#!/usr/bin/env python3
from docker import from_env as docker_from_env, DockerClient
from docker.models.services import Service
from requests import Session
from base64 import b64encode
from typing import List
from os import environ


DRY_RUN = False
DRY_RUN = True


# Map of Docker service names to Azure DevOps CI pipeline definition IDs
SERVICE_MAPPER = {
    'byndle_demofrontend': 18,
    'byndle_demobackend': 16,
    'byndle_frontend': 17,
    'byndle_backend': 14,
    'byndle_nextcom': 14,
}


class DevOpsAPI: # https://learn.microsoft.com/en-us/rest/api/azure/devops
    "Limited Azure DevOps API client"
    base: str = 'https://dev.azure.com/enevo'
    proj: str = 'Byndle'
    ver: str = '7.1'
    ses: Session

    def __init__(self, token=environ.get('AZDO_PAT')):
        if token is None:
            raise Exception(
                    'env var AZDO_PAT needs to be set to a valid Azure DevOps access token!')

        self.ses = Session()
        self.ses.params['api-version'] = self.ver
        self.set_token(token)

    def set_token(self, token):
        self.ses.headers['Authorization'] = 'Basic ' + b64encode(
            bytes(':' + token, 'UTF-8')).decode()

    def builds(self, definition, top=1):
        json = self.ses.get('{}/{}/_apis/build/builds?definitions={}&$top={}'.format(
            self.base, self.proj, definition, top
        )).json()
        return json['value'][-1]


class Deployer: # https://docker-py.readthedocs.io/en/stable/index.html
    "Uses DevOpsAPI to fetch build IDs needed to deploy Docker swarm"
    svcs: List[Service]
    dock: DockerClient
    az: DevOpsAPI
    is_prod: bool

    def __init__(self, is_prod = False):
        if environ.get('DOCKER_HOST') is None:
            raise Exception(
                    'env var DOCKER_HOST needs to be set to deploy Docker swarm!')

        self.is_prod = is_prod
        self.dock = docker_from_env()
        self.az = DevOpsAPI()
        self.svcs = self.dock.services.list()

        self.svc_name = lambda is_front: 'byndle_{}{}end'.format(
            '' if self.is_prod else 'demo',
            'front' if is_front else 'back')
        
    def img_name(self, svc_name, top):
        return 'enevodocker/enevoleads{}e:{}_{}'.format(
            'f' if 'front' in svc_name else 'b',
            'prod' if self.is_prod else 'stage',
            self.get_build_id(svc_name, top))

    def get_build_id(self, service, top):
        return self.az.builds(SERVICE_MAPPER[service], top)['id']

    def get_svc(self, name):
        for svc in self.svcs:
            if svc.name == name:
                return svc

    def deploy(self, name, top=1):
        img = self.img_name(name, top)
        print('Deploying image {} on service {}'.format(img, name))
        return self.get_svc(name).update(image=img, name=name)


if __name__ == '__main__':
    from getopt import GetoptError, getopt
    from sys import argv

    def usage():
        print(
            'Usage: {} [option(s)]\n'.format(argv[0]) +
            '\n\t-p\tUse production environment' +
            '\n\t-f\tDeploy frontend service' +
            '\n\t-b\tDeploy backend service' +
            '\n\t-n\tDeploy nextcom service' +
            '\n\t-r{x}\tDeploy x number of builds back' +
            '\n\t-h\tShow this help')
        exit(1)

    is_prod = False
    svcs = []
    top = 1

    try:
        opts, args = getopt(argv[1:], 'pfbnhr:')
    except GetoptError as exc:
        print('\nError: {}\n'.format(exc))
        usage()

    if '-p' in [opt for opt, _arg in opts]:
        is_prod = True

    dep = Deployer(is_prod)

    for opt, arg in opts:
        if opt == '-f':
            svcs.append(dep.svc_name(True))
        elif opt == '-b':
            svcs.append(dep.svc_name(False))
        elif opt == '-n':
            svcs.append('byndle_nextcom')
        elif opt == '-r':
            top += int(arg)
        elif opt == '-h':
            usage()

    if len(svcs) == 0:
        usage()

    if DRY_RUN:
        for svc in svcs:
            print('Would deploy image {} on service {}'.format(
                dep.img_name(svc, top), svc))
        exit(0)

    for svc in svcs:
        res = dep.deploy(svc, top)

        if res['Warnings']:
            from json import dumps
            print(dumps(res, indent=2))

    print('Done! 🤗')