import re
import regex, util

class Token(object):
    def __init__(self, name, rule, y, x, s, parent=None, matchd={}, link=None):
        self.name      = name
        self.rule      = rule
        self.y         = y
        self.x         = x
        self.string    = s
        self.parent    = parent
        self.matchd    = matchd
        self.link      = link
        self.loverride = None
        self.goverride = None
        assert parent is None or hasattr(parent, 'name'), 'oh no %r' % parent
    def parents(self):
        if self.parent is not None:
            parents = self.parent.parents()
            parents.append(self.parent)
            return parents
        else:
            return []
    def domain(self):
        if self.parent is not None:
            names = self.parent.domain()
        else:
            names = []
        if self.link and not self.link.startswith('middle'):
            names.append(self.rule.name)
        return names
    def fqlist(self):
        if self.parent is not None:
            names = self.parent.domain()
        else:
            names = []
        if self.link == 'start':
            names.append(self.rule.name)
        names.append(self.name)
        return names
    def fqname(self):
        names = self.fqlist()
        return '.'.join(names)
    def copy(self):
        return Token(self.name, self.rule, self.y, self.x, self.string,
                     self.parent, self.matchd)
    def add_to_string(self, s):
        self.string += s
    def end_x(self):
        return self.x + len(self.string)
    def __eq__(self, other):
        return (self.y == other.y and self.x == other.x
                and self.name == other.name and self.parent is other.parent and
                self.string == other.string)
    def __repr__(self):
        if len(self.string) < 10:
            s = self.string
        else:
            s = self.string[:10] + '...'
        fields = (self.fqname(), self.rule, self.y, self.x, s)
        return "<Token(%r, %r, %d, %d, %r)>" % fields

class Rule:
    reflags = 0
    def __init__(self, name):
        assert regex.valid_token_name.match(name), 'invalid name %r' % name
        assert not regex.reserved_token_names.match(name), \
            "rule name %r is reserved and thus illegal" % name
        self.name = name
    def match(self, lexer, parent):
        raise Exception, "not implemented"
    def lex(self, lexer, parent, match):
        raise Exception, "not implemented"
    def make_token(self, lexer, s, name, parent=None, matchd={}, link=None):
        t = Token(name, self, lexer.y, lexer.x, s, parent, matchd, link)
        lexer.x += len(s)
        return t
    def get_line(self, lexer):
        return lexer.lines[lexer.y] + '\n'

class PatternRule(Rule):
    def __init__(self, name, pattern):
        Rule.__init__(self, name)
        self.pattern = pattern
        self.re = re.compile(self.pattern, self.reflags)
    def match(self, lexer, parent):
        return self.re.match(self.get_line(lexer), lexer.x)
    def lex(self, lexer, parent, m):
        if m:
            yield self.make_token(lexer, m.group(0), self.name, parent, m.groupdict())
        raise StopIteration
class NocasePatternRule(PatternRule):
    reflags = re.IGNORECASE

class OverridePatternRule(PatternRule):
    def lex(self, lexer, parent, m):
        if m:
            a = lexer.mode.window.application
            d = m.groupdict()
            try:
                names   = d['grammar'].split('.')
                grammar = a.globals()[names.pop(0)]
                for name in names:
                    grammar = getattr(grammar, name)
                lexer.loverride['%s.start' % d['token']] = grammar
            except Exception:
                #raise
                pass
            yield self.make_token(lexer, m.group(0), self.name, parent, d)
        raise StopIteration

class ContextPatternRule(PatternRule):
    def __init__(self, name, pattern, fallback):
        Rule.__init__(self, name)
        self.pattern     = pattern
        self.fallback_re = re.compile(fallback, self.reflags)
    def match(self, lexer, parent):
        try:
            r = re.compile(self.pattern % parent.matchd)
        except KeyError:
            r = self.fallback_re
        return r.match(self.get_line(lexer), lexer.x)
class NocaseContextPatternRule(ContextPatternRule):
    reflags = re.IGNORECASE

class PatternGroupRule(PatternRule):
    def __init__(self, name, *args):
        assert args and len(args) % 2 == 0
        i = 0
        pairs = []
        while i < len(args):
            tokname, pattern = args[i], args[i+1]
            pairs.append((name, re.compile(pattern, self.reflags)))
            i += 2
        Rule.__init__(self, name)
        self.pairs = tuple(pairs)
    def match(self, lexer, parent):
        x       = lexer.x
        matches = []
        line    = self.get_line(lexer)
        for (tokname, tokre) in self.pairs:
            m = tokre.match(line, x)
            if m:
                x += len(m.group(0))
                matches.append((tokname, m))
            else:
                return []
        assert len(matches) == len(self.pairs)
        return matches
    def lex(self, lexer, parent, matches):
        if matches:
            for (tokname, m) in matches:
                yield self.make_token(lexer, m.group(0), tokname, parent, m.groupdict())
        raise StopIteration

class RegionRule(Rule):
    def __init__(self, name, *args):
        Rule.__init__(self, name)
        assert len(args) > 1
        args = list(args)
        self.pairs    = []
        self.start_re = re.compile(args.pop(0), self.reflags)
        while len(args) > 1:
            grammar = args.pop(0)
            pattern = args.pop(0)
            assert hasattr(grammar, 'rules'), repr(grammar)
            assert type(pattern) == type(''), repr(pattern)
            self.pairs.append((grammar, pattern))
        if len(args) == 1:
            self.pairs.append((grammar, None))

    def match(self, lexer, parent):
        return self.start_re.match(self.get_line(lexer), lexer.x)
    def lex(self, lexer, parent, m):
        assert m
        # ok, so since we had a match, we need to create our start token, who
        # will be the ancestor to all other tokens matched in this region
        matchd = m.groupdict()
        parent = self.make_token(lexer, m.group(0), 'start', parent, matchd, 'start')
        yield parent

        # now we will loop over the different pairs of grammars/stop-patterns in
        # this region, and return the resulting token; we start at 0
        for tok in self._lex_loop(lexer, [parent], matchd, 0):
            yield tok
        raise StopIteration
    def resume(self, lexer, toresume):
        assert toresume, "can't resume without tokens to resume!"
        # ok, so we need to figure out in which of the grammars of our region
        # we are resuming. to do this we calculate i, a position in our list
        # of grammar/stop-pattern pairs
        if toresume[0].link == 'start':
            i = 0
        else:
            m = regex.middle_token_name.match(toresume[0].link)
            assert m
            i = int(m.group(1)) + 1
            assert i > 0 and i < len(self.pairs)

        # now we will loop over the different pairs of grammars/stop-patterns in
        # this region, and return the resulting token; we start at i
        for tok in self._lex_loop(lexer, toresume, toresume[0].matchd, i):
            yield tok
        raise StopIteration
    def _lex_loop(self, lexer, toresume, matchd, i):
        # we need to loop over our grammar/stop-pattern pairs
        while i < len(self.pairs):
            # for each one, we will compile our stop-regex, and figure out the
            # name of the stop token to be created if this stop-regex matches.
            fqname = toresume[0].fqname()
            if fqname in lexer.loverride:
                grammar = lexer.loverride[fqname]
                del lexer.loverride[fqname]
                #toresume[0].loverride = grammar
            elif fqname in lexer.goverride:
                grammar = lexer.goverride[fqname]
                #toresume[0].goverride = grammar
            #elif toresume[0].loverride:
            #    grammar = toresume[0].loverride
            #elif toresume[0].goverride:
            #    grammar = toresume[0].goverride
            else:
                grammar = self.pairs[i][0]

            if self.pairs[i][1]:
                stopre = re.compile(self.pairs[i][1] % matchd, self.reflags)
            else:
                stopre = None
            if i == len(self.pairs) - 1:
                tokname = 'end'
            else:
                tokname = 'middle%d' % i

            # ok, so now loop over all the tokens in the current grammar, until
            # the stop-token (if any) is found, and return each result as we get
            # it.
            for tok in self._lex(lexer, toresume, tokname, stopre, grammar):
                yield tok

            # ok, so now either we found the stop-token, and have a new parent
            # for future tokens (if any), or we are done.
            if tok.name == tokname:
                toresume = [tok]
                matchd.update(tok.matchd)
            else:
                raise StopIteration
            i += 1
        # assuming we make it through all our grammars, and find the end-token,
        # then we need to signal that we are done.
        raise StopIteration
    def _lex(self, lexer, toresume, stopname, stopre, grammar):
        assert toresume
        parent  = toresume[0]
        reenter = len(toresume) > 1
        null_t  = None

        # ok, so there are only two way we want to exit this loop: either we
        # lex the whole document, or we encounter the stop-token.
        done = False
        while not done and lexer.y < len(lexer.lines):
            line  = self.get_line(lexer)
            old_y = lexer.y
            while not done and lexer.y == old_y and lexer.x < len(line):
                # ok, so reenter gets priority, since the current input might be
                # intended for nested grammar. so handle it here
                if reenter:
                    reenter = False
                    for t in toresume[1].rule.resume(lexer, toresume[1:]):
                        yield t
                # since we might have changed our x/y coordinates, we need to
                # do some checks here, and maybe finish or change our coordintes
                if lexer.y >= len(lexer.lines):
                    raise StopIteration
                elif lexer.x >= len(line):
                    lexer.y += 1
                    lexer.x = 0

                # ok, so get the *now* current line
                line = self.get_line(lexer)

                if stopre:
                    # if we are looking for a stop-token, do that check now
                    m = stopre.match(line, lexer.x)
                    if m:
                        if null_t:
                            # if we have a null token waiting, return it first.
                            yield null_t
                            null_t = None
                        # ok, now return the stop-token, and signal that we are
                        # done and no more input is to be consumed
                        yield self.make_token(lexer, m.group(0), stopname,
                                              parent, m.groupdict(), stopname)
                        done = True
                        break

                m = None
                # start checking our rules to see if we can match the input
                for rule in grammar.rules:
                    m = rule.match(lexer, parent)
                    if m:
                        # ok great, we have a match
                        if null_t:
                            # if we have a null token waiting, return it first.
                            yield null_t
                            null_t = None
                        # ok, now for every token this rules has created, we
                        # return them, one by one.
                        for t in rule.lex(lexer, parent, m):
                            yield t
                        break

                if not m:
                    # we didn't find a match on a rule, so add this character to
                    # the current null token (creating a new one if necessary);
                    if not null_t:
                        null_t = Token('null', None, lexer.y, lexer.x, '', parent)
                    null_t.add_to_string(line[lexer.x])
                    lexer.x += 1

            # ok, we are at the end of a line of input. so, if we have a null
            # token waiting, now is the time to return it
            if null_t:
                yield null_t
                null_t = None
            if not done and old_y == lexer.y:
                lexer.y += 1
                lexer.x = 0
        raise StopIteration
class NocaseRegionRule(RegionRule):
    reflags = re.IGNORECASE

class Grammar:
    rules = []
grammar = Grammar()

class Lexer:
    def __init__(self, mode, grammar):
        self.mode     = mode
        self.grammar  = grammar
        self.y        = 0
        self.x        = 0
        self.lines    = None
        self.loverride = {}
        self.goverride = {}
        assert self.grammar.rules
    def get_line(self):
        return self.lines[self.y] + '\n'
    def lex(self, lines, y=0, x=0):
        self.action = 'lex'
        self.y      = y
        self.x      = x
        self.lines  = lines
        self.loverride = {}
        for t in self._lex():
            yield t
        raise StopIteration
    def resume(self, lines, y, x, token):
        self.action = 'resume'
        self.y      = y
        self.x      = x
        self.lines  = lines
        self.tokens = []
        self.loverride = {}
        toresume = token.parents()

        i = 1
        while i < len(toresume):
            if toresume[i].link and toresume[i].link != 'start':
                del toresume[i-1]
            else:
                i += 1

        if toresume:
            for t in toresume[0].rule.resume(self, toresume):
                yield t
        for t in self._lex():
            yield t
        raise StopIteration

    def _lex(self):
        parent = None
        while self.y < len(self.lines):
            null_t = None
            line = self.get_line()
            while self.x < len(line):
                m = None
                for rule in self.grammar.rules:
                    m = rule.match(self, parent)
                    if m:
                        if null_t:
                            yield null_t
                            null_t = None
                        for t in rule.lex(self, parent, m):
                            yield t
                        break

                if self.y >= len(self.lines):
                    break
                line = self.get_line()
                if not m:
                    if self.x < len(line):
                        if null_t is None:
                            null_t = Token('null', None, self.y, self.x, '', parent)
                        null_t.add_to_string(line[self.x])
                        self.x += 1
            if null_t:
                yield null_t
            self.y += 1
            self.x = 0
        raise StopIteration