#!/usr/bin/env python
# ***** BEGIN LICENSE BLOCK *****
# Version: MPL 1.1/GPL 2.0/LGPL 2.1
# 
# The contents of this file are subject to the Mozilla Public License
# Version 1.1 (the "License"); you may not use this file except in
# compliance with the License. You may obtain a copy of the License at
# http://www.mozilla.org/MPL/
# 
# Software distributed under the License is distributed on an "AS IS"
# basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
# License for the specific language governing rights and limitations
# under the License.
# 
# The Original Code is Komodo code.
# 
# The Initial Developer of the Original Code is ActiveState Software Inc.
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# 
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#   ActiveState Software Inc
# 
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"""Python support for CodeIntel"""

import os
from os.path import (isfile, isdir, exists, dirname, splitext,
                     join, basename, normcase)
import sys
import logging
import random
import parser
from glob import glob
import weakref
import re
import imp
from pprint import pprint, pformat
import itertools

import SilverCity
from SilverCity.Lexer import Lexer
from SilverCity import ScintillaConstants
from SilverCity.Keywords import python_keywords

from codeintel2.common import *
from codeintel2.citadel import (CitadelBuffer, CitadelEvaluator, ImportHandler,
                                CitadelLangIntel)
from codeintel2.indexer import PreloadLibRequest
from codeintel2 import pythoncile
from codeintel2.util import banner, indent, markup_text, isident, isdigit
from codeintel2 import tree
from codeintel2.tree_python import PythonTreeEvaluator, PythonImportLibGenerator
from codeintel2.langintel import (ParenStyleCalltipIntelMixin,
                                  ProgLangTriggerIntelMixin,
                                  PythonCITDLExtractorMixin)

from codeintel2.tree import tree_from_cix

if _xpcom_:
    from xpcom.server import UnwrapObject



#---- globals

_SCAN_BINARY_FILES = False

lang = "Python"
log = logging.getLogger("codeintel.python")
#log.setLevel(logging.DEBUG)

CACHING = True #DEPRECATED: kill it

# See http://effbot.org/zone/pythondoc.htm
_g_pythondoc_tags = list(sorted("param keyparam return exception def "
                                "defreturn see link linkplain".split()))

_g_python_magic_method_names = sorted([
    '__init__',
    '__new__',
    '__del__',
    '__repr__',
    '__str__',
    '__lt__',
    '__le__',
    '__eq__',
    '__ne__',
    '__gt__',
    '__ge__',
    '__cmp__',
    '__rcmp__',
    '__hash__',
    '__nonzero__',
    '__unicode__',
    # Attribute access
    '__getattr__',
    '__setattr__',
    '__delattr__',
    # New style classes
    '__getattribute__',
    '__call__',
    # Sequence classes
    '__len__',
    '__getitem__',
    '__setitem__',
    '__delitem__',
    '__iter__',
    '__reversed__',
    '__contains__',
    '__getslice__',
    '__setslice__',
    '__delslice__',
    # Integer like operators
    '__add__',
    '__sub__',
    '__mul__',
    '__floordiv__',
    '__mod__',
    '__divmod__',
    '__pow__',
    '__lshift__',
    '__rshift__',
    '__and__',
    '__xor__',
    '__or__',
    '__div__',
    '__truediv__',
    '__radd__',
    '__rsub__',
    '__rmul__',
    '__rdiv__',
    '__rtruediv__',
    '__rfloordiv__',
    '__rmod__',
    '__rdivmod__',
    '__rpow__',
    '__rlshift__',
    '__rrshift__',
    '__rand__',
    '__rxor__',
    '__ror__',
    '__iadd__',
    '__isub__',
    '__imul__',
    '__idiv__',
    '__itruediv__',
    '__ifloordiv__',
    '__imod__',
    '__ipow__',
    '__ilshift__',
    '__irshift__',
    '__iand__',
    '__ixor__',
    '__ior__',
    '__neg__',
    '__pos__',
    '__abs__',
    '__invert__',
    '__complex__',
    '__int__',
    '__long__',
    '__float__',
    '__oct__',
    '__hex__',
    '__index__',
    '__coerce__',
    # Context managers
    '__enter__',
    '__exit__',
])

#---- language support

class PythonLexer(Lexer):
    lang = lang
    def __init__(self):
        self._properties = SilverCity.PropertySet()
        self._lexer = SilverCity.find_lexer_module_by_id(ScintillaConstants.SCLEX_PYTHON)
        self._keyword_lists = [
            SilverCity.WordList(python_keywords),
            SilverCity.WordList(""), # hilighted identifiers
        ]


class PythonImportsEvaluator(Evaluator):
    lang = lang

    def __str__(self):
        return "Python imports"
    def eval(self, mgr):
        try:
            imp_prefix = self.trg.extra["imp_prefix"]
            if imp_prefix:
                libs = self.buf.libs
                if not imp_prefix[0]:
                    if not imp_prefix[-1]:
                        # Deal with last item being empty, i.e. "from ."
                        imp_prefix = imp_prefix[:-1]
                    lookuppath = self.buf.path
                    while imp_prefix and not imp_prefix[0]:
                        lookuppath = dirname(lookuppath)
                        imp_prefix = imp_prefix[1:]
                    libs = [mgr.db.get_lang_lib(self.lang, "curdirlib",
                                                  [lookuppath])]
                else:
                    # We use a special lib generator - that will lazily load
                    # additional directory libs when there are no matches found.
                    # This is a smart import facility - to detect imports from
                    # a parent directory when they are not explicitly on the
                    # included path list, quite common for Django and other
                    # Python frameworks that mangle the sys.path at runtime.
                    libs = PythonImportLibGenerator(mgr, self.lang,
                                                    self.buf.path, imp_prefix,
                                                    libs)
                self.ctlr.set_desc("subimports of '%s'" % '.'.join(imp_prefix))
                cplns = []
                for lib in libs:
                    imports = lib.get_blob_imports(imp_prefix)
                    if imports:
                        cplns.extend(
                            ((is_dir_import and "directory" or "module"), name)
                            for name, is_dir_import in imports
                        )
                        
                    if self.trg.type == "module-members":
                        # Also add top-level members of the specified module.
                        dotted_prefix = '.'.join(imp_prefix)
                        if lib.has_blob(dotted_prefix):
                            blob = lib.get_blob(dotted_prefix)
                            for name in blob.names:
                                elem = blob.names[name]
                                cplns.append((elem.get("ilk") or elem.tag, name))
                            
                            #TODO: Consider using the value of __all__
                            #      if defined.
                            for e in blob:
                                attrs = e.get("attributes", "").split()
                                if "__hidden__" not in attrs:
                                    try:
                                        cplns += self._members_from_elem(e, mgr)
                                    except CodeIntelError, ex:
                                        log.warn("%s (skipping members for %s)",
                                                  ex, e)
                    if cplns:
                        break
                if cplns:
                    cplns = list(set(cplns))  # remove duplicates
            else:
                self.ctlr.set_desc("available imports")
                all_imports = set()
                for lib in self.buf.libs:
                    all_imports.update(lib.get_blob_imports(imp_prefix))
                cplns = [((is_dir_import and "directory" or "module"), name)
                         for name, is_dir_import in all_imports]
            if cplns:
                cplns.sort(key=lambda i: i[1].upper())
                self.ctlr.set_cplns(cplns)
        finally:
            self.ctlr.done("success")

    #XXX: This function is shamelessly copy/pasted from
    #     tree_python.py:PythonTreeEvaluator because there was no clear
    #     way to reuse this shared functionality. See another XXX below, though.
    def _members_from_elem(self, elem, mgr):
        """Return the appropriate set of autocomplete completions for
        the given element. Typically this is just one, but can be more for
        '*'-imports
        """
        members = set()
        if elem.tag == "import":
            alias = elem.get("alias")
            symbol_name = elem.get("symbol")
            module_name = elem.get("module")
            if symbol_name:
                import_handler = mgr.citadel.import_handler_from_lang(self.trg.lang)
                try:
                    blob = import_handler.import_blob_name(
                                module_name, self.buf.libs, self.ctlr)
                except:
                    log.warn("limitation in handling imports in imported modules")
                    raise

                if symbol_name == "*": # can it be so?
                    for m_name, m_elem in blob.names.items():
                        m_type = m_elem.get("ilk") or m_elem.tag
                        members.add( (m_type, m_name) )
                elif symbol_name in blob.names:
                    symbol = blob.names[symbol_name]
                    member_type = (symbol.get("ilk") or symbol.tag)
                    members.add( (member_type, alias or symbol_name) )
                else:
                    # To correctly determine the type, we'd need to
                    # examine all the imports of this blob, and then see
                    # if any of those imports match the name... which is
                    # better left to the tree evaluator (tree_python).
                    #
                    # For now, we just add it as an unknown type.
                    members.add( ('unknown', alias or symbol_name))
                    log.info("could not resolve symbol %r on %r, added as 'unknown'",
                             symbol_name, module_name)
            else:
                cpln_name = alias or module_name.split('.', 1)[0]
                members.add( ("module", cpln_name) )
        else:
            members.add((elem.get("ilk") or elem.tag, elem.get("name")) )
        return members


class PythonLangIntel(CitadelLangIntel, ParenStyleCalltipIntelMixin,
                      ProgLangTriggerIntelMixin,
                      PythonCITDLExtractorMixin):
    lang = lang
    interpreterPrefName = "python"
    extraPathsPrefName = "pythonExtraPaths"

    # Used by ProgLangTriggerIntelMixin.preceding_trg_from_pos().
    trg_chars = tuple(" (.")
    
    def async_eval_at_trg(self, buf, trg, ctlr):
        if _xpcom_:
            trg = UnwrapObject(trg)
            ctlr = UnwrapObject(ctlr)
        ctlr.start(buf, trg)
        if trg.type in ("object-members", "call-signature",
                        "literal-members") or \
           trg.form == TRG_FORM_DEFN:
            line = buf.accessor.line_from_pos(trg.pos)
            if trg.type == "literal-members":
                # We could leave this to citdl_expr_from_trg, but this is a
                # little bit faster, since we already know the citdl expr.
                citdl_expr = trg.extra.get("citdl_expr")
            else:
                try:
                    citdl_expr = self.citdl_expr_from_trg(buf, trg)
                except CodeIntelError, ex:
                    ctlr.error(str(ex))
                    ctlr.done("error")
                    return
            evalr = PythonTreeEvaluator(ctlr, buf, trg, citdl_expr, line)
            buf.mgr.request_eval(evalr)
        elif trg.id == (self.lang, TRG_FORM_CPLN, "magic-symbols"):
            symbolstype = trg.extra.get("symbolstype")
            cplns = []
            if symbolstype == "string":
                cplns = [("variable", "__main__")]
            elif symbolstype == "def":
                cplns = [("function", t + "(self") for t in _g_python_magic_method_names]
            elif symbolstype == "global":
                text = trg.extra.get("text")
                if text.endswith("if"):
                    # Add the extended name version.
                    cplns = [("variable", t) for t in ("__file__", "__loader__", "__name__ == '__main__':", "__package__")]
                else:
                    cplns = [("variable", t) for t in ("__file__", "__loader__", "__name__", "__package__")]
            ctlr.set_cplns(cplns)
            ctlr.done("success")
        elif trg.id == (self.lang, TRG_FORM_CPLN, "pythondoc-tags"):
            #TODO: Would like a "tag" completion image name.
            cplns = [("variable", t) for t in _g_pythondoc_tags]
            ctlr.set_cplns(cplns)
            ctlr.done("success")
        elif trg.type == "available-exceptions":
            evalr = PythonTreeEvaluator(ctlr, buf, trg, None, -1)
            buf.mgr.request_eval(evalr)
        elif trg.type in ("available-imports", "module-members"):
            evalr = PythonImportsEvaluator(ctlr, buf, trg)
            buf.mgr.request_eval(evalr)
        else:
            raise NotImplementedError("not yet implemented: completion for "
                                      "Python '%s' trigger" % trg.name)

    # Note: Python 1.5.2 does not support sys.version_info.
    info_cmd = (
        r"import sys;"
        r"sys.stdout.write('.'.join(map(str, sys.version_info))+'\n');"
        r"sys.stdout.write(sys.prefix+'\n');"
        r"sys.stdout.write('\n'.join(sys.path));")

    def _python_info_from_python(self, python, env):
        """Call the given Python and return:
            (<version>, <sys.prefix>, <lib-dir>, <site-lib-dir>, <sys.path>)

        TODO: Unicode path issues?
        """
        import process
        argv = [python, "-c", self.info_cmd]
        log.debug("run `%s -c ...'", python)
        p = process.ProcessOpen(argv, env=env.get_all_envvars(), stdin=None)
        stdout, stderr = p.communicate()
        stdout_lines = stdout.splitlines(0)
        retval = p.returncode
        if retval:
            log.warn("failed to determine Python info:\n"
                     "  path: %s\n"
                     "  retval: %s\n"
                     "  stdout:\n%s\n"
                     "  stderr:\n%s\n",
                     python, retval, indent('\n'.join(stdout_lines)),
                     indent(stderr))

        # We are only to rely on the first 2 digits being in the form x.y.
        ver_match = re.search("([0-9]+.[0-9]+)", stdout_lines[0])
        if ver_match:
            ver = ver_match.group(1)
        else:
            ver = None
        prefix = stdout_lines[1]
        if sys.platform == "win32":
            libdir = join(prefix, "Lib")
        else:
            libdir = join(prefix, "lib", "python"+ver)
        sitelibdir = join(libdir, "site-packages")
        sys_path = stdout_lines[2:]
        return ver, prefix, libdir, sitelibdir, sys_path

    def _gen_python_import_paths_from_dirs(self, dirs):
        """Generate all Python import paths from a given list of dirs.
        
        This involves handling .pth files on the given dirs. It generates
        import "paths" rather than "dirs" because Python .egg files can be
        returned.
        
        Dev Notes:
        - Python's .pth files can have *executable* Python code. This
          currently is not handled (those kinds of lines are skipped).
        """
        for dir in dirs:
            if not exists(dir):
                continue
            yield dir
            try:
                for pth_path in glob(join(dir, "*.pth")):
                    for p in self._gen_python_import_paths_from_pth_path(pth_path):
                        yield p
            except EnvironmentError, ex:
                log.warn("error analyzing .pth files in '%s': %s", dir, ex)

    def _gen_python_import_paths_from_pth_path(self, pth_path):
        pth_dir = dirname(pth_path)
        for line in open(pth_path, 'r'):
            line = line.strip()
            if line.startswith("#"): # comment line
                continue
            path = join(pth_dir, line)
            if exists(path):
                yield path

    def _extra_dirs_from_env(self, env):
        extra_dirs = set()
        for pref in env.get_all_prefs(self.extraPathsPrefName):
            if not pref: continue
            extra_dirs.update(d.strip() for d in pref.split(os.pathsep)
                              if exists(d.strip()))
        if extra_dirs:
            extra_dirs = set(
                self._gen_python_import_paths_from_dirs(extra_dirs)
            )                
            log.debug("Python extra lib dirs: %r", extra_dirs)
        return tuple(extra_dirs)

    def interpreter_from_env(self, env):
        """Returns:
            - absolute path to either the preferred or
              default system interpreter
            - None if none of the above exists
        """
        # Gather information about the current python.
        python = None
        if env.has_pref(self.interpreterPrefName):
            python = env.get_pref(self.interpreterPrefName).strip() or None
        
        if not python or not exists(python):
            import which
            syspath = env.get_envvar("PATH", "") 
            path = [d.strip() for d in syspath.split(os.pathsep)
                              if d.strip()]
            try:
                python = which.which("python", path=path) 
            except which.WhichError:
                pass # intentionally supressed

        if python:
            python = os.path.abspath(python)

        return python

    def python_info_from_env(self, env):
        cache_key = self.lang + "-info"
        info = env.cache.get(cache_key)
        if info is None:
            python = self.interpreter_from_env(env)
            if not python:
                log.warn("no Python was found from which to determine the "
                         "codeintel information")
                info = None, None, None, None, []
            else:
                info = self._python_info_from_python(python, env)
        return info

    def _buf_indep_libs_from_env(self, env):
        """Create the buffer-independent list of libs."""
        cache_key = self.lang + "-libs"
        libs = env.cache.get(cache_key)
        if libs is None:
            env.add_pref_observer(self.interpreterPrefName, self._invalidate_cache)
            env.add_pref_observer(self.extraPathsPrefName,
                                  self._invalidate_cache_and_rescan_extra_dirs)
            env.add_pref_observer("codeintel_selected_catalogs",
                                  self._invalidate_cache)
            db = self.mgr.db

            ver, prefix, libdir, sitelibdir, sys_path \
                = self.python_info_from_env(env)
            libs = []

            # - extradirslib
            extra_dirs = self._extra_dirs_from_env(env)
            if extra_dirs:
                libs.append( db.get_lang_lib(self.lang, "extradirslib",
                                extra_dirs) )

            # Figure out which sys.path dirs belong to which lib.
            paths_from_libname = {"sitelib": [], "envlib": [], "stdlib": []}
            canon_sitelibdir = sitelibdir and normcase(sitelibdir) or None
            canon_prefix = prefix and normcase(prefix) or None
            canon_libdir = normcase(libdir)
            canon_libdir_plat_prefix = normcase(join(libdir, "plat-"))
            canon_libdir_lib_prefix = normcase(join(libdir, "lib-"))
            for dir in sys_path:
                STATE = "envlib"
                canon_dir = normcase(dir)
                if dir == "": # -> curdirlib (already handled)
                    continue
                elif canon_dir.endswith(".zip") and isfile(dir):
                    log.warn("`%s': not handling .zip file on Python sys.path",
                             dir)
                    continue
                elif canon_dir.endswith(".egg") and isfile(dir):
                    #log.warn("`%s': not handling .egg file on Python sys.path",
                    #         dir)
                    continue
                elif canon_dir.startswith(canon_sitelibdir):
                    STATE = "sitelib"
                # Check against the known list of standard library locations.
                elif canon_dir == canon_libdir or \
                     canon_dir.startswith(canon_libdir_plat_prefix) or \
                     canon_dir.startswith(canon_libdir_lib_prefix):
                    STATE = "stdlib"
                if not exists(dir):
                    continue
                paths_from_libname[STATE].append(dir)
            log.debug("Python %s paths for each lib:\n%s",
                      ver, indent(pformat(paths_from_libname)))

            # - envlib, sitelib, cataloglib, stdlib
            if paths_from_libname["envlib"]:
                libs.append( db.get_lang_lib(self.lang, "envlib", 
                                paths_from_libname["envlib"]) )
            if paths_from_libname["sitelib"]:
                libs.append( db.get_lang_lib(self.lang, "sitelib", 
                                paths_from_libname["sitelib"]) )
            catalog_selections = env.get_pref("codeintel_selected_catalogs")
            libs += [
                db.get_catalog_lib(self.lang, catalog_selections),
                db.get_stdlib(self.lang, ver)
            ]
            env.cache[cache_key] = libs

        return libs

    def libs_from_buf(self, buf):
        env = buf.env

        # A buffer's libs depend on its env and the buf itself so
        # we cache it on the env and key off the buffer.
        cache_key = self.lang + "-buf-libs"
        cache = env.cache.get(cache_key) # <buf-weak-ref> -> <libs>
        if cache is None:
            cache = weakref.WeakKeyDictionary()
            env.cache[cache_key] = cache

        if buf not in cache:
            # - curdirlib
            # Using the dirname of this buffer isn't always right, but
            # hopefully is a good first approximation.
            cwd = dirname(buf.path)
            if cwd == "<Unsaved>":
                libs = []
            else:
                libs = [ self.mgr.db.get_lang_lib(self.lang, "curdirlib",
                                                  [dirname(buf.path)]) ]

            libs += self._buf_indep_libs_from_env(env)
            cache[buf] = libs
        return cache[buf]

    def _invalidate_cache(self, env, pref_name):
        for key in (self.lang + "-buf-libs", self.lang + "-libs"):
            if key in env.cache:
                log.debug("invalidate '%s' cache on %r", key, env)
                del env.cache[key]

    def _invalidate_cache_and_rescan_extra_dirs(self, env, pref_name):
        self._invalidate_cache(env, pref_name)
        extra_dirs = self._extra_dirs_from_env(env)
        if extra_dirs:
            extradirslib = self.mgr.db.get_lang_lib(
                self.lang, "extradirslib", extra_dirs)
            request = PreloadLibRequest(extradirslib)
            self.mgr.idxr.stage_request(request, 1.0)


#class PythonCitadelEvaluator(CitadelEvaluator):
#    def post_process_cplns(self, cplns):
#        """Drop special __FOO__ methods.
#        
#        Note: Eventually for some Python completions we might want to leave
#        these in. For example:
#        
#            class Bar(Foo):
#                def __init__(self):
#                    Foo.<|>    # completions should include "__init__" here
#        """
#        for i in range(len(cplns)-1, -1, -1):
#            value = cplns[i][1]
#            if value.startswith("__") and value.endswith("__"):
#                del cplns[i]
#        return CitadelEvaluator.post_process_cplns(self, cplns)


# "from", "from .", "from .."
_dotted_from_rx = re.compile(r'from($|\s+\.+)')

class PythonBuffer(CitadelBuffer):
    lang = lang
    # Fillup chars for Python: basically, any non-identifier char.
    # - remove '*' from fillup chars because: "from foo import <|>*"
    cpln_fillup_chars = "~`!@#$%^&()-=+{}[]|\\;:'\",.<>?/ "
    cpln_stop_chars = "~`!@#$%^&*()-=+{}[]|\\;:'\",.<>?/ "
    sce_prefixes = ["SCE_P_"]

    cb_show_if_empty = True

    @property
    def libs(self):
        return self.langintel.libs_from_buf(self)

    def trg_from_pos(self, pos, implicit=True):
        """Python trigger types:

        python-complete-object-members
        python-calltip-call-signature
        python-complete-pythondoc-tags
        complete-available-imports
        complete-module-members
        
        Not yet implemented:
            complete-available-classes
            calltip-base-signature
        """
        DEBUG = False # not using 'logging' system, because want to be fast
        if DEBUG:
            print "\n----- Python trg_from_pos(pos=%r, implicit=%r) -----"\
                  % (pos, implicit)

        if pos == 0:
            return None
        accessor = self.accessor
        last_pos = pos - 1
        last_char = accessor.char_at_pos(last_pos)
        if DEBUG:
            print "  last_pos: %s" % last_pos
            print "  last_char: %r" % last_char

        # Quick out if the preceding char isn't a trigger char.
        if last_char not in " .(@_":
            if DEBUG:
                print "trg_from_pos: no: %r is not in ' .(@'_" % last_char
            return None

        style = accessor.style_at_pos(last_pos)
        if DEBUG:
            style_names = self.style_names_from_style_num(style)
            print "  style: %s (%s)" % (style, ", ".join(style_names))

        if last_char == "@":
            # Possibly python-complete-pythondoc-tags (the only trigger
            # on '@').
            #
            # Notes:
            # - PythonDoc 2.1b6 started allowing pythondoc tags in doc
            #   strings which we are yet supporting here.
            # - Trigger in comments should only happen if the comment
            #   begins with the "##" pythondoc signifier. We don't
            #   bother checking that (PERF).
            if style in self.comment_styles():
                # Only trigger at start of comment line.
                WHITESPACE = tuple(" \t")
                SENTINEL = 20
                i = last_pos-1
                while i >= max(0, last_pos-SENTINEL):
                    ch = accessor.char_at_pos(i)
                    if ch == "#":
                        return Trigger(self.lang, TRG_FORM_CPLN,
                                       "pythondoc-tags", pos, implicit)
                    elif ch in WHITESPACE:
                        pass
                    else:
                        return None
                    i -= 1
            return None

        # Remaing triggers should never trigger in some styles.
        if (implicit and style in self.implicit_completion_skip_styles and last_char != '_'
            or style in self.completion_skip_styles):
            if DEBUG:
                print "trg_from_pos: no: completion is suppressed "\
                      "in style at %s: %s (%s)"\
                      % (last_pos, style, ", ".join(style_names))
            return None

        if last_char == " ":
            # used for:
            #    * complete-available-imports
            #    * complete-module-members
            #    * complete-available-exceptions

            # Triggering examples ('_' means a space here):
            #   import_                 from_
            # Non-triggering examples:
            #   from FOO import_        Ximport_
            # Not bothering to support:
            #;  if FOO:import_          FOO;import_

            # Typing a space is very common so lets have a quick out before
            # doing the more correct processing:
            if last_pos-1 < 0 or accessor.char_at_pos(last_pos-1) not in "tm,":
                return None

            working_text = accessor.text_range(max(0,last_pos-200),
                                               last_pos)
            line = self._last_logical_line(working_text).strip()
            if not line: return None
            ch = line[-1]
            line = line.replace('\t', ' ')

            # from <|>
            # import <|>
            if line == "from" or line == "import":
                return Trigger(self.lang, TRG_FORM_CPLN,
                               "available-imports", pos, implicit,
                               imp_prefix=())

            # is it "from FOO import <|>" ?
            if line.endswith(" import"):
                if line.startswith('from '):
                    imp_prefix = tuple(line[len('from '):-len(' import')].strip().split('.'))
                    return Trigger(self.lang, TRG_FORM_CPLN,
                               "module-members", pos, implicit,
                               imp_prefix=imp_prefix)

            if line == "except" or line.endswith(" except"):
                return Trigger(self.lang, TRG_FORM_CPLN,
                               "available-exceptions", pos, implicit)

            if ch == ',':
                # is it "from FOO import BAR, <|>" ?
                if line.startswith('from ') and ' import ' in line:
                    imp_prefix = tuple(line[len('from '):line.index(' import')].strip().split('.'))
                    # Need better checks
                    return Trigger(self.lang, TRG_FORM_CPLN,
                               "module-members", pos, implicit,
                               imp_prefix=imp_prefix)

        elif last_char == '.': # must be "complete-object-members" or None
            # If the first non-whitespace character preceding the '.' in the
            # same statement is an identifer character then trigger, if it
            # is a ')', then _maybe_ we should trigger (yes if this is
            # function call paren).
            #
            # Triggering examples:
            #   FOO.            FOO .                       FOO; BAR.
            #   FOO().          FOO.BAR.                    FOO(BAR, BAZ.
            #   FOO().BAR.      FOO("blah();", "blam").     FOO = {BAR.
            #   FOO(BAR.        FOO[BAR.
            #   ...more cases showing possible delineation of expression
            # Non-triggering examples:
            #   FOO..
            #   FOO[1].         too hard to determine sequence element types
            #   from FOO import (BAR.         
            # Not sure if want to support:
            #   "foo".          do we want to support literals? what about
            #                   lists? tuples? dicts?
            working_text = accessor.text_range(max(0,last_pos-200),
                                               last_pos)
            line = self._last_logical_line(working_text).strip()
            if line:
                ch = line[-1]
                if (isident(ch) or isdigit(ch) or ch in '.)'):
                    line = line.replace('\t', ' ')
                    m = _dotted_from_rx.match(line)
                    if m:
                        dots = len(m.group(1).strip())
                        # magic value for imp_prefix, means "from .<|>"
                        imp_prefix = tuple('' for i in xrange(dots+2))
                        return Trigger(self.lang, TRG_FORM_CPLN,
                                       "available-imports", pos, implicit,
                                       imp_prefix=imp_prefix)
                    elif line.startswith('from '):
                        if ' import ' in line:
                            # we're in "from FOO import BAR." territory,
                            # which is not a trigger
                            return None
                        # from FOO.
                        imp_prefix = tuple(line[len('from '):].strip().split('.'))
                        return Trigger(self.lang, TRG_FORM_CPLN,
                                       "available-imports", pos, implicit,
                                       imp_prefix=imp_prefix)
                    elif line.startswith('import '):
                        # import FOO.
                        # figure out the dotted parts of "FOO" above
                        imp_prefix = tuple(line[len('import '):].strip().split('.'))
                        return Trigger(self.lang, TRG_FORM_CPLN,
                                       "available-imports", pos, implicit,
                                       imp_prefix=imp_prefix)
                    else:
                        return Trigger(self.lang, TRG_FORM_CPLN,
                                       "object-members", pos, implicit)
                elif ch in ("\"'"):
                    return Trigger(self.lang, TRG_FORM_CPLN,
                                   "literal-members", pos, implicit,
                                   citdl_expr="str")
            else:
                ch = None
            if DEBUG:
                print "trg_from_pos: no: non-ws char preceding '.' is not "\
                      "an identifier char or ')': %r" % ch
            return None

        elif last_char == "_":
            # used for:
            #    * complete-magic-symbols

            # Triggering examples:
            #   def __<|>init__
            #   if __<|>name__ == '__main__':
            #   __<|>file__

            # Ensure double "__".
            if last_pos-1 < 0 or accessor.char_at_pos(last_pos-1) != "_":
                return None

            beforeChar = None
            beforeStyle = None
            if last_pos-2 >= 0:
                beforeChar = accessor.char_at_pos(last_pos-2)
                beforeStyle = accessor.style_at_pos(last_pos-2)

            if DEBUG:
                print "trg_from_pos:: checking magic symbol, beforeChar: %r" % (beforeChar)
            if beforeChar and beforeChar in "\"'" and beforeStyle in self.string_styles():
                if DEBUG:
                    print "trg_from_pos:: magic-symbols - string"
                return Trigger(self.lang, TRG_FORM_CPLN,
                               "magic-symbols", last_pos-1, implicit,
                               symbolstype="string")

            elif beforeChar == "." and beforeStyle != style:
                # Turned this off, as it interferes with regular "xxx." object
                # completions.
                return None

            if beforeStyle == style:
                # No change in styles between the characters -- abort.
                return None

            text = accessor.text_range(max(0,last_pos-20), last_pos-1).strip()
            if beforeChar and beforeChar in " \t":
                if text.endswith("def"):
                    if DEBUG:
                        print "trg_from_pos:: magic-symbols - def"
                    return Trigger(self.lang, TRG_FORM_CPLN,
                                   "magic-symbols", last_pos-1, implicit,
                                   symbolstype="def")
            if DEBUG:
                print "trg_from_pos:: magic-symbols - global"
            return Trigger(self.lang, TRG_FORM_CPLN,
                           "magic-symbols", last_pos-1, implicit,
                           symbolstype="global", text=text)

        elif last_char == '(':
            # If the first non-whitespace character preceding the '(' in the
            # same statement is an identifer character then trigger calltip,
            #
            # Triggering examples:
            #   FOO.            FOO (                       FOO; BAR(
            #   FOO.BAR(        FOO(BAR, BAZ(               FOO = {BAR(
            #   FOO(BAR(        FOO[BAR(
            # Non-triggering examples:
            #   FOO()(      a function call returning a callable that is
            #               immediately called again is too rare to bother
            #               with
            #   def foo(    might be a "calltip-base-signature", but this
            #               trigger is not yet implemented
            #   import (    will be handled by complete_members
            #   class Foo(  is an "complete-available-classes" trigger,
            #               but this is not yet implemented
            working_text = accessor.text_range(max(0,last_pos-200), last_pos)
            line = self._last_logical_line(working_text).rstrip()
            if line:
                ch = line[-1]
                if isident(ch) or isdigit(ch):
                    # If this is:
                    #   def foo(
                    # then this might be the (as yet unimplemented)
                    # "calltip-base-signature" trigger or it should not be a
                    # trigger point.
                    #
                    # If this is:
                    #   class Foo(
                    # then this should be the (as yet unimplemented)
                    # "complete-available-classes" trigger.
                    line = line.replace('\t', ' ')
                    lstripped = line.lstrip()
                    if lstripped.startswith("def"):
                        if DEBUG: print "trg_from_pos: no: point is function declaration"
                    elif lstripped.startswith("class") and '(' not in lstripped:
                        # Second test is necessary to not exclude:
                        #   class Foo(bar(<|>
                        if DEBUG: print "trg_from_pos: no: point is class declaration"
                    elif lstripped.startswith('from ') and ' import' in lstripped:
                        # Need better checks
                        # is it "from FOO import (<|>" ?
                        imp_prefix = tuple(lstripped[len('from '):lstripped.index(' import')].split('.'))
                        if DEBUG: print "trg_from_pos: from FOO import ("
                        return Trigger(self.lang, TRG_FORM_CPLN,
                                   "module-members", pos, implicit,
                                   imp_prefix=imp_prefix)
                    else:
                        return Trigger(self.lang, TRG_FORM_CALLTIP,
                                       "call-signature", pos, implicit)
                else:
                    if DEBUG:
                        print "trg_from_pos: no: non-ws char preceding "\
                              "'(' is not an identifier char: %r" % ch
            else:
                if DEBUG: print "trg_from_pos: no: no chars preceding '('"
            return None

    def _last_logical_line(self, text):
        lines = text.splitlines(0) or ['']
        logicalline = lines.pop()
        while lines and lines[-1].endswith('\\'):
            logicalline = lines.pop()[:-1] + ' ' + logicalline
        return logicalline



class PythonImportHandler(ImportHandler):
    lang = lang #XXX do this for other langs as well
    PATH_ENV_VAR = "PYTHONPATH"
    sep = '.'

    def __init__(self, mgr):
        ImportHandler.__init__(self, mgr)
        self.__stdCIXScanId = None

    #TODO: may not be used. If so, drop it.
    def _shellOutForPath(self, compiler):
        import process
        argv = [compiler, "-c", "import sys; print('\\n'.join(sys.path))"]
        # Can't use -E to ignore PYTHONPATH because older versions of
        # Python don't have it (e.g. v1.5.2).
        env = dict(os.environ)
        if "PYTHONPATH" in env: del env["PYTHONPATH"]
        if "PYTHONHOME" in env: del env["PYTHONHOME"]
        if "PYTHONSTARTUP" in env: del env["PYTHONSTARTUP"]

        p = process.ProcessOpen(argv, env=env, stdin=None)
        stdout, stderr = p.communicate()
        retval = p.returncode
        path = [line for line in stdout.splitlines(0)]
        if path and (path[0] == "" or path[0] == os.getcwd()):
            del path[0] # cwd handled separately
        return path

    def setCorePath(self, compiler=None, extra=None):
        if compiler is None:
            import which
            compiler = which.which("python")
        self.corePath = self._shellOutForPath(compiler)

    def _findScannableFiles(self,
                            (files, searchedDirs, skipRareImports,
                             importableOnly),
                            dirname, names):
        if sys.platform.startswith("win"):
            cpath = dirname.lower()
        else:
            cpath = dirname
        if cpath in searchedDirs:
            while names:
                del names[0]
            return
        else:
            searchedDirs[cpath] = 1
        if skipRareImports:
            if (basename(dirname) == "encodings"
                and "undefined.py" in names):
                # Skip most of the specific encoding definitions (saves
                # about 50 files).
                names = [n for n in names if n == "__init__.py"
                         or os.path.splitext(n)[0].endswith("_codec")]
        for i in range(len(names)-1, -1, -1): # backward so can del from list
            path = os.path.join(dirname, names[i])
            if os.path.isdir(path):
                if skipRareImports:
                    # Skip Python's test package (saves over 200 files)
                    # and other likely test dirs.
                    if names[i] in ("test", "tests"):
                        del names[i]
                        continue
                if importableOnly:
                    possibles = [os.path.join(path, "__init__.py"),
                                 os.path.join(path, "__init__.pyc"),
                                 os.path.join(path, "__init__.pyo")]
                    for possible in possibles:
                        if os.path.isfile(possible):
                            break
                    else:
                        del names[i] # don't traverse non-package dirs
                        continue
                if path.endswith(os.path.join("win32com", "gen_py")):
                    del names[i]
                    continue
            elif os.path.splitext(names[i])[1] in self._gen_suffixes():
                #XXX The list of Python extensions should be settable on
                #    the ImportHandler and Komodo should set whatever is
                #    set in prefs.
                #XXX This check for "Python" files should probably include
                #    python scripts, which might likely not have the
                #    extension: need to grow filetype-from-content smarts.
                files.append(path)

    def genScannableFiles(self, path=None, skipRareImports=False,
                          importableOnly=False):
        if path is None:
            path = self._getPath()
        searchedDirs = {}
        for dirname in path:
            #XXX Use os.walk().
            files = []
            os.path.walk(dirname, self._findScannableFiles,
                         (files, searchedDirs, skipRareImports,
                          importableOnly))
            for file in files:
                yield file

    def _gen_suffixes(self):
        """Generate a sequence of scannable file suffixes in the
           preferred order of scanning. 
        """
        yield ".py"
        yield ".pyw"
        
        if _SCAN_BINARY_FILES:
            yield ".pyc"
            yield ".pyo"
            for suffix, mode, mod_type in imp.get_suffixes():
                if suffix[0] == '.' and mod_type  == imp.C_EXTENSION:
                    yield suffix

    def find_importables_in_dir(self, imp_dir):
        """See citadel.py::ImportHandler.find_importables_in_dir() for
        details.

        Importables for Python look like this:
            {"foo":    ("foo.py",             None,       False),
             "foolib": ("foolib/__init__.py", "__init__", False),
             "bar":    ("bar.pyc",            None,       False),
             "baz":    ("baz.pyo",            None,       False),
             "qoox":   ("qoox.pyd",           None,       False),
             "qooz":   ("qooz.so",            None,       False),

        Note: .pyd are .so handling depends on the platform.
        
        If several files happen to have the same name but different
        suffixes, the one with preferred suffix wins. The suffixe preference
        is defined by the order of elements in the sequence generated
        by _gen_suffixes().
        
        This particularly means that sources always win over binaries.
        """
        if imp_dir == "<Unsaved>":
            #TODO: stop these getting in here.
            return {}
        
        importables = {}
        
        if os.path.isdir(imp_dir):
            suffixes = dict((s, i) for i, s
                                   in enumerate(self._gen_suffixes(), 1))
            modules = []
            for name in os.listdir(imp_dir):
                mod, suffix = os.path.splitext(name)
                if mod != '__init__':
                    init = os.path.join(name, '__init__.py')
                    if os.path.exists(os.path.join(imp_dir, init)):
                            modules.append((0, name, (init, '__init__', False)))
                    else:
                        if suffix in suffixes:
                            modules.append((suffixes[suffix], mod,
                                            (name, None, False)))
            
            modules.sort(key=lambda mod: mod[0])
            
            for _, mod, importable in modules:
                if mod not in importables:
                    importables[mod] = importable
        
        return importables


class PythonCILEDriver(CILEDriver):
    lang = lang

    def scan_purelang(self, buf):
        #log.warn("TODO: python cile that uses elementtree")
        content = buf.accessor.text
        if isinstance(content, unicode):
            encoding = buf.encoding or "utf-8"
            try:
                content = content.encode(encoding)
            except UnicodeError, ex:
                raise CodeIntelError("cannot encode Python content as %r (%s)"
                                     % (encoding, ex))
        el = pythoncile.scan_et(content, buf.path, lang=self.lang)
        return el

    def scan_binary(self, buf):
        from codeintel2 import pybinary
        python = buf.langintel.interpreter_from_env(buf.env)
        if not python:
            raise CodeIntelError("cannot find a usable Python interpreter")
        cix = pybinary.safe_scan(buf.path, python)
        return tree_from_cix(cix)


#---- internal support stuff




#---- registration

def register(mgr):
    """Register language support with the Manager."""
    mgr.set_lang_info(lang,
                      silvercity_lexer=PythonLexer(),
                      buf_class=PythonBuffer,
                      langintel_class=PythonLangIntel,
                      import_handler_class=PythonImportHandler,
                      cile_driver_class=PythonCILEDriver,
                      is_cpln_lang=True)

