# -*- coding: utf-8 -*-

# Copyright (c) 2017 - 2019 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Parse a ProtoBuf protocol file and retrieve messages, enums, services and
rpc methods.

It is based on the Python class browser found in this package.
"""


import re

import Utilities
import Utilities.ClassBrowsers as ClassBrowsers
from . import ClbrBaseClasses

SUPPORTED_TYPES = [ClassBrowsers.PROTO_SOURCE]
    
_getnext = re.compile(
    r"""
    (?P<String>
        " [^"\\\n]* (?: \\. [^"\\\n]*)* "
    )

|   (?P<Comment>
        ^ [ \t]* // .*? $
    |
        ^ [ \t]* /\* .*? \*/
    )

|   (?P<Message>
        ^
        (?P<MessageIndent> [ \t]* )
        message [ \t]+
        (?P<MessageName> [a-zA-Z_] [a-zA-Z0-9_]* )
        [ \t]* {
    )

|   (?P<Enum>
        ^
        (?P<EnumIndent> [ \t]* )
        enum [ \t]+
        (?P<EnumName> [a-zA-Z_] [a-zA-Z0-9_]* )
        [ \t]* {
    )

|   (?P<Service>
        ^
        (?P<ServiceIndent> [ \t]* )
        service [ \t]+
        (?P<ServiceName> [a-zA-Z_] [a-zA-Z0-9_]* )
        [ \t]* {
    )

|   (?P<Method>
        ^
        (?P<MethodIndent> [ \t]* )
        rpc [ \t]+
        (?P<MethodName> [a-zA-Z_] [a-zA-Z0-9_]* )
        [ \t]*
        \(
        (?P<MethodSignature> [^)]+? )
        \)
        [ \t]+
        returns
        [ \t]*
        \(
        (?P<MethodReturn> [^)]+? )
        \)
        [ \t]*
    )

|   (?P<Begin>
        [ \t]* {
    )

|   (?P<End>
        [ \t]* } [ \t]* ;?
    )""",
    re.VERBOSE | re.DOTALL | re.MULTILINE).search

# function to replace comments
_commentsub = re.compile(r"""//[^\n]*\n|//[^\n]*$""").sub
# function to normalize whitespace
_normalize = re.compile(r"""[ \t]{2,}""").sub

_modules = {}                           # cache of modules we've seen


class VisibilityMixin(ClbrBaseClasses.ClbrVisibilityMixinBase):
    """
    Mixin class implementing the notion of visibility.
    """
    def __init__(self):
        """
        Constructor
        """
        self.setPublic()


class Message(ClbrBaseClasses.Module, VisibilityMixin):
    """
    Class to represent a ProtoBuf Message.
    """
    def __init__(self, module, name, file, lineno):
        """
        Constructor
        
        @param module name of the module containing this message
        @type str
        @param name name of this message
        @type str
        @param file filename containing this message
        @type str
        @param lineno linenumber of the message definition
        @type int
        """
        ClbrBaseClasses.Module.__init__(self, module, name, file, lineno)
        VisibilityMixin.__init__(self)


class Enum(ClbrBaseClasses.Enum, VisibilityMixin):
    """
    Class to represent a ProtoBuf Enum.
    """
    def __init__(self, module, name, file, lineno):
        """
        Constructor
        
        @param module name of the module containing this enum
        @type str
        @param name name of this enum
        @type str
        @param file filename containing this enum
        @type str
        @param lineno linenumber of the message enum
        @type int
        """
        ClbrBaseClasses.Enum.__init__(self, module, name, file, lineno)
        VisibilityMixin.__init__(self)


class Service(ClbrBaseClasses.Class, VisibilityMixin):
    """
    Class to represent a ProtoBuf Service.
    """
    def __init__(self, module, name, file, lineno):
        """
        Constructor
        
        @param module name of the module containing this service
        @type str
        @param name name of this service
        @type str
        @param file filename containing this service
        @type str
        @param lineno linenumber of the service definition
        @type int
        """
        ClbrBaseClasses.Class.__init__(self, module, name, None, file,
                                       lineno)
        VisibilityMixin.__init__(self)


class ServiceMethod(ClbrBaseClasses.Function, VisibilityMixin):
    """
    Class to represent a ProtoBuf Service Method.
    """
    def __init__(self, name, file, lineno, signature, returns):
        """
        Constructor
        
        @param name name of this service method
        @type str
        @param file filename containing this service method
        @type str
        @param lineno linenumber of the service method definition
        @type int
        @param signature parameter list of the service method
        @type str
        @param returns return type of the service method
        @type str
        """
        ClbrBaseClasses.Function.__init__(self, None, name, file, lineno,
                                          signature,
                                          annotation="-> {0}".format(returns))
        VisibilityMixin.__init__(self)


def readmodule_ex(module, path=None):
    """
    Read a ProtoBuf protocol file and return a dictionary of messages, enums,
    services and rpc methods.

    @param module name of the ProtoBuf protocol file
    @type str
    @param path path the file should be searched in
    @type list of str
    @return the resulting dictionary
    @rtype dict
    """
    global _modules
    
    dictionary = {}

    if module in _modules:
        # we've seen this file before...
        return _modules[module]

    # search the path for the file
    f = None
    fullpath = [] if path is None else path[:]
    f, file, (suff, mode, type) = ClassBrowsers.find_module(module, fullpath)
    if f:
        f.close()
    if type not in SUPPORTED_TYPES:
        # not ProtoBuf protocol source, can't do anything with this module
        _modules[module] = dictionary
        return dictionary

    _modules[module] = dictionary
    classstack = []  # stack of (class, indent) pairs
    indent = 0
    try:
        src = Utilities.readEncodedFile(file)[0]
    except (UnicodeError, IOError):
        # can't do anything with this module
        _modules[module] = dictionary
        return dictionary

    lineno, last_lineno_pos = 1, 0
    lastGlobalEntry = None
    cur_obj = None
    i = 0
    while True:
        m = _getnext(src, i)
        if not m:
            break
        start, i = m.span()

        if m.start("Method") >= 0:
            # found a method definition or function
            thisindent = indent
            meth_name = m.group("MethodName")
            meth_sig = m.group("MethodSignature")
            meth_sig = meth_sig and meth_sig.replace('\\\n', '') or ''
            meth_sig = _commentsub('', meth_sig)
            meth_sig = _normalize(' ', meth_sig)
            meth_return = m.group("MethodReturn")
            meth_return = meth_return and meth_return.replace('\\\n', '') or ''
            meth_return = _commentsub('', meth_return)
            meth_return = _normalize(' ', meth_return)
            lineno = lineno + src.count('\n', last_lineno_pos, start)
            last_lineno_pos = start
            # close all interfaces/modules indented at least as much
            while classstack and classstack[-1][1] >= thisindent:
                if classstack[-1][0] is not None:
                    # record the end line
                    classstack[-1][0].setEndLine(lineno - 1)
                del classstack[-1]
            if classstack:
                # it's an interface/module method
                cur_class = classstack[-1][0]
                if isinstance(cur_class, Service):
                    # it's a method
                    f = ServiceMethod(meth_name, file, lineno, meth_sig,
                                      meth_return)
                    cur_class._addmethod(meth_name, f)
                # else it's a nested def
                else:
                    f = None
            else:
                # the file is incorrect, ignore the entry
                continue
            if not classstack:
                if lastGlobalEntry:
                    lastGlobalEntry.setEndLine(lineno - 1)
                lastGlobalEntry = f
            if cur_obj and isinstance(cur_obj, ServiceMethod):
                cur_obj.setEndLine(lineno - 1)
            cur_obj = f
            classstack.append((f, thisindent))  # Marker for nested fns

        elif m.start("String") >= 0:
            pass

        elif m.start("Comment") >= 0:
            pass

        elif m.start("Message") >= 0:
            # we found a message definition
            thisindent = indent
            indent += 1
            # close all messages/services indented at least as much
            while classstack and classstack[-1][1] >= thisindent:
                if classstack[-1][0] is not None:
                    # record the end line
                    classstack[-1][0].setEndLine(lineno - 1)
                del classstack[-1]
            lineno = lineno + src.count('\n', last_lineno_pos, start)
            last_lineno_pos = start
            message_name = m.group("MessageName")
            # remember this message
            cur_class = Message(module, message_name, file, lineno)
            if not classstack:
                dictionary[message_name] = cur_class
            else:
                msg = classstack[-1][0]
                msg._addclass(message_name, cur_class)
            if not classstack:
                if lastGlobalEntry:
                    lastGlobalEntry.setEndLine(lineno - 1)
                lastGlobalEntry = cur_class
            cur_obj = cur_class
            classstack.append((cur_class, thisindent))

        elif m.start("Enum") >= 0:
            # we found a message definition
            thisindent = indent
            indent += 1
            # close all messages/services indented at least as much
            while classstack and classstack[-1][1] >= thisindent:
                if classstack[-1][0] is not None:
                    # record the end line
                    classstack[-1][0].setEndLine(lineno - 1)
                del classstack[-1]
            lineno = lineno + src.count('\n', last_lineno_pos, start)
            last_lineno_pos = start
            enum_name = m.group("EnumName")
            # remember this Enum
            cur_class = Enum(module, enum_name, file, lineno)
            if not classstack:
                dictionary[enum_name] = cur_class
            else:
                enum = classstack[-1][0]
                enum._addclass(enum_name, cur_class)
            if not classstack:
                if lastGlobalEntry:
                    lastGlobalEntry.setEndLine(lineno - 1)
                lastGlobalEntry = cur_class
            cur_obj = cur_class
            classstack.append((cur_class, thisindent))

        elif m.start("Service") >= 0:
            # we found a message definition
            thisindent = indent
            indent += 1
            # close all messages/services indented at least as much
            while classstack and classstack[-1][1] >= thisindent:
                if classstack[-1][0] is not None:
                    # record the end line
                    classstack[-1][0].setEndLine(lineno - 1)
                del classstack[-1]
            lineno = lineno + src.count('\n', last_lineno_pos, start)
            last_lineno_pos = start
            service_name = m.group("ServiceName")
            # remember this Service
            cur_class = Service(module, service_name, file, lineno)
            if not classstack:
                dictionary[service_name] = cur_class
            else:
                service = classstack[-1][0]
                service._addclass(service_name, cur_class)
            if not classstack:
                if lastGlobalEntry:
                    lastGlobalEntry.setEndLine(lineno - 1)
                lastGlobalEntry = cur_class
            cur_obj = cur_class
            classstack.append((cur_class, thisindent))

        elif m.start("Begin") >= 0:
            # a begin of a block we are not interested in
            indent += 1

        elif m.start("End") >= 0:
            # an end of a block
            indent -= 1

        else:
            assert 0, "regexp _getnext found something unexpected"

    return dictionary
