import os
from pythonbrew.basecommand import Command
from pythonbrew.define import PATH_PYTHONS, PATH_BIN
from pythonbrew.util import Package, symlink, unlink
from pythonbrew.log import logger

class SymlinkCommand(Command):
    name = "symlink"
    usage = "%prog [OPTIONS] [SCRIPT]"
    summary = "Create/Remove a symbolic link on your $PATH"
    
    def __init__(self):
        super(SymlinkCommand, self).__init__()
        self.parser.add_option(
            "-p", "--python",
            dest="pythons",
            action="append",
            default=[],
            help="Use the specified python version.",
            metavar='VERSION'
        )
        self.parser.add_option(
            "-r", "--remove",
            dest="remove",
            action="store_true",
            default=False,
            help="Remove the all symbolic link."
        )
        self.parser.add_option(
            "-d", "--default",
            dest="default",
            default=None,
            help="Use as default the specified python version."
        )
    
    def run_command(self, options, args):
        if options.default:
            # create only one instance as default of an application.
            pythons = self._get_pythons([options.default])
            for pkgname in pythons:
                if args:
                    bin = args[0]
                    self._symlink(bin, bin, pkgname)
                else:
                    self._symlink('python', 'py', pkgname)
        else:
            pythons = self._get_pythons(options.pythons)
            for pkgname in pythons:
                if options.remove:
                    # remove symlinks
                    for bin in os.listdir(PATH_BIN):
                        path = os.path.join(PATH_BIN, bin)
                        if os.path.islink(path):
                            unlink(path)
                else:
                    # create symlinks
                    if args:
                        bin = args[0]
                        self._symlink_version_suffix(bin, bin, pkgname)
                    else:
                        self._symlink_version_suffix('python', 'py', pkgname)
                    
    def _symlink_version_suffix(self, srcbin, dstbin, pkgname):
        """Create a symlink. add version suffix.
        """
        version = Package(pkgname).version
        dstbin = '%s%s' % (dstbin, version)
        self._symlink(srcbin, dstbin, pkgname)
    
    def _symlink(self, srcbin, dstbin, pkgname):
        """Create a symlink.
        """
        src = os.path.join(PATH_PYTHONS, pkgname, 'bin', srcbin)
        dst = os.path.join(PATH_BIN, dstbin)
        if os.path.isfile(src):
            symlink(src, dst)
        else:
            logger.info("%s: File not found" % src)
    
    def _get_pythons(self, _pythons):
        """Get the installed python versions list.
        """
        pythons = [Package(p).name for p in _pythons]
        return [d for d in sorted(os.listdir(PATH_PYTHONS)) 
                if not pythons or d in pythons]

SymlinkCommand()