# -*- coding: utf-8 -*-

"""
Word completion for the eric-ide shell.

<h4>NOTE for eric-ide variant</h4>

    This version is a re-implementation of rlcompleter as found in the Python3
    library. It is modified to work with the eric-ide debug client.

<h4>Original rlcompleter documentation</h4>

    The completer completes keywords, built-ins and globals in a selectable
    namespace (which defaults to __main__); when completing NAME.NAME..., it
    evaluates (!) the expression up to the last dot and completes its attributes.

    It's very cool to do "import sys" type "sys.", hit the completion key (twice),
    and see the list of names defined by the sys module!

    Tip: to use the tab key as the completion key, call

        readline.parse_and_bind("tab: complete")

    <b>Notes</b>:
    <ul>
    <li>
    Exceptions raised by the completer function are *ignored* (and
    generally cause the completion to fail).  This is a feature -- since
    readline sets the tty device in raw (or cbreak) mode, printing a
    traceback wouldn't work well without some complicated hoopla to save,
    reset and restore the tty state.
    </li>
    <li>
    The evaluation of the NAME.NAME... form may cause arbitrary
    application defined code to be executed if an object with a
    __getattr__ hook is found.  Since it is the responsibility of the
    application (or the user) to enable this feature, I consider this an
    acceptable risk.  More complicated expressions (e.g. function calls or
    indexing operations) are *not* evaluated.
    </li>
    <li>
    When the original stdin is not a tty device, GNU readline is never
    used, and this module (and the readline module) are silently inactive.
    </li>
    </ul>
"""

import builtins
import contextlib
import inspect
import keyword
import re
import sys
import warnings

import __main__

__all__ = ["Completer"]


class Completer:
    """
    Class implementing the command line completer object.
    """

    def __init__(self, namespace=None):
        """
        Constructor

        Completer([namespace]) -> completer instance.

        If unspecified, the default namespace where completions are performed
        is __main__ (technically, __main__.__dict__). Namespaces should be
        given as dictionaries.

        Completer instances should be used as the completion mechanism of
        readline via the set_completer() call:

        readline.set_completer(Completer(my_namespace).complete)

        @param namespace namespace for the completer (defaults to None)
        @type dict or FrameLocalsProxy (optional)
        @exception TypeError raised to indicate a wrong data structure of
            the namespace object
        """
        if namespace and not isinstance(
            namespace, (dict, sys._getframe().f_locals.__class__)
        ):
            raise TypeError(
                "namespace must be a dictionary or since 3.13 a FrameLocalsProxy"
            )

        # Don't bind to namespace quite yet, but flag whether the user wants a
        # specific namespace or to use __main__.__dict__. This will allow us
        # to bind to __main__.__dict__ at completion time, not now.
        if namespace is None:
            self.use_main_ns = True
        else:
            self.use_main_ns = False
            self.namespace = namespace

    def complete(self, text, state):
        """
        Public method to return the next possible completion for 'text'.

        This is called successively with state == 0, 1, 2, ... until it
        returns None.  The completion should begin with 'text'.

        @param text text to be completed
        @type str
        @param state state of the completion
        @type int
        @return possible completions
        @rtype list of str
        """
        if self.use_main_ns:
            self.namespace = __main__.__dict__

        if state == 0:
            with warnings.catch_warnings(action="ignore"):
                if "." in text:
                    self.matches = self.attr_matches(text)
                else:
                    self.matches = self.global_matches(text)
        try:
            return self.matches[state]
        except IndexError:
            return None

    def _callable_postfix(self, val, word):
        """
        Protected method to check for a callable.

        @param val value to check
        @type Any
        @param word word to amend
        @type str
        @return amended word
        @rtype str
        """
        if callable(val):
            word += "("
            with contextlib.suppress(ValueError):
                if not inspect.signature(val).parameters:
                    word += ")"

        return word

    def global_matches(self, text):
        """
        Public method to compute matches when text is a simple name.

        @param text text to be completed
        @type str
        @return list of all keywords, built-in functions and names currently
            defined in self.namespace that match
        @rtype list of str
        """
        matches = []
        seen = {"__builtins__"}
        n = len(text)
        for word in keyword.kwlist + keyword.softkwlist:
            if word[:n] == text:
                seen.add(word)
                if word in {"finally", "try"}:
                    word += ":"
                elif word not in {
                    "False",
                    "None",
                    "True",
                    "break",
                    "continue",
                    "pass",
                    "else",
                    "_",
                }:
                    word += " "
                matches.append(word)
        for nspace in [self.namespace, builtins.__dict__]:
            for word, val in nspace.items():
                if word[:n] == text and word not in seen:
                    seen.add(word)
                    matches.append(self._callable_postfix(val, word))
        return matches

    def attr_matches(self, text):
        """
        Public method to compute matches when text contains a dot.

        Assuming the text is of the form NAME.NAME....[NAME], and is
        evaluatable in self.namespace, it will be evaluated and its attributes
        (as revealed by dir()) are used as possible completions.  (For class
        instances, class members are are also considered.)

        <b>WARNING</b>: this can still invoke arbitrary C code, if an object
        with a __getattr__ hook is evaluated.

        @param text text to be completed
        @type str
        @return list of all matches
        @rtype list of str
        """
        m = re.match(r"(\w+(\.\w+)*)\.(\w*)", text)
        if not m:
            return []
        expr, attr = m.group(1, 3)
        try:
            thisobject = eval(expr, {}, self.namespace)  # secok
        except Exception:
            return []

        # get the content of the object, except __builtins__
        words = set(dir(thisobject))
        words.discard("__builtins__")

        if hasattr(thisobject, "__class__"):
            words.add("__class__")
            words.update(get_class_members(thisobject.__class__))
        attribute_matches = []
        n = len(attr)
        if attr == "":
            noprefix = "_"
        elif attr == "_":
            noprefix = "__"
        else:
            noprefix = None
        while True:
            for word in words:
                if word[:n] == attr and not (noprefix and word[: n + 1] == noprefix):
                    attribute_match = "{0}.{1}".format(expr, word)
                    if isinstance(getattr(type(thisobject), word, None), property):
                        # thisobject.word is a method decorated by `@property`.
                        # What follows applies a postfix if thisobject.word is
                        # callable, but now we know that this is not callable
                        # (because it is a property). Also, getattr(thisobject, word)
                        # will evaluate the property method, which is not desirable.
                        attribute_matches.append(attribute_match)
                        continue
                    value = getattr(thisobject, word, None)
                    if value is not None:
                        attribute_matches.append(
                            self._callable_postfix(value, attribute_match)
                        )
                    else:
                        attribute_matches.append(attribute_match)
            if attribute_matches or not noprefix:
                break
            noprefix = "__" if noprefix == "_" else None
        attribute_matches.sort()
        return attribute_matches


def get_class_members(klass):
    """
    Module function to retrieve the class members.

    @param klass class object to be analyzed
    @type Any
    @return list of all names defined in the class
    @rtype list of str
    """
    ret = dir(klass)
    if hasattr(klass, "__bases__"):
        for base in klass.__bases__:
            ret += get_class_members(base)
    return ret


#
# eflag: noqa = M-111
