import argparse
import contextlib
import json
import subprocess
import threading
from collections.abc import Callable, Iterable
from types import ModuleType
from typing import Any

from clan_lib.cmd import run
from clan_lib.flake.flake import Flake
from clan_lib.nix import nix_eval
from clan_lib.persist.inventory_store import InventoryStore

"""
This module provides dynamic completions.
The completions should feel fast.
We target a maximum of 1second on our average machine.
"""


argcomplete: ModuleType | None = None
with contextlib.suppress(ImportError):
    import argcomplete  # type: ignore[no-redef]


# The default completion timeout for commands
COMPLETION_TIMEOUT: int = 3


def clan_dir(flake: str | None) -> str | None:
    from clan_lib.dirs import get_clan_flake_toplevel_or_env

    path_result = get_clan_flake_toplevel_or_env()
    return str(path_result) if path_result is not None else None


def complete_machines(
    prefix: str, parsed_args: argparse.Namespace, **kwargs: Any
) -> Iterable[str]:
    """
    Provides completion functionality for machine names configured in the clan.
    """
    machines: list[str] = []

    def run_cmd() -> None:
        try:
            if (clan_dir_result := clan_dir(None)) is not None:
                flake = clan_dir_result
            else:
                flake = "."

            inventory = InventoryStore(Flake(str(flake))).read()
            machines.extend(inventory.get("machines", {}).keys())

        except subprocess.CalledProcessError:
            pass

    thread = threading.Thread(target=run_cmd)
    thread.start()
    thread.join(timeout=COMPLETION_TIMEOUT)

    if thread.is_alive():
        return iter([])

    machines_dict = dict.fromkeys(machines, "machine")
    return machines_dict


def complete_services_for_machine(
    prefix: str, parsed_args: argparse.Namespace, **kwargs: Any
) -> Iterable[str]:
    """
    Provides completion functionality for machine facts generation services.
    """
    services: list[str] = []
    # TODO: consolidate, if multiple machines are used
    machines: list[str] = parsed_args.machines

    def run_cmd() -> None:
        try:
            if (clan_dir_result := clan_dir(None)) is not None:
                flake = clan_dir_result
            else:
                flake = "."
            services_result = json.loads(
                run(
                    nix_eval(
                        flags=[
                            f"{flake}#nixosConfigurations.{machines[0]}.config.clan.core.facts.services",
                            "--apply",
                            "builtins.attrNames",
                        ],
                    ),
                ).stdout.strip()
            )

            services.extend(services_result)
        except subprocess.CalledProcessError:
            pass

    thread = threading.Thread(target=run_cmd)
    thread.start()
    thread.join(timeout=COMPLETION_TIMEOUT)

    if thread.is_alive():
        return iter([])

    services_dict = dict.fromkeys(services, "service")
    return services_dict


def complete_backup_providers_for_machine(
    prefix: str, parsed_args: argparse.Namespace, **kwargs: Any
) -> Iterable[str]:
    """
    Provides completion functionality for machine backup providers.
    """
    providers: list[str] = []
    machine: str = parsed_args.machine

    def run_cmd() -> None:
        try:
            if (clan_dir_result := clan_dir(None)) is not None:
                flake = clan_dir_result
            else:
                flake = "."
            providers_result = json.loads(
                run(
                    nix_eval(
                        flags=[
                            f"{flake}#nixosConfigurations.{machine}.config.clan.core.backups.providers",
                            "--apply",
                            "builtins.attrNames",
                        ],
                    ),
                ).stdout.strip()
            )

            providers.extend(providers_result)
        except subprocess.CalledProcessError:
            pass

    thread = threading.Thread(target=run_cmd)
    thread.start()
    thread.join(timeout=COMPLETION_TIMEOUT)

    if thread.is_alive():
        return iter([])

    providers_dict = dict.fromkeys(providers, "provider")
    return providers_dict


def complete_state_services_for_machine(
    prefix: str, parsed_args: argparse.Namespace, **kwargs: Any
) -> Iterable[str]:
    """
    Provides completion functionality for machine state providers.
    """
    providers: list[str] = []
    machine: str = parsed_args.machine

    def run_cmd() -> None:
        try:
            if (clan_dir_result := clan_dir(None)) is not None:
                flake = clan_dir_result
            else:
                flake = "."
            providers_result = json.loads(
                run(
                    nix_eval(
                        flags=[
                            f"{flake}#nixosConfigurations.{machine}.config.clan.core.state",
                            "--apply",
                            "builtins.attrNames",
                        ],
                    ),
                ).stdout.strip()
            )

            providers.extend(providers_result)
        except subprocess.CalledProcessError:
            pass

    thread = threading.Thread(target=run_cmd)
    thread.start()
    thread.join(timeout=COMPLETION_TIMEOUT)

    if thread.is_alive():
        return iter([])

    providers_dict = dict.fromkeys(providers, "service")
    return providers_dict


def complete_secrets(
    prefix: str, parsed_args: argparse.Namespace, **kwargs: Any
) -> Iterable[str]:
    """
    Provides completion functionality for clan secrets
    """
    from clan_lib.flake.flake import Flake

    from .secrets.secrets import list_secrets

    flake = clan_dir_result if (clan_dir_result := clan_dir(None)) is not None else "."

    secrets = list_secrets(Flake(flake).path)

    secrets_dict = dict.fromkeys(secrets, "secret")
    return secrets_dict


def complete_users(
    prefix: str, parsed_args: argparse.Namespace, **kwargs: Any
) -> Iterable[str]:
    """
    Provides completion functionality for clan users
    """
    from pathlib import Path

    from .secrets.users import list_users

    flake = clan_dir_result if (clan_dir_result := clan_dir(None)) is not None else "."

    users = list_users(Path(flake))

    users_dict = dict.fromkeys(users, "user")
    return users_dict


def complete_groups(
    prefix: str, parsed_args: argparse.Namespace, **kwargs: Any
) -> Iterable[str]:
    """
    Provides completion functionality for clan groups
    """
    from pathlib import Path

    from .secrets.groups import list_groups

    flake = clan_dir_result if (clan_dir_result := clan_dir(None)) is not None else "."

    groups_list = list_groups(Path(flake))
    groups = [group.name for group in groups_list]

    groups_dict = dict.fromkeys(groups, "group")
    return groups_dict


def complete_target_host(
    prefix: str, parsed_args: argparse.Namespace, **kwargs: Any
) -> Iterable[str]:
    """
    Provides completion functionality for target_host for a specific machine
    """
    target_hosts: list[str] = []
    machine: str = parsed_args.machine

    def run_cmd() -> None:
        try:
            if (clan_dir_result := clan_dir(None)) is not None:
                flake = clan_dir_result
            else:
                flake = "."
            target_host_result = json.loads(
                run(
                    nix_eval(
                        flags=[
                            f"{flake}#nixosConfigurations.{machine}.config.clan.core.networking.targetHost",
                        ],
                    ),
                ).stdout.strip()
            )

            target_hosts.append(target_host_result)
        except subprocess.CalledProcessError:
            pass

    thread = threading.Thread(target=run_cmd)
    thread.start()
    thread.join(timeout=COMPLETION_TIMEOUT)

    if thread.is_alive():
        return iter([])

    providers_dict = dict.fromkeys(target_hosts, "target_host")
    return providers_dict


def complete_tags(
    prefix: str, parsed_args: argparse.Namespace, **kwargs: Any
) -> Iterable[str]:
    """
    Provides completion functionality for tags inside the inventory
    """
    tags: list[str] = []
    threads = []

    def run_computed_tags_cmd() -> None:
        try:
            if (clan_dir_result := clan_dir(None)) is not None:
                flake = clan_dir_result
            else:
                flake = "."

            inventory_store = InventoryStore(Flake(str(flake)))
            inventory = inventory_store.get_readonly_raw()
            if "tags" in inventory:
                tags.extend(inventory["tags"].keys())

        except subprocess.CalledProcessError:
            pass

    def run_machines_tags_cmd() -> None:
        machine_tags: list[str] = []
        try:
            if (clan_dir_result := clan_dir(None)) is not None:
                flake = clan_dir_result
            else:
                flake = "."
            inventory_store = InventoryStore(Flake(str(flake)))
            inventory = inventory_store.get_readonly_raw()
            machine_tags_result = inventory.get("machines")
            if machine_tags_result is None:
                return

            for machine in machine_tags_result.values():
                machine_tags.extend(machine.get("tags", []))

            tags.extend(machine_tags)
        except subprocess.CalledProcessError:
            pass

    def start_thread(target_function: Callable) -> threading.Thread:
        thread = threading.Thread(target=target_function)
        thread.start()
        return thread

    functions_to_run = [
        run_computed_tags_cmd,
        run_machines_tags_cmd,
    ]

    threads = [start_thread(func) for func in functions_to_run]

    for thread in threads:
        thread.join(timeout=COMPLETION_TIMEOUT)

    if any(thread.is_alive() for thread in threads):
        return iter([])

    providers_dict = dict.fromkeys(tags, "tag")
    return providers_dict


def add_dynamic_completer(
    action: argparse.Action,
    completer: Callable[..., Iterable[str]],
) -> None:
    """
    Add a completion function to an argparse action, this will only be added,
    if the argcomplete module is loaded.
    """
    if argcomplete:
        # mypy doesn't check this correctly, so we ignore it
        action.completer = completer  # type: ignore[attr-defined]