from typing import Optional
from pyinfra import host
from pyinfra.api import deploy
from pyinfra.operations import apt, files, server, dnf
from pyinfra.facts.server import LinuxName
from pyinfra.facts import server as server_facts


ELIXIR_DEFAULTS = {
    "elixir_version": "1.13.4",
    "erlang_version": "25",
}


def install_for_ubuntu():
    elixir_is_updated = False
    erlang_is_updated = False

    wanted_elixir_version = host.data.elixir_version
    wanted_erlang_version = host.data.erlang_version

    elixir_command = host.get_fact(server_facts.Which, command="elixir")
    if elixir_command:
        elixir_version = host.get_fact(ElixirVersion)
        elixir_is_updated = elixir_version == wanted_elixir_version

    erlang_command = host.get_fact(server_facts.Which, command="erl")
    if erlang_command:
        erlang_version = host.get_fact(ErlangVersion)
        erlang_is_updated = erlang_version == wanted_erlang_version

    if elixir_is_updated and erlang_is_updated:
        return

    # elixir is non trivial to install because we can't
    # rely on the ubuntu package repo to be updated
    #
    # so we use the Erlang Solutions repository as recommended by elixir themselves.

    erlang_repo_deb_path = "/tmp/erlang-solutions.deb"
    files.download(
        name="download erlang solutions repo deb file",
        src="https://packages.erlang-solutions.com/erlang-solutions_2.0_all.deb",
        dest=erlang_repo_deb_path,
    )

    apt.deb(
        name="install erlang solutions repo",
        src=erlang_repo_deb_path,
    )

    # TODO: we don't need to update if we already installed the deb
    apt.update(cache_time=3600)

    # its in two separate steps as recommended by readme. who am i to judge
    apt.packages(
        name="install erlang",
        packages=[
            f"erlang={otp_version}" if otp_version else f"erlang",
            f"erlang-manpages={otp_version}" if otp_version else f"erlang-manpages",
        ],
    )
    apt.packages(
        name="install elixir",
        packages=[f"elixir={elixir_version}" if elixir_version else "elixir"],
    )


@deploy("Install Elixir", data_defaults=ELIXIR_DEFAULTS)
def install():
    linux_name = host.get_fact(LinuxName)
    if linux_name == "Fedora":
        dnf.packages(["erlang", "elixir"])
    else:
        install_for_ubuntu()
    server.shell(name="test elixir exists", commands=["elixir -v"])