# coding=utf-8

# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2019 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT

import base64
import hashlib
import os

__author__ = "Eli Carter"


class HtpasswdDoesNotExists(Exception):
    pass


class HtpasswdFile(object):
    """
    A class for manipulating htpasswd files.
    """

    def __init__(self, filename, create=False):
        self.entries = []
        self.filename = filename
        if not create:
            if os.path.exists(self.filename):
                self.load()
            else:
                raise HtpasswdDoesNotExists(f"{self.filename} does not exist")

    def load(self):
        """
        Read the htpasswd file into memory.
        """
        self.entries = []
        with open(self.filename, 'r', encoding='utf-8') as f:
            for line in f:
                username, pwhash = line.split(':')
                entry = [username, pwhash.rstrip()]
                self.entries.append(entry)

    def save(self):
        """
        Write the htpasswd file to disk
        """
        with open(self.filename, 'w', encoding='utf-8') as f:
            for entry in self.entries:
                f.write(f"{entry[0]}:{entry[1]}\n")

    def update(self, username, password):
        """
        Replace the entry for the given user, or add it if new.
        """
        # Generate a random salt
        salt = os.urandom(16)

        # Hash the password using PBKDF2 with HMAC-SHA256
        pwhash = hashlib.pbkdf2_hmac('sha256', password.encode('utf-8'), salt, 100000)

        # Store the salt along with the hash to use it during password verification
        stored_password = base64.b64encode(salt + pwhash).decode('utf-8')

        # Find matching entries
        matching_entries = [entry for entry in self.entries
                            if entry[0] == username]
        if matching_entries:
            matching_entries[0][1] = stored_password
        else:
            self.entries.append([username, stored_password])

    def delete(self, username):
        """
        Remove the entry for the given user.
        """
        self.entries = [entry for entry in self.entries
                        if entry[0] != username]