, and *parent* is an
    another Python object (e.g. a module or a class) to which *obj*
    belongs to.
    """
    from sphinx.ext.autodoc import AutoDirective, DataDocumenter, \
        ModuleDocumenter

    if inspect.ismodule(obj):
        # ModuleDocumenter.can_document_member always returns False
        return ModuleDocumenter

    # Construct a fake documenter for *parent*
    if parent is not None:
        parent_doc_cls = get_documenter(parent, None)
    else:
        parent_doc_cls = ModuleDocumenter

    if hasattr(parent, '__name__'):
        parent_doc = parent_doc_cls(FakeDirective(), parent.__name__)
    else:
        parent_doc = parent_doc_cls(FakeDirective(), "")

    # Get the corrent documenter class for *obj*
    classes = [cls for cls in AutoDirective._registry.values()
               if cls.can_document_member(obj, '', False, parent_doc)]
    if classes:
        classes.sort(key=lambda cls: cls.priority)
        return classes[-1]
    else:
        return DataDocumenter


# -- .. autosummary:: ---------------------------------------------------------

class Autosummary(Directive):
    """
    Pretty table containing short signatures and summaries of functions etc.

    autosummary can also optionally generate a hidden toctree:: node.
    """

    required_arguments = 0
    optional_arguments = 0
    final_argument_whitespace = False
    has_content = True
    option_spec = {
        'toctree': directives.unchanged,
        'nosignatures': directives.flag,
        'template': directives.unchanged,
    }

    def warn(self, msg):
        self.warnings.append(self.state.document.reporter.warning(
            msg, line=self.lineno))

    def run(self):
        self.env = env = self.state.document.settings.env
        self.genopt = {}
        self.warnings = []

        names = [x.strip().split()[0] for x in self.content
                 if x.strip() and re.search(r'^[~a-zA-Z_]', x.strip()[0])]
        items = self.get_items(names)
        nodes = self.get_table(items)

        if 'toctree' in self.options:
            suffixes = env.config.source_suffix
            # adapt to a change with sphinx 1.3:
            # for sphinx >= 1.3 env.config.source_suffix is a list
            # see sphinx-doc/sphinx@bf3bdcc7f505a2761c0e83c9b1550e7206929f74
            if list(map(int, sphinx.__version__.split(".")[:2])) < [1, 3]:
                suffixes = [suffixes]
            dirname = posixpath.dirname(env.docname)

            tree_prefix = self.options['toctree'].strip()
            docnames = []
            for name, sig, summary, real_name in items:
                docname = posixpath.join(tree_prefix, real_name)
                for suffix in suffixes:
                    if docname.endswith(suffix):
                        docname = docname[:-len(suffix)]
                        break
                docname = posixpath.normpath(posixpath.join(dirname, docname))
                if docname not in env.found_docs:
                    self.warn('toctree references unknown document %r'
                              % docname)
                docnames.append(docname)

            tocnode = addnodes.toctree()
            tocnode['includefiles'] = docnames
            tocnode['entries'] = [(None, docname_) for docname_ in docnames]
            tocnode['maxdepth'] = -1
            tocnode['glob'] = None

            tocnode = autosummary_toc('', '', tocnode)
            nodes.append(tocnode)

        return self.warnings + nodes

    def get_items(self, names):
        """Try to import the given names, and return a list of
        ``[(name, signature, summary_string, real_name), ...]``.
        """
        env = self.state.document.settings.env

        prefixes = get_import_prefixes_from_env(env)

        items = []

        max_item_chars = 50

        for name in names:
            display_name = name
            if name.startswith('~'):
                name = name[1:]
                display_name = name.split('.')[-1]

            try:
                real_name, obj, parent = import_by_name(name,
                                                        prefixes=prefixes)
            except ImportError:
                self.warn('failed to import %s' % name)
                items.append((name, '', '', name))
                continue

            # NB. using real_name here is important, since Documenters
            #     handle module prefixes slightly differently
            documenter = get_documenter(obj, parent)(self, real_name)
            if not documenter.parse_name():
                self.warn('failed to parse name %s' % real_name)
                items.append((display_name, '', '', real_name))
                continue
            if not documenter.import_object():
                self.warn('failed to import object %s' % real_name)
                items.append((display_name, '', '', real_name))
                continue

            # -- Grab the signature

            sig = documenter.format_signature()
            if not sig:
                sig = ''
            else:
                max_chars = max(10, max_item_chars - len(display_name))
                sig = mangle_signature(sig, max_chars=max_chars)
                sig = sig.replace('*', r'\*')

            # -- Grab the summary

            doc = list(documenter.process_doc(documenter.get_doc()))

            while doc and not doc[0].strip():
                doc.pop(0)
            m = re.search(r"^([A-Z][^A-Z]*?\.\s)", " ".join(doc).strip())
            if m:
                summary = m.group(1).strip()
            elif doc:
                summary = doc[0].strip()
            else:
                summary = ''

            items.append((display_name, sig, summary, real_name))

        return items

    def get_table(self, items):
        """Generate a proper list of table nodes for autosummary:: directive.

        *items* is a list produced by :meth:`get_items`.
        """
        table_spec = addnodes.tabular_col_spec()
        table_spec['spec'] = 'LL'

        table = autosummary_table('')
        real_table = nodes.table('')
        table.append(real_table)
        group = nodes.tgroup('', cols=2)
        real_table.append(group)
        group.append(nodes.colspec('', colwidth=10))
        group.append(nodes.colspec('', colwidth=90))
        body = nodes.tbody('')
        group.append(body)

        def append_row(*column_texts):
            row = nodes.row('')
            for text in column_texts:
                node = nodes.paragraph('')
                vl = ViewList()
                vl.append(text, '<autosummary>')
                self.state.nested_parse(vl, 0, node)
                try:
                    if isinstance(node[0], nodes.paragraph):
                        node = node[0]
                except IndexError:
                    pass
                row.append(nodes.entry('', node))
            body.append(row)

        for name, sig, summary, real_name in items:
            qualifier = 'obj'
            if 'nosignatures' not in self.options:
                col1 = ':%s:`%s <%s>`\ %s' % (qualifier, name, real_name, sig)
            else:
                col1 = ':%s:`%s <%s>`' % (qualifier, name, real_name)
            col2 = summary
            append_row(col1, col2)

        return [table_spec, table]


def mangle_signature(sig, max_chars=30):
    """Reformat a function signature to a more compact form."""
    s = re.sub(r"^\((.*)\)$", r"\1", sig).strip()

    # Strip strings (which can contain things that confuse the code below)
    s = re.sub(r"\\\\", "", s)
    s = re.sub(r"\\'", "", s)
    s = re.sub(r"'[^']*'", "", s)

    # Parse the signature to arguments + options
    args = []
    opts = []

    opt_re = re.compile(r"^(.*, |)([a-zA-Z0-9_*]+)=")
    while s:
        m = opt_re.search(s)
        if not m:
            # The rest are arguments
            args = s.split(', ')
            break

        opts.insert(0, m.group(2))
        s = m.group(1)[:-2]

    # Produce a more compact signature
    sig = limited_join(", ", args, max_chars=max_chars - 2)
    if opts:
        if not sig:
            sig = "[%s]" % limited_join(", ", opts, max_chars=max_chars - 4)
        elif len(sig) < max_chars - 4 - 2 - 3:
            sig += "[, %s]" % limited_join(
                ", ", opts, max_chars=max_chars - len(sig) - 4 - 2)

    return u"(%s)" % sig


def limited_join(sep, items, max_chars=30, overflow_marker="..."):
    """Join a number of strings to one, limiting the length to *max_chars*.

    If the string overflows this limit, replace the last fitting item by
    *overflow_marker*.

    Returns: joined_string
    """
    full_str = sep.join(items)
    if len(full_str) < max_chars:
        return full_str

    n_chars = 0
    n_items = 0
    for j, item in enumerate(items):
        n_chars += len(item) + len(sep)
        if n_chars < max_chars - len(overflow_marker):
            n_items += 1
        else:
            break

    return sep.join(list(items[:n_items]) + [overflow_marker])

# -- Importing items ----------------------------------------------------------


def get_import_prefixes_from_env(env):
    """
    Obtain current Python import prefixes (for `import_by_name`)
    from ``document.env``
    """
    prefixes = [None]

    currmodule = env.temp_data.get('py:module')
    if currmodule:
        prefixes.insert(0, currmodule)

    currclass = env.temp_data.get('py:class')
    if currclass:
        if currmodule:
            prefixes.insert(0, currmodule + "." + currclass)
        else:
            prefixes.insert(0, currclass)

    return prefixes


def import_by_name(name, prefixes=[None]):
    """Import a Python object that has the given *name*, under one of the
    *prefixes*.  The first name that succeeds is used.
    """
    tried = []
    for prefix in prefixes:
        try:
            if prefix:
                prefixed_name = '.'.join([prefix, name])
            else:
                prefixed_name = name
            obj, parent = _import_by_name(prefixed_name)
            return prefixed_name, obj, parent
        except ImportError:
            tried.append(prefixed_name)
    raise ImportError('no module named %s' % ' or '.join(tried))


def _import_by_name(name):
    """Import a Python object given its full name."""
    try:
        name_parts = name.split('.')

        # try first interpret `name` as MODNAME.OBJ
        modname = '.'.join(name_parts[:-1])
        if modname:
            try:
                __import__(modname)
                mod = sys.modules[modname]
                return getattr(mod, name_parts[-1]), mod
            except (ImportError, IndexError, AttributeError):
                pass

        # ... then as MODNAME, MODNAME.OBJ1, MODNAME.OBJ1.OBJ2, ...
        last_j = 0
        modname = None
        for j in reversed(range(1, len(name_parts) + 1)):
            last_j = j
            modname = '.'.join(name_parts[:j])
            try:
                __import__(modname)
            except ImportError:
                continue
            if modname in sys.modules:
                break

        if last_j < len(name_parts):
            parent = None
            obj = sys.modules[modname]
            for obj_name in name_parts[last_j:]:
                parent = obj
                obj = getattr(obj, obj_name)
            return obj, parent
        else:
            return sys.modules[modname], None
    except (ValueError, ImportError, AttributeError, KeyError) as e:
        raise ImportError(*e.args)


# -- :autolink: (smart default role) ------------------------------------------

def autolink_role(typ, rawtext, etext, lineno, inliner,
                  options={}, content=[]):
    """Smart linking role.

    Expands to ':obj:`text`' if `text` is an object that can be imported;
    otherwise expands to '*text*'.
    """
    env = inliner.document.settings.env
    r = env.get_domain('py').role('obj')(
        'obj', rawtext, etext, lineno, inliner, options, content)
    pnode = r[0][0]

    prefixes = get_import_prefixes_from_env(env)
    try:
        name, obj, parent = import_by_name(pnode['reftarget'], prefixes)
    except ImportError:
        content = pnode[0]
        r[0][0] = nodes.emphasis(rawtext, content[0].astext(),
                                 classes=content['classes'])
    return r


def process_generate_options(app):
    genfiles = app.config.autosummary_generate

    ext = app.config.source_suffix
    # Sometimes readthedocs messes with this setting.
    if isinstance(ext, list):
        ext = ext[0]

    if genfiles and not hasattr(genfiles, '__len__'):
        env = app.builder.env
        genfiles = [x + ext for x in env.found_docs
                    if os.path.isfile(env.doc2path(x))]

    if not genfiles:
        return

    from .generate import generate_autosummary_docs

    genfiles = [genfile + (not genfile.endswith(ext) and ext or '')
                for genfile in genfiles]

    generate_autosummary_docs(genfiles, builder=app.builder,
                              warn=app.warn, info=app.info, suffix=ext,
                              base_path=app.srcdir)


def setup(app):
    # I need autodoc
    app.setup_extension('sphinx.ext.autodoc')
    app.add_node(autosummary_toc,
                 html=(autosummary_toc_visit_html, autosummary_noop),
                 latex=(autosummary_noop, autosummary_noop),
                 text=(autosummary_noop, autosummary_noop),
                 man=(autosummary_noop, autosummary_noop),
                 texinfo=(autosummary_noop, autosummary_noop))
    app.add_node(autosummary_table,
                 html=(autosummary_table_visit_html, autosummary_noop),
                 latex=(autosummary_noop, autosummary_noop),
                 text=(autosummary_noop, autosummary_noop),
                 man=(autosummary_noop, autosummary_noop),
                 texinfo=(autosummary_noop, autosummary_noop))
    app.add_directive('autosummary', Autosummary)
    app.add_role('autolink', autolink_role)
    app.connect('doctree-read', process_autosummary_toc)
    app.connect('builder-inited', process_generate_options)
    app.add_config_value('autosummary_generate', [], True)
