#!/usr/bin/env python2

from __future__ import absolute_import
from __future__ import print_function

import inspect
import os
import sys
import textwrap

def _modify_path():
    message_buffers_path = os.path.join(os.path.dirname(__file__), '..', 'victor-clad', 'tools', 'message-buffers')
    if message_buffers_path not in sys.path:
        sys.path.insert(0, message_buffers_path)

_modify_path()

from clad import ast
from clad import clad
from emitters import CPP_emitter

class UnionSwitchEmitter(ast.NodeVisitor):
    "An emitter that generates the handler switch statement."
    
    CPPLite = False
    groupSwitchPrefix = None
    groupedSwitchMembers = []
    
    def __init__(self, output=sys.stdout, include_extension=None):
        self.output = output
    
    def visit_UnionDecl(self, node):
        globals = dict(
            union_name=node.name,
            qualified_union_name=node.fully_qualified_name(),
        )
        
        self.writeHeader(node, globals)
        self.writeMemberCases(node, globals)
        self.writeFooter(node, globals)
        
    def writeHeader(self, node, globals):
        self.output.write(textwrap.dedent('''\
        switch(msg.{tagAccessor}) {{
        default:
        \tProcessBadTag_{union_name}(msg.{tagAccessor});
        \tbreak;
        ''').format(tagAccessor = 'tag' if self.CPPLite else 'GetTag()', **globals))

    
    def writeFooter(self, node, globals):
        if self.groupedSwitchMembers:
            for member in self.groupedSwitchMembers:
                self.output.write('case {member_tag}:\n'.format(member_tag=member.tag))
            self.output.write('\tProcess_{group_prefix}(msg);\n\tbreak;\n'.format(group_prefix=self.groupSwitchPrefix))
        self.output.write('}\n')
        
    def writeMemberCases(self, node, globals):
        for member in node.members():
            if self.groupSwitchPrefix is not None and member.name.startswith(self.groupSwitchPrefix):
                self.groupedSwitchMembers.append(member)
            elif self.CPPLite:
                self.output.write(textwrap.dedent('''\
                    case {member_tag}:
                    \tProcess_{member_name}(msg.{member_name});
                    \tbreak;
                    ''').format(member_tag=member.tag, member_name=member.name, **globals))
            else:
                self.output.write(textwrap.dedent('''\
                    case {qualified_union_name}::Tag::{member_name}:
                    \tProcess_{member_name}(msg.Get_{member_name}());
                    \tbreak;
                    ''').format(member_name=member.name, **globals))

if __name__ == '__main__':
    from clad import emitterutil
    from emitters import CPP_emitter
    
    if 'CPPLite' in sys.argv[0]: # These should be arguments
        UnionSwitchEmitter.CPPLite = True
        UnionSwitchEmitter.groupSwitchPrefix = "anim"
    
    emitterutil.c_main(language='C++', extension='_switch.def',
        emitter_types=[UnionSwitchEmitter],
        use_inclusion_guards=False)