#!/usr/bin/env python
# QAPI texi generator
#
# This work is licensed under the terms of the GNU LGPL, version 2+.
# See the COPYING file in the top-level directory.
"""This script produces the documentation of a qapi schema in texinfo format"""
import re
import sys

import qapi

MSG_FMT = """
@deftypefn {type} {{}} {name}

{body}

@end deftypefn

""".format

TYPE_FMT = """
@deftp {{{type}}} {name}

{body}

@end deftp

""".format

EXAMPLE_FMT = """@example
{code}
@end example
""".format


def subst_strong(doc):
    """Replaces *foo* by @strong{foo}"""
    return re.sub(r'\*([^*\n]+)\*', r'@emph{\1}', doc)


def subst_emph(doc):
    """Replaces _foo_ by @emph{foo}"""
    return re.sub(r'\b_([^_\n]+)_\b', r' @emph{\1} ', doc)


def subst_vars(doc):
    """Replaces @var by @code{var}"""
    return re.sub(r'@([\w-]+)', r'@code{\1}', doc)


def subst_braces(doc):
    """Replaces {} with @{ @}"""
    return doc.replace('{', '@{').replace('}', '@}')


def texi_example(doc):
    """Format @example"""
    # TODO: Neglects to escape @ characters.
    # We should probably escape them in subst_braces(), and rename the
    # function to subst_special() or subs_texi_special().  If we do that, we
    # need to delay it until after subst_vars() in texi_format().
    doc = subst_braces(doc).strip('\n')
    return EXAMPLE_FMT(code=doc)


def texi_format(doc):
    """
    Format documentation

    Lines starting with:
    - |: generates an @example
    - =: generates @section
    - ==: generates @subsection
    - 1. or 1): generates an @enumerate @item
    - */-: generates an @itemize list
    """
    lines = []
    doc = subst_braces(doc)
    doc = subst_vars(doc)
    doc = subst_emph(doc)
    doc = subst_strong(doc)
    inlist = ''
    lastempty = False
    for line in doc.split('\n'):
        empty = line == ''

        # FIXME: Doing this in a single if / elif chain is
        # problematic.  For instance, a line without markup terminates
        # a list if it follows a blank line (reaches the final elif),
        # but a line with some *other* markup, such as a = title
        # doesn't.
        #
        # Make sure to update section "Documentation markup" in
        # docs/qapi-code-gen.txt when fixing this.
        if line.startswith('| '):
            line = EXAMPLE_FMT(code=line[2:])
        elif line.startswith('= '):
            line = '@section ' + line[2:]
        elif line.startswith('== '):
            line = '@subsection ' + line[3:]
        elif re.match(r'^([0-9]*\.) ', line):
            if not inlist:
                lines.append('@enumerate')
                inlist = 'enumerate'
            line = line[line.find(' ')+1:]
            lines.append('@item')
        elif re.match(r'^[*-] ', line):
            if not inlist:
                lines.append('@itemize %s' % {'*': '@bullet',
                                              '-': '@minus'}[line[0]])
                inlist = 'itemize'
            lines.append('@item')
            line = line[2:]
        elif lastempty and inlist:
            lines.append('@end %s\n' % inlist)
            inlist = ''

        lastempty = empty
        lines.append(line)

    if inlist:
        lines.append('@end %s\n' % inlist)
    return '\n'.join(lines)


def texi_body(doc):
    """Format the main documentation body"""
    return texi_format(str(doc.body)) + '\n'


def texi_enum_value(value):
    """Format a table of members item for an enumeration value"""
    return '@item @code{%s}\n' % value.name


def texi_member(member):
    """Format a table of members item for an object type member"""
    return '@item @code{%s}%s\n' % (
        member.name, ' (optional)' if member.optional else '')


def texi_members(doc, what, member_func, show_undocumented):
    """Format the table of members"""
    items = ''
    for section in doc.args.itervalues():
        if not section.content and not show_undocumented:
            continue          # Undocumented TODO require doc and drop
        if section.content:
            desc = str(section)
        else:
            desc = 'Not documented'
        items += member_func(section.member) + texi_format(desc) + '\n'
    if not items:
        return ''
    return '\n@b{%s:}\n@table @asis\n%s@end table\n' % (what, items)


def texi_sections(doc):
    """Format additional sections following arguments"""
    body = ''
    for section in doc.sections:
        name, doc = (section.name, str(section))
        func = texi_format
        if name.startswith('Example'):
            func = texi_example

        if name:
            # prefer @b over @strong, so txt doesn't translate it to *Foo:*
            body += '\n\n@b{%s:}\n' % name

        body += func(doc)
    return body


def texi_entity(doc, what, member_func=texi_member,
                show_undocumented=False):
    return (texi_body(doc)
            + texi_members(doc, what, member_func, show_undocumented)
            + texi_sections(doc))


class QAPISchemaGenDocVisitor(qapi.QAPISchemaVisitor):
    def __init__(self):
        self.out = None
        self.cur_doc = None

    def visit_begin(self, schema):
        self.out = ''

    def visit_enum_type(self, name, info, values, prefix):
        doc = self.cur_doc
        if self.out:
            self.out += '\n'
        self.out += TYPE_FMT(type='Enum',
                             name=doc.symbol,
                             body=texi_entity(doc, 'Values',
                                              member_func=texi_enum_value,
                                              show_undocumented=True))

    def visit_object_type(self, name, info, base, members, variants):
        doc = self.cur_doc
        if not variants:
            typ = 'Struct'
        elif variants._tag_name:        # TODO unclean member access
            typ = 'Flat Union'
        else:
            typ = 'Simple Union'
        if self.out:
            self.out += '\n'
        self.out += TYPE_FMT(type=typ,
                             name=doc.symbol,
                             body=texi_entity(doc, 'Members'))

    def visit_alternate_type(self, name, info, variants):
        doc = self.cur_doc
        if self.out:
            self.out += '\n'
        self.out += TYPE_FMT(type='Alternate',
                             name=doc.symbol,
                             body=texi_entity(doc, 'Members'))

    def visit_command(self, name, info, arg_type, ret_type,
                      gen, success_response, boxed):
        doc = self.cur_doc
        if self.out:
            self.out += '\n'
        self.out += MSG_FMT(type='Command',
                            name=doc.symbol,
                            body=texi_entity(doc, 'Arguments'))

    def visit_event(self, name, info, arg_type, boxed):
        doc = self.cur_doc
        if self.out:
            self.out += '\n'
        self.out += MSG_FMT(type='Event',
                            name=doc.symbol,
                            body=texi_entity(doc, 'Arguments'))

    def symbol(self, doc, entity):
        self.cur_doc = doc
        entity.visit(self)
        self.cur_doc = None

    def freeform(self, doc):
        assert not doc.args
        if self.out:
            self.out += '\n'
        self.out += texi_body(doc) + texi_sections(doc)


def texi_schema(schema):
    """Convert QAPI schema documentation to Texinfo"""
    gen = QAPISchemaGenDocVisitor()
    gen.visit_begin(schema)
    for doc in schema.docs:
        if doc.symbol:
            gen.symbol(doc, schema.lookup_entity(doc.symbol))
        else:
            gen.freeform(doc)
    return gen.out


def main(argv):
    """Takes schema argument, prints result to stdout"""
    if len(argv) != 2:
        print >>sys.stderr, "%s: need exactly 1 argument: SCHEMA" % argv[0]
        sys.exit(1)

    schema = qapi.QAPISchema(argv[1])
    if not qapi.doc_required:
        print >>sys.stderr, ("%s: need pragma 'doc-required' "
                             "to generate documentation" % argv[0])
    print texi_schema(schema)


if __name__ == '__main__':
    main(sys.argv)