#!/usr/bin/env python3
import configparser
import json
import os
import socket
import sys

import dotenv
import toml
import yaml
from jinja2 import Environment, TemplateError
import argparse

argsparser = argparse.ArgumentParser(description='Jinja Template Helper')

infilegroup = argsparser.add_mutually_exclusive_group(required=False)
infilegroup.add_argument('--yaml', dest='yaml_file', type=str, required=False,
                         help='YAML file path')
infilegroup.add_argument('--json', dest='json_file', type=str, required=False,
                         help='JSON file path')
infilegroup.add_argument('--toml', dest='toml_file', type=str, required=False,
                         help='TOML file path')
infilegroup.add_argument('--ini', dest='ini_file', type=str, required=False,
                         help='INI fil path')

argsparser.add_argument('--env', dest='env_file', type=bool, required=False, default=False,
                        help='Load .env file from current directory')

argsparser.add_argument('--output', default='/dev/stdout',
                        help='Output File')
argsparser.add_argument('infile', metavar="input-file",
                        help="Input File")


# Print Errors
def print_error(*args, **kwargs):
    print(*args, file=sys.stderr, **kwargs)


# Jinja Environment
# -----------------
jenv = Environment(autoescape=True,
                   trim_blocks=False,
                   keep_trailing_newline=True,
                   optimized=True)


# Jinja Filters
# -------------
def filter_env(name, defvalue=""):
    return os.getenv(name, defvalue)


def filter_domain2ldap(value, unit='dc', delimiter='.'):
    parts = value.split(delimiter)
    concat_domain = ""
    for part in parts:
        if len(concat_domain) > 0:
            concat_domain += ","
        concat_domain = concat_domain + unit + "=" + part
    return concat_domain


def filter_hostbyaddr(value):
    addr = socket.gethostbyaddr(value)
    if addr:
        return addr[0]


def filter_hostbyname(value):
    return socket.gethostbyname(value)


jenv.filters['env'] = filter_env
jenv.filters['ldap_dn'] = filter_domain2ldap
jenv.filters['hostbyaddr'] = filter_hostbyaddr
jenv.filters['hostbyname'] = filter_hostbyname


# Loader
# ------
def load_template(filename):
    try:
        with open(filename) as file_:
            template = jenv.from_string(file_.read())
        return template
    except TemplateError as exc:
        print_error("Template Error:", exc.message)
        return None


def load_yaml_file(filename):
    if os.path.isfile(filename):
        with open(filename, 'r') as instream:
            try:
                return yaml.safe_load(instream)
            except yaml.YAMLError as exc:
                print_error("YAML error:", exc)
    else:
        print_error("ERROR:", filename, "- File not found")

    return None


def load_toml_file(filename):
    if os.path.isfile(filename):
        with open(filename, 'r') as instream:
            try:
                return toml.load(instream)
            except toml.TomlDecodeError as exc:
                print_error("TOML error:", exc)
    else:
        print_error("ERROR:", filename, "- File not found")

    return None


def load_json_file(filename):
    if os.path.isfile(filename):
        with open(filename, 'r') as instream:
            try:
                return json.load(instream)
            except json.JSONDecodeError as exc:
                print_error("JSON error: [", exc.lineno, ",", exc.colno, "]", exc.msg)
    else:
        print_error("ERROR:", filename, "- File not found")

    return None


def load_ini_file(filename):
    iniparser = configparser.ConfigParser()
    if os.path.isfile(filename):
        iniparser.read(filename)
        return iniparser.items()
    else:
        print_error("ERROR:", filename, "- File not found")

    return None


# Render
# ------
def render_template(template, outfile, variables=None):
    try:
        with open(outfile, 'w') as file_:
            file_.write(template.render(variables)) if variables else file_.write(template.render())

    except TemplateError as exc:
        print_error("Rendering Error:", exc.message)


if __name__ == '__main__':
    # Read command line arguments
    args = argsparser.parse_args()

    tpl = load_template(args.infile)
    content = None

    # If template was found
    if tpl:
        if args.env_file:
            dotenv.load_dotenv(dotenv.find_dotenv(raise_error_if_not_found=False))
        # Load content from file, if present
        if args.yaml_file:
            content = load_yaml_file(args.yaml_file)
        elif args.json_file:
            content = load_json_file(args.json_file)
        elif args.toml_file:
            content = load_toml_file(args.toml_file)
        elif args.ini_file:
            content = load_ini_file(args.ini_file)

        # Render template with or without external content
        render_template(tpl, args.output, content) if content else render_template(tpl, args.output)
    else:
        exit(1)

    exit(0)