import argparse
import functools
import getpass
import operator
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 . import sops
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_admin_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_keys(collect_keys_for_path(secret_path)),
            )
        )
    return changed_files


def collect_keys_for_type(folder: Path) -> set[tuple[str, sops.KeyType]]:
    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[tuple[str, sops.KeyType]]:
    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,
    git_commit: bool = True,
) -> None:
    if add_groups is None:
        add_groups = []
    if add_machines is None:
        add_machines = []
    if add_users is None:
        add_users = []
    key = ensure_admin_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, key.key_type) not in recipient_keys:
        recipient_keys.add((key.pubkey, key.key_type))
        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_keys(recipient_keys))
    files_to_commit.append(secret_path)
    if git_commit:
        commit_files(
            files_to_commit,
            flake_dir,
            f"Update secret {secret_path.parent.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)
    member = group_folder / name
    if member.exists():
        if not member.is_symlink():
            msg = f"Cannot add user '{name}' to {group_folder.parent.name} secret. {member} exists but is not a symlink"
            raise ClanError(msg)
        # return early if the symlink already points to the correct target
        if member.resolve() == source:
            return []
        member.unlink()

    member.symlink_to(os.path.relpath(source, member.parent))
    changed = [member]
    if do_update_keys:
        changed.extend(
            update_keys(
                group_folder.parent,
                sorted_keys(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_keys(collect_keys_for_path(group_folder.parent))
    )


sorted_keys = functools.partial(sorted, key=operator.itemgetter(0))


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_admin_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)