""" @package antlr3.tree
@brief ANTLR3 runtime package, treewizard module

A utility module to create ASTs at runtime.
See <http://www.antlr.org/wiki/display/~admin/2007/07/02/Exploring+Concept+of+TreeWizard> for an overview. Note that the API of the Python implementation is slightly different.

"""

# begin[licence]
#
# [The "BSD licence"]
# Copyright (c) 2005-2008 Terence Parr
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from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from antlr3.constants import INVALID_TOKEN_TYPE
from antlr3.tokens import CommonToken
from antlr3.tree import CommonTree, CommonTreeAdaptor
import six
from six.moves import range


def computeTokenTypes(tokenNames):
  """
    Compute a dict that is an inverted index of
    tokenNames (which maps int token types to names).
    """

  if tokenNames is None:
    return {}

  return dict((name, type) for type, name in enumerate(tokenNames))


## token types for pattern parser
EOF = -1
BEGIN = 1
END = 2
ID = 3
ARG = 4
PERCENT = 5
COLON = 6
DOT = 7

class TreePatternLexer(object):

  def __init__(self, pattern):
    ## The tree pattern to lex like "(A B C)"
    self.pattern = pattern

    ## Index into input string
    self.p = -1

    ## Current char
    self.c = None

    ## How long is the pattern in char?
    self.n = len(pattern)

    ## Set when token type is ID or ARG
    self.sval = None

    self.error = False

    self.consume()

  __idStartChar = frozenset(
      'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_')
  __idChar = __idStartChar | frozenset('0123456789')

  def nextToken(self):
    self.sval = ''
    while self.c != EOF:
      if self.c in (' ', '\n', '\r', '\t'):
        self.consume()
        continue

      if self.c in self.__idStartChar:
        self.sval += self.c
        self.consume()
        while self.c in self.__idChar:
          self.sval += self.c
          self.consume()

        return ID

      if self.c == '(':
        self.consume()
        return BEGIN

      if self.c == ')':
        self.consume()
        return END

      if self.c == '%':
        self.consume()
        return PERCENT

      if self.c == ':':
        self.consume()
        return COLON

      if self.c == '.':
        self.consume()
        return DOT

      if self.c == '[':  # grab [x] as a string, returning x
        self.consume()
        while self.c != ']':
          if self.c == '\\':
            self.consume()
            if self.c != ']':
              self.sval += '\\'

            self.sval += self.c

          else:
            self.sval += self.c

          self.consume()

        self.consume()
        return ARG

      self.consume()
      self.error = True
      return EOF

    return EOF

  def consume(self):
    self.p += 1
    if self.p >= self.n:
      self.c = EOF

    else:
      self.c = self.pattern[self.p]


class TreePatternParser(object):

  def __init__(self, tokenizer, wizard, adaptor):
    self.tokenizer = tokenizer
    self.wizard = wizard
    self.adaptor = adaptor
    self.ttype = tokenizer.nextToken()  # kickstart

  def pattern(self):
    if self.ttype == BEGIN:
      return self.parseTree()

    elif self.ttype == ID:
      node = self.parseNode()
      if self.ttype == EOF:
        return node

      return None  # extra junk on end

    return None

  def parseTree(self):
    if self.ttype != BEGIN:
      return None

    self.ttype = self.tokenizer.nextToken()
    root = self.parseNode()
    if root is None:
      return None

    while self.ttype in (BEGIN, ID, PERCENT, DOT):
      if self.ttype == BEGIN:
        subtree = self.parseTree()
        self.adaptor.addChild(root, subtree)

      else:
        child = self.parseNode()
        if child is None:
          return None

        self.adaptor.addChild(root, child)

    if self.ttype != END:
      return None

    self.ttype = self.tokenizer.nextToken()
    return root

  def parseNode(self):
    # "%label:" prefix
    label = None

    if self.ttype == PERCENT:
      self.ttype = self.tokenizer.nextToken()
      if self.ttype != ID:
        return None

      label = self.tokenizer.sval
      self.ttype = self.tokenizer.nextToken()
      if self.ttype != COLON:
        return None

      self.ttype = self.tokenizer.nextToken()  # move to ID following colon

    # Wildcard?
    if self.ttype == DOT:
      self.ttype = self.tokenizer.nextToken()
      wildcardPayload = CommonToken(0, '.')
      node = WildcardTreePattern(wildcardPayload)
      if label is not None:
        node.label = label
      return node

    # "ID" or "ID[arg]"
    if self.ttype != ID:
      return None

    tokenName = self.tokenizer.sval
    self.ttype = self.tokenizer.nextToken()

    if tokenName == 'nil':
      return self.adaptor.nil()

    text = tokenName
    # check for arg
    arg = None
    if self.ttype == ARG:
      arg = self.tokenizer.sval
      text = arg
      self.ttype = self.tokenizer.nextToken()

    # create node
    treeNodeType = self.wizard.getTokenType(tokenName)
    if treeNodeType == INVALID_TOKEN_TYPE:
      return None

    node = self.adaptor.createFromType(treeNodeType, text)
    if label is not None and isinstance(node, TreePattern):
      node.label = label

    if arg is not None and isinstance(node, TreePattern):
      node.hasTextArg = True

    return node


class TreePattern(CommonTree):
  """
    When using %label:TOKENNAME in a tree for parse(), we must
    track the label.
    """

  def __init__(self, payload):
    CommonTree.__init__(self, payload)

    self.label = None
    self.hasTextArg = None

  def toString(self):
    if self.label is not None:
      return '%' + self.label + ':' + CommonTree.toString(self)

    else:
      return CommonTree.toString(self)


class WildcardTreePattern(TreePattern):
  pass


class TreePatternTreeAdaptor(CommonTreeAdaptor):
  """This adaptor creates TreePattern objects for use during scan()"""

  def createWithPayload(self, payload):
    return TreePattern(payload)


class TreeWizard(object):
  """
    Build and navigate trees with this object.  Must know about the names
    of tokens so you have to pass in a map or array of token names (from which
    this class can build the map).  I.e., Token DECL means nothing unless the
    class can translate it to a token type.

    In order to create nodes and navigate, this class needs a TreeAdaptor.

    This class can build a token type -> node index for repeated use or for
    iterating over the various nodes with a particular type.

    This class works in conjunction with the TreeAdaptor rather than moving
    all this functionality into the adaptor.  An adaptor helps build and
    navigate trees using methods.  This class helps you do it with string
    patterns like "(A B C)".  You can create a tree from that pattern or
    match subtrees against it.
    """

  def __init__(self, adaptor=None, tokenNames=None, typeMap=None):
    self.adaptor = adaptor
    if typeMap is None:
      self.tokenNameToTypeMap = computeTokenTypes(tokenNames)

    else:
      if tokenNames is not None:
        raise ValueError("Can't have both tokenNames and typeMap")

      self.tokenNameToTypeMap = typeMap

  def getTokenType(self, tokenName):
    """Using the map of token names to token types, return the type."""

    try:
      return self.tokenNameToTypeMap[tokenName]
    except KeyError:
      return INVALID_TOKEN_TYPE

  def create(self, pattern):
    """
        Create a tree or node from the indicated tree pattern that closely
        follows ANTLR tree grammar tree element syntax:

        (root child1 ... child2).

        You can also just pass in a node: ID

        Any node can have a text argument: ID[foo]
        (notice there are no quotes around foo--it's clear it's a string).

        nil is a special name meaning "give me a nil node".  Useful for
        making lists: (nil A B C) is a list of A B C.
        """

    tokenizer = TreePatternLexer(pattern)
    parser = TreePatternParser(tokenizer, self, self.adaptor)
    return parser.pattern()

  def index(self, tree):
    """Walk the entire tree and make a node name to nodes mapping.

        For now, use recursion but later nonrecursive version may be
        more efficient.  Returns a dict int -> list where the list is
        of your AST node type.  The int is the token type of the node.
        """

    m = {}
    self._index(tree, m)
    return m

  def _index(self, t, m):
    """Do the work for index"""

    if t is None:
      return

    ttype = self.adaptor.getType(t)
    elements = m.get(ttype)
    if elements is None:
      m[ttype] = elements = []

    elements.append(t)
    for i in range(self.adaptor.getChildCount(t)):
      child = self.adaptor.getChild(t, i)
      self._index(child, m)

  def find(self, tree, what):
    """Return a list of matching token.

        what may either be an integer specifzing the token type to find or
        a string with a pattern that must be matched.

        """

    if isinstance(what, six.integer_types):
      return self._findTokenType(tree, what)

    elif isinstance(what, six.string_types):
      return self._findPattern(tree, what)

    else:
      raise TypeError("'what' must be string or integer")

  def _findTokenType(self, t, ttype):
    """Return a List of tree nodes with token type ttype"""

    nodes = []

    def visitor(tree, parent, childIndex, labels):
      nodes.append(tree)

    self.visit(t, ttype, visitor)

    return nodes

  def _findPattern(self, t, pattern):
    """Return a List of subtrees matching pattern."""

    subtrees = []

    # Create a TreePattern from the pattern
    tokenizer = TreePatternLexer(pattern)
    parser = TreePatternParser(tokenizer, self, TreePatternTreeAdaptor())
    tpattern = parser.pattern()

    # don't allow invalid patterns
    if (tpattern is None or tpattern.isNil() or
        isinstance(tpattern, WildcardTreePattern)):
      return None

    rootTokenType = tpattern.getType()

    def visitor(tree, parent, childIndex, label):
      if self._parse(tree, tpattern, None):
        subtrees.append(tree)

    self.visit(t, rootTokenType, visitor)

    return subtrees

  def visit(self, tree, what, visitor):
    """Visit every node in tree matching what, invoking the visitor.

        If what is a string, it is parsed as a pattern and only matching
        subtrees will be visited.
        The implementation uses the root node of the pattern in combination
        with visit(t, ttype, visitor) so nil-rooted patterns are not allowed.
        Patterns with wildcard roots are also not allowed.

        If what is an integer, it is used as a token type and visit will match
        all nodes of that type (this is faster than the pattern match).
        The labels arg of the visitor action method is never set (it's None)
        since using a token type rather than a pattern doesn't let us set a
        label.
        """

    if isinstance(what, six.integer_types):
      self._visitType(tree, None, 0, what, visitor)

    elif isinstance(what, six.string_types):
      self._visitPattern(tree, what, visitor)

    else:
      raise TypeError("'what' must be string or integer")

  def _visitType(self, t, parent, childIndex, ttype, visitor):
    """Do the recursive work for visit"""

    if t is None:
      return

    if self.adaptor.getType(t) == ttype:
      visitor(t, parent, childIndex, None)

    for i in range(self.adaptor.getChildCount(t)):
      child = self.adaptor.getChild(t, i)
      self._visitType(child, t, i, ttype, visitor)

  def _visitPattern(self, tree, pattern, visitor):
    """
        For all subtrees that match the pattern, execute the visit action.
        """

    # Create a TreePattern from the pattern
    tokenizer = TreePatternLexer(pattern)
    parser = TreePatternParser(tokenizer, self, TreePatternTreeAdaptor())
    tpattern = parser.pattern()

    # don't allow invalid patterns
    if (tpattern is None or tpattern.isNil() or
        isinstance(tpattern, WildcardTreePattern)):
      return

    rootTokenType = tpattern.getType()

    def rootvisitor(tree, parent, childIndex, labels):
      labels = {}
      if self._parse(tree, tpattern, labels):
        visitor(tree, parent, childIndex, labels)

    self.visit(tree, rootTokenType, rootvisitor)

  def parse(self, t, pattern, labels=None):
    """
        Given a pattern like (ASSIGN %lhs:ID %rhs:.) with optional labels
        on the various nodes and '.' (dot) as the node/subtree wildcard,
        return true if the pattern matches and fill the labels Map with
        the labels pointing at the appropriate nodes.  Return false if
        the pattern is malformed or the tree does not match.

        If a node specifies a text arg in pattern, then that must match
        for that node in t.
        """

    tokenizer = TreePatternLexer(pattern)
    parser = TreePatternParser(tokenizer, self, TreePatternTreeAdaptor())
    tpattern = parser.pattern()

    return self._parse(t, tpattern, labels)

  def _parse(self, t1, t2, labels):
    """
        Do the work for parse. Check to see if the t2 pattern fits the
        structure and token types in t1.  Check text if the pattern has
        text arguments on nodes.  Fill labels map with pointers to nodes
        in tree matched against nodes in pattern with labels.
        """

    # make sure both are non-null
    if t1 is None or t2 is None:
      return False

    # check roots (wildcard matches anything)
    if not isinstance(t2, WildcardTreePattern):
      if self.adaptor.getType(t1) != t2.getType():
        return False

      if t2.hasTextArg and self.adaptor.getText(t1) != t2.getText():
        return False

    if t2.label is not None and labels is not None:
      # map label in pattern to node in t1
      labels[t2.label] = t1

    # check children
    n1 = self.adaptor.getChildCount(t1)
    n2 = t2.getChildCount()
    if n1 != n2:
      return False

    for i in range(n1):
      child1 = self.adaptor.getChild(t1, i)
      child2 = t2.getChild(i)
      if not self._parse(child1, child2, labels):
        return False

    return True

  def equals(self, t1, t2, adaptor=None):
    """
        Compare t1 and t2; return true if token types/text, structure match
        exactly.
        The trees are examined in their entirety so that (A B) does not match
        (A B C) nor (A (B C)).
        """

    if adaptor is None:
      adaptor = self.adaptor

    return self._equals(t1, t2, adaptor)

  def _equals(self, t1, t2, adaptor):
    # make sure both are non-null
    if t1 is None or t2 is None:
      return False

    # check roots
    if adaptor.getType(t1) != adaptor.getType(t2):
      return False

    if adaptor.getText(t1) != adaptor.getText(t2):
      return False

    # check children
    n1 = adaptor.getChildCount(t1)
    n2 = adaptor.getChildCount(t2)
    if n1 != n2:
      return False

    for i in range(n1):
      child1 = adaptor.getChild(t1, i)
      child2 = adaptor.getChild(t2, i)
      if not self._equals(child1, child2, adaptor):
        return False

    return True