#!/usr/bin/env python2.7
# -*- coding: utf-8 -*-

################################################################################
#
#  qooxdoo - the new era of web development
#
#  http://qooxdoo.org
#
#  Copyright:
#    2006-2010 1&1 Internet AG, Germany, http://www.1und1.de
#
#  License:
#    LGPL: http://www.gnu.org/licenses/lgpl.html
#    EPL: http://www.eclipse.org/org/documents/epl-v10.php
#    See the LICENSE file in the project's top-level directory for details.
#
#  Authors:
#    * Thomas Herchenroeder (thron7)
#
################################################################################

'''provide extra path functions beyond os.path'''

import os, sys, re, types
import urllib, urlparse
from misc.NameSpace import NameSpace

def getCommonSuffix(p1, p2):
    #p1, p2 = map(os.path.normcase, (p1, p2)) # this helps on win32 for comparison, but breaks bug#1507
    return getCommonSuffixS(p1, p2)  # dispatch to real implementation


def getCommonPrefix(p1, p2):
    #p1, p2 = map(os.path.normcase, (p1, p2)) # this helps on win32 for comparison, but breaks bug#1507
    return getCommonPrefixS(p1, p2)  # dispatch to real implementation

# -- string-based versions ----------------------------------------------------

def _getCommonPrefixS(p1, p2):  # String-based
    '''computes the common prefix of p1, p2, and returns the common prefix and the two
       different suffixes'''
    pre = sfx1 = sfx2 = ""

    # catch corner cases
    if (len(p1) == 0 or len(p2) == 0): return "",p1,p2
    if p1 == p2: return p1,"",""

    # treat the others
    len_p1 = len(p1)
    len_p2 = len(p2)
    # compare paths char by char
    for i in range(len_p1):
        k = i      # k will keep the last common index - i don't trust 'i' after the for loop
        if i >= len_p2:
            k -= 1 # correct to last common index (a value of -1 is fine)
            break
        elif p1[i] == p2[i]:
            continue
        else:
            k -= 1 # correct to last common index
            break
    # assert: 'k' points to last common char of the operands, -1 means no commonality

    # make sure path elements are treated atomic (no split in the middle of a dir name)
    # check whether the commonality did not end in a dir boundary
    if (k==-1): # there is no commonality
        pass
    elif (p1[k] != os.sep):  # the last common char was not a '/'
        # need longer path for later test
        if len_p1 > len_p2: longer = p1
        else              : longer = p2

        # check for cases where a prefix ending seemingly 'in between' is ok
        if (p1 == p2):                   # they're identical (redunant here, but for clarity)
            pass                            # that's ok
        elif (k+1 in (len_p1,len_p2)     # one ends at k
            and longer[k+1] == os.sep):  # and the longer continues with '/'
            pass                            # that's ok
        else:
            # Then: we have to step backwards to find the last os.sep
            # calculate backwards to the last encountered os.sep or the beginning of the string
            #print ">>> searching backward"
            j = p1.rfind(os.sep,0,k)
            if j >-1:
                k = j 
            else: # there is no os.sep in the commen prefix so use start of string
                k = j  # this complies with the suffix "[k+1:]" slice later
    # assert: 'k' points to dir boundary (os.sep or EOS)

    # assign results
    pre  = p1[0:k+1]
    sfx1 = p1[k+1:]
    sfx2 = p2[k+1:]

    return pre,sfx1,sfx2


def getCommonPrefixS(p1, p2):  # String-based
    p1, p2 = map(os.path.normpath, (p1, p2))
    # undo normpath abnormalities
    if p1=='.': p1=''
    if p2=='.': p2=''
    pre,sfx1,sfx2 = _getCommonPrefixS(p1, p2)

    # fix surrounding os.sep's
    # the intention here is to clear unnecessary trailing separators, and 
    # artificial leading separators that stem from the splitting
    if len(pre)>1:        # only if there's a real prefix (not '' or just '/')
        if pre.endswith(os.sep): # clear trailing '/'
            pre  = pre[:-len(os.sep)]
        if len(sfx1)>1 and sfx1.startswith(os.sep): # clear leading '/'
            sfx1 = sfx1[len(os.sep):]
        if len(sfx2)>1 and sfx2.startswith(os.sep): # clear leading '/'
            sfx2 = sfx2[len(os.sep):]

    #for elem in pre,sfx1,sfx2:
    #    if isinstance(elem, types.StringTypes):
    #        elem = elem.decode('utf-8')

    return pre,sfx1,sfx2


def getCommonSuffixS(p1, p2):  # String-based
    'use getCommonPrefixS, but with reversed arguments and return values'
    p1, p2 = map(os.path.normpath, (p1, p2))
    # undo normpath abnormalities
    if p1=='.': p1=''
    if p2=='.': p2=''

    p1r = p1[::-1]  # this is string reverse in Python
    p2r = p2[::-1]
    sfx, pre1, pre2 = _getCommonPrefixS(p1r, p2r)
    sfx  = sfx[::-1]
    pre1 = pre1[::-1]
    pre2 = pre2[::-1]

    # fix surrounding os.sep's
    if (len(pre1)==0 and len(pre2)==0):  # leave ('','',sfx) alone
        pass
    elif sfx.startswith(os.sep):  # don't return a real suffix that looks like an absolute path
        sfx = sfx[len(os.sep):]   # skip the leading os.sep
        if pre1=='': pre1 += os.sep    # and push it to the prefixes
        if pre2=='': pre2 += os.sep
    if len(pre1)>1 and pre1.endswith(os.sep):
        pre1 = pre1[:-len(os.sep)]
    if len(pre2)>1 and pre2.endswith(os.sep):
        pre2 = pre2[:-len(os.sep)]

    return pre1, pre2, sfx
    #return pre1.decode('utf-8'),pre2.decode('utf-8'),sfx.decode('utf-8')

# -- array-based versions ----------------------------------------------------

def _getCommonPrefixA(pa1, pa2):
    '''comparing lists of strings, returning common head list and separate tail lists'''
    def getCommonPrefixRec(pre, sfx1, sfx2):
        if sfx1 == [] or sfx2 == []:
            return pre, sfx1, sfx2
        if sfx1[0] == sfx2[0]:
            pre.append(sfx1[0])
            return getCommonPrefixRec(pre, sfx1[1:], sfx2[1:])
        else:
            return pre, sfx1, sfx2

    def getCommonPrefixIter(_, pa1, pa2):
        prefix  = []
        sfx1    = []
        sfx2    = []
        if pa1 == [] or pa2 == []:
            return prefix, pa1, pa2
        len_pa1 = len(pa1)
        len_pa2 = len(pa2)
        for i in range(min(len_pa1, len_pa2)):
            if pa1[i] == pa2[i]:
                prefix.append(pa1[i])
            else:
                break
        if len_pa1 >= i+1:
            sfx1 = pa1[i+1:]
        if len_pa2 >= i+1:
            sfx2 = pa2[i+1:]
        return prefix, sfx1, sfx2

    #return getCommonPrefixRec([], pa1, pa2)
    return getCommonPrefixIter([], pa1, pa2)


def getCommonPrefixA(p1, p2):  # Array-based
    '''treat directory names atomic, so that "a/b.1/c" and "a/b.2/d" will have
       ("a", "b.1/c", "b.2/d") and not ("a/b.", "1/c", "2/d")'''
    
    if (len(p1) == 0 or len(p2) == 0): return "",p1,p2
    # don't compare a mix of absolute and relative paths
    if ((p1[0]==os.sep and p2[0]!=os.sep) or
        (p1[0]!=os.sep and ps2[0]==os.sep)):
        return "",p1,p2
    pa1 = p1.split(os.sep)
    pa2 = p2.split(os.sep)
    prea, sfx1a, sfx2a = _getCommonPrefixA(pa1, pa2)

    # the lambda is necessary to coerce a single array argument into a varargs list for join()
    # (through *x), and to catch the empty list corner case, since join chokes on empty
    # argument lists
    return map(lambda x: ((len(x)>0 and os.path.join(*x)) or ""), (prea, sfx1a, sfx2a))


def getCommonSuffixA(p1, p2):  # Array-based
    '''uses _getCommonPrefixA as well by reversing arguments and return values; such a pitty that
       there is no functional equivalent to array.reverse(), which is destructive :-('''
    
    if (len(p1) == 0 or len(p2) == 0): return p1,p2,""
    pa1 = p1.split(os.sep)
    pa1.reverse()
    pa2 = p2.split(os.sep)
    pa2.reverse()
    sfxa, pre1a, pre2a = _getCommonPrefixA(pa1, pa2)
    pre1a.reverse()
    pre2a.reverse()
    sfxa.reverse()

    return map(lambda x: ((len(x)>0 and os.path.join(*x)) or ""), (pre1a, pre2a, sfxa))

# -- other helpers ------------------------------------------------------------

def posifyPath(path):
    "replace '\' with '/' in strings"
    posix_sep = '/'
    npath = path.replace(os.sep, posix_sep)
    return npath


def rel_from_to(fromdir, todir, commonroot=None):
    def part_to_ups (part):
        #"../.."
        if part == '': return "."
        a1 = part.split(os.sep)
        s  = []
        for i in a1:           
          s.append( "..")
        return os.sep.join(s)

    if not os.path.isabs(fromdir):
        fromdir = os.path.abspath(fromdir)
    if not os.path.isabs(todir):
        todir   = os.path.abspath(todir)
    pre,sfx1,sfx2 = getCommonPrefix(fromdir,todir)
    ups = part_to_ups(sfx1)

    return os.path.join(ups,sfx2)

# -- test functions -----------------------------------------------------------

def _testCP():
    'test getCommonPrefix()'
    tests = [
        (('', ''), ('','','')),                                                             # #1
        (('a', ''), ('','a','')),                                                           # #2
        (('/a', ''), ('','/a','')),                                                         # #3
        (('', 'a'), ('','','a')),                                                           # #4
        (('', '/a'), ('','','/a')),                                                         # #5
        (('/a', 'e/f/g'), ('','/a','e/f/g')),                                               # #6
        (('/a/b/c', '/a/b/c/d/e'), ('/a/b/c','','d/e')),                                    # #7
        (('/a/b/c', '/a/b/c/d/'), ('/a/b/c','','d')),                                       # #8
        (('/a/b/c', '/a/b/c/d'), ('/a/b/c','','d')),                                        # #9
        (('/a/b/c', '/a/b/c/'), ('/a/b/c','','')),                                          # #10
        (('/a/b/c', '/a/b/c'), ('/a/b/c','','')),                                           # #11
        (('/a/b/c', '/a/b/'), ('/a/b','c','')),                                             # #12
        (('/a/b/c', '/a/b'), ('/a/b','c','')),                                              # #13
        (('/a/b/c', '/a/'), ('/a','b/c','')),                                               # #14
        (('/a/b/c', '/a'), ('/a','b/c','')),                                                # #15
        (('/a/b/c', '/'), ('/','a/b/c','')),                                                # #16
        (('/a/b/x.1/c', '/a/b/x.2/c'),   ('/a/b','x.1/c','x.2/c')),                         # #17
        (('x.1/a/b/c', 'x.2/a/b/c/d'), ('','x.1/a/b/c','x.2/a/b/c/d')),                     # #18
        (('/a/b/x1', '/a/b/x1y'),   ('/a/b','x1','x1y')),                                   # #19
        (('a/b/./c', 'a/b/c/d'), ('a/b/c','','d')),                                         # #20
        (('a/b/c', 'a/b/c/././d'), ('a/b/c','','d')),                                       # #21
        (('a/b/../c', 'a/c/d'), ('a/c','','d')),                                            # #22
        (('a/b/c', 'a/b/c/../d'), ('a/b','c','d')),                                         # #23
        (('../../../a/b/c', '../../a/b/c/d'), ('../..','../a/b/c','a/b/c/d')),              # #24
        (('../../../a/b/c', '../../x/y/../z/../../../a/b/c/d'), ('../../../a/b/c','','d')), # #25
    ]

    for idx, t in enumerate(tests):
        x = getCommonPrefix(*t[0])
        assert x == t[1], "#%d: %r !=> %r" % (idx+1, t[0], x)


def _testCS():
    'test getCommonSuffix()'
    tests = [
        (('', ''), ('','','')),                                                             # #1
        (('a', ''), ('a','','')),                                                           # #2
        (('/a', ''), ('/a','','')),                                                         # #3
        (('', 'a'), ('','a','')),                                                           # #4
        (('', '/a'), ('','/a','')),                                                         # #5
        (('/a', 'e/f/g'), ('/a','e/f/g','')),                                               # #6
        (('a/b/c','a/b/c'), ('','','a/b/c')),                                               # #7
        (('/a/b/c','/a/b/c'), ('','','/a/b/c')),                                            # #8
        (('x/y/a/b/c','/a/b/c'), ('x/y','/','a/b/c')),                                      # #9
        (('/y/a/b/c','/a/b/c'), ('/y','/','a/b/c')),                                        # #10
        (('y/a/b/c','/a/b/c'), ('y','/','a/b/c')),                                          # #11
        (('/a/b/c','/a/b/c'), ('','','/a/b/c')),                                            # #12
        (('a/b/c','/a/b/c'), ('','/','a/b/c')),                                             # #13
        (('/b/c','/a/b/c'), ('/','/a','b/c')),                                              # #14
        (('b/c','/a/b/c'), ('','/a','b/c')),                                                # #15
        (('/c','/a/b/c'), ('/','/a/b','c')),                                                # #16
        (('c','/a/b/c'), ('','/a/b','c')),                                                  # #17
        (('','/a/b/c'), ('','/a/b/c','')),                                                  # #18
    ]

    for t in tests:
        x = getCommonSuffix(*t[0])
        assert x == t[1], "%r != %r" % (x, t[1])
        

# -- Path-like Classes --------------------------------------------------------

class BasePath(object):

    def __init__ (self, val=None):
        self._data = None
        self.value(val)
    
    def value(self, val=None):
        mval = self._data
        if val != None:
            assert isinstance(val, types.StringTypes)
            self._data = unicode(val)
        return mval

URL          = NameSpace()
URL.PROT_SCH = 0
URL.NET_LOC  = 1
URL.PATH     = 2
URL.PARAMS   = 3
URL.QUERY    = 4
URL.FRAG     = 5

class OsPath(BasePath):

    def __init__(self, val=None):
        super(OsPath, self).__init__(val)
        self._data = os.path.normpath(self._data)

    def join(self, other):
        val = os.path.join(self.value(), other.value())
        val = os.path.normpath(val)
        return OsPath(val)

    def toUri(self):
        uri = self.value()
        uri = os.path.normpath(uri)
        uri = posifyPath(uri)
        return uri


class Uri(BasePath):

    def __init__(self, val=None):
        self._is_encoded = False
        super(Uri, self).__init__(val)
        uri = self._data
        if os.path.splitdrive(uri)[0] != u'':
            nuri = u'file:' + urllib.pathname2url(uri)
            self._is_encoded = True
        elif not re.search(r'^[a-zA-Z]+://', uri): # it is without 'http://'
            nuri = posifyPath(uri)
        else:
            nuri = uri
        self._data = nuri

    thisdirs = ['.', './', './.']  # ways of saying "this directory"

    def join(self, other):
        some_encoded = False
        if self._is_encoded or other._is_encoded:
            some_encoded = True
        if not some_encoded:  # use values verbatim for urljoin
            val1 = self.value()
            val2 = other.value()
        else:                 # use all encoded values for urljoin
            if self._is_encoded:
                val1 = self.value()
            else:
                val1 = self.encodedValue()
            if other._is_encoded:
                val2 = other.value()
            else:
                val2 = other.encodedValue()
        if (val1 in self.thisdirs
            and val2 in self.thisdirs):
            # urlparse.urljoin collapses e.g. "./" and "." into ""!
            nuri = Uri(".")
        else:
            nuri = Uri(urlparse.urljoin(val1, val2))
        if some_encoded:
            nuri._is_encoded = True
        return nuri

    def ensureTrailingSlash(self):
        'ensure trailing /'
        val = self.value()
        if val[-1] != '/':
            self.value(val + '/')
            
    def ensureNoTrailingSlash(self):
        'ensure no trailing /'
        val = self.value()
        if val[-1] == "/":
            self.value(val[:-1])
            
    def encodedValue(self, val=None):
        v = super(Uri, self).value(val)
        if self._is_encoded:
            return v
        else:
            return self._encodeUri(v)

    def _encodeUri(self, uri=None):
        # apply urllib.quote, but only to path part of uri
        if not uri:
            uri   = self._data
        if True:
            parts = urlparse.urlparse(uri)
            nparts= []
            for i in range(len(parts)):
                if i<=1:   # skip schema and netlock parts
                    nparts.append(parts[i])
                else:
                    nparts.append(urllib.quote(parts[i].encode('utf-8')))
            nuri  = urlparse.urlunparse(nparts)
        return nuri


