###
# Copyright (c) 2002-2005, Jeremiah Fincher
# Copyright (c) 2008, James Vega
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#   * Redistributions of source code must retain the above copyright notice,
#     this list of conditions, and the following disclaimer.
#   * Redistributions in binary form must reproduce the above copyright notice,
#     this list of conditions, and the following disclaimer in the
#     documentation and/or other materials provided with the distribution.
#   * Neither the name of the author of this software nor the name of
#     contributors to this software may be used to endorse or promote products
#     derived from this software without specific prior written consent.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
###

import os
import sys
import ast
import time
import types
import textwrap
import traceback
import collections
from itertools import imap

from str import format
from file import mktemp

import crypt

def abbrev(strings, d=None):
    """Returns a dictionary mapping unambiguous abbreviations to full forms."""
    def eachSubstring(s):
        for i in xrange(1, len(s)+1):
            yield s[:i]
    if len(strings) != len(set(strings)):
        raise ValueError, \
              'strings given to utils.abbrev have duplicates: %r' % strings
    if d is None:
        d = {}
    for s in strings:
        for abbreviation in eachSubstring(s):
            if abbreviation not in d:
                d[abbreviation] = s
            else:
                if abbreviation not in strings:
                    d[abbreviation] = None
    removals = []
    for key in d:
        if d[key] is None:
            removals.append(key)
    for key in removals:
        del d[key]
    return d

def timeElapsed(elapsed, short=False, leadingZeroes=False, years=True,
                weeks=True, days=True, hours=True, minutes=True, seconds=True):
    """Given <elapsed> seconds, returns a string with an English description of
    the amount of time passed.  leadingZeroes determines whether 0 days, 0
    hours, etc. will be printed; the others determine what larger time periods
    should be used.
    """
    ret = []
    before = False
    def Format(s, i):
        if i or leadingZeroes or ret:
            if short:
                ret.append('%s%s' % (i, s[0]))
            else:
                ret.append(format('%n', (i, s)))
    elapsed = int(elapsed)

    # Handle negative times
    if elapsed < 0:
        before = True
        elapsed = -elapsed

    assert years or weeks or days or \
           hours or minutes or seconds, 'One flag must be True'
    if years:
        (yrs, elapsed) = (elapsed // 31536000, elapsed % 31536000)
        Format('year', yrs)
    if weeks:
        (wks, elapsed) = (elapsed // 604800, elapsed % 604800)
        Format('week', wks)
    if days:
        (ds, elapsed) = (elapsed // 86400, elapsed % 86400)
        Format('day', ds)
    if hours:
        (hrs, elapsed) = (elapsed // 3600, elapsed % 3600)
        Format('hour', hrs)
    if minutes or seconds:
        (mins, secs) = (elapsed // 60, elapsed % 60)
        if leadingZeroes or mins:
            Format('minute', mins)
        if seconds:
            leadingZeroes = True
            Format('second', secs)
    if not ret:
        raise ValueError, 'Time difference not great enough to be noted.'
    result = ''
    if short:
        result = ' '.join(ret)
    else:
        result = format('%L', ret)
    if before:
        result += ' ago'
    return result

def findBinaryInPath(s):
    """Return full path of a binary if it's in PATH, otherwise return None."""
    cmdLine = None
    for dir in os.getenv('PATH').split(':'):
        filename = os.path.join(dir, s)
        if os.path.exists(filename):
            cmdLine = filename
            break
    return cmdLine

def sortBy(f, L):
    """Uses the decorate-sort-undecorate pattern to sort L by function f."""
    for (i, elt) in enumerate(L):
        L[i] = (f(elt), i, elt)
    L.sort()
    for (i, elt) in enumerate(L):
        L[i] = L[i][2]

def saltHash(password, salt=None, hash='sha'):
    if salt is None:
        salt = mktemp()[:8]
    if hash == 'sha':
        hasher = crypt.sha
    elif hash == 'md5':
        hasher = crypt.md5
    return '|'.join([salt, hasher((salt + password).encode('utf8')).hexdigest()])

_astStr2 = ast.Str if sys.version_info[0] < 3 else ast.Bytes
def safeEval(s, namespace={'True': True, 'False': False, 'None': None}):
    """Evaluates s, safely.  Useful for turning strings into tuples/lists/etc.
    without unsafely using eval()."""
    try:
        node = ast.parse(s)
    except SyntaxError, e:
        raise ValueError, 'Invalid string: %s.' % e
    nodes = ast.parse(s).body
    if not nodes:
        if node.__class__ is ast.Module:
            return node.doc
        else:
            raise ValueError, format('Unsafe string: %q', s)
    node = nodes[0]
    def checkNode(node):
        if node.__class__ is ast.Expr:
            node = node.value
        if node.__class__ in (ast.Num,
                              ast.Str,
                              _astStr2):
            return True
        elif node.__class__ in (ast.List,
                              ast.Tuple):
            return all([checkNode(x) for x in node.elts])
        elif node.__class__ is ast.Dict:
            return all([checkNode(x) for x in node.values]) and \
                    all([checkNode(x) for x in node.values])
        elif node.__class__ is ast.Name:
            if node.id in namespace:
                return True
            else:
                return False
        else:
            return False
    if checkNode(node):
        return eval(s, namespace, namespace)
    else:
        raise ValueError, format('Unsafe string: %q', s)

def exnToString(e):
    """Turns a simple exception instance into a string (better than str(e))"""
    strE = str(e)
    if strE:
        return '%s: %s' % (e.__class__.__name__, strE)
    else:
        return e.__class__.__name__

class IterableMap(object):
    """Define .iteritems() in a class and subclass this to get the other iters.
    """
    def iteritems(self):
        raise NotImplementedError

    def iterkeys(self):
        for (key, _) in self.iteritems():
            yield key
    __iter__ = iterkeys

    def itervalues(self):
        for (_, value) in self.iteritems():
            yield value

    def items(self):
        return list(self.iteritems())

    def keys(self):
        return list(self.iterkeys())

    def values(self):
        return list(self.itervalues())

    def __len__(self):
        ret = 0
        for _ in self.iteritems():
            ret += 1
        return ret

    def __nonzero__(self):
        for _ in self.iteritems():
            return True
        return False


class InsensitivePreservingDict(collections.MutableMapping):
    def key(self, s):
        """Override this if you wish."""
        if s is not None:
            s = s.lower()
        return s

    def __init__(self, dict=None, key=None):
        if key is not None:
            self.key = key
        self.data = {}
        if dict is not None:
            self.update(dict)

    def __repr__(self):
        return '%s(%s)' % (self.__class__.__name__,
                           super(InsensitivePreservingDict, self).__repr__())

    def fromkeys(cls, keys, s=None, dict=None, key=None):
        d = cls(dict=dict, key=key)
        for key in keys:
            d[key] = s
        return d
    fromkeys = classmethod(fromkeys)

    def __getitem__(self, k):
        return self.data[self.key(k)][1]

    def __setitem__(self, k, v):
        self.data[self.key(k)] = (k, v)

    def __delitem__(self, k):
        del self.data[self.key(k)]

    def __iter__(self):
        return iter(self.data)

    def __len__(self):
        return len(self.data)

    def iteritems(self):
        return self.data.itervalues()

    def keys(self):
        L = []
        for (k, _) in self.iteritems():
            L.append(k)
        return L

    def __reduce__(self):
        return (self.__class__, (dict(self.data.values()),))


class NormalizingSet(set):
    def __init__(self, iterable=()):
        iterable = imap(self.normalize, iterable)
        super(NormalizingSet, self).__init__(iterable)

    def normalize(self, x):
        return x

    def add(self, x):
        return super(NormalizingSet, self).add(self.normalize(x))

    def remove(self, x):
        return super(NormalizingSet, self).remove(self.normalize(x))

    def discard(self, x):
        return super(NormalizingSet, self).discard(self.normalize(x))

    def __contains__(self, x):
        return super(NormalizingSet, self).__contains__(self.normalize(x))
    has_key = __contains__

def stackTrace(frame=None, compact=True):
    if frame is None:
        frame = sys._getframe()
    if compact:
        L = []
        while frame:
            lineno = frame.f_lineno
            funcname = frame.f_code.co_name
            filename = os.path.basename(frame.f_code.co_filename)
            L.append('[%s|%s|%s]' % (filename, funcname, lineno))
            frame = frame.f_back
        return textwrap.fill(' '.join(L))
    else:
        return traceback.format_stack(frame)

def callTracer(fd=None, basename=True):
    if fd is None:
        fd = sys.stdout
    def tracer(frame, event, _):
        if event == 'call':
            code = frame.f_code
            lineno = frame.f_lineno
            funcname = code.co_name
            filename = code.co_filename
            if basename:
                filename = os.path.basename(filename)
            print >>fd, '%s: %s(%s)' % (filename, funcname, lineno)
    return tracer

# vim:set shiftwidth=4 softtabstop=4 expandtab textwidth=79: