#!/usr/bin/env python3
# Eryn Wells <eryn@erynwells.me>

import argparse
import datetime
import subprocess
from typing import List
from .scripting import Command


DATE_FORMAT = "%Y-%m-%d"


class DeploymentCommand(Command):
    @property
    def help(self) -> str:
        return 'Deployment tools'

    def add_arguments(self, parser: argparse.ArgumentParser):
        commands = parser.add_subparsers(title="Deployment", required=True)

        deployment_command = commands.add_parser(
            'next-tag',
            help='Calculate the next deployment tag for a given date, examining all other tags for that day'
        )
        deployment_command.add_argument(
            '--date', '-d',
            type=self.__class__.parse_date_argument,
            default=datetime.date.today(),
            help="date to calculate a new deployment tag for (default: today)"
        )
        deployment_command.set_defaults(handler=self.handle_next_deployment_tag_command)

    @staticmethod
    def parse_date_argument(date_string: str) -> datetime.date:
        return datetime.datetime.strptime(date_string, DATE_FORMAT).date()

    def handle_next_deployment_tag_command(self, args: argparse.Namespace):
        next_deployment_tag = deployment_tag_for_date(args.date)
        print(next_deployment_tag)

def deployment_tag_for_date(date: datetime.date) -> str:
    formatted_date = date.strftime(DATE_FORMAT)

    def deploy_tag_filter(tag):
        return tag.startswith("deploy-") and formatted_date in tag

    filtered_tags = sorted(filter(deploy_tag_filter, git_tags()))

    if len(filtered_tags) == 0:
        return f"deploy-{formatted_date}-01"
    else:
        last_tag = filtered_tags[-1]
        components = last_tag.split("-")
        if len(components) == 5:
            # A previous numbered deployment. Add one to the last deployment
            # number.
            deployment_number = int(components[-1]) + 1
            return f"deploy-{formatted_date}-{deployment_number:02}"
        else:
            # An old style deployment tag that doesn't have a number. There
            # should only ever be one of these.
            assert len(filtered_tags) == 1
            return f"deploy-{formatted_date}-02"


def git_tags() -> List[str]:
    return subprocess.check_output(
        "git tag -l",
        shell=True,
        encoding="utf-8"
    ).splitlines()