"""
package model for python PAckage INTrospection
"""

# TODO: use pkginfo.sdist more

import info
import os
import pip
import shutil
import subprocess
import sys
import tarfile
import tempfile
import urllib2
import urlparse
import utils

from subprocess import check_call as call

__all__ = ['Package']

class Package(object):
    """
    class for python package introspection.
    constructor takes the package 'src'
    """

    def __init__(self, src, verbose=True):
        """
        - src : URL or filesystem path to the package
        """
        self.src = src
        self.verbose = verbose

        # ephemeral data
        self._tmppath = None
        self._egg_info_path = None
        self._build_path = None
        self._pkg_info_path = None

        # package metadata provider
        # TODO: this should be chooseable but currently the keys of the
        # interfaces are not the same
        self.package_info = info.EggInfo

        # TODO: list of temporary files/directories to be deleted

    def _log(self, message):
        if self.verbose:
            print '>>> %s' % message

    def _path(self):
        """filesystem path to package directory"""

        self._log(">>> _path:Getting path to package")

        # return cached copy if it exists
        if self._tmppath:
            return self._tmppath

        # fetch from the web if a URL
        tmpfile = None
        src = self.src
        if utils.isURL(self.src):
            tmpfile = src = self.fetch()

        # unpack if an archive
        if self._is_archive(src):
            try:
                self._unpack(src)
            finally:
                if tmpfile:
                    os.remove(tmpfile)
            return self._tmppath

        return self.src

    def fetch(self, filename=None):
        """fetch from remote source to a temporary file"""
        if filename is None:
            fd, filename = tempfile.mkstemp()
            os.close(fd)
        fp = file(filename, 'w')
        resource = urllib2.urlopen(self.src)
        fp.write(resource.read())
        fp.close()
        return filename

    def _unpack(self, archive):
        """unpack the archive to a temporary destination"""
        # TODO: should handle zipfile additionally at least
        # Ideally, this would be pluggable, etc
        assert tarfile.is_tarfile(archive), "%s is not an archive" % self.src
        tf = tarfile.TarFile.open(archive)
        self._tmppath = tempfile.mkdtemp()
        members = tf.getmembers()

        # cut off the top level directory
        members = [i for i in members if os.path.sep in i.name]
        tld = set()
        for member in members:
            directory, member.name = member.name.split(os.path.sep, 1)
            tld.add(directory)
        assert len(tld) == 1

        # extract
        for member in members:
            tf.extract(member, path=self._tmppath)
        tf.close()

    def _is_archive(self, path):
        """returns if the filesystem path is an archive"""
        # TODO: should handle zipfile additionally at least
        # Ideally, this would be pluggable, etc
        return tarfile.is_tarfile(path)

    def _cleanup(self):
        if self._tmppath:
            shutil.rmtree(self._tmppath)
        self._tmppath = None

    __del__ = _cleanup

    ### python-package-specific functionality

    def info(self):
        """return info dictionary for package"""
        self._log(">>> Getting the info")
        return self.package_info(self._path())()

    def dependencies(self):
        return self.package_info(self._path()).dependencies()

    def extension(self):
        """filename extension of the package"""

        print ">>> extension:Getting package"
        package = self.package()
        print ">>> extension:package=%s" % package

        # determine the extension (XXX hacky)
        extensions = ('.tar.gz', '.zip', '.tar.bz2')
        for ext in extensions:
            if package.endswith(ext):
                return ext

        raise Exception("Extension %s not found: %s" % (extensions, package))

    def package(self, destination=None):
        """
        repackage the package to ensure its actually in the right form
        and return the path to the destination
        - destination: if given, path to put the build in
        """

        self._log("package: Getting package directory, destination=%s" % repr(destination))

        if self._build_path:
            self._log("package: build_path already set: %s" % self._build_path)
            if destination:
                shutil.copy(self._build_path, destination)
                return os.path.abspath(destination)

            # return cached copy
            return self._build_path

        path = self._path()
        dist = os.path.join(path, 'dist')
        self._log("package: dist directory: %s; (path=%s)" % (dist, path))
        if os.path.exists(dist):
            shutil.rmtree(dist)

        command = [sys.executable, 'setup.py', 'sdist']
        self._log("package: running: %s" % ' '.join(command))
        call(command, cwd=path)
        self._log("package: done running setup.py dist")

        assert os.path.exists(dist)
        contents = os.listdir(dist)
        assert len(contents) == 1

        self._build_path = os.path.join(dist, contents[0])

        # destination
        # use an evil recursive trick
        if destination:
            return self.package(destination=destination)

        return self._build_path

    def download(self, directory):
        """download a package and all its dependencies using pip"""
        if not os.path.exists(directory):
            os.makedirs(directory)
        assert os.path.isdir(directory)
        pip.main(['install', '--download', directory, self.src])

    def pypi(self, directory):
        """
        download packages for a pypi directory structure
        http://k0s.org/portfolio/pypi.html
        """
        if not os.path.exists(directory):
            os.makedirs(directory)
        assert os.path.isdir(directory)
        tempdir = tempfile.mkdtemp()
        try:
            self.download(tempdir)
            files = os.listdir(tempdir)
            self._log(">>> Files: %s" % files)
            for f in files:

                # full path
                src = os.path.join(tempdir, f)

                # make a package of the thing
                print ">>> pypi:Packaging %s" % src
                package = Package(src)
                print ">>> pypi:DONE packaging %s" % src

                # get destination dirname, filename
                print ">>> pypi:Getting PyPI path"
                dirname, filename = package.pypi_path()
                print ">>> pypi:DONE PyPI path: %s/%s" % (dirname, filename)

                # make the directory if it doesn't exist
                subdir = os.path.join(directory, dirname)
                if not os.path.exists(subdir):
                    os.makedirs(subdir)
                assert os.path.isdir(subdir)

                # move the file
                print ">>> pypi:Moving to PyPI path %s/%s" % (subdir, filename)
                package.package(destination=os.path.join(subdir, filename))
                print ">>> Done with %s" % src
        finally:
            shutil.rmtree(tempdir)

    def pypi_path(self):
        """
        returns subpath 2-tuple appropriate for pypi path structure:
        http://k0s.org/portfolio/pypi.html
        """
        self._log(">>> pypi_path:Getting info")
        info = self.info()
        self._log(">>> pypi_path:DONE getting info")

        # determine the extension
        self._log(">>> pypi_path:Getting extension")
        extension = self.extension()
        self._log(">>> pypi_path:DONE Getting extension: %s" % extension)

        # get the filename destination
        name = info['Name']
        version = info['Version']
        filename = '%s-%s%s' % (name, version, extension)
        return name, filename


class PackageSet(object):
    """
    a group of packages
    """

    def __init__(self, *packages):
        self.packages = []
        for package in packages:
            self.add(package)
        raise NotImplementedError

    def add(self, package):
        """
        add a package to the instance.
        If Package instance, add that, otherwise convert
        """

    __iadd__ = add

    def dependencies(self):
        """return dependecies for each package"""

    def unroll_dependencies(self):
        """unroll dependencies for a package set"""