"""
specialized local path implementation.

This Path implementation offers some methods like chmod(), owner()
and so on that may only make sense on unix.

"""
from __future__ import generators
import sys, os, stat, re, atexit
import py
from py.__.path import common

iswin32 = sys.platform == "win32"

if iswin32: 
    from py.__.path.local.win import WinMixin as PlatformMixin
else:
    from py.__.path.local.posix import PosixMixin as PlatformMixin

class LocalPath(common.FSPathBase, PlatformMixin):
    """ Local path implementation offering access/modification
        methods similar to os.path.
    """
    _path_cache = {}
    
    sep = os.sep
    class Checkers(common.FSCheckers):
        def _stat(self):
            try:
                return self._statcache
            except AttributeError:
                try:
                    self._statcache = self.path.stat()
                except py.error.ELOOP:
                    self._statcache = self.path.lstat()
                return self._statcache

        def dir(self):
            return stat.S_ISDIR(self._stat().mode)

        def file(self):
            return stat.S_ISREG(self._stat().mode)

        def exists(self):
            return self._stat()

        def link(self):
            st = self.path.lstat()
            return stat.S_ISLNK(st.mode)

    def __new__(cls, path=None):
        """ Initialize and return a local Path instance.

        Path can be relative to the current directory.
        If it is None then the current working directory is taken.
        Note that Path instances always carry an absolute path.
        Note also that passing in a local path object will simply return
        the exact same path object. Use new() to get a new copy.
        """
        if isinstance(path, common.FSPathBase):
            if path.__class__ == cls:
                return path
            path = path.strpath
        # initialize the path
        self = object.__new__(cls)
        if not path:
            self.strpath = os.getcwd()
        elif isinstance(path, str):
            self.strpath = os.path.abspath(os.path.normpath(str(path)))
        else:
            raise ValueError("can only pass None, Path instances "
                             "or non-empty strings to LocalPath")
        assert isinstance(self.strpath, str)
        return self

    def __hash__(self):
        return hash(self.strpath)

    def computehash(self, hashtype="md5", chunksize=524288):
        """ return hexdigest of hashvalue for this file. """
        hash = self._gethashinstance(hashtype)
        f = self.open('rb')
        try:
            while 1:
                buf = f.read(chunksize)
                if not buf:
                    return hash.hexdigest()
                hash.update(buf) 
        finally:
            f.close()

    def new(self, **kw):
        """ create a modified version of this path.
            the following keyword arguments modify various path parts:

              a:/some/path/to/a/file.ext
              ||                            drive
                |-------------|             dirname
                                |------|    basename
                                |--|        purebasename
                                    |--|    ext
        """
        obj = object.__new__(self.__class__)
        drive, dirname, basename, purebasename,ext = self._getbyspec(
             "drive,dirname,basename,purebasename,ext")
        if 'basename' in kw:
            if 'purebasename' in kw or 'ext' in kw:
                raise ValueError("invalid specification %r" % kw)
        else:
            pb = kw.setdefault('purebasename', purebasename)
            try:
                ext = kw['ext']
            except KeyError:
                pass
            else:
                if ext and not ext.startswith('.'):
                    ext = '.' + ext
            kw['basename'] = pb + ext

        kw.setdefault('drive', drive)
        kw.setdefault('dirname', dirname)
        kw.setdefault('sep', self.sep)
        obj.strpath = os.path.normpath(
            "%(drive)s%(dirname)s%(sep)s%(basename)s" % kw)
        return obj
    
    def _getbyspec(self, spec):
        """ return a sequence of specified path parts.  'spec' is
            a comma separated string containing path part names.
            according to the following convention:
            a:/some/path/to/a/file.ext
            ||                            drive
              |-------------|             dirname
                              |------|    basename
                              |--|        purebasename
                                  |--|    ext
        """
        res = []
        parts = self.strpath.split(self.sep)

        args = filter(None, spec.split(',') )
        append = res.append
        for name in args:
            if name == 'drive':
                append(parts[0])
            elif name == 'dirname':
                append(self.sep.join(['']+parts[1:-1]))
            else:
                basename = parts[-1]
                if name == 'basename':
                    append(basename)
                else:
                    i = basename.rfind('.')
                    if i == -1:
                        purebasename, ext = basename, ''
                    else:
                        purebasename, ext = basename[:i], basename[i:]
                    if name == 'purebasename':
                        append(purebasename)
                    elif name == 'ext':
                        append(ext)
                    else:
                        raise ValueError, "invalid part specification %r" % name
        return res

    def join(self, *args, **kwargs):
        """ return a new path by appending all 'args' as path
        components.  if abs=1 is used restart from root if any
        of the args is an absolute path.
        """
        if not args:
            return self
        strpath = self.strpath
        sep = self.sep
        strargs = [str(x) for x in args]
        if kwargs.get('abs', 0):
            for i in range(len(strargs)-1, -1, -1):
                if os.path.isabs(strargs[i]):
                    strpath = strargs[i]
                    strargs = strargs[i+1:]
                    break
        for arg in strargs:
            arg = arg.strip(sep)
            if py.std.sys.platform == 'win32':
                # allow unix style paths even on windows.
                arg = arg.strip('/')
                arg = arg.replace('/', sep)
            if arg:
                if not strpath.endswith(sep):
                    strpath += sep
                strpath += arg
        obj = self.new()
        obj.strpath = os.path.normpath(strpath)
        return obj

    def __eq__(self, other):
        s1 = str(self)
        s2 = str(other)
        if iswin32: 
            s1 = s1.lower()
            s2 = s2.lower()
        return s1 == s2

    def open(self, mode='r'):
        """ return an opened file with the given mode. """
        return self._callex(open, self.strpath, mode)

    def listdir(self, fil=None, sort=None):
        """ list directory contents, possibly filter by the given fil func
            and possibly sorted.
        """
        if isinstance(fil, str):
            fil = common.fnmatch(fil)
        res = []
        for name in self._callex(os.listdir, self.strpath):
            childurl = self.join(name)
            if fil is None or fil(childurl):
                res.append(childurl)
        if callable(sort):
            res.sort(sort)
        elif sort:
            res.sort()
        return res

    def size(self):
        """ return size of the underlying file object """
        return self.stat().size

    def mtime(self):
        """ return last modification time of the path. """
        return self.stat().mtime

    def copy(self, target, archive=False):
        """ copy path to target."""
        assert not archive, "XXX archive-mode not supported"
        if self.check(file=1):
            if target.check(dir=1):
                target = target.join(self.basename)
            assert self!=target
            copychunked(self, target)
        else:
            target.ensure(dir=1)
            def rec(p):
                return p.check(link=0)
            for x in self.visit(rec=rec):
                relpath = x.relto(self)
                newx = target.join(relpath)
                if x.check(link=1):
                    newx.mksymlinkto(x.readlink())
                elif x.check(file=1):
                    copychunked(x, newx)
                elif x.check(dir=1):
                    newx.ensure(dir=1)

    def rename(self, target):
        """ rename this path to target. """
        return self._callex(os.rename, str(self), str(target))

    def dump(self, obj, bin=1):
        """ pickle object into path location"""
        f = self.open('wb')
        try:
            self._callex(py.std.cPickle.dump, obj, f, bin)
        finally:
            f.close()

    def mkdir(self, *args):
        """ create & return the directory joined with args. """
        p = self.join(*args)
        self._callex(os.mkdir, str(p))
        return p

    def write(self, content, mode='wb'):
        """ write string content into path. """
        s = str(content)
        f = self.open(mode)
        try:
            f.write(s)
        finally:
            f.close()

    def _ensuredirs(self):
        parent = self.dirpath()
        if parent == self:
            return self
        if parent.check(dir=0):
            parent._ensuredirs()
        if self.check(dir=0):
            try:
                self.mkdir()
            except py.error.EEXIST:
                # race condition: file/dir created by another thread/process.
                # complain if it is not a dir
                if self.check(dir=0):
                    raise
        return self

    def ensure(self, *args, **kwargs):
        """ ensure that an args-joined path exists (by default as
            a file). if you specify a keyword argument 'dir=True'
            then the path is forced to be a directory path.
        """
        p = self.join(*args)
        if kwargs.get('dir', 0):
            return p._ensuredirs()
        else:
            p.dirpath()._ensuredirs()
            if not p.check(file=1):
                p.write("")
            return p

    def stat(self):
        """ Return an os.stat() tuple. """
        stat = self._callex(os.stat, self.strpath)
        return self._makestat(stat)

    def lstat(self):
        """ Return an os.lstat() tuple. """
        return self._makestat(self._callex(os.lstat, self.strpath))

    # xlocal implementation
    def setmtime(self, mtime=None):
        """ set modification time for the given path.  if 'mtime' is None
        (the default) then the file's mtime is set to current time.

        Note that the resolution for 'mtime' is platform dependent.
        """
        if mtime is None:
            return self._callex(os.utime, self.strpath, mtime)
        try:
            return self._callex(os.utime, self.strpath, (-1, mtime))
        except py.error.EINVAL:
            return self._callex(os.utime, self.strpath, (self.atime(), mtime))

    def chdir(self):
        """ change directory to self and return old current directory """
        old = self.__class__()
        self._callex(os.chdir, self.strpath)
        return old

    def realpath(self):
        """ return a new path which contains no symbolic links."""
        return self.__class__(os.path.realpath(self.strpath))

    def atime(self):
        """ return last access time of the path. """
        return self.stat().atime

    def __repr__(self):
        return 'local(%r)' % self.strpath

    def __str__(self):
        """ return string representation of the Path. """
        return self.strpath

    def pypkgpath(self, pkgname=None):
        """ return the path's package path by looking for the given
            pkgname.  If pkgname is None then look for the last
            directory upwards which still contains an __init__.py.
            Return None if a pkgpath can not be determined.
        """
        pkgpath = None
        for parent in self.parts(reverse=True):
            if pkgname is None:
                if parent.check(file=1):
                    continue
                if parent.join('__init__.py').check():
                    pkgpath = parent
                    continue
                return pkgpath
            else:
                if parent.basename == pkgname:
                    return parent
        return pkgpath

    def _prependsyspath(self, path):
        s = str(path)
        if s != sys.path[0]:
            #print "prepending to sys.path", s
            sys.path.insert(0, s)

    def pyimport(self, modname=None, ensuresyspath=True):
        """ return path as an imported python module.
            if modname is None, look for the containing package
            and construct an according module name.
            The module will be put/looked up in sys.modules.
        """
        if not self.check():
            raise py.error.ENOENT(self)
        #print "trying to import", self
        pkgpath = None
        if modname is None:
            #try:
            #    return self._module
            #except AttributeError:
            #    pass
            pkgpath = self.pypkgpath()
            if pkgpath is not None:
                if ensuresyspath:
                    self._prependsyspath(pkgpath.dirpath())
                pkg = __import__(pkgpath.basename, None, None, [])
                
                if hasattr(pkg, '__pkg__'):
                    modname = pkg.__pkg__.getimportname(self)
                    assert modname is not None, "package %s doesn't know %s" % (
                                                pkg.__name__, self)
                
                else:
                    names = self.new(ext='').relto(pkgpath.dirpath())
                    names = names.split(self.sep)
                    modname = ".".join(names)
            else:
                # no package scope, still make it possible
                if ensuresyspath:
                    self._prependsyspath(self.dirpath())
                modname = self.purebasename
            mod = __import__(modname, None, None, ['__doc__'])
            #self._module = mod
            return mod
        else:
            try:
                return sys.modules[modname]
            except KeyError:
                # we have a custom modname, do a pseudo-import
                mod = py.std.new.module(modname)
                mod.__file__ = str(self)
                sys.modules[modname] = mod
                try:
                    execfile(str(self), mod.__dict__)
                except:
                    del sys.modules[modname]
                    raise
                return mod

    def _getpymodule(self):
        """resolve this path to a module python object. """
        if self.ext != '.c':
            return super(LocalPath, self)._getpymodule()
        from py.__.misc.buildcmodule import make_module_from_c
        mod = make_module_from_c(self)
        return mod

    def _getpycodeobj(self):
        """ read the path and compile it to a code object. """
        dotpy = self.check(ext='.py')
        if dotpy:
            my_magic     = py.std.imp.get_magic()
            my_timestamp = int(self.mtime())
            if __debug__:
                pycfile = self + 'c'
            else:
                pycfile = self + 'o'
            try:
                f = pycfile.open('rb')
                try:
                    header = f.read(8)
                    if len(header) == 8:
                        magic, timestamp = py.std.struct.unpack('<4si', header)
                        if magic == my_magic and timestamp == my_timestamp:
                            co = py.std.marshal.load(f)
                            path1 = co.co_filename
                            path2 = str(self)
                            if path1 == path2:
                                return co
                            try:
                                if os.path.samefile(path1, path2):
                                    return co
                            except (OSError,          # probably path1 not found
                                    AttributeError):  # samefile() not available
                                pass
                finally:
                    f.close()
            except py.error.Error:
                pass
        s = self.read(mode='rU') + '\n'
        codeobj = compile(s, str(self), 'exec', generators.compiler_flag)
        if dotpy:
            try:
                f = pycfile.open('wb')
                f.write(py.std.struct.pack('<4si', 'TEMP', -1))  # fixed below
                py.std.marshal.dump(codeobj, f)
                f.flush()
                f.seek(0)
                f.write(py.std.struct.pack('<4si', my_magic, my_timestamp))
                f.close()
            except py.error.Error:
                pass
        return codeobj

    def sysexec(self, *argv):
        """ return stdout-put from executing a system child process,
            where the self path points to the binary (XXX or script)
            to be executed. Note that this process is directly
            invoked and not through a system shell.
        """
        from py.compat.subprocess import Popen, PIPE
        argv = map(str, argv)
        proc = Popen([str(self)] + list(argv), stdout=PIPE, stderr=PIPE)
        stdout, stderr = proc.communicate()
        ret = proc.wait()
        if ret != 0:
            raise py.process.cmdexec.Error(ret, ret, str(self),
                                           stdout, stderr,)
        return stdout

    def sysfind(cls, name, checker=None):
        """ return a path object found by looking at the systems
            underlying PATH specification. If the checker is not None
            it will be invoked to filter matching paths.  If a binary
            cannot be found, None is returned
            Note: This is probably not working on plain win32 systems
            but may work on cygwin.
        """
        if os.path.isabs(name):
            p = py.path.local(name)
            if p.check(file=1):
                return p
        else:
            if py.std.sys.platform == 'win32':
                paths = py.std.os.environ['Path'].split(';')
                try:
                    systemroot = os.environ['SYSTEMROOT']
                except KeyError:
                    pass
                else:
                    paths = [re.sub('%SystemRoot%', systemroot, path)
                             for path in paths]
                tryadd = '', '.exe', '.com', '.bat' # XXX add more?
            else:
                paths = py.std.os.environ['PATH'].split(':')
                tryadd = ('',)

            for x in paths:
                for addext in tryadd:
                    p = py.path.local(x).join(name, abs=True) + addext
                    try:
                        if p.check(file=1):
                            if checker:
                                if not checker(p):
                                    continue
                            return p
                    except py.error.EACCES:
                        pass
        return None
    sysfind = classmethod(sysfind)

    def _gethomedir(cls):
        try:
            x = os.environ['HOME']
        except KeyError:
            x = os.environ['HOMEPATH']
        return cls(x)
    _gethomedir = classmethod(_gethomedir)

    #"""
    #special class constructors for local filesystem paths
    #"""
    def get_temproot(cls):
        """ return the system's temporary directory
            (where tempfiles are usually created in)
        """
        return py.path.local(py.std.tempfile.gettempdir())
    get_temproot = classmethod(get_temproot)

    def mkdtemp(cls):
        """ return a Path object pointing to a fresh new temporary directory
            (which we created ourself).
        """
        import tempfile
        tries = 10
        for i in range(tries):
            dname = tempfile.mktemp()
            dpath = cls(tempfile.mktemp())
            try:
                dpath.mkdir()
            except (py.error.EEXIST, py.error.EPERM, py.error.EACCES):
                continue
            return dpath
        raise py.error.ENOENT(dpath, "could not create tempdir, %d tries" % tries)
    mkdtemp = classmethod(mkdtemp)

    def make_numbered_dir(cls, prefix='session-', rootdir=None, keep=3,
                          lock_timeout = 172800):   # two days
        """ return unique directory with a number greater than the current
            maximum one.  The number is assumed to start directly after prefix.
            if keep is true directories with a number less than (maxnum-keep)
            will be removed.
        """
        if rootdir is None:
            rootdir = cls.get_temproot()

        def parse_num(path):
            """ parse the number out of a path (if it matches the prefix) """
            bn = path.basename
            if bn.startswith(prefix):
                try:
                    return int(bn[len(prefix):])
                except ValueError:
                    pass

        # compute the maximum number currently in use with the
        # prefix
        lastmax = None
        while True:
            maxnum = -1
            for path in rootdir.listdir():
                num = parse_num(path)
                if num is not None:
                    maxnum = max(maxnum, num)

            # make the new directory
            try:
                udir = rootdir.mkdir(prefix + str(maxnum+1))
            except py.error.EEXIST:
                # race condition: another thread/process created the dir
                # in the meantime.  Try counting again
                if lastmax == maxnum:
                    raise
                lastmax = maxnum
                continue
            break

        # put a .lock file in the new directory that will be removed at
        # process exit
        lockfile = udir.join('.lock')
        mypid = os.getpid()
        if hasattr(lockfile, 'mksymlinkto'):
            lockfile.mksymlinkto(str(mypid))
        else:
            lockfile.write(str(mypid))
        def try_remove_lockfile():
            # in a fork() situation, only the last process should
            # remove the .lock, otherwise the other processes run the
            # risk of seeing their temporary dir disappear.  For now
            # we remove the .lock in the parent only (i.e. we assume
            # that the children finish before the parent).
            if os.getpid() != mypid:
                return
            try:
                lockfile.remove()
            except py.error.Error:
                pass
        atexit.register(try_remove_lockfile)

        # prune old directories
        if keep:
            for path in rootdir.listdir():
                num = parse_num(path)
                if num is not None and num <= (maxnum - keep):
                    lf = path.join('.lock')
                    try:
                        t1 = lf.lstat().mtime
                        t2 = lockfile.lstat().mtime
                        if abs(t2-t1) < lock_timeout:
                            continue   # skip directories still locked
                    except py.error.Error:
                        pass   # assume that it means that there is no 'lf'
                    try:
                        path.remove(rec=1)
                    except py.error.Error:
                        pass
        
        # make link...
        try:
            username = os.environ['USER']           #linux, et al
        except KeyError:
            try:
                username = os.environ['USERNAME']   #windows
            except KeyError:
                username = 'current'

        src  = str(udir)
        dest = src[:src.rfind('-')] + '-' + username
        try:
            os.unlink(dest)
        except OSError:
            pass
        try:
            os.symlink(src, dest)
        except (OSError, AttributeError): # AttributeError on win32
            pass

        return udir
    make_numbered_dir = classmethod(make_numbered_dir)

def copychunked(src, dest):
    chunksize = 524288 # half a meg of bytes
    fsrc = src.open('rb')
    try:
        fdest = dest.open('wb')
        try:
            while 1:
                buf = fsrc.read(chunksize)
                if not buf:
                    break
                fdest.write(buf)
        finally:
            fdest.close()
    finally:
        fsrc.close()
