import os
import shlex
import errno
import logging
import urlparse
import time

import wizard
from wizard import shell, util

def fill_url(dir, url=None):
    if url:
        return url

    # hook hook

    # try the directory
    homedir, _, web_path = dir.partition("/web_scripts")
    if web_path:
        return urlparse.ParseResult(
                "http",
                util.get_dir_owner(homedir) + ".scripts.mit.edu",
                web_path.rstrip('/'),
                "", "", "")

    # try the environment
    host = os.getenv("WIZARD_WEB_HOST")
    path = os.getenv("WIZARD_WEB_PATH")
    if host is not None and path is not None:
        return urlparse.ParseResult(
                "http",
                host,
                path.rstrip('/'),
                "", "", "")

    return None

def get_quota_usage_and_limit(dir=None):
    """
    Returns a tuple (quota usage, quota limit).  Works only for scripts
    servers.  Values are in KiB.  Returns ``(0, None)`` if we couldn't figure it out.
    """
    exc = None
    # sometimes the volume is busy; so we try several times
    for i in range(0, 3):
        try:
            return _get_quota_usage_and_limit(dir)
        except QuotaParseError as e:
            exc = e
            time.sleep(3) # give it a chance
    raise exc

def _get_quota_usage_and_limit(dir=None):
    # XXX: The correct way is to implement Python modules implementing
    # bindings for all the appropriate interfaces
    def parse_last_quote(ret):
        return ret.rstrip('\'').rpartition('\'')[2]
    if dir is None:
        dir = os.getcwd()
    sh = shell.Shell()
    try:
        cell = parse_last_quote(sh.eval("fs", "whichcell", "-path", dir))
    except shell.CallError:
        return (0, None)
    except OSError as e:
        if e.errno == errno.ENOENT:
            return (0, None)
        raise
    mount = None
    while dir:
        try:
            volume = parse_last_quote(sh.eval("fs", "lsmount", dir))[1:]
            break
        except shell.CallError:
            dir = os.path.dirname(dir)
        except OSError as e:
            if e.errno == errno.ENOENT:
                return (0, None)
            raise
    if not volume: return (0, None)
    try:
        result = sh.eval("vos", "examine", "-id", volume, "-cell", cell).splitlines()
    except OSError:
        try:
            result = sh.eval("/usr/sbin/vos", "examine", "-id", volume, "-cell", cell).splitlines()
        except OSError:
            return (0, None)
    except shell.CallError:
        return (0, None)
    try:
        usage = int(result[0].split()[3])
        limit = int(result[3].split()[1]) # XXX: FRAGILE
    except ValueError:
        raise QuotaParseError("vos examine output was:\n\n" + "\n".join(result))
    return (usage, limit)

# XXX: Possibly in the wrong module
def get_disk_usage(dir=None, excluded_dir=".git"):
    """
    Recursively determines the disk usage of a directory, excluding
    .git directories.  Value is in bytes.
    """
    if dir is None: dir = os.getcwd()
    sum_sizes = 0
    for root, _, files in os.walk(dir):
        for name in files:
            if not os.path.join(root, name).startswith(dir + excluded_dir):
                sum_sizes += os.path.getsize(os.path.join(root, name))
    return sum_sizes
class QuotaParseError(wizard.Error):
    def __init__(self, msg):
        self.msg = msg
    def __str__(self):
        return """

ERROR: Could not parse quota. %s
""" % self.msg