"""Plugins for backup.py

Plugins should expose 3 functions:
    init(cfg, *args)
    pre()
    post()

init() will set up any variables that it needs.
pre() runs before the backup
run() runs the actual backup
post() runs after the backup
"""

# this is kinda hacky; anything better?
import sys, os, glob
sys.path.insert(0, os.path.dirname(__file__))
import traceback
import subprocess, time

class PluginNotFoundError(Exception):
    pass

def run(cfg, plugin, *args, **kwargs):
    """This runs a plugin.
    @param plugin: a string value for a file that is importable.
    @type plugin: string"""
    try:
        module = __import__(plugin)
    except:
        #traceback.print_exc()
        raise PluginNotFoundError("Plugin %s not found." % plugin)
    try:
        module.init(cfg, *args, **kwargs)
        module.pre()
        module.run()
        module.post()
        del(module)
    except:
        traceback.print_exc()
        print plugin

"""Common utilities for plugins."""

class PluginError(Exception):
    pass

def normalize_path(path, cwd=True):
    path = os.path.expandvars(path)
    path = os.path.expanduser(path)
    path = path.replace("/", os.path.sep)
    if cwd: path = unicode(os.path.abspath(path))
    else: path = unicode(path)
    path = glob.glob(path)
    return path

def print_exec(command):
    "Execute `command` as a subprocess and print its output."
    cmd = subprocess.Popen(command, shell=True)
    cmd.wait()
    return cmd.returncode

def prune(path):
    "Remove empty directories, depth first."
    pass