"""Abstract persistence API for per-conversation share links."""

from __future__ import annotations

import secrets
from abc import ABC, abstractmethod
from typing import Any

# Unambiguous alphabet — no 0/O/1/I/L so codes are easy to read and type.
_CODE_ALPHABET = "ABCDEFGHJKMNPQRSTUVWXYZ23456789"


def generate_share_code(length: int = 8) -> str:
    """Return a random, unguessable, human-readable share code."""
    return "".join(secrets.choice(_CODE_ALPHABET) for _ in range(length))


class ThreadShareStore(ABC):
    @abstractmethod
    async def create(self, owner_user_id: str, thread_id: str, *, mode: str = "import") -> dict[str, Any]:
        """Create a new share link for one conversation and return its record.

        ``mode`` is ``"import"`` (recipient copies the conversation) or
        ``"view"`` (a public read-only static page).
        """
        raise NotImplementedError

    @abstractmethod
    async def get(self, share_code: str) -> dict[str, Any] | None:
        """Look up a share by code regardless of owner (None if missing)."""
        raise NotImplementedError

    @abstractmethod
    async def get_active_for_thread(self, owner_user_id: str, thread_id: str, *, mode: str = "import") -> dict[str, Any] | None:
        """Return the owner's non-revoked share of ``mode`` for ``thread_id``, if any.

        Used so re-sharing the same conversation in the same mode reuses its
        existing code instead of minting a new one each time.
        """
        raise NotImplementedError

    @abstractmethod
    async def list_for_owner(self, owner_user_id: str) -> list[dict[str, Any]]:
        """List all share links created by ``owner_user_id`` (newest first)."""
        raise NotImplementedError

    @abstractmethod
    async def revoke(self, share_code: str, owner_user_id: str) -> bool:
        """Revoke a share link. Returns False if missing or not owned."""
        raise NotImplementedError