#    (C) Copyright 2015-2017 Sei Lisa. All rights reserved.
#
#    This file is part of LSL PyOptimizer.
#
#    LSL PyOptimizer is free software: you can redistribute it and/or
#    modify it under the terms of the GNU General Public License as
#    published by the Free Software Foundation, either version 3 of the
#    License, or (at your option) any later version.
#
#    LSL PyOptimizer is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with LSL PyOptimizer. If not, see <http://www.gnu.org/licenses/>.

# Optimizer class that wraps and calls the other parts.

import lslfuncs

from lslfoldconst import foldconst
from lslrenamer import renamer
from lsldeadcode import deadcode

class optimizer(foldconst, renamer, deadcode):

    # Default values per type when declaring variables
    DefaultValues = {'integer': 0, 'float': 0.0, 'string': u'',
        'key': lslfuncs.Key(u''), 'vector': lslfuncs.ZERO_VECTOR,
        'rotation': lslfuncs.ZERO_ROTATION, 'list': []
        }

    # explicitly exclude assignments
    binary_ops = frozenset(('+','-','*','/','%','<<','>>','<','<=','>','>=',
        '==','!=','|','^','&','||','&&'))
    assign_ops = frozenset(('=','+=','-=','*=','/=','%=','&=','|=','^=','<<=','>>='))

    def Cast(self, value, newtype):
        """Return a CAST node if the types are not equal, otherwise the
        value unchanged.
        """
        if value['t'] == newtype:
            return value
        ret = {'nt':'CAST', 't':newtype, 'ch':[value]}
        if 'SEF' in value:
            ret['SEF'] = True
        if 'X' in value:
            ret['X'] = value['X']
        return ret

    def optimize(self, treesymtab, options = ('optimize','constfold','dcr',
                 'warntabs')):
        """Optimize the symbolic table symtab in place. Requires a table of
        predefined functions for folding constants.
        """
        if 'optimize' not in options:
            return treesymtab

        # Don't perform "a"+"b"  ->  "ab" unless explicitly requested.
        self.addstrings = 'addstrings' in options

        self.foldtabs = 'foldtabs' in options
        self.warntabs = 'warntabs' in options

        self.shrinknames = 'shrinknames' in options

        self.constfold = 'constfold' in options
        self.optlistlength = 'listlength' in options
        self.dcr = 'dcr' in options

        # Math that works fine except in rare corner-cases can be optimized.
        self.cornermath = 'cornermath' in options

        tree, symtab = self.tree, self.symtab = treesymtab

        self.globalmode = False

        if self.dcr:
            if self.constfold:
                self.FoldScript(warningpass=False)

            self.RemoveDeadCode()

        # Make another fold pass, since RemoveDeadCode can embed expressions
        # into other expressions and generate unoptimized code.
        # Or make the first pass here if DCR is disabled.
        if self.constfold:
            self.FoldScript(warningpass=True)

        if self.shrinknames:
            self.ShrinkNames()

        treesymtab = (self.tree, self.symtab)
        del self.tree
        del self.symtab
        return treesymtab