import string

import re

###$ event <<expand-word>>

###$ win <Alt-slash>

###$ unix <Alt-slash>

class AutoExpand:

    menudefs = [

        ('edit', [

            ('E_xpand Word', '<<expand-word>>'),

         ]),

    ]

    wordchars = string.ascii_letters + string.digits + "_"

    def __init__(self, editwin):

        self.text = editwin.text

        self.state = None

    def expand_word_event(self, event):

        curinsert = self.text.index("insert")

        curline = self.text.get("insert linestart", "insert lineend")

        if not self.state:

            words = self.getwords()

            index = 0

        else:

            words, index, insert, line = self.state

            if insert != curinsert or line != curline:

                words = self.getwords()

                index = 0

        if not words:

            self.text.bell()

            return "break"

        word = self.getprevword()

        self.text.delete("insert - %d chars" % len(word), "insert")

        newword = words[index]

        index = (index + 1) % len(words)

        if index == 0:

            self.text.bell()            # Warn we cycled around

        self.text.insert("insert", newword)

        curinsert = self.text.index("insert")

        curline = self.text.get("insert linestart", "insert lineend")

        self.state = words, index, curinsert, curline

        return "break"

    def getwords(self):

        word = self.getprevword()

        if not word:

            return []

        before = self.text.get("1.0", "insert wordstart")

        wbefore = re.findall(r"\b" + word + r"\w+\b", before)

        del before

        after = self.text.get("insert wordend", "end")

        wafter = re.findall(r"\b" + word + r"\w+\b", after)

        del after

        if not wbefore and not wafter:

            return []

        words = []

        dict = {}

        # search backwards through words before

        wbefore.reverse()

        for w in wbefore:

            if dict.get(w):

                continue

            words.append(w)

            dict[w] = w

        # search onwards through words after

        for w in wafter:

            if dict.get(w):

                continue

            words.append(w)

            dict[w] = w

        words.append(word)

        return words

    def getprevword(self):

        line = self.text.get("insert linestart", "insert")

        i = len(line)

        while i > 0 and line[i-1] in self.wordchars:

            i = i-1

        return line[i:]