#!/usr/bin/env python3
"""Generates Nvim help docs from C docstrings, by parsing Doxygen XML.

This would be easier using lxml and XSLT, but:

  1. This should avoid needing Python dependencies, especially ones that are
     C modules that have library dependencies (lxml requires libxml and
     libxslt).
  2. I wouldn't know how to deal with nested indentation in <para> tags using
     XSLT.

Each function :help block is formatted as follows:

  - Max width of 78 columns (`text_width`).
  - Indent with spaces (not tabs).
  - Indent of 16 columns for body text.
  - 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 os
import re
import sys
import shutil
import textwrap
import subprocess
import collections
import msgpack

from xml.dom import minidom

if sys.version_info[0] < 3 or sys.version_info[1] < 5:
    print("requires Python 3.5+")
    sys.exit(1)

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

text_width = 78
script_path = os.path.abspath(__file__)
base_dir = os.path.dirname(os.path.dirname(script_path))
out_dir = os.path.join(base_dir, 'tmp-{mode}-doc')
filter_cmd = '%s %s' % (sys.executable, script_path)
seen_funcs = set()
lua2dox_filter = os.path.join(base_dir, 'scripts', 'lua2dox_filter')

CONFIG = {
    'api': {
        'filename': 'api.txt',
        # String used to find the start of the generated part of the doc.
        'section_start_token': '*api-global*',
        # Section ordering.
        'section_order': [
            'vim.c',
            'buffer.c',
            'window.c',
            'tabpage.c',
            'ui.c',
        ],
        # List of files/directories for doxygen to read, separated by blanks
        'files': os.path.join(base_dir, 'src/nvim/api'),
        # file patterns used by doxygen
        'file_patterns': '*.h *.c',
        # Only function with this prefix are considered
        'func_name_prefix': 'nvim_',
        # Section name overrides.
        'section_name': {
            'vim.c': 'Global',
        },
        # Module name overrides (for Lua).
        'module_override': {},
        # Append the docs for these modules, do not start a new section.
        'append_only': [],
    },
    'lua': {
        'filename': 'if_lua.txt',
        'section_start_token': '*lua-vim*',
        'section_order': [
            'vim.lua',
            'shared.lua',
        ],
        'files': ' '.join([
            os.path.join(base_dir, 'src/nvim/lua/vim.lua'),
            os.path.join(base_dir, 'runtime/lua/vim/shared.lua'),
        ]),
        'file_patterns': '*.lua',
        'func_name_prefix': '',
        'section_name': {},
        'module_override': {
            # `shared` functions are exposed on the `vim` module.
            'shared': 'vim',
        },
        'append_only': [
            'shared.lua',
        ],
    },
}

param_exclude = (
    'channel_id',
)

# Annotations are displayed as line items after API function descriptions.
annotation_map = {
    'FUNC_API_FAST': '{fast}',
}


# Tracks `xrefsect` titles.  As of this writing, used only for separating
# deprecated functions.
xrefs = set()


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


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 get_children(parent, name):
    """Yield 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):
    """Get the first matching child node."""
    for child in get_children(parent, name):
        return child
    return None


def clean_text(text):
    """Cleans text.

    Only cleans superfluous whitespace at the moment.
    """
    return ' '.join(text.split()).strip()


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(parent, preformatted=False):
    """Combine all text in a node."""
    if parent.nodeType == parent.TEXT_NODE:
        return parent.data

    out = ''
    for node in parent.childNodes:
        if node.nodeType == node.TEXT_NODE:
            out += node.data if preformatted else clean_text(node.data)
        elif node.nodeType == node.ELEMENT_NODE:
            out += ' ' + get_text(node, preformatted)
    return out


# 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):
    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 update_params_map(parent, ret_map, width=62):
    """Updates `ret_map` with name:desc key-value pairs extracted
    from a Doxygen <parameterlist>.
    """
    items = []
    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
        items.append((name.strip(), node))
    # `ret_map` is a name:desc map.
    for name, node in items:
        desc = ''
        desc_node = get_child(node, 'parameterdescription')
        if desc_node:
            desc = parse_parblock(desc_node, width=width,
                                  indent=(' ' * len(name)))
            ret_map[name] = desc
    return ret_map


def fmt_params_map_as_vimhelp(m, width=62):
    """Renders a params map as Vim :help text."""
    name_length = 0
    for name, desc in m.items():
        name_length = max(name_length, len(name) + 4)
    out = ''
    for name, desc in m.items():
        name = '    {}'.format('{{{}}}'.format(name).ljust(name_length))
        out += '{}{}\n'.format(name, desc)
    return out.rstrip()


def render_node(n, text, prefix='', indent='', width=62):
    """Renders a node as Vim help text, recursively traversing all descendants."""
    text = ''
    # space_preceding = (len(text) > 0 and ' ' == text[-1][-1])
    # text += (int(not space_preceding) * ' ')

    if n.nodeType == n.TEXT_NODE:
        # `prefix` is NOT sent to doc_wrap, it was already handled by now.
        text += doc_wrap(n.data, indent=indent, width=width)
    elif n.nodeName == 'computeroutput':
        text += ' `{}` '.format(get_text(n))
    elif n.nodeName == 'preformatted':
        o = get_text(n, preformatted=True)
        ensure_nl = '' if o[-1] == '\n' else '\n'
        text += ' >{}{}\n<'.format(ensure_nl, o)
    elif is_inline(n):
        for c in n.childNodes:
            text += render_node(c, text)
        text = doc_wrap(text, 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:
            text += (
                indent
                + prefix
                + render_node(c, text, indent=indent + (' ' * len(prefix)), width=width)
            )
    elif n.nodeName in ('para', 'heading'):
        for c in n.childNodes:
            text += render_node(c, text, indent=indent, width=width)
        if is_inline(n):
            text = doc_wrap(text, indent=indent, width=width)
    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 += 'Note:\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 n.getAttribute('kind') in ('return', 'see')):
        text += '    '
        for c in n.childNodes:
            text += render_node(c, text, indent='    ', width=width)
    else:
        raise RuntimeError('unhandled node type: {}\n{}'.format(
            n.nodeName, n.toprettyxml(indent='  ', newl='\n')))
    return text


def para_as_map(parent, indent='', width=62):
    """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': []
    }

    if is_inline(parent):
        chunks['text'] = clean_lines(doc_wrap(render_node(parent, ''),
            indent=indent, width=width).strip())

    # 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 = ''
    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)
            else:
                raise RuntimeError('unhandled simplesect: {}\n{}'.format(
                    child.nodeName, child.toprettyxml(indent='  ', newl='\n')))
        else:
            text += render_node(child, text, indent=indent, width=width)

    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).lstrip())
    for child in groups['seealso']:
        chunks['seealso'].append(render_node(
            child, '', indent=indent, width=width))
    for child in groups['xrefs']:
        title = get_text(get_child(child, 'xreftitle'))
        xrefs.add(title)
        xrefdesc = render_para(get_child(child, 'xrefdescription'), width=width)
        chunks['xrefs'].append(doc_wrap(xrefdesc, prefix='{}: '.format(title),
                                        width=width) + '\n')

    return chunks


def render_para(parent, indent='', width=62):
    """Renders Doxygen <para> containing arbitrary nodes.

    NB: Blank lines in a docstring manifest as <para> tags.
    """
    para = para_as_map(parent, indent, width)

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

    # 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_params_map_as_vimhelp(para['params'], width=width))
    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)

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


def parse_parblock(parent, prefix='', width=62, indent=''):
    """Renders a nested block of <para> tags as Vim help text."""
    paragraphs = []
    for child in parent.childNodes:
        paragraphs.append(render_para(child, width=width, indent=indent))
        paragraphs.append('')
    return clean_lines('\n'.join(paragraphs).strip())


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

    Returns two maps:
      1. Functions
      2. Deprecated functions

    The `fmt_vimhelp` parameter controls some special cases for use by
    fmt_doxygen_xml_as_vimhelp(). (TODO: ugly :)
    """
    global xrefs
    xrefs = set()
    functions = {}  # Map of func_name:docstring.
    deprecated_functions = {}  # 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()))

        if not fmt_vimhelp:
            pass
        elif mode == 'lua':
            fstem = compoundname.split('.')[0]
            fstem = CONFIG[mode]['module_override'].get(fstem, fstem)
            vimtag = '*{}.{}()*'.format(fstem, name)
        else:
            vimtag = '*{}()*'.format(name)

        params = []
        type_length = 0

        for param in get_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 mode == 'lua':
                # that's how it comes out of lua2dox
                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))

        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())

        prefix = '%s(' % name
        suffix = '%s)' % ', '.join('{%s}' % a[1] for a in params
                                   if a[0] not in ('void', 'Error'))
        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 = (text_width - 8) - len(prefix)

            if len(prefix) + len(suffix) > lhs:
                signature = vimtag.rjust(text_width) + '\n'
                signature += doc_wrap(suffix, width=text_width-8, prefix=prefix,
                                      func=True)
            else:
                signature = prefix + suffix
                signature += vimtag.rjust(text_width - len(signature))

        paras = []
        desc = find_first(member, 'detaileddescription')
        if desc:
            for child in desc.childNodes:
                paras.append(para_as_map(child))  #, width=width, indent=indent))
            if DEBUG:
                print(textwrap.indent(
                    re.sub(r'\n\s*\n+', '\n',
                           desc.toprettyxml(indent='  ', newl='\n')), ' ' * 16))

        fn = {
            'annotations': list(annotations),
            'signature': signature,
            'parameters': params,
            'parameters_doc': [],
            'doc': [],
            'return': '',
            'seealso': '',
        }
        if fmt_vimhelp:
            fn['desc_node'] = desc  # HACK :(

        for m in paras:
            if 'text' in m:
                if not m['text'] == '':
                    fn['doc'].append(m['text'])
            if 'params' in m:
                fn['parameters_doc'] += m['params']
            if 'return' in m:
                fn['return'] = m['return']
            if 'seealso' in m:
                fn['seealso'] = m['xrefs']

        if INCLUDE_C_DECL:
            fn['c_decl'] = c_decl

        if 'Deprecated' in xrefs:
            deprecated_functions[name] = fn
        elif name.startswith(CONFIG[mode]['func_name_prefix']):
            functions[name] = fn

        xrefs.clear()

    return (functions, deprecated_functions)


def fmt_doxygen_xml_as_vimhelp(filename, mode):
    """Formats functions from doxygen XML into Vim :help format.

    Returns two strings:
      1. Functions in Vim :help format
      2. Deprecated functions (handled by caller, or ignored)
    """
    functions = {}  # Map of func_name:docstring.
    deprecated_functions = {}  # Map of func_name:docstring.
    fns, deprecated_fns = extract_from_xml(filename, mode, True)

    for name, fn in fns.items():
        if fn['desc_node']:
            doc = parse_parblock(fn['desc_node'])
        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), ' ' * 16)
        func_doc = re.sub(r'^\s+([<>])$', r'\1', func_doc, flags=re.M)

        if 'Deprecated' in xrefs:
            deprecated_functions.append(func_doc)
        elif name.startswith(CONFIG[mode]['func_name_prefix']):
            functions[name] = func_doc

        xrefs.clear()

    return ('\n\n'.join(list(functions.values())),
            '\n\n'.join(deprecated_fns),
            functions)


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
    for i, line in enumerate(lines, 1):
        if tokenstr in line:
            break
    i = max(0, i - 2)
    with open(filename, 'wt') as fp:
        fp.writelines(lines[0:i])


def gen_docs(config):
    """Generate documentation.

    Doxygen is called and configured through stdin.
    """
    for mode in CONFIG:
        functions = {}  # Map of func_name:docstring.
        mpack_file = os.path.join(
            base_dir, 'runtime', 'doc',
            CONFIG[mode]['filename'].replace('.txt', '.mpack'))
        if os.path.exists(mpack_file):
            os.remove(mpack_file)

        output_dir = out_dir.format(mode=mode)
        p = subprocess.Popen(['doxygen', '-'], stdin=subprocess.PIPE)
        p.communicate(
            config.format(
                input=CONFIG[mode]['files'],
                output=output_dir,
                filter=filter_cmd,
                file_patterns=CONFIG[mode]['file_patterns'])
            .encode('utf8')
        )
        if p.returncode:
            sys.exit(p.returncode)

        doc_maps = {}
        sections = {}
        intros = {}
        sep = '=' * text_width

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

        # generate docs for section intros
        for compound in dom.getElementsByTagName('compound'):
            if compound.getAttribute('kind') != 'group':
                continue

            groupname = get_text(find_first(compound, 'name'))
            groupxml = os.path.join(base, '%s.xml' %
                                    compound.getAttribute('refid'))

            desc = find_first(minidom.parse(groupxml), 'detaileddescription')
            if desc:
                doc = parse_parblock(desc)
                if doc:
                    intros[groupname] = doc

        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'):
                mpack = extract_from_xml(os.path.join(base, '{}.xml'.format(
                    compound.getAttribute('refid'))), mode, False)

                functions_text, deprecated_text, fns = fmt_doxygen_xml_as_vimhelp(
                    os.path.join(base, '{}.xml'.format(
                                 compound.getAttribute('refid'))), mode)
                # Collect functions from all modules (for the current `mode`).
                functions = {**functions, **fns}

                if not functions_text and not deprecated_text:
                    continue
                else:
                    name = os.path.splitext(os.path.basename(filename))[0]
                    if name == 'ui':
                        name = name.upper()
                    else:
                        name = name.title()

                    doc = ''

                    intro = intros.get('api-%s' % name.lower())
                    if intro:
                        doc += '\n\n' + intro

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

                    if INCLUDE_DEPRECATED and deprecated_text:
                        doc += '\n\n\nDeprecated %s Functions: ~\n\n' % name
                        doc += deprecated_text

                    if doc:
                        filename = os.path.basename(filename)
                        name = CONFIG[mode]['section_name'].get(filename, name)

                        if mode == 'lua':
                            title = 'Lua module: {}'.format(name.lower())
                            helptag = '*lua-{}*'.format(name.lower())
                        else:
                            title = '{} Functions'.format(name)
                            helptag = '*api-{}*'.format(name.lower())
                        sections[filename] = (title, helptag, doc)
                        doc_maps[filename] = mpack

        if not sections:
            return

        docs = ''

        i = 0
        for filename in CONFIG[mode]['section_order']:
            if filename not in sections:
                raise RuntimeError(
                    'found new module "{}"; update the "section_order" map'.format(
                        filename))
            title, helptag, section_doc = sections.pop(filename)
            i += 1
            if filename not in CONFIG[mode]['append_only']:
                docs += sep
                docs += '\n%s%s' % (title,
                                    helptag.rjust(text_width - len(title)))
            docs += section_doc
            docs += '\n\n\n'

        docs = docs.rstrip() + '\n\n'
        docs += ' vim:tw=78:ts=8:ft=help:norl:\n'

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

        delete_lines_below(doc_file, CONFIG[mode]['section_start_token'])
        with open(doc_file, 'ab') as fp:
            fp.write(docs.encode('utf8'))

        with open(mpack_file, 'wb') as fp:
            fp.write(msgpack.packb(doc_maps, use_bin_type=True))

        shutil.rmtree(output_dir)


def filter_source(filename):
    name, extension = os.path.splitext(filename)
    if extension == '.lua':
        p = subprocess.run([lua2dox_filter, filename], 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))


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/*
    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__":
    if len(sys.argv) > 1:
        filter_source(sys.argv[1])
    else:
        gen_docs(Doxyfile)

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