#!/usr/bin/env python3

import boto3
import base64
import os
import configparser
from botocore.exceptions import ClientError
from jinja2 import Environment, FileSystemLoader


def get_secret(secret_name):
    # Create a Secrets Manager client
    session = boto3.session.Session()
    client = session.client(
        service_name='secretsmanager',
        region_name=os.getenv('AWS_REGION')
    )

    try:
        get_secret_value_response = client.get_secret_value(
            SecretId=secret_name
        )
    except ClientError as e:
        if e.response['Error']['Code'] == 'DecryptionFailureException':
            # Secrets Manager can't decrypt the protected secret text using the
            # provided KMS key.
            # Deal with the exception here, and/or rethrow at your discretion.
            raise e
        elif e.response['Error']['Code'] == 'InternalServiceErrorException':
            # An error occurred on the server side.
            # Deal with the exception here, and/or rethrow at your discretion.
            raise e
        elif e.response['Error']['Code'] == 'InvalidParameterException':
            # You provided an invalid value for a parameter.
            # Deal with the exception here, and/or rethrow at your discretion.
            raise e
        elif e.response['Error']['Code'] == 'InvalidRequestException':
            # You provided a parameter value that is not valid for the current
            # state of the resource.
            # Deal with the exception here, and/or rethrow at your discretion.
            raise e
        elif e.response['Error']['Code'] == 'ResourceNotFoundException':
            # We can't find the resource that you asked for.
            # Deal with the exception here, and/or rethrow at your discretion.
            raise e
    else:
        # Decrypts secret using the associated KMS CMK.
        # Depending on whether the secret is a string or binary, one of these
        # fields will be populated.
        if 'SecretString' in get_secret_value_response:
            return get_secret_value_response['SecretString']
        else:
            return base64.b64decode(get_secret_value_response['SecretBinary'])


"""
This script setup Gerrit configuration and its plugins when the container spins up.

It reads from:
 - AWS Secret Manager: Statically defined.
 - gerrit.setup: Statically defined.
 - environment variables: Dinamycally defined.

"""

secretIds = [
    "ssh_host_ecdsa_384_key",
    "ssh_host_ecdsa_384_key.pub",
    "ssh_host_ecdsa_521_key",
    "ssh_host_ecdsa_521_key.pub",
    "ssh_host_ecdsa_key",
    "ssh_host_ecdsa_key.pub",
    "ssh_host_ed25519_key",
    "ssh_host_ed25519_key.pub",
    "ssh_host_rsa_key",
    "ssh_host_rsa_key.pub"
]

GERRIT_KEY_PREFIX = "gerrit_secret_"
GERRIT_CONFIG_DIRECTORY = "/var/gerrit/etc/"

print("Installing SSH Keys from Secret Manager in directory: " +
      GERRIT_CONFIG_DIRECTORY)
for secretId in secretIds:
    print("* Installing SSH Key: " + secretId)
    with open(GERRIT_CONFIG_DIRECTORY + secretId, 'w', encoding='utf-8') as f:
        f.write(get_secret(GERRIT_KEY_PREFIX + secretId))

GERRIT_SSH_DIRECTORY = "/var/gerrit/.ssh"
GERRIT_REPLICATION_SSH_KEYS = GERRIT_SSH_DIRECTORY + "/id_rsa"

print("Installing Replication SSH Keys from Secret Manager in: " +
      GERRIT_REPLICATION_SSH_KEYS)

if not os.path.exists(GERRIT_SSH_DIRECTORY):
    os.mkdir(GERRIT_SSH_DIRECTORY)
    os.chmod(GERRIT_SSH_DIRECTORY, 0o700)

with open(GERRIT_REPLICATION_SSH_KEYS, 'w', encoding='utf-8') as f:
    f.write(get_secret(GERRIT_KEY_PREFIX + 'replication_user_id_rsa'))
os.chmod(GERRIT_REPLICATION_SSH_KEYS, 0o400)

file_loader = FileSystemLoader(GERRIT_CONFIG_DIRECTORY)
env = Environment(loader=file_loader)

print("Setting Register Email Private Key in '" +
      GERRIT_CONFIG_DIRECTORY + "secure.config'")
template = env.get_template("secure.config.template")
with open(GERRIT_CONFIG_DIRECTORY + "secure.config", 'w',
          encoding='utf-8') as f:
    f.write(template.render(
        REGISTER_EMAIL_PRIVATE_KEY=get_secret(
            GERRIT_KEY_PREFIX + "registerEmailPrivateKey"),
        LDAP_PASSWORD=get_secret(GERRIT_KEY_PREFIX + "ldapPassword"),
        SMTP_PASSWORD=get_secret(GERRIT_KEY_PREFIX + "smtpPassword"))
    )

BASE_CONFIG_DIR = "/tmp"
config = configparser.ConfigParser()
config.read(BASE_CONFIG_DIR + '/gerrit.setup')
print("Setting Gerrit config in '" + GERRIT_CONFIG_DIRECTORY + "gerrit.config'")
template = env.get_template("gerrit.config.template")

config_for_template = {}
try:
    # If we don't need the monitoring stack we can avoid to set this token
    prometheus_bearer_token = get_secret(GERRIT_KEY_PREFIX + "prometheus_bearer_token")
    config_for_template['PROMETHEUS_BEARER_TOKEN'] = prometheus_bearer_token
except ClientError as e:
    if e.response['Error']['Code'] == 'ResourceNotFoundException':
         print("[WARN] PROMETHEUS_BEARER_TOKEN not set")
    else:
        raise e

with open(GERRIT_CONFIG_DIRECTORY + "gerrit.config", 'w',
          encoding='utf-8') as f:
    config_for_template.update({
        'LDAP_SERVER': config['ldap']['server'],
        'LDAP_USERNAME': config['ldap']['username'],
        'LDAP_ACCOUNT_BASE': config['ldap']['accountBase'],
        'LDAP_GROUP_BASE': config['ldap']['groupBase'],
        'SMTP_SERVER': config['smtp']["server"],
        'SMTP_USER': config['smtp']["user"],
        'SMTP_DOMAIN': config['smtp']["domain"]
    })
    f.write(template.render(config_for_template))

containerSlave = os.getenv('CONTAINER_SLAVE')
if (not containerSlave):
    print("Setting Replication config in '" +
          GERRIT_CONFIG_DIRECTORY + "replication.config'")
    config.read(BASE_CONFIG_DIR + '/replication.setup')
    template = env.get_template("replication.config.template")
    with open(GERRIT_CONFIG_DIRECTORY + "replication.config", 'w', encoding='utf-8') as f:
        f.write(template.render(
                SLAVE_1_URL=config['remote-slave']['url'],
                SLAVE_1_AMDIN_URL=config['remote-slave']['adminUrl']
                ))