"""
Utilities for end-users.
"""

from __future__ import absolute_import
import __main__

from jedi import Interpreter


def setup_readline():
    """
    Install Jedi completer to :mod:`readline`.

    This function setups :mod:`readline` to use Jedi in Python interactive
    shell.  If you want to use custom ``PYTHONSTARTUP`` file, you can call
    this function like this:

    >>> from jedi.utils import setup_readline
    >>> setup_readline()

    """
    try:
        import readline
    except ImportError:
        print("Module readline not available.")
    else:
        class JediRL():
            def complete(self, text, state):
                """
                This complete stuff is pretty weird, a generator would make
                a lot more sense, but probably due to backwards compatibility
                this is still the way how it works.

                The only important part is the ``Interpreter`` call, everything
                else hsa been copied from the ``rlcompleter`` std. library
                module.
                """
                if state == 0:
                    namespace = __main__.__dict__
                    completions = Interpreter(text, [namespace]).completions()
                    self.matches = [text + c.complete for c in completions]
                try:
                    return self.matches[state]
                except IndexError:
                    return None

        readline.set_completer(JediRL().complete)

        readline.parse_and_bind("tab: complete")
        # No delimiters, Jedi handles that.
        readline.set_completer_delims('')