from configHandler import idleConf

class History:

    def __init__(self, text, output_sep = "\n"):

        self.text = text

        self.history = []

        self.history_prefix = None

        self.history_pointer = None

        self.output_sep = output_sep

        self.cyclic = idleConf.GetOption("main", "History", "cyclic", 1, "bool")

        text.bind("<<history-previous>>", self.history_prev)

        text.bind("<<history-next>>", self.history_next)

    def history_next(self, event):

        self.history_do(0)

        return "break"

    def history_prev(self, event):

        self.history_do(1)

        return "break"

    def _get_source(self, start, end):

        # Get source code from start index to end index.  Lines in the

        # text control may be separated by sys.ps2 .

        lines = self.text.get(start, end).split(self.output_sep)

        return "\n".join(lines)

    def _put_source(self, where, source):

        output = self.output_sep.join(source.split("\n"))

        self.text.insert(where, output)

    def history_do(self, reverse):

        nhist = len(self.history)

        pointer = self.history_pointer

        prefix = self.history_prefix

        if pointer is not None and prefix is not None:

            if self.text.compare("insert", "!=", "end-1c") or \

               self._get_source("iomark", "end-1c") != self.history[pointer]:

                pointer = prefix = None

        if pointer is None or prefix is None:

            prefix = self._get_source("iomark", "end-1c")

            if reverse:

                pointer = nhist

            else:

                if self.cyclic:

                    pointer = -1

                else:

                    self.text.bell()

                    return

        nprefix = len(prefix)

        while 1:

            if reverse:

                pointer = pointer - 1

            else:

                pointer = pointer + 1

            if pointer < 0 or pointer >= nhist:

                self.text.bell()

                if not self.cyclic and pointer < 0:

                    return

                else:

                    if self._get_source("iomark", "end-1c") != prefix:

                        self.text.delete("iomark", "end-1c")

                        self._put_source("iomark", prefix)

                    pointer = prefix = None

                break

            item = self.history[pointer]

            if item[:nprefix] == prefix and len(item) > nprefix:

                self.text.delete("iomark", "end-1c")

                self._put_source("iomark", item)

                break

        self.text.mark_set("insert", "end-1c")

        self.text.see("insert")

        self.text.tag_remove("sel", "1.0", "end")

        self.history_pointer = pointer

        self.history_prefix = prefix

    def history_store(self, source):

        source = source.strip()

        if len(source) > 2:

            # avoid duplicates

            try:

                self.history.remove(source)

            except ValueError:

                pass

            self.history.append(source)

        self.history_pointer = None

        self.history_prefix = None