#!/usr/bin/python
##############################################################################
# Copyright (c) 2018 OPNFV and others.
#
# All rights reserved. This program and the accompanying materials
# are made available under the terms of the Apache License, Version 2.0
# which accompanies this distribution, and is available at
# http://www.apache.org/licenses/LICENSE-2.0
##############################################################################
"""This module does blah blah."""
import argparse
import ipaddress
import logging
import os
import yaml
from jinja2 import Environment, FileSystemLoader
from subprocess import CalledProcessError, check_output

PARSER = argparse.ArgumentParser()
PARSER.add_argument("--yaml", "-y", type=str, required=True)
PARSER.add_argument("--jinja2", "-j", type=str, required=True)
ARGS = PARSER.parse_args()

# Processor architecture vs DPKG architecture mapping
DPKG_ARCH_TABLE = {
    'aarch64': 'arm64',
    'x86_64': 'amd64',
}
ARCH_DPKG_TABLE = dict(zip(DPKG_ARCH_TABLE.values(), DPKG_ARCH_TABLE.keys()))

# Custom filter to allow simple IP address operations returning
# a new address from an upper or lower (negative) index
def ipaddr_index(base_address, index):
    """Return IP address in given network at given index"""
    try:
        base_address_str = unicode(base_address)
    #pylint: disable=unused-variable
    except NameError as ex:
        base_address_str = str(base_address)
    return ipaddress.ip_address(base_address_str) + int(index)

# Custom filter to transform a prefix netmask to IP address format netmask
def netmask(prefix):
    """Get netmask from prefix length integer"""
    try:
        prefix_str = unicode(prefix)
    except NameError as ex:
        prefix_str = str(prefix)
    return ipaddress.IPv4Network("1.0.0.0/"+prefix_str).netmask

# Custom filter to convert between processor architecture
# (as reported by $(uname -m)) and DPKG-style architecture
def dpkg_arch(arch, to_dpkg=True):
    """Return DPKG-compatible from processor arch and vice-versa"""
    if to_dpkg:
        return DPKG_ARCH_TABLE[arch]
    else:
        return ARCH_DPKG_TABLE[arch]

ENV = Environment(loader=FileSystemLoader(os.path.dirname(ARGS.jinja2)))
ENV.filters['ipaddr_index'] = ipaddr_index
ENV.filters['netmask'] = netmask
ENV.filters['dpkg_arch'] = dpkg_arch

# Run `eyaml decrypt` on the whole file, but only if PDF data is encrypted
# Note: eyaml return code is 0 even if keys are not available
try:
    if os.path.isfile(ARGS.yaml) and 'ENC[PKCS7' in open(ARGS.yaml).read():
        DICT = yaml.safe_load(check_output(['eyaml', 'decrypt',
                                            '-f', ARGS.yaml]))
except CalledProcessError as ex:
    logging.error('eyaml decryption failed! Fallback to raw data.')
except OSError as ex:
    logging.warn('eyaml not found, skipping decryption. Fallback to raw data.')
try:
    DICT['details']
except (NameError, TypeError) as ex:
    with open(ARGS.yaml) as _:
        DICT = yaml.safe_load(_)

# If an installer descriptor file (IDF) exists, include it (temporary)
IDF_PATH = '/idf-'.join(os.path.split(ARGS.yaml))
if os.path.exists(IDF_PATH):
    with open(IDF_PATH) as _:
        IDF = yaml.safe_load(_)
        DICT['idf'] = IDF['idf']

# Print dictionary generated from yaml (uncomment for debug)
# print(DICT)

# Render template and print generated conf to console
TEMPLATE = ENV.get_template(os.path.basename(ARGS.jinja2))

#pylint: disable=superfluous-parens
print(TEMPLATE.render(conf=DICT))