import argparse
import getpass
import os
import shutil
import sys
from collections.abc import Callable
from dataclasses import dataclass
from pathlib import Path
from typing import IO

from clan_cli import tty
from clan_cli.clan_uri import FlakeId
from clan_cli.completions import (
    add_dynamic_completer,
    complete_groups,
    complete_machines,
    complete_secrets,
    complete_users,
)
from clan_cli.errors import ClanError
from clan_cli.git import commit_files

from .folders import (
    list_objects,
    sops_groups_folder,
    sops_machines_folder,
    sops_secrets_folder,
    sops_users_folder,
)
from .sops import decrypt_file, encrypt_file, ensure_sops_key, read_key, update_keys
from .types import VALID_SECRET_NAME, secret_name_type


def update_secrets(
    flake_dir: Path, filter_secrets: Callable[[Path], bool] = lambda _: True
) -> list[Path]:
    changed_files = []
    for name in list_secrets(flake_dir):
        secret_path = sops_secrets_folder(flake_dir) / name
        if not filter_secrets(secret_path):
            continue
        changed_files.extend(
            update_keys(
                secret_path,
                sorted(collect_keys_for_path(secret_path)),
            )
        )
    return changed_files


def collect_keys_for_type(folder: Path) -> set[str]:
    if not folder.exists():
        return set()
    keys = set()
    for p in folder.iterdir():
        if not p.is_symlink():
            continue
        try:
            target = p.resolve()
        except FileNotFoundError:
            tty.warn(f"Ignoring broken symlink {p}")
            continue
        kind = target.parent.name
        if folder.name != kind:
            tty.warn(f"Expected {p} to point to {folder} but points to {target.parent}")
            continue
        keys.add(read_key(target))
    return keys


def collect_keys_for_path(path: Path) -> set[str]:
    keys = set()
    keys.update(collect_keys_for_type(path / "machines"))
    keys.update(collect_keys_for_type(path / "users"))
    groups = path / "groups"
    if not groups.is_dir():
        return keys
    for group in groups.iterdir():
        keys.update(collect_keys_for_type(group / "machines"))
        keys.update(collect_keys_for_type(group / "users"))
    return keys


def encrypt_secret(
    flake_dir: Path,
    secret_path: Path,
    value: IO[str] | str | bytes | None,
    add_users: list[str] | None = None,
    add_machines: list[str] | None = None,
    add_groups: list[str] | None = None,
) -> None:
    if add_groups is None:
        add_groups = []
    if add_machines is None:
        add_machines = []
    if add_users is None:
        add_users = []
    key = ensure_sops_key(flake_dir)
    recipient_keys = set()

    files_to_commit = []
    for user in add_users:
        files_to_commit.extend(
            allow_member(
                users_folder(secret_path),
                sops_users_folder(flake_dir),
                user,
                False,
            )
        )

    for machine in add_machines:
        files_to_commit.extend(
            allow_member(
                machines_folder(secret_path),
                sops_machines_folder(flake_dir),
                machine,
                False,
            )
        )

    for group in add_groups:
        files_to_commit.extend(
            allow_member(
                groups_folder(secret_path),
                sops_groups_folder(flake_dir),
                group,
                False,
            )
        )

    recipient_keys = collect_keys_for_path(secret_path)

    if key.pubkey not in recipient_keys:
        recipient_keys.add(key.pubkey)
        files_to_commit.extend(
            allow_member(
                users_folder(secret_path),
                sops_users_folder(flake_dir),
                key.username,
                False,
            )
        )

    secret_path = secret_path / "secret"
    encrypt_file(secret_path, value, sorted(recipient_keys))
    files_to_commit.append(secret_path)
    commit_files(
        files_to_commit,
        flake_dir,
        f"Update secret {secret_path.name}",
    )


def remove_secret(flake_dir: Path, secret: str) -> None:
    path = sops_secrets_folder(flake_dir) / secret
    if not path.exists():
        msg = f"Secret '{secret}' does not exist"
        raise ClanError(msg)
    shutil.rmtree(path)
    commit_files(
        [path],
        flake_dir,
        f"Remove secret {secret}",
    )


def remove_command(args: argparse.Namespace) -> None:
    remove_secret(args.flake.path, args.secret)


def add_secret_argument(parser: argparse.ArgumentParser, autocomplete: bool) -> None:
    secrets_parser = parser.add_argument(
        "secret",
        metavar="secret-name",
        help="the name of the secret",
        type=secret_name_type,
    )
    if autocomplete:
        add_dynamic_completer(secrets_parser, complete_secrets)


def machines_folder(secret_path: Path) -> Path:
    return secret_path / "machines"


def users_folder(secret_path: Path) -> Path:
    return secret_path / "users"


def groups_folder(secret_path: Path) -> Path:
    return secret_path / "groups"


def list_directory(directory: Path) -> str:
    if not directory.exists():
        return f"{directory} does not exist"
    msg = f"\n{directory} contains:"
    for f in directory.iterdir():
        msg += f"\n  {f.name}"
    return msg


def allow_member(
    group_folder: Path, source_folder: Path, name: str, do_update_keys: bool = True
) -> list[Path]:
    source = source_folder / name
    if not source.exists():
        msg = f"Cannot encrypt {group_folder.parent.name} for '{name}' group. '{name}' group does not exist in {source_folder}: "
        msg += list_directory(source_folder)
        raise ClanError(msg)
    group_folder.mkdir(parents=True, exist_ok=True)
    user_target = group_folder / name
    if user_target.exists():
        if not user_target.is_symlink():
            msg = f"Cannot add user '{name}' to {group_folder.parent.name} secret. {user_target} exists but is not a symlink"
            raise ClanError(msg)
        user_target.unlink()

    user_target.symlink_to(os.path.relpath(source, user_target.parent))
    changed = [user_target]
    if do_update_keys:
        changed.extend(
            update_keys(
                group_folder.parent,
                sorted(collect_keys_for_path(group_folder.parent)),
            )
        )
    return changed


def disallow_member(group_folder: Path, name: str) -> list[Path]:
    target = group_folder / name
    if not target.exists():
        msg = f"{name} does not exist in group in {group_folder}: "
        msg += list_directory(group_folder)
        raise ClanError(msg)

    keys = collect_keys_for_path(group_folder.parent)

    if len(keys) < 2:
        msg = f"Cannot remove {name} from {group_folder.parent.name}. No keys left. Use 'clan secrets remove {name}' to remove the secret."
        raise ClanError(msg)
    target.unlink()

    if len(os.listdir(group_folder)) == 0:
        group_folder.rmdir()

    if len(os.listdir(group_folder.parent)) == 0:
        group_folder.parent.rmdir()

    return update_keys(
        target.parent.parent, sorted(collect_keys_for_path(group_folder.parent))
    )


def has_secret(secret_path: Path) -> bool:
    return (secret_path / "secret").exists()


def list_secrets(flake_dir: Path, pattern: str | None = None) -> list[str]:
    path = sops_secrets_folder(flake_dir)

    def validate(name: str) -> bool:
        return (
            VALID_SECRET_NAME.match(name) is not None
            and has_secret(sops_secrets_folder(flake_dir) / name)
            and (pattern is None or pattern in name)
        )

    return list_objects(path, validate)


@dataclass
class ListSecretsOptions:
    flake: FlakeId
    pattern: str | None


def list_command(args: argparse.Namespace) -> None:
    options = ListSecretsOptions(
        flake=args.flake,
        pattern=args.pattern,
    )
    lst = list_secrets(options.flake.path, options.pattern)
    if len(lst) > 0:
        print("\n".join(lst))


def decrypt_secret(flake_dir: Path, secret_path: Path) -> str:
    ensure_sops_key(flake_dir)
    path = secret_path / "secret"
    if not path.exists():
        msg = f"Secret '{secret_path!s}' does not exist"
        raise ClanError(msg)
    return decrypt_file(path)


def get_command(args: argparse.Namespace) -> None:
    print(
        decrypt_secret(
            args.flake.path, sops_secrets_folder(args.flake.path) / args.secret
        ),
        end="",
    )


def set_command(args: argparse.Namespace) -> None:
    env_value = os.environ.get("SOPS_NIX_SECRET")
    secret_value: str | IO[str] | None = sys.stdin
    if args.edit:
        secret_value = None
    elif env_value:
        secret_value = env_value
    elif tty.is_interactive():
        secret_value = getpass.getpass(prompt="Paste your secret: ")
    encrypt_secret(
        args.flake.path,
        sops_secrets_folder(args.flake.path) / args.secret,
        secret_value,
        args.user,
        args.machine,
        args.group,
    )


def rename_command(args: argparse.Namespace) -> None:
    flake_dir = args.flake.path
    old_path = sops_secrets_folder(flake_dir) / args.secret
    new_path = sops_secrets_folder(flake_dir) / args.new_name
    if not old_path.exists():
        msg = f"Secret '{args.secret}' does not exist"
        raise ClanError(msg)
    if new_path.exists():
        msg = f"Secret '{args.new_name}' already exists"
        raise ClanError(msg)
    old_path.rename(new_path)
    commit_files(
        [old_path, new_path],
        flake_dir,
        f"Rename secret {args.secret} to {args.new_name}",
    )


def register_secrets_parser(subparser: argparse._SubParsersAction) -> None:
    parser_list = subparser.add_parser("list", help="list secrets")
    parser_list.add_argument(
        "pattern",
        nargs="?",
        help="a pattern to filter the secrets. All secrets containing the pattern will be listed.",
    )
    parser_list.set_defaults(func=list_command)

    parser_get = subparser.add_parser("get", help="get a secret")
    add_secret_argument(parser_get, True)
    parser_get.set_defaults(func=get_command)

    parser_set = subparser.add_parser("set", help="set a secret")
    add_secret_argument(parser_set, False)
    set_group_action = parser_set.add_argument(
        "--group",
        type=str,
        action="append",
        default=[],
        help="the group to import the secrets to (can be repeated)",
    )
    add_dynamic_completer(set_group_action, complete_groups)
    machine_parser = parser_set.add_argument(
        "--machine",
        type=str,
        action="append",
        default=[],
        help="the machine to import the secrets to (can be repeated)",
    )
    add_dynamic_completer(machine_parser, complete_machines)
    set_user_action = parser_set.add_argument(
        "--user",
        type=str,
        action="append",
        default=[],
        help="the user to import the secrets to (can be repeated)",
    )
    add_dynamic_completer(set_user_action, complete_users)
    parser_set.add_argument(
        "-e",
        "--edit",
        action="store_true",
        default=False,
        help="edit the secret with $EDITOR instead of pasting it",
    )
    parser_set.set_defaults(func=set_command)

    parser_rename = subparser.add_parser("rename", help="rename a secret")
    add_secret_argument(parser_rename, True)
    parser_rename.add_argument("new_name", type=str, help="the new name of the secret")
    parser_rename.set_defaults(func=rename_command)

    parser_remove = subparser.add_parser("remove", help="remove a secret")
    add_secret_argument(parser_remove, True)
    parser_remove.set_defaults(func=remove_command)