#!/usr/bin/env python3

import argparse
import getpass
import json
import os
import sys
import urllib.parse
from os import environ, mkdir
from os.path import isdir, isfile, join
from typing import Union

import argcomplete
import requests
import yaml
from requests.exceptions import JSONDecodeError as RequestsJSONDecodeError
from requests.models import HTTPBasicAuth
from simplejson.errors import JSONDecodeError as SimplejsonJSONDecodeError


# Helper functions
def error(description: str, error: str) -> list[dict]:
    response = []
    reply = {}
    # https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/406
    reply["Code"] = 406
    reply["Description"] = description
    reply["Error"] = error
    response.append(reply)
    return response


def get_config(config_filename: str):
    with open(config_filename, "r") as fh:
        return yaml.safe_load(fh.read())


def nested_out(input, tabs="") -> str:
    string = ""
    if isinstance(input, str) or isinstance(input, int):
        string += "{}\n".format(input)
    elif isinstance(input, dict):
        for key, value in input.items():
            string += "{}{}: {}".format(tabs, key,
                                        nested_out(value, tabs + " "))
    elif isinstance(input, list):
        for entry in input:
            string += "{}\n{}".format(tabs, nested_out(entry, tabs + " "))
    return string


def output(response: list[dict], jsonout: bool = False):
    try:
        if jsonout:
            print(json.dumps(response))
        else:
            print(nested_out(response))
    except BrokenPipeError:
        pass


# Define the runner for each command
def run_add(url: str, jsonout: bool, headers: dict):
    print(url)
    response = requests.put(url, headers=headers)
    output(response.json(), jsonout)


def run_complete(shell: Union[None, str]):
    if not shell or shell in ["bash", "zsh"]:
        os.system("register-python-argcomplete knotctl")
    elif shell == "fish":
        os.system("register-python-argcomplete --shell fish knotctl")
    elif shell == "tcsh":
        os.system("register-python-argcomplete --shell tcsh knotctl")


def run_config(
    config_filename: str,
    baseurl: Union[None, str] = None,
    username: Union[None, str] = None,
    password: Union[None, str] = None,
):
    config = {"baseurl": baseurl, "username": username, "password": password}
    needed = []
    if not baseurl:
        needed.append("baseurl")
    if not username:
        needed.append("username")
    for need in needed:
        if need == "":
            output(
                error("Can not configure without {}".format(need),
                      "No {}".format(need)))
            sys.exit(1)
        config[need] = input("Enter {}:".format(need))

    if not password:
        try:
            config["password"] = getpass.getpass()
        except EOFError:
            output(error("Can not configure without password", "No password"))
            sys.exit(1)

    with open(config_filename, "w") as fh:
        fh.write(yaml.dump(config))


def run_delete(url: str, jsonout: bool, headers: dict):
    response = requests.delete(url, headers=headers)
    reply = response.json()
    if not reply and response.status_code == requests.codes.ok:
        reply = [{"Code": 200, "Description": "{} deleted".format(url)}]

    output(reply, jsonout)


def run_list(url: str,
             jsonout: bool,
             headers: dict,
             ret=False) -> Union[None, str]:
    response = requests.get(url, headers=headers)
    string = response.json()
    if ret:
        return string
    else:
        output(string, jsonout)


def run_update(url: str, jsonout: bool, headers: dict):
    response = requests.patch(url, headers=headers)
    output(response.json(), jsonout)


# Set up the url
def setup_url(
    baseurl: str,
    arguments: Union[None, list[str]],
    data: Union[None, str],
    name: Union[None, str],
    rtype: Union[None, str],
    ttl: Union[None, str],
    zone: Union[None, str],
) -> str:
    url = baseurl + "/zones"
    if zone:
        if not zone.endswith("."):
            zone += "."
        url += "/{}".format(zone)
    if name and zone:
        url += "/records/{}".format(name)
    if zone and name and rtype:
        url += "/{}".format(rtype)
    if data and zone and name and rtype:
        url += "/{}".format(data)
    if ttl and data and zone and name and rtype:
        url += "/{}".format(ttl)
    if data and zone and name and rtype and arguments:
        url += "?"
        for arg in arguments:
            if not url.endswith("?"):
                url += "&"
            key, value = arg.split("=")
            url += key + "=" + urllib.parse.quote_plus(value)

    if ttl and (not rtype or not name or not zone):
        output(
            error("ttl only makes sense with rtype, name and zone",
                  "Missing parameter"))
        sys.exit(1)
    if rtype and (not name or not zone):
        output(
            error("rtype only makes sense with name and zone",
                  "Missing parameter"))
        sys.exit(1)
    if name and not zone:
        output(error("name only makes sense with a zone", "Missing parameter"))
        sys.exit(1)
    return url


# Entry point to program
def main() -> int:
    # Grab user input
    parser = argparse.ArgumentParser()
    parser.add_argument("--json", action=argparse.BooleanOptionalAction)
    subparsers = parser.add_subparsers(dest="command")
    addcmd = subparsers.add_parser("add")
    addcmd.add_argument("-d", "--data", required=True)
    addcmd.add_argument("-n", "--name", required=True)
    addcmd.add_argument("-r", "--rtype", required=True)
    addcmd.add_argument("-t", "--ttl")
    addcmd.add_argument("-z", "--zone", required=True)

    completecmd = subparsers.add_parser("completion")
    completecmd.add_argument("-s", "--shell")

    configcmd = subparsers.add_parser("config")
    configcmd.add_argument("-b", "--baseurl")
    configcmd.add_argument("-p", "--password")
    configcmd.add_argument("-u", "--username")

    deletecmd = subparsers.add_parser("delete")
    deletecmd.add_argument("-d", "--data")
    deletecmd.add_argument("-n", "--name")
    deletecmd.add_argument("-r", "--rtype")
    deletecmd.add_argument("-z", "--zone", required=True)

    listcmd = subparsers.add_parser("list")
    listcmd.add_argument("-d", "--data")
    listcmd.add_argument("-n", "--name")
    listcmd.add_argument("-r", "--rtype")
    listcmd.add_argument("-z", "--zone")

    updatecmd = subparsers.add_parser("update")
    updatecmd.add_argument(
        "-a",
        "--argument",
        nargs="*",
        help="Specify key - value pairs to be updated: name=dns1.example.com.",
        required=True,
    )
    updatecmd.add_argument("-d", "--data", required=True)
    updatecmd.add_argument("-n", "--name", required=True)
    updatecmd.add_argument("-r", "--rtype", required=True)
    updatecmd.add_argument("-t", "--ttl")
    updatecmd.add_argument("-z", "--zone", required=True)

    argcomplete.autocomplete(parser)
    args = parser.parse_args()
    if args.command == "completion":
        run_complete(args.shell)
        return 0

    # Make sure we have config
    config_basepath = join(environ["HOME"], ".knot")
    config_filename = join(config_basepath, "config")

    if not isdir(config_basepath):
        mkdir(config_basepath)

    if args.command == "config":
        run_config(args.baseurl, args.username, args.password)
        return 0

    if not isfile(config_filename):
        print("You need to configure knotctl before proceeding")
        run_config(config_filename)

    config = get_config(config_filename)
    baseurl = config["baseurl"]
    username = config["username"]
    password = config["password"]

    # Authenticate
    basic = HTTPBasicAuth(username, password)
    response = requests.get(baseurl + "/user/login", auth=basic)
    try:
        token = response.json()["token"]
    except KeyError:
        output(response.json())
        return 1
    headers = {"Authorization": "Bearer {}".format(token)}

    # Route based on command
    ttl = None
    if 'ttl' in args:
        ttl = args.ttl
    if args.command != "update":
        args.argument = None
    if args.command == "add" and not ttl:
        if args.zone.endswith('.'):
            zname = args.zone
        else:
            zname = args.zone + '.'
        soa_url = setup_url(baseurl, None, None, zname, "SOA", None,
                            args.zone)
        soa_json = run_list(soa_url, True, headers, ret=True)
        ttl = soa_json[0]["ttl"]

    try:
        url = setup_url(baseurl, args.argument, args.data, args.name,
                        args.rtype, ttl, args.zone)
    except AttributeError:
        parser.print_help(sys.stderr)
        return 1

    try:
        if args.command == "add":
            run_add(url, args.json, headers)
        elif args.command == "delete":
            run_delete(url, args.json, headers)
        elif args.command == "list":
            run_list(url, args.json, headers)
        elif args.command == "update":
            run_update(url, args.json, headers)
    except (RequestsJSONDecodeError, SimplejsonJSONDecodeError):
        output(
            error("Could not decode api response as JSON", "Could not decode"))
    return 0


if __name__ == "__main__":
    sys.exit(main())