import re as re_mod
import abc as abc_mod
import collections as col_mod

INDENT = "    "
_NODES = []


class ListAdapter(col_mod.MutableSequence):
    def __init__(self, *args):
        self.items = []
        for arg in args:
            self.append(arg)
    def __len__(self): 
        return len(self.items)
    def __contains__(self, val): 
        return val in self.items
    def __iter__(self): 
        return iter(self.items)
    def __getitem__(self, index):
        return self.items[index]
    def __setitem__(self, index, val):
        self.items[index] = val
    def __delitem__(self, index):
        del self.items[index]
    def insert(self, index, val):
        self.items.insert(index, val)
    def __eq__(self, val):
        return self.items == val
    def __ne__(self, val):
        return self.items != val
    def __lt__(self, val):
        return self.items < val
    def __le__(self, val):
        return self.items <= val
    def __gt__(self, val):
        return self.items > val
    def __ge__(self, val):
        return self.items >= val
    def __repr__(self):
        return repr(self.items)


class ParserError(Exception): pass
class InvalidLineError(ParserError): pass
class NodeCompleteError(InvalidLineError): pass
class DirectiveError(ParserError): pass
class NestingLimitError(ParserError): pass
class NodeMatchError(ParserError): pass


class Node(object):
    """
    The apache parser node.

    """
    __metaclass__ = abc_mod.ABCMeta

    MATCH_RE = ".*"
    def __init__(self):
        self.lines = []
        self._content = None
        self._complete = False
        self.changed = False
    @property
    def complete(self):
        return self._complete
    @complete.setter
    def complete(self, val):
        self._complete = val
    @classmethod
    def match(cls, line):
        if line is None:
            return False
        return bool(re_mod.match(cls.MATCH_RE, line))
    @property
    def content(self):
        return "\n".join(self.lines)
    @property
    def stable(self):
        return True
    def add_line(self, line):
        if "\n" in line:
            raise InvalidLineError("Lines cannot contain newlines.")
        if self.complete:
            raise NodeCompleteError(line)
        self.lines.append(line)
        if not line.endswith("\\"):
            self.complete = True
    def __str__(self):
        if self.changed:
            return self.content or ""
        return "\n".join(self.lines)
    def pprint(self, depth=0):
        return "%s%s" % (INDENT*depth, str(self).lstrip())
    

class CommentNode(Node):
    """A comment."""
    MATCH_RE = r"\s*#(.*[^\\])?$"
    def add_line(self, line):
        if line.endswith("\\"):
            raise InvalidLineError("Comments cannot have line continuations.")
        super(CommentNode, self).add_line(line)
        self._content = line.split("#", 1)[1]
    def __str__(self):
        if not self.lines:
            raise NodeCompleteError("Can't turn an uninitialized comment node into a string.")
        if self.changed:
            return "#"+self._content
        return super(CommentNode, self).__str__()
_NODES.append(CommentNode)


class BlankNode(Node):
    """A blank line."""
    MATCH_RE = "\s*$"
    def add_line(self, line):
        if line.endswith("\\"):
            raise InvalidLineError("Blank lines cannot have line continuations.")
        super(BlankNode, self).add_line(line)
        self._content = ""
    def pprint(self, depth=0):
        return ""
_NODES.append(BlankNode)


class Directive(Node):
    """A configuration directive."""
    NAME_RE = "[a-zA-Z]\w*"

    def __init__(self):
        super(Directive, self).__init__()
        self._stable = False

    class Name(object):
        # cannot be changed once set
        def __get__(self, obj, cls):
            if not hasattr(obj, "_name"):
                raise NodeCompleteError("Name has not been set yet.")
            return obj._name
        def __set__(self, obj, value):
            if hasattr(obj, "_name") and obj._name is not None:
                raise DirectiveError("Name is already set.  Cannot set to %s" % value)
            if not re_mod.match(obj.NAME_RE, value):
                raise DirectiveError("Invalid name: %s" % value)
            obj._name = value
            obj._stable = True # name is the first thing in the line
    name = Name()

    class Arguments(object):
        def __get__(self, obj, cls):
            if not hasattr(obj, "_arguments"):
                class ValidatedArgs(ListAdapter):
                    """
                    Validate the addition, change, or removal of arguments.

                    """
                    def __setitem__(self, index, val):
                        #self.validate_general(val)
                        self.items[index] = val
                        if obj.complete:
                            obj.changed = True
                    def __delitem__(self, index):
                        del self.items[index]
                        if obj.complete:
                            obj.changed = True
                    def insert(self, index, val):
                        # append calls this
                        #self.validate_general(val)
                        self.items.insert(index, val)
                        if obj.complete:
                            obj.changed = True
                    def validate_general(self, val):
                        #if "<" in line or ">" in line:
                        #if re_mod.match("([^\"'<>]*('.*?'|\".*?\"))*[^<>]*$", line):
                        if not re_mod.match("'.*'$|\".*\"$", val) and ("<" in val or ">" in val):
                            raise DirectiveError("Angle brackets not allowed in directive args.  Received: %s" % val)
                obj._arguments = ValidatedArgs()
            return obj._arguments
    arguments = Arguments()

    def add_to_header(self, line):
        if self.complete:
            raise NodeCompleteError("Cannot add to the header of a complete directive.")
        if not line:
            raise DirectiveError("An empty line is not a valid header line.")
        stable = True
        if line[-1] == "\\":
            line = line[:-1]
            stable = False
        parts = line.strip().split()
        try:
            self.name
        except NodeCompleteError:
            self.name = parts[0]
            parts = parts[1:]
        for part in parts:
            self.arguments.append(part)
        self._stable = stable

    @abc_mod.abstractmethod
    def add_line(self, line):
        super(Directive, self).add_line(line)

    @property
    def stable(self):
        return self._stable

    @property
    def complete(self):
        return super(Directive, Directive).complete.fget(self)
    @complete.setter
    def complete(self, val):
        if val and not self.stable:
            raise NodeCompleteError("Can't set an unstable Directive to complete.")
        super(Directive, Directive).complete.fset(self, val)

    @property
    def content(self):
        name = self.name if not self.arguments else self.name + " "
        return "%s%s" % (name, " ".join(arg for arg in self.arguments))

    def __repr__(self):
        name = self.name or ""
        if name:
            name += " "
        return "<%sDirective at %s>" % (
                name,
                id(self),
                )
    def pprint(self, depth=0):
        return "%s%s %s" % (
                INDENT*depth, 
                self.name, 
                " ".join([arg for arg in self.arguments]),
                )


class SimpleDirective(Directive):
    MATCH_RE = r"\s*%s(\s+.*)*\s*[\\]?$" % Directive.NAME_RE
    def add_line(self, line):
        try:
            self.add_to_header(line)
        except DirectiveError as e:
            raise InvalidLineError(str(e))
        super(SimpleDirective, self).add_line(line)
    def __str__(self):
        if not self.lines:
            raise NodeCompleteError("Can't turn an uninitialized simple directive into a string.")
        return super(SimpleDirective, self).__str__()
_NODES.append(SimpleDirective)


class ComplexNode(Node):
    """
    A node that is composed of a list of other nodes.

    """
    NESTING_LIMIT = 10
    def __init__(self, candidates):
        super(ComplexNode, self).__init__()
        self.candidates = candidates

    class Nodes(object):
        def __get__(self, obj, cls):
            if not hasattr(obj, "_nodes"):
                class ChangeAwareNodes(ListAdapter):
                    # disallow changing completion status of nodes once added?
                    def __setitem__(self, index, val):
                        self.items[index] = val
                        if obj.complete:
                            obj.changed = True
                    def __delitem__(self, index):
                        del self.items[index]
                        if obj.complete:
                            obj.changed = True
                    def insert(self, index, val):
                        self.items.insert(index, val)
                        if obj.complete:
                            obj.changed = True
                    @property
                    def stable(self):
                        #if not self.items or self.items[-1].complete:
                        #    return True
                        #return False
                        return all(item.stable for item in self.items)
                    def __repr__(self):
                        return repr(self.items)
                    @property
                    def directives(self):
                        if not obj.complete or obj.changed or not hasattr(self, "_names"):
                            self._directives = {}
                            for item in self.items:
                                if isinstance(item, Directive):
                                    if item.name not in self._directives:
                                        self._directives[item.name] = []
                                    if item not in self._directives[item.name]:
                                        self._directives[item.name].append(item)
                        return self._directives       
                        #result = {}
                        #for item in self.items:
                        #    if isinstance(item, Directive):
                        #        if item.name not in result:
                        #            result[item.name] = []
                        #        if item not in result[item.name]:
                        #            result[item.name].append(item)
                        #return result
                obj._nodes = ChangeAwareNodes()
            return obj._nodes
    nodes = Nodes()

    @property
    def complete(self):
        return self._complete
    @complete.setter
    def complete(self, val):
        if val and not self.nodes.stable:
            raise NodeCompleteError("The node list is not stable.  Likely the last node is still waiting for additional lines.")
        super(ComplexNode, ComplexNode).complete.fset(self, val)
    
    @property
    def stable(self):
        return self.nodes.stable

    def get_node(self, line):
        for node_cls in self.candidates:
            if node_cls.match(line):
                return node_cls()
        raise NodeMatchError("No matching node: %s" % line)

    def add_line(self, line, depth=0):
        if self.complete:
            raise NodeCompleteError("Can't add lines to a complete Node.")
        if depth > self.NESTING_LIMIT:
            raise NestingLimitError("Cannot nest directives more than %s levels." % self.NESTING_LIMIT)
        
        if not self.nodes.stable:
            node = self.nodes[-1]
            if isinstance(node, ComplexDirective):
                node.add_line(line, depth=depth+1)
            else:
                node.add_line(line)
        else:
            newnode = self.get_node(line)
            newnode.add_line(line)
            self.nodes.append(newnode)
        if not self.nodes.stable:
            self.complete = False

    def __str__(self):
        if not self.complete:
            raise NodeCompleteError("Can't turn an incomplete complex node into a string.")
        return "\n".join(str(node) for node in self.nodes)
    def pprint(self, depth=0):
        if not self.complete:
            raise NodeCompleteError("Can't print an incomplete complex node.")
        return "\n".join(node.pprint(depth) for node in self.nodes)


class ComplexDirective(Directive):
    MATCH_RE = r"\s*<\s*%s(\s+[^>]*)*\s*(>\s*|[\\])$" % Directive.NAME_RE
    BODY_CLASS = ComplexNode
    CANDIDATES = _NODES

    def __init__(self):
        super(ComplexDirective, self).__init__()
        self.header = SimpleDirective()
        self.body = self.BODY_CLASS(self.CANDIDATES)
        self.tail = ""
        self.tailmatch = False

    @property
    def name(self):
        return self.header.name
    @property
    def arguments(self):
        return self.header.arguments
    @property
    def stable(self):
        #return self.header.stable and self.body.stable
        return self.complete

    @property
    def complete(self):
        if self.body.complete and not self.header.complete:
            raise NodeCompleteError("Body is complete but header isn't.")
        if self.tailmatch and not self.body.complete:
            raise NodeCompleteError("Tail is matched but body is not complete.")
        return self.header.complete and self.body.complete and self.tailmatch
    @complete.setter
    def complete(self, val):
        if val and not (self.body.complete and self.header.complete and self.tailmatch):
            raise NodeCompleteError("Cannot set a complex directive to complete if its parts aren't complete")
        if not val and self.body.complete and self.header.complete and self.tailmatch:
            raise NodeCompleteError("Cannot set a complex directive to not complete if its parts are all complete")
        super(ComplexDirective, ComplexDirective).complete.fset(self, val)

    def add_line(self, line, depth=0):
        if self.complete:
            raise NodeCompleteError("Can't add lines to a complete Node.")
        if not self.header.complete:
            try:
                super(ComplexDirective, self).add_line(line)
            except NodeCompleteError:
                pass
            if ">" in line:
                header, remainder = line.split(">", 1)
                if remainder.strip() != "":
                    raise InvalidLineError("Directive header has an extraneous tail: %s" % line) 
            else:
                header = line
            header = header.lstrip()
            if header and header.startswith("<"):
                try:
                    self.header.name
                except NodeCompleteError:
                    header = header[1:]
            if header and "<" in header:
                raise InvalidLineError("Angle brackets not allowed in complex directive header.  Received: %s" % line)
            if header:
                try:
                    self.header.add_to_header(header)
                except (NodeCompleteError, DirectiveError) as e:
                    raise InvalidLineError(str(e))
            if ">" in line:
                self.header.complete = True
        elif not self.body.stable:
            self.body.add_line(line, depth+1)
        elif re_mod.match("\s*</%s>\s*" % self.name, line):
            self.body.complete = True
            self.tail = line
            self.tailmatch = True
        elif not self.body.complete:
            self.body.add_line(line, depth+1)
        else:
            raise InvalidLineError("Expecting closing tag.  Got: %s" % line)
                
    def __str__(self):
        if not self.lines:
            raise NodeCompleteError("Can't turn an uninitialized complex directive into a string.")
        if not self.complete:
            raise NodeCompleteError("Can't turn an incomplete complex directive into a string.")
        return "%s\n%s%s%s" % (
                "\n".join(self.lines), 
                self.body, 
                "\n" if self.body.nodes else "",
                self.tail,
                )
    def pprint(self, depth=0):
        if not self.complete:
            raise NodeCompleteError("Can't print an incomplete complex directive.")
        return "%s<%s>\n%s%s%s</%s>" % (
                INDENT*depth, 
                self.header.pprint(), 
                self.body.pprint(depth=depth+1), 
                "\n" if self.body.nodes else "",
                INDENT*depth,
                self.name,
                ) 
_NODES.append(ComplexDirective)


class ApacheConfParser(ComplexNode):
    def __init__(self, source, infile=True, delay=False, count=None):
        """Count is the starting number for line counting..."""
        super(ApacheConfParser, self).__init__(_NODES)
        self.source = source.splitlines()
        if infile:
            self.source = (line.strip("\n") for line in open(source))
        self.count = count
        if not delay:
            self.parse()

    def parse(self):
        if self.complete:
            return
        for line in self.source:
            if self.count is not None:
                print(self.count)
                self.count += 1
            self.add_line(line)
        self.complete = True