#!/usr/bin/env python3
"""Generates Nvim :help docs from C/Lua docstrings, using Doxygen.

Also generates *.mpack files. To inspect the *.mpack structure:
    :new | put=v:lua.vim.inspect(v:lua.vim.mpack.unpack(readfile('runtime/doc/api.mpack','B')))

Flow:
    main
      extract_from_xml
        fmt_node_as_vimhelp   \
          para_as_map          } recursive
            update_params_map /
              render_node

TODO: eliminate this script and use Lua+treesitter (requires parsers for C and
Lua markdown-style docstrings).

The generated :help text for each function is formatted as follows:

  - Max width of 78 columns (`text_width`).
  - Indent with spaces (not tabs).
  - Indent of 4 columns for body text (`indentation`).
  - Function signature and helptag (right-aligned) on the same line.
    - Signature and helptag must have a minimum of 8 spaces between them.
    - If the signature is too long, it is placed on the line after the helptag.
      Signature wraps at `text_width - 8` characters with subsequent
      lines indented to the open parenthesis.
    - Subsection bodies are indented an additional 4 spaces.
  - Body consists of function description, parameters, return description, and
    C declaration (`INCLUDE_C_DECL`).
  - Parameters are omitted for the `void` and `Error *` types, or if the
    parameter is marked as [out].
  - Each function documentation is separated by a single line.
"""
import argparse
import os
import re
import sys
import shutil
import textwrap
import subprocess
import collections
import msgpack
import logging
from pathlib import Path

from xml.dom import minidom

MIN_PYTHON_VERSION = (3, 6)
MIN_DOXYGEN_VERSION = (1, 9, 0)

if sys.version_info < MIN_PYTHON_VERSION:
    print("requires Python {}.{}+".format(*MIN_PYTHON_VERSION))
    sys.exit(1)

doxygen_version = tuple((int(i) for i in subprocess.check_output(["doxygen", "-v"],
                        universal_newlines=True).split()[0].split('.')))

if doxygen_version < MIN_DOXYGEN_VERSION:
    print("\nRequires doxygen {}.{}.{}+".format(*MIN_DOXYGEN_VERSION))
    print("Your doxygen version is {}.{}.{}\n".format(*doxygen_version))
    sys.exit(1)


# Need a `nvim` that supports `-l`, try the local build
nvim_path = Path(__file__).parent / "../build/bin/nvim"
if nvim_path.exists():
    nvim = str(nvim_path)
else:
    # Until 0.9 is released, use this hacky way to check that "nvim -l foo.lua" works.
    nvim_out = subprocess.check_output(['nvim', '-h'], universal_newlines=True)
    nvim_version = [line for line in nvim_out.split('\n')
                    if '-l ' in line]
    if len(nvim_version) == 0:
        print((
            "\nYou need to have a local Neovim build or a `nvim` version 0.9 for `-l` "
            "support to build the documentation."))
        sys.exit(1)
    nvim = 'nvim'


# DEBUG = ('DEBUG' in os.environ)
INCLUDE_C_DECL = ('INCLUDE_C_DECL' in os.environ)
INCLUDE_DEPRECATED = ('INCLUDE_DEPRECATED' in os.environ)

log = logging.getLogger(__name__)

LOG_LEVELS = {
    logging.getLevelName(level): level for level in [
        logging.DEBUG, logging.INFO, logging.ERROR
    ]
}

text_width = 78
indentation = 4
script_path = os.path.abspath(__file__)
base_dir = os.path.dirname(os.path.dirname(script_path))
out_dir = os.path.join(base_dir, 'tmp-{target}-doc')
filter_cmd = '%s %s' % (sys.executable, script_path)
msgs = []  # Messages to show on exit.
lua2dox = os.path.join(base_dir, 'scripts', 'lua2dox.lua')

CONFIG = {
    'api': {
        'mode': 'c',
        'filename': 'api.txt',
        # Section ordering.
        'section_order': [
            'vim.c',
            'vimscript.c',
            'command.c',
            'options.c',
            'buffer.c',
            'extmark.c',
            'window.c',
            'win_config.c',
            'tabpage.c',
            'autocmd.c',
            'ui.c',
        ],
        # List of files/directories for doxygen to read, relative to `base_dir`
        'files': ['src/nvim/api'],
        # file patterns used by doxygen
        'file_patterns': '*.h *.c',
        # Only function with this prefix are considered
        'fn_name_prefix': 'nvim_',
        # Section name overrides.
        'section_name': {
            'vim.c': 'Global',
        },
        # For generated section names.
        'section_fmt': lambda name: f'{name} Functions',
        # Section helptag.
        'helptag_fmt': lambda name: f'*api-{name.lower()}*',
        # Per-function helptag.
        'fn_helptag_fmt': lambda fstem, name: f'*{name}()*',
        # Module name overrides (for Lua).
        'module_override': {},
        # Append the docs for these modules, do not start a new section.
        'append_only': [],
    },
    'lua': {
        'mode': 'lua',
        'filename': 'lua.txt',
        'section_order': [
            '_editor.lua',
            '_inspector.lua',
            'shared.lua',
            'loader.lua',
            'uri.lua',
            'ui.lua',
            'filetype.lua',
            'keymap.lua',
            'fs.lua',
            'secure.lua',
            'version.lua',
            'iter.lua',
        ],
        'files': [
            'runtime/lua/vim/iter.lua',
            'runtime/lua/vim/_editor.lua',
            'runtime/lua/vim/shared.lua',
            'runtime/lua/vim/loader.lua',
            'runtime/lua/vim/uri.lua',
            'runtime/lua/vim/ui.lua',
            'runtime/lua/vim/filetype.lua',
            'runtime/lua/vim/keymap.lua',
            'runtime/lua/vim/fs.lua',
            'runtime/lua/vim/secure.lua',
            'runtime/lua/vim/version.lua',
            'runtime/lua/vim/_inspector.lua',
        ],
        'file_patterns': '*.lua',
        'fn_name_prefix': '',
        'section_name': {
            'lsp.lua': 'core',
            '_inspector.lua': 'inspector',
        },
        'section_fmt': lambda name: (
            'Lua module: vim'
            if name.lower() == '_editor'
            else f'Lua module: {name.lower()}'),
        'helptag_fmt': lambda name: (
            '*lua-vim*'
            if name.lower() == '_editor'
            else f'*lua-{name.lower()}*'),
        'fn_helptag_fmt': lambda fstem, name: (
            f'*vim.{name}()*'
            if fstem.lower() == '_editor'
            else f'*{name}()*'
            if name[0].isupper()
            else f'*{fstem}.{name}()*'),
        'module_override': {
            # `shared` functions are exposed on the `vim` module.
            'shared': 'vim',
            '_inspector': 'vim',
            'uri': 'vim',
            'ui': 'vim.ui',
            'loader': 'vim.loader',
            'filetype': 'vim.filetype',
            'keymap': 'vim.keymap',
            'fs': 'vim.fs',
            'secure': 'vim.secure',
            'version': 'vim.version',
            'iter': 'vim.iter',
        },
        'append_only': [
            'shared.lua',
        ],
    },
    'lsp': {
        'mode': 'lua',
        'filename': 'lsp.txt',
        'section_order': [
            'lsp.lua',
            'buf.lua',
            'diagnostic.lua',
            'codelens.lua',
            'tagfunc.lua',
            'semantic_tokens.lua',
            'handlers.lua',
            'util.lua',
            'log.lua',
            'rpc.lua',
            'protocol.lua',
        ],
        'files': [
            'runtime/lua/vim/lsp',
            'runtime/lua/vim/lsp.lua',
        ],
        'file_patterns': '*.lua',
        'fn_name_prefix': '',
        'section_name': {'lsp.lua': 'lsp'},
        'section_fmt': lambda name: (
            'Lua module: vim.lsp'
            if name.lower() == 'lsp'
            else f'Lua module: vim.lsp.{name.lower()}'),
        'helptag_fmt': lambda name: (
            '*lsp-core*'
            if name.lower() == 'lsp'
            else f'*lsp-{name.lower()}*'),
        'fn_helptag_fmt': lambda fstem, name: (
            f'*vim.lsp.{name}()*'
            if fstem == 'lsp' and name != 'client'
            else (
                '*vim.lsp.client*'
                # HACK. TODO(justinmk): class/structure support in lua2dox
                if 'lsp.client' == f'{fstem}.{name}'
                else f'*vim.lsp.{fstem}.{name}()*')),
        'module_override': {},
        'append_only': [],
    },
    'diagnostic': {
        'mode': 'lua',
        'filename': 'diagnostic.txt',
        'section_order': [
            'diagnostic.lua',
        ],
        'files': ['runtime/lua/vim/diagnostic.lua'],
        'file_patterns': '*.lua',
        'fn_name_prefix': '',
        'section_name': {'diagnostic.lua': 'diagnostic'},
        'section_fmt': lambda _: 'Lua module: vim.diagnostic',
        'helptag_fmt': lambda _: '*diagnostic-api*',
        'fn_helptag_fmt': lambda fstem, name: f'*vim.{fstem}.{name}()*',
        'module_override': {},
        'append_only': [],
    },
    'treesitter': {
        'mode': 'lua',
        'filename': 'treesitter.txt',
        'section_order': [
            'treesitter.lua',
            'language.lua',
            'query.lua',
            'highlighter.lua',
            'languagetree.lua',
            'dev.lua',
        ],
        'files': [
            'runtime/lua/vim/treesitter.lua',
            'runtime/lua/vim/treesitter/',
        ],
        'file_patterns': '*.lua',
        'fn_name_prefix': '',
        'section_name': {},
        'section_fmt': lambda name: (
            'Lua module: vim.treesitter'
            if name.lower() == 'treesitter'
            else f'Lua module: vim.treesitter.{name.lower()}'),
        'helptag_fmt': lambda name: (
            '*lua-treesitter-core*'
            if name.lower() == 'treesitter'
            else f'*lua-treesitter-{name.lower()}*'),
        'fn_helptag_fmt': lambda fstem, name: (
            f'*vim.{fstem}.{name}()*'
            if fstem == 'treesitter'
            else f'*{name}()*'
            if name[0].isupper()
            else f'*vim.treesitter.{fstem}.{name}()*'),
        'module_override': {},
        'append_only': [],
    }
}

param_exclude = (
    'channel_id',
)

# Annotations are displayed as line items after API function descriptions.
annotation_map = {
    'FUNC_API_FAST': '|api-fast|',
    'FUNC_API_CHECK_TEXTLOCK': 'not allowed when |textlock| is active',
    'FUNC_API_REMOTE_ONLY': '|RPC| only',
    'FUNC_API_LUA_ONLY': 'Lua |vim.api| only',
}


# Raises an error with details about `o`, if `cond` is in object `o`,
# or if `cond()` is callable and returns True.
def debug_this(o, cond=True):
    name = ''
    if cond is False:
        return
    if not isinstance(o, str):
        try:
            name = o.nodeName
            o = o.toprettyxml(indent='  ', newl='\n')
        except Exception:
            pass
    if (cond is True
            or (callable(cond) and cond())
            or (not callable(cond) and cond in o)):
        raise RuntimeError('xxx: {}\n{}'.format(name, o))


# Appends a message to a list which will be printed on exit.
def msg(s):
    msgs.append(s)


# Print all collected messages.
def msg_report():
    for m in msgs:
        print(f'    {m}')


# Print collected messages, then throw an exception.
def fail(s):
    msg_report()
    raise RuntimeError(s)


def find_first(parent, name):
    """Finds the first matching node within parent."""
    sub = parent.getElementsByTagName(name)
    if not sub:
        return None
    return sub[0]


def iter_children(parent, name):
    """Yields matching child nodes within parent."""
    for child in parent.childNodes:
        if child.nodeType == child.ELEMENT_NODE and child.nodeName == name:
            yield child


def get_child(parent, name):
    """Gets the first matching child node."""
    for child in iter_children(parent, name):
        return child
    return None


def self_or_child(n):
    """Gets the first child node, or self."""
    if len(n.childNodes) == 0:
        return n
    return n.childNodes[0]


def align_tags(line):
    tag_regex = r"\s(\*.+?\*)(?:\s|$)"
    tags = re.findall(tag_regex, line)

    if len(tags) > 0:
        line = re.sub(tag_regex, "", line)
        tags = " " + " ".join(tags)
        line = line + (" " * (78 - len(line) - len(tags))) + tags
    return line


def clean_lines(text):
    """Removes superfluous lines.

    The beginning and end of the string is trimmed.  Empty lines are collapsed.
    """
    return re.sub(r'\A\n\s*\n*|\n\s*\n*\Z', '', re.sub(r'(\n\s*\n+)+', '\n\n', text))


def is_blank(text):
    return '' == clean_lines(text)


def get_text(n, preformatted=False):
    """Recursively concatenates all text in a node tree."""
    text = ''
    if n.nodeType == n.TEXT_NODE:
        return n.data
    if n.nodeName == 'computeroutput':
        for node in n.childNodes:
            text += get_text(node)
        return '`{}`'.format(text)
    for node in n.childNodes:
        if node.nodeType == node.TEXT_NODE:
            text += node.data
        elif node.nodeType == node.ELEMENT_NODE:
            text += get_text(node, preformatted)
    return text


# Gets the length of the last line in `text`, excluding newline ("\n") char.
def len_lastline(text):
    lastnl = text.rfind('\n')
    if -1 == lastnl:
        return len(text)
    if '\n' == text[-1]:
        return lastnl - (1 + text.rfind('\n', 0, lastnl))
    return len(text) - (1 + lastnl)


def len_lastline_withoutindent(text, indent):
    n = len_lastline(text)
    return (n - len(indent)) if n > len(indent) else 0


# Returns True if node `n` contains only inline (not block-level) elements.
def is_inline(n):
    # if len(n.childNodes) == 0:
    #     return n.nodeType == n.TEXT_NODE or n.nodeName == 'computeroutput'
    for c in n.childNodes:
        if c.nodeType != c.TEXT_NODE and c.nodeName != 'computeroutput':
            return False
        if not is_inline(c):
            return False
    return True


def doc_wrap(text, prefix='', width=70, func=False, indent=None):
    """Wraps text to `width`.

    First line is prefixed with `prefix`, subsequent lines are aligned.
    If `func` is True, only wrap at commas.
    """
    if not width:
        # return prefix + text
        return text

    # Whitespace used to indent all lines except the first line.
    indent = ' ' * len(prefix) if indent is None else indent
    indent_only = (prefix == '' and indent is not None)

    if func:
        lines = [prefix]
        for part in text.split(', '):
            if part[-1] not in ');':
                part += ', '
            if len(lines[-1]) + len(part) > width:
                lines.append(indent)
            lines[-1] += part
        return '\n'.join(x.rstrip() for x in lines).rstrip()

    # XXX: Dummy prefix to force TextWrapper() to wrap the first line.
    if indent_only:
        prefix = indent

    tw = textwrap.TextWrapper(break_long_words=False,
                              break_on_hyphens=False,
                              width=width,
                              initial_indent=prefix,
                              subsequent_indent=indent)
    result = '\n'.join(tw.wrap(text.strip()))

    # XXX: Remove the dummy prefix.
    if indent_only:
        result = result[len(indent):]

    return result


def max_name(names):
    if len(names) == 0:
        return 0
    return max(len(name) for name in names)


def update_params_map(parent, ret_map, width=text_width - indentation):
    """Updates `ret_map` with name:desc key-value pairs extracted
    from Doxygen XML node `parent`.
    """
    params = collections.OrderedDict()
    for node in parent.childNodes:
        if node.nodeType == node.TEXT_NODE:
            continue
        name_node = find_first(node, 'parametername')
        if name_node.getAttribute('direction') == 'out':
            continue
        name = get_text(name_node)
        if name in param_exclude:
            continue
        params[name.strip()] = node
    max_name_len = max_name(params.keys()) + 8
    # `ret_map` is a name:desc map.
    for name, node in params.items():
        desc = ''
        desc_node = get_child(node, 'parameterdescription')
        if desc_node:
            desc = fmt_node_as_vimhelp(
                    desc_node, width=width, indent=(' ' * max_name_len))
            ret_map[name] = desc
    return ret_map


def render_node(n, text, prefix='', indent='', width=text_width - indentation,
                fmt_vimhelp=False):
    """Renders a node as Vim help text, recursively traversing all descendants."""

    def ind(s):
        return s if fmt_vimhelp else ''

    text = ''
    # space_preceding = (len(text) > 0 and ' ' == text[-1][-1])
    # text += (int(not space_preceding) * ' ')

    if n.nodeName == 'preformatted':
        o = get_text(n, preformatted=True)
        ensure_nl = '' if o[-1] == '\n' else '\n'
        if o[0:4] == 'lua\n':
            text += '>lua{}{}\n<'.format(ensure_nl, o[3:-1])
        elif o[0:4] == 'vim\n':
            text += '>vim{}{}\n<'.format(ensure_nl, o[3:-1])
        else:
            text += '>{}{}\n<'.format(ensure_nl, o)

    elif is_inline(n):
        text = doc_wrap(get_text(n), prefix=prefix, indent=indent, width=width)
    elif n.nodeName == 'verbatim':
        # TODO: currently we don't use this. The "[verbatim]" hint is there as
        # a reminder that we must decide how to format this if we do use it.
        text += ' [verbatim] {}'.format(get_text(n))
    elif n.nodeName == 'listitem':
        for c in n.childNodes:
            result = render_node(
                c,
                text,
                indent=indent + (' ' * len(prefix)),
                width=width
            )
            if is_blank(result):
                continue
            text += indent + prefix + result
    elif n.nodeName in ('para', 'heading'):
        did_prefix = False
        for c in n.childNodes:
            if (is_inline(c)
                    and '' != get_text(c).strip()
                    and text
                    and ' ' != text[-1]):
                text += ' '
            text += render_node(c, text, prefix=(prefix if not did_prefix else ''), indent=indent, width=width)
            did_prefix = True
    elif n.nodeName == 'itemizedlist':
        for c in n.childNodes:
            text += '{}\n'.format(render_node(c, text, prefix='• ',
                                              indent=indent, width=width))
    elif n.nodeName == 'orderedlist':
        i = 1
        for c in n.childNodes:
            if is_blank(get_text(c)):
                text += '\n'
                continue
            text += '{}\n'.format(render_node(c, text, prefix='{}. '.format(i),
                                              indent=indent, width=width))
            i = i + 1
    elif n.nodeName == 'simplesect' and 'note' == n.getAttribute('kind'):
        text += '\nNote:\n    '
        for c in n.childNodes:
            text += render_node(c, text, indent='    ', width=width)
        text += '\n'
    elif n.nodeName == 'simplesect' and 'warning' == n.getAttribute('kind'):
        text += 'Warning:\n    '
        for c in n.childNodes:
            text += render_node(c, text, indent='    ', width=width)
        text += '\n'
    elif n.nodeName == 'simplesect' and 'see' == n.getAttribute('kind'):
        text += ind('  ')
        # Example:
        #   <simplesect kind="see">
        #     <para>|autocommand|</para>
        #   </simplesect>
        for c in n.childNodes:
            text += render_node(c, text, prefix='• ', indent='    ', width=width)
    elif n.nodeName == 'simplesect' and 'return' == n.getAttribute('kind'):
        text += ind('    ')
        for c in n.childNodes:
            text += render_node(c, text, indent='    ', width=width)
    elif n.nodeName == 'computeroutput':
        return get_text(n)
    else:
        raise RuntimeError('unhandled node type: {}\n{}'.format(
            n.nodeName, n.toprettyxml(indent='  ', newl='\n')))

    return text


def para_as_map(parent, indent='', width=text_width - indentation, fmt_vimhelp=False):
    """Extracts a Doxygen XML <para> node to a map.

    Keys:
        'text': Text from this <para> element
        'params': <parameterlist> map
        'return': List of @return strings
        'seealso': List of @see strings
        'xrefs': ?
    """
    chunks = {
        'text': '',
        'params': collections.OrderedDict(),
        'return': [],
        'seealso': [],
        'xrefs': []
    }

    # Ordered dict of ordered lists.
    groups = collections.OrderedDict([
        ('params', []),
        ('return', []),
        ('seealso', []),
        ('xrefs', []),
    ])

    # Gather nodes into groups.  Mostly this is because we want "parameterlist"
    # nodes to appear together.
    text = ''
    kind = ''
    last = ''
    if is_inline(parent):
        # Flatten inline text from a tree of non-block nodes.
        text = doc_wrap(render_node(parent, "", fmt_vimhelp=fmt_vimhelp),
                        indent=indent, width=width)
    else:
        prev = None  # Previous node
        for child in parent.childNodes:
            if child.nodeName == 'parameterlist':
                groups['params'].append(child)
            elif child.nodeName == 'xrefsect':
                groups['xrefs'].append(child)
            elif child.nodeName == 'simplesect':
                last = kind
                kind = child.getAttribute('kind')
                if kind == 'return' or (kind == 'note' and last == 'return'):
                    groups['return'].append(child)
                elif kind == 'see':
                    groups['seealso'].append(child)
                elif kind in ('note', 'warning'):
                    text += render_node(child, text, indent=indent,
                                        width=width, fmt_vimhelp=fmt_vimhelp)
                else:
                    raise RuntimeError('unhandled simplesect: {}\n{}'.format(
                        child.nodeName, child.toprettyxml(indent='  ', newl='\n')))
            else:
                if (prev is not None
                        and is_inline(self_or_child(prev))
                        and is_inline(self_or_child(child))
                        and '' != get_text(self_or_child(child)).strip()
                        and text
                        and ' ' != text[-1]):
                    text += ' '

                text += render_node(child, text, indent=indent, width=width,
                                    fmt_vimhelp=fmt_vimhelp)
                prev = child

    chunks['text'] += text

    # Generate map from the gathered items.
    if len(groups['params']) > 0:
        for child in groups['params']:
            update_params_map(child, ret_map=chunks['params'], width=width)
    for child in groups['return']:
        chunks['return'].append(render_node(
            child, '', indent=indent, width=width, fmt_vimhelp=fmt_vimhelp))
    for child in groups['seealso']:
        # Example:
        #   <simplesect kind="see">
        #     <para>|autocommand|</para>
        #   </simplesect>
        chunks['seealso'].append(render_node(
            child, '', indent=indent, width=width, fmt_vimhelp=fmt_vimhelp))

    xrefs = set()
    for child in groups['xrefs']:
        # XXX: Add a space (or any char) to `title` here, otherwise xrefs
        # ("Deprecated" section) acts very weird...
        title = get_text(get_child(child, 'xreftitle')) + ' '
        xrefs.add(title)
        xrefdesc = get_text(get_child(child, 'xrefdescription'))
        chunks['xrefs'].append(doc_wrap(xrefdesc, prefix='{}: '.format(title),
                                        width=width) + '\n')

    return chunks, xrefs


def fmt_node_as_vimhelp(parent, width=text_width - indentation, indent='',
                        fmt_vimhelp=False):
    """Renders (nested) Doxygen <para> nodes as Vim :help text.

    NB: Blank lines in a docstring manifest as <para> tags.
    """
    rendered_blocks = []

    def fmt_param_doc(m):
        """Renders a params map as Vim :help text."""
        max_name_len = max_name(m.keys()) + 4
        out = ''
        for name, desc in m.items():
            name = '  • {}'.format('{{{}}}'.format(name).ljust(max_name_len))
            out += '{}{}\n'.format(name, desc)
        return out.rstrip()

    def has_nonexcluded_params(m):
        """Returns true if any of the given params has at least
        one non-excluded item."""
        if fmt_param_doc(m) != '':
            return True

    for child in parent.childNodes:
        para, _ = para_as_map(child, indent, width, fmt_vimhelp)

        # Generate text from the gathered items.
        chunks = [para['text']]
        if len(para['params']) > 0 and has_nonexcluded_params(para['params']):
            chunks.append('\nParameters: ~')
            chunks.append(fmt_param_doc(para['params']))
        if len(para['return']) > 0:
            chunks.append('\nReturn: ~')
            for s in para['return']:
                chunks.append(s)
        if len(para['seealso']) > 0:
            chunks.append('\nSee also: ~')
            for s in para['seealso']:
                chunks.append(s)
        for s in para['xrefs']:
            chunks.append(s)

        rendered_blocks.append(clean_lines('\n'.join(chunks).strip()))
        rendered_blocks.append('')

    return clean_lines('\n'.join(rendered_blocks).strip())


def extract_from_xml(filename, target, width, fmt_vimhelp):
    """Extracts Doxygen info as maps without formatting the text.

    Returns two maps:
      1. Functions
      2. Deprecated functions

    The `fmt_vimhelp` variable controls some special cases for use by
    fmt_doxygen_xml_as_vimhelp(). (TODO: ugly :)
    """
    fns = {}  # Map of func_name:docstring.
    deprecated_fns = {}  # Map of func_name:docstring.

    dom = minidom.parse(filename)
    compoundname = get_text(dom.getElementsByTagName('compoundname')[0])
    for member in dom.getElementsByTagName('memberdef'):
        if member.getAttribute('static') == 'yes' or \
                member.getAttribute('kind') != 'function' or \
                member.getAttribute('prot') == 'private' or \
                get_text(get_child(member, 'name')).startswith('_'):
            continue

        loc = find_first(member, 'location')
        if 'private' in loc.getAttribute('file'):
            continue

        return_type = get_text(get_child(member, 'type'))
        if return_type == '':
            continue

        if return_type.startswith(('ArrayOf', 'DictionaryOf')):
            parts = return_type.strip('_').split('_')
            return_type = '{}({})'.format(parts[0], ', '.join(parts[1:]))

        name = get_text(get_child(member, 'name'))

        annotations = get_text(get_child(member, 'argsstring'))
        if annotations and ')' in annotations:
            annotations = annotations.rsplit(')', 1)[-1].strip()
        # XXX: (doxygen 1.8.11) 'argsstring' only includes attributes of
        # non-void functions.  Special-case void functions here.
        if name == 'nvim_get_mode' and len(annotations) == 0:
            annotations += 'FUNC_API_FAST'
        annotations = filter(None, map(lambda x: annotation_map.get(x),
                                       annotations.split()))

        params = []
        type_length = 0

        for param in iter_children(member, 'param'):
            param_type = get_text(get_child(param, 'type')).strip()
            param_name = ''
            declname = get_child(param, 'declname')
            if declname:
                param_name = get_text(declname).strip()
            elif CONFIG[target]['mode'] == 'lua':
                # XXX: this is what lua2dox gives us...
                param_name = param_type
                param_type = ''

            if param_name in param_exclude:
                continue

            if fmt_vimhelp and param_type.endswith('*'):
                param_type = param_type.strip('* ')
                param_name = '*' + param_name

            type_length = max(type_length, len(param_type))
            params.append((param_type, param_name))

        # Handle Object Oriented style functions here.
        #   We make sure they have "self" in the parameters,
        #   and a parent function
        if return_type.startswith('function') \
                and len(return_type.split(' ')) >= 2 \
                and any(x[1] == 'self' for x in params):
            split_return = return_type.split(' ')
            name = f'{split_return[1]}:{name}'

        c_args = []
        for param_type, param_name in params:
            c_args.append(('    ' if fmt_vimhelp else '') + (
                '%s %s' % (param_type.ljust(type_length), param_name)).strip())

        if not fmt_vimhelp:
            pass
        else:
            fstem = '?'
            if '.' in compoundname:
                fstem = compoundname.split('.')[0]
                fstem = CONFIG[target]['module_override'].get(fstem, fstem)
            vimtag = CONFIG[target]['fn_helptag_fmt'](fstem, name)

        prefix = '%s(' % name
        suffix = '%s)' % ', '.join('{%s}' % a[1] for a in params
                                   if a[0] not in ('void', 'Error', 'Arena',
                                                   'lua_State'))

        if not fmt_vimhelp:
            c_decl = '%s %s(%s);' % (return_type, name, ', '.join(c_args))
            signature = prefix + suffix
        else:
            c_decl = textwrap.indent('%s %s(\n%s\n);' % (return_type, name,
                                                         ',\n'.join(c_args)),
                                     '    ')

            # Minimum 8 chars between signature and vimtag
            lhs = (width - 8) - len(vimtag)

            if len(prefix) + len(suffix) > lhs:
                signature = vimtag.rjust(width) + '\n'
                signature += doc_wrap(suffix, width=width, prefix=prefix,
                                      func=True)
            else:
                signature = prefix + suffix
                signature += vimtag.rjust(width - len(signature))

        # Tracks `xrefsect` titles.  As of this writing, used only for separating
        # deprecated functions.
        xrefs_all = set()
        paras = []
        brief_desc = find_first(member, 'briefdescription')
        if brief_desc:
            for child in brief_desc.childNodes:
                para, xrefs = para_as_map(child)
                xrefs_all.update(xrefs)

        desc = find_first(member, 'detaileddescription')
        if desc:
            for child in desc.childNodes:
                para, xrefs = para_as_map(child)
                paras.append(para)
                xrefs_all.update(xrefs)
            log.debug(
                textwrap.indent(
                    re.sub(r'\n\s*\n+', '\n',
                           desc.toprettyxml(indent='  ', newl='\n')),
                    ' ' * indentation))

        fn = {
            'annotations': list(annotations),
            'signature': signature,
            'parameters': params,
            'parameters_doc': collections.OrderedDict(),
            'doc': [],
            'return': [],
            'seealso': [],
        }
        if fmt_vimhelp:
            fn['desc_node'] = desc
            fn['brief_desc_node'] = brief_desc

        for m in paras:
            if 'text' in m:
                if not m['text'] == '':
                    fn['doc'].append(m['text'])
            if 'params' in m:
                # Merge OrderedDicts.
                fn['parameters_doc'].update(m['params'])
            if 'return' in m and len(m['return']) > 0:
                fn['return'] += m['return']
            if 'seealso' in m and len(m['seealso']) > 0:
                fn['seealso'] += m['seealso']

        if INCLUDE_C_DECL:
            fn['c_decl'] = c_decl

        if 'Deprecated' in str(xrefs_all):
            deprecated_fns[name] = fn
        elif name.startswith(CONFIG[target]['fn_name_prefix']):
            fns[name] = fn

    fns = collections.OrderedDict(sorted(
        fns.items(),
        key=lambda key_item_tuple: key_item_tuple[0].lower()))
    deprecated_fns = collections.OrderedDict(sorted(deprecated_fns.items()))
    return fns, deprecated_fns


def fmt_doxygen_xml_as_vimhelp(filename, target):
    """Entrypoint for generating Vim :help from from Doxygen XML.

    Returns 2 items:
      1. Vim help text for functions found in `filename`.
      2. Vim help text for deprecated functions.
    """
    fns_txt = {}  # Map of func_name:vim-help-text.
    deprecated_fns_txt = {}  # Map of func_name:vim-help-text.
    fns, _ = extract_from_xml(filename, target, text_width, True)

    for name, fn in fns.items():
        # Generate Vim :help for parameters.
        if fn['desc_node']:
            doc = fmt_node_as_vimhelp(fn['desc_node'], fmt_vimhelp=True)
        if not doc and fn['brief_desc_node']:
            doc = fmt_node_as_vimhelp(fn['brief_desc_node'])
        if not doc and name.startswith("nvim__"):
            continue
        if not doc:
            doc = 'TODO: Documentation'

        annotations = '\n'.join(fn['annotations'])
        if annotations:
            annotations = ('\n\nAttributes: ~\n' +
                           textwrap.indent(annotations, '    '))
            i = doc.rfind('Parameters: ~')
            if i == -1:
                doc += annotations
            else:
                doc = doc[:i] + annotations + '\n\n' + doc[i:]

        if INCLUDE_C_DECL:
            doc += '\n\nC Declaration: ~\n>\n'
            doc += fn['c_decl']
            doc += '\n<'

        func_doc = fn['signature'] + '\n'
        func_doc += textwrap.indent(clean_lines(doc), ' ' * indentation)

        # Verbatim handling.
        func_doc = re.sub(r'^\s+([<>])$', r'\1', func_doc, flags=re.M)

        split_lines = func_doc.split('\n')
        start = 0
        while True:
            try:
                start = split_lines.index('>', start)
            except ValueError:
                break

            try:
                end = split_lines.index('<', start)
            except ValueError:
                break

            split_lines[start + 1:end] = [
                ('    ' + x).rstrip()
                for x in textwrap.dedent(
                    "\n".join(
                        split_lines[start+1:end]
                    )
                ).split("\n")
            ]

            start = end

        func_doc = "\n".join(map(align_tags, split_lines))

        if (name.startswith(CONFIG[target]['fn_name_prefix'])
           and name != "nvim_error_event"):
            fns_txt[name] = func_doc

    return ('\n\n'.join(list(fns_txt.values())),
            '\n\n'.join(list(deprecated_fns_txt.values())))


def delete_lines_below(filename, tokenstr):
    """Deletes all lines below the line containing `tokenstr`, the line itself,
    and one line above it.
    """
    lines = open(filename).readlines()
    i = 0
    found = False
    for i, line in enumerate(lines, 1):
        if tokenstr in line:
            found = True
            break
    if not found:
        raise RuntimeError(f'not found: "{tokenstr}"')
    i = max(0, i - 2)
    with open(filename, 'wt') as fp:
        fp.writelines(lines[0:i])


def main(doxygen_config, args):
    """Generates:

    1. Vim :help docs
    2. *.mpack files for use by API clients

    Doxygen is called and configured through stdin.
    """
    for target in CONFIG:
        if args.target is not None and target != args.target:
            continue
        mpack_file = os.path.join(
            base_dir, 'runtime', 'doc',
            CONFIG[target]['filename'].replace('.txt', '.mpack'))
        if os.path.exists(mpack_file):
            os.remove(mpack_file)

        output_dir = out_dir.format(target=target)
        log.info("Generating documentation for %s in folder %s",
                 target, output_dir)
        debug = args.log_level >= logging.DEBUG
        p = subprocess.Popen(
                ['doxygen', '-'],
                stdin=subprocess.PIPE,
                # silence warnings
                # runtime/lua/vim/lsp.lua:209: warning: argument 'foo' not found
                stderr=(subprocess.STDOUT if debug else subprocess.DEVNULL))
        p.communicate(
            doxygen_config.format(
                input=' '.join(
                    [f'"{file}"' for file in CONFIG[target]['files']]),
                output=output_dir,
                filter=filter_cmd,
                file_patterns=CONFIG[target]['file_patterns'])
            .encode('utf8')
        )
        if p.returncode:
            sys.exit(p.returncode)

        fn_map_full = {}  # Collects all functions as each module is processed.
        sections = {}
        section_docs = {}
        sep = '=' * text_width

        base = os.path.join(output_dir, 'xml')
        dom = minidom.parse(os.path.join(base, 'index.xml'))

        # Generate module-level (section) docs (@defgroup).
        for compound in dom.getElementsByTagName('compound'):
            if compound.getAttribute('kind') != 'group':
                continue

            # Doxygen "@defgroup" directive.
            groupname = get_text(find_first(compound, 'name'))
            groupxml = os.path.join(base, '%s.xml' %
                                    compound.getAttribute('refid'))

            group_parsed = minidom.parse(groupxml)
            doc_list = []
            brief_desc = find_first(group_parsed, 'briefdescription')
            if brief_desc:
                for child in brief_desc.childNodes:
                    doc_list.append(fmt_node_as_vimhelp(child))

            desc = find_first(group_parsed, 'detaileddescription')
            if desc:
                doc = fmt_node_as_vimhelp(desc)

                if doc:
                    doc_list.append(doc)

            section_docs[groupname] = "\n".join(doc_list)

        # Generate docs for all functions in the current module.
        for compound in dom.getElementsByTagName('compound'):
            if compound.getAttribute('kind') != 'file':
                continue

            filename = get_text(find_first(compound, 'name'))
            if filename.endswith('.c') or filename.endswith('.lua'):
                xmlfile = os.path.join(base, '{}.xml'.format(compound.getAttribute('refid')))
                # Extract unformatted (*.mpack).
                fn_map, _ = extract_from_xml(xmlfile, target, 9999, False)
                # Extract formatted (:help).
                functions_text, deprecated_text = fmt_doxygen_xml_as_vimhelp(
                    os.path.join(base, '{}.xml'.format(compound.getAttribute('refid'))), target)

                if not functions_text and not deprecated_text:
                    continue
                else:
                    filename = os.path.basename(filename)
                    name = os.path.splitext(filename)[0].lower()
                    sectname = name.upper() if name == 'ui' else name.title()
                    sectname = CONFIG[target]['section_name'].get(filename, sectname)
                    title = CONFIG[target]['section_fmt'](sectname)
                    section_tag = CONFIG[target]['helptag_fmt'](sectname)
                    # Module/Section id matched against @defgroup.
                    #   "*api-buffer*" => "api-buffer"
                    section_id = section_tag.strip('*')

                    doc = ''
                    section_doc = section_docs.get(section_id)
                    if section_doc:
                        doc += '\n\n' + section_doc

                    if functions_text:
                        doc += '\n\n' + functions_text

                    if INCLUDE_DEPRECATED and deprecated_text:
                        doc += f'\n\n\nDeprecated {sectname} Functions: ~\n\n'
                        doc += deprecated_text

                    if doc:
                        sections[filename] = (title, section_tag, doc)
                        fn_map_full.update(fn_map)

        if len(sections) == 0:
            fail(f'no sections for target: {target} (look for errors near "Preprocessing" log lines above)')
        if len(sections) > len(CONFIG[target]['section_order']):
            raise RuntimeError(
                'found new modules "{}"; update the "section_order" map'.format(
                    set(sections).difference(CONFIG[target]['section_order'])))
        first_section_tag = sections[CONFIG[target]['section_order'][0]][1]

        docs = ''

        for filename in CONFIG[target]['section_order']:
            try:
                title, section_tag, section_doc = sections.pop(filename)
            except KeyError:
                msg(f'warning: empty docs, skipping (target={target}): {filename}')
                msg(f'    existing docs: {sections.keys()}')
                continue
            if filename not in CONFIG[target]['append_only']:
                docs += sep
                docs += '\n{}{}'.format(title, section_tag.rjust(text_width - len(title)))
            docs += section_doc
            docs += '\n\n\n'

        docs = docs.rstrip() + '\n\n'
        docs += f' vim:tw=78:ts=8:sw={indentation}:sts={indentation}:et:ft=help:norl:\n'

        doc_file = os.path.join(base_dir, 'runtime', 'doc',
                                CONFIG[target]['filename'])

        if os.path.exists(doc_file):
            delete_lines_below(doc_file, first_section_tag)
        with open(doc_file, 'ab') as fp:
            fp.write(docs.encode('utf8'))

        fn_map_full = collections.OrderedDict(sorted(fn_map_full.items()))
        with open(mpack_file, 'wb') as fp:
            fp.write(msgpack.packb(fn_map_full, use_bin_type=True))

        if not args.keep_tmpfiles:
            shutil.rmtree(output_dir)

    msg_report()


def filter_source(filename, keep_tmpfiles):
    output_dir = out_dir.format(target='lua2dox')
    name, extension = os.path.splitext(filename)
    if extension == '.lua':
        args = [str(nvim), '-l', lua2dox, filename] + (['--outdir', output_dir] if keep_tmpfiles else [])
        p = subprocess.run(args, stdout=subprocess.PIPE)
        op = ('?' if 0 != p.returncode else p.stdout.decode('utf-8'))
        print(op)
    else:
        """Filters the source to fix macros that confuse Doxygen."""
        with open(filename, 'rt') as fp:
            print(re.sub(r'^(ArrayOf|DictionaryOf)(\(.*?\))',
                         lambda m: m.group(1)+'_'.join(
                             re.split(r'[^\w]+', m.group(2))),
                         fp.read(), flags=re.M))


def parse_args():
    targets = ', '.join(CONFIG.keys())
    ap = argparse.ArgumentParser(
        description="Generate helpdoc from source code")
    ap.add_argument(
        "--log-level", "-l", choices=LOG_LEVELS.keys(),
        default=logging.getLevelName(logging.ERROR), help="Set log verbosity"
    )
    ap.add_argument('source_filter', nargs='*',
                    help="Filter source file(s)")
    ap.add_argument('-k', '--keep-tmpfiles', action='store_true',
                    help="Keep temporary files (tmp-xx-doc/ directories, including tmp-lua2dox-doc/ for lua2dox.lua quasi-C output)")
    ap.add_argument('-t', '--target',
                    help=f'One of ({targets}), defaults to "all"')
    return ap.parse_args()


Doxyfile = textwrap.dedent('''
    OUTPUT_DIRECTORY       = {output}
    INPUT                  = {input}
    INPUT_ENCODING         = UTF-8
    FILE_PATTERNS          = {file_patterns}
    RECURSIVE              = YES
    INPUT_FILTER           = "{filter}"
    EXCLUDE                =
    EXCLUDE_SYMLINKS       = NO
    EXCLUDE_PATTERNS       = */private/* */health.lua */_*.lua
    EXCLUDE_SYMBOLS        =
    EXTENSION_MAPPING      = lua=C
    EXTRACT_PRIVATE        = NO

    GENERATE_HTML          = NO
    GENERATE_DOCSET        = NO
    GENERATE_HTMLHELP      = NO
    GENERATE_QHP           = NO
    GENERATE_TREEVIEW      = NO
    GENERATE_LATEX         = NO
    GENERATE_RTF           = NO
    GENERATE_MAN           = NO
    GENERATE_DOCBOOK       = NO
    GENERATE_AUTOGEN_DEF   = NO

    GENERATE_XML           = YES
    XML_OUTPUT             = xml
    XML_PROGRAMLISTING     = NO

    ENABLE_PREPROCESSING   = YES
    MACRO_EXPANSION        = YES
    EXPAND_ONLY_PREDEF     = NO
    MARKDOWN_SUPPORT       = YES
''')

if __name__ == "__main__":
    args = parse_args()
    print("Setting log level to %s" % args.log_level)
    args.log_level = LOG_LEVELS[args.log_level]
    log.setLevel(args.log_level)
    log.addHandler(logging.StreamHandler())

    # When invoked as a filter, args won't be passed, so use an env var.
    if args.keep_tmpfiles:
        os.environ['NVIM_KEEP_TMPFILES'] = '1'
    keep_tmpfiles = ('NVIM_KEEP_TMPFILES' in os.environ)

    if len(args.source_filter) > 0:
        filter_source(args.source_filter[0], keep_tmpfiles)
    else:
        main(Doxyfile, args)

# vim: set ft=python ts=4 sw=4 tw=79 et :