# -*- coding: utf-8 -*-

# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2018 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT
#

import os

PROC_LVE = '/proc/lve'
LIMIT_LVP_ID = 4294967295


class ProcLveError(Exception):
    pass


class NoSuchLvp(ProcLveError):
    pass


class ProcLve:

    def __init__(self, proc_lve=PROC_LVE):
        self._lvp = 'lvp'
        self.list = 'list'
        self.proc_lve = proc_lve
        self._version = None

    def proc_lve_list(self):
        """
        Return path to /proc/lve/list
        """
        return os.path.join(self.proc_lve, self.list)

    def version(self):
        """
        Return /proc/lve filesystem version
        """
        if self._version is not None:
            return self._version
        with open(self.proc_lve_list(), encoding='utf-8') as f:
            line = f.read(3)  # we need only first three symbols for parse version
        self._version = int(line.rsplit(':', 1)[0])
        return self._version

    def proc_lve_map(self):
        return os.path.join(self.proc_lve, 'map')

    def proc_lve_resellers(self):
        """
        Return path to /proc/lve/resellers
        """
        return os.path.join(self.proc_lve, 'resellers')

    def resellers_supported(self):
        """
        Check present /proc/lve/resellers
        """
        return os.path.exists(self.proc_lve_resellers())

    def get_list_path(self, lvp_id=0):
        """
        Generate path to list file
        """
        if lvp_id == 0:
            return self.proc_lve_list()
        else:
            return os.path.join(self.proc_lve_resellers(), self._lvp + str(lvp_id), self.list)

    def _extract_id(self, line):
        return int(line.split()[0].split(',')[-1])

    def _lines(self, lvp_id=0):
        path = self.get_list_path(lvp_id=lvp_id)
        try:
            with open(path, encoding='utf-8') as list_:
                lines = list_.read().strip()
        except IOError as e:
            if e.errno == 2:  # 2 code error - No such file or directory
                raise NoSuchLvp(f'No such lvp id {lvp_id}') from e
            else:
                raise
        lines = lines.split('\n')[1:]
        for line in lines:
            yield self._extract_id(line), line.rstrip(os.linesep)

    def lines(self, lvp_id=0, without_limits=True):
        for lve_id, line in self._lines(lvp_id=lvp_id):
            if lve_id == LIMIT_LVP_ID and without_limits:
                continue
            yield line

    def lve_id_list(self, lvp_id=0):
        for lve_id, _ in self._lines(lvp_id=lvp_id):
            if lve_id in (LIMIT_LVP_ID, 0):
                continue
            yield lve_id

    def lvp_id_list(self):
        """
        Obtain from /proc/lve/resellers lvp id list
        """
        for lvp_dir in os.listdir(self.proc_lve_resellers()):
            if lvp_dir.startswith(self._lvp):
                yield int(lvp_dir[len(self._lvp):])

    def check_inside_list(self, id_, lvp_id=0):
        for lve_id in self.lve_id_list(lvp_id=lvp_id):
            if lve_id == id_:
                return True

    def exist_lvp(self, lvp_id):
        """
        Check present lve top container
        """
        return os.path.exists(self.get_list_path(lvp_id))

    def detect_inside_lvp(self, id_):
        """
        Find in which lve top container
        """
        for lvp_id in self.lvp_id_list():
            if self.exist_lvp(lvp_id) and self.check_inside_list(id_, lvp_id):
                return lvp_id

    def map(self):
        """
        Obtain map from /proc/lve/map as dict
        """
        map_dict = {}
        with open(self.proc_lve_map(), encoding='utf-8') as map_:
            lines = map_.read().strip()
        lines = lines.split('\n')[1:]
        for line in lines:
            lve_id_str, lvp_id_str = line.strip().split()
            map_dict[int(lve_id_str)] = int(lvp_id_str)
        return map_dict

    def map_lve_id_list(self, lvp_id):
        return [lve_id_ for lve_id_, lvp_id_ in list(self.map().items()) if lvp_id_ == lvp_id]