#!/usr/bin/env python
import os
from argparse import ArgumentParser, RawDescriptionHelpFormatter
import json
import sys


PROG_DESCRIPTION = """
GlusterFS Mountbroker user management
"""

args = None


def ok(message=""):
    if (not args and "-j" in sys.argv) or (args and args.json):
        print json.dumps({"ok": True, "message": message})
    else:
        if message:
            print message

    sys.exit(0)


def notok(message=""):
    if (not args and "-j" in sys.argv) or (args and args.json):
        print json.dumps({"ok": False, "message": message})
    else:
        print "error: %s" % message

    # Always return zero due to limitation while executing
    # as `gluster system:: execute`
    sys.exit(0)


class NoStdErrParser(ArgumentParser):
    """
    with gluster system:: execute, stderr gives
    "Unable to end. Error : Bad file descriptor" error,
    so deriving new class, prints error message and
    exits with zero.
    """
    def error(self, message):
        notok(message)


class MountbrokerUserMgmt(object):
    def __init__(self, volfile):
        self.volfile = volfile
        self._options = {}
        self.commented_lines = []
        self._parse()

    def _parse(self):
        with open(self.volfile, "r") as f:
            for line in f:
                line = line.strip()
                if line.startswith("option "):
                    key, value = line.split(" ")[1:]
                    self._options[key] = value
                if line.startswith("#"):
                    self.commented_lines.append(line)

    def _get_write_data(self):
        op = "volume management\n"
        op += "    type mgmt/glusterd\n"
        for k, v in self._options.iteritems():
            op += "    option %s %s\n" % (k, v)
        for line in self.commented_lines:
            op += "    %s\n" % line
        op += "end-volume"
        return op

    def save(self):
        with open(self.volfile + "_tmp", "w") as f:
            f.write(self._get_write_data())
            f.flush()
            os.fsync(f.fileno())
        os.rename(self.volfile + "_tmp", self.volfile)

    def set_opt(self, key, value):
        self._options[key] = value.strip()

    def remove_opt(self, key):
        if key in self._options:
            del(self._options[key])

    def add_user(self, user, volumes):
        vols = set()
        for k, v in self._options.iteritems():
            if k.startswith("mountbroker-geo-replication.") \
               and user == k.split(".")[-1]:
                vols.update(v.split(","))

        vols.update(volumes)
        self.set_opt("mountbroker-geo-replication.%s" % user,
                     ",".join(vols))

    def remove_volume(self, user, volumes):
        vols = set()
        for k, v in self._options.iteritems():
            if k.startswith("mountbroker-geo-replication.") \
               and user == k.split(".")[-1]:
                vols.update(v.split(","))

        for v1 in volumes:
            vols.discard(v1)

        if vols:
            self.set_opt("mountbroker-geo-replication.%s" % user,
                         ",".join(vols))
        else:
            self.remove_opt("mountbroker-geo-replication.%s" % user)

    def remove_user(self, user):
        self.remove_opt("mountbroker-geo-replication.%s" % user)

    def info(self):
        data = {"users": []}

        for k, v in self._options.iteritems():
            if k.startswith("mountbroker-geo-replication."):
                data["users"].append(
                    {"name": k.split(".")[-1], "volumes": v.split(",")}
                )
            else:
                data[k] = v

        return data


def format_info(data):
    op = "%s %s\n" % ("Option".ljust(50), "Value".ljust(50))
    op += ("-" * 101) + "\n"
    for key, value in data.iteritems():
        if key != "users":
            op += "%s %s\n" % (key.ljust(50), value)

    op += "\nUsers: %s\n" % ("None" if not data["users"] else "")
    for user in data["users"]:
        op += "%s: %s\n" % (user["name"], ", ".join(user["volumes"]))
    op += "\n\n"
    return op


def _get_args():
    parser = NoStdErrParser(formatter_class=RawDescriptionHelpFormatter,
                            description=PROG_DESCRIPTION)

    parser.add_argument('-j', dest="json", help="JSON output",
                        action="store_true")
    subparsers = parser.add_subparsers(title='subcommands', dest='cmd')
    parser_useradd = subparsers.add_parser('user')
    parser_userdel = subparsers.add_parser('userdel')
    parser_volumedel = subparsers.add_parser('volumedel')
    subparsers.add_parser('info')
    parser_opt = subparsers.add_parser('opt')
    parser_optdel = subparsers.add_parser('optdel')

    parser_useradd.add_argument('username', help="Username", type=str)
    parser_useradd.add_argument('volumes', type=str, default='',
                                help="Volumes list. ',' separated")

    parser_volumedel.add_argument('username', help="Username", type=str)
    parser_volumedel.add_argument('volumes', type=str, default='',
                                help="Volumes list. ',' separated")

    parser_userdel.add_argument('username', help="Username", type=str)

    parser_opt.add_argument('opt_name', help="Name", type=str)
    parser_opt.add_argument('opt_value', help="Value", type=str)

    parser_optdel.add_argument('opt_name', help="Name", type=str)

    return parser.parse_args()


def main():
    global args
    args = _get_args()

    m = MountbrokerUserMgmt("@GLUSTERD_VOLFILE@")

    if args.cmd == "opt":
        m.set_opt(args.opt_name, args.opt_value)
    elif args.cmd == "optdel":
        m.remove_opt(args.opt_name)
    elif args.cmd == "userdel":
        m.remove_user(args.username)
    elif args.cmd == "user":
        volumes = [v.strip() for v in args.volumes.split(",")
                   if v.strip() != ""]
        m.add_user(args.username, volumes)
    elif args.cmd == "volumedel":
        volumes = [v.strip() for v in args.volumes.split(",")
                   if v.strip() != ""]
        m.remove_volume(args.username, volumes)
    elif args.cmd == "info":
        info = m.info()
        if not args.json:
            info = format_info(info)
        ok(info)

    if args.cmd != "info":
        m.save()
        ok()

if __name__ == "__main__":
    main()