"""Slack Block Kit transport adapter (design §3.3.1, §7.1 P1).

The first concrete :class:`~agent_team.transport.base.Transport` implementation.
P1 ships the human gate over **one** transport (Slack first), so this adapter
must satisfy the §3.3.1 contracts the durable responder depends on:

* :meth:`SlackTransport.post_question` renders a :class:`QuestionSet` as a Slack
  Block Kit message, embeds the ``question_id`` in the message ``callback_id``
  (Slack's native callback metadata, the analogue of the GitHub ``<!-- shq:... -->``
  marker), posts it via an **injected** poster callable, and returns the Slack
  message ``ts`` as the ``channel_ref`` stored on the ledger row.
* :meth:`SlackTransport.parse_answer` normalizes an inbound Slack payload
  (an interactive ``block_actions`` callback or a plain text/slash reply) to
  ``(question_id, answer, via)`` for the first-answer-wins compare-and-set.

This module is **transport I/O only** and carries no live wiring: the network
call is a dependency-injected ``poster`` callable, so the adapter is unit
testable and ships nothing provisioned. A production deployment supplies a
poster backed by the Composio Slack connector or ``slack_sdk`` (design §3 —
"the R720 routes Slack/Jira/Notion through" the Composio connector); the
foundation must not import or require either, so the default poster raises a
clear "not configured" error rather than reaching the network.
"""

from __future__ import annotations

from collections.abc import Callable, Mapping, Sequence
from typing import Any

from agent_team.transport.base import (
    NormalizedAnswer,
    QuestionSet,
    Transport,
)

__all__ = [
    "CALLBACK_ID_PREFIX",
    "VIA_SLACK",
    "SlackPostError",
    "SlackPoster",
    "SlackTransport",
    "build_callback_id",
    "build_question_blocks",
    "parse_callback_id",
]

# ``via`` channel-identity tag recorded in the ledger's ``answered_via`` column
# for the audit trail (§3.3.1).
VIA_SLACK = "slack"

# Namespacing prefix for the embedded ``callback_id`` so an inbound Slack
# interaction can be unambiguously mapped back to its ledger ``question_id``.
# Mirrors the GitHub ``<!-- shq:... -->`` marker convention (``shq`` = Sea Haven
# question) from the base module.
CALLBACK_ID_PREFIX = "shq"

# Type of the network seam: given the rendered Slack message kwargs, perform the
# ``chat.postMessage`` and return the response payload. The only field this
# adapter requires from the response is the message ``ts`` (the ``channel_ref``).
SlackPoster = Callable[[dict[str, Any]], Mapping[str, Any]]


class SlackPostError(RuntimeError):
    """Raised when posting a Slack message fails or no poster is configured.

    The §3.3.1 delivery rule writes the ledger row ``open`` *before* posting, so
    a raised :class:`SlackPostError` leaves the row ``open`` with no
    ``channel_ref`` and the reconcile loop retries delivery idempotently. The
    caller (responder/delivery loop) is expected to catch this and leave the row
    for reconcile rather than treating the question as delivered.
    """


def _default_poster(_message: dict[str, Any]) -> Mapping[str, Any]:
    """Default poster: refuse to reach the network (pre-deployment scaffolding).

    The foundation must not provision or wire live infrastructure, so a
    :class:`SlackTransport` constructed without an explicit ``poster`` cannot
    post. Production injects a poster backed by the Composio Slack connector or
    ``slack_sdk``.
    """
    raise SlackPostError(
        "SlackTransport has no poster configured; inject a Slack poster "
        "callable (Composio connector / slack_sdk) before posting."
    )


def build_callback_id(question_id: str) -> str:
    """Embed ``question_id`` in a namespaced Slack ``callback_id``.

    Slack echoes the message-level ``callback_id`` back on every interaction
    payload, so it is the natural carrier for the ledger ``question_id``
    (§3.3.1: "Slack ``callback_id``").
    """
    return f"{CALLBACK_ID_PREFIX}:{question_id}"


def parse_callback_id(callback_id: str) -> str:
    """Recover the ``question_id`` from a :func:`build_callback_id` value.

    Accepts both the namespaced form (``shq:<question_id>``) and a bare
    ``question_id`` (defensive, in case a payload surfaces the id directly).
    Raises :class:`ValueError` on an empty / malformed callback id so a
    mis-mapped answer fails loudly instead of being silently mis-attributed.
    """
    if not callback_id:
        raise ValueError("empty callback_id")
    prefix = f"{CALLBACK_ID_PREFIX}:"
    if callback_id.startswith(prefix):
        question_id = callback_id[len(prefix) :]
        if not question_id:
            raise ValueError(f"callback_id missing question_id: {callback_id!r}")
        return question_id
    return callback_id


def build_question_blocks(
    question_set: QuestionSet, deadline: str
) -> list[dict[str, Any]]:
    """Render a :class:`QuestionSet` as Slack Block Kit blocks.

    Surfaces optional ``context`` (``repo`` / ``summary``) as a context block,
    lists the ordered questions, and footnotes the ``deadline`` so Adam sees the
    answer window. Returns a plain JSON-serializable list (no Slack SDK types),
    keeping the adapter dependency-free.
    """
    blocks: list[dict[str, Any]] = [
        {
            "type": "header",
            "text": {
                "type": "plain_text",
                "text": f"Agent-team needs input (turn {question_set.turn})",
            },
        }
    ]

    context_elements: list[dict[str, Any]] = []
    repo = question_set.context.get("repo")
    if repo:
        context_elements.append({"type": "mrkdwn", "text": f"*repo:* {repo}"})
    summary = question_set.context.get("summary")
    if summary:
        context_elements.append({"type": "mrkdwn", "text": str(summary)})
    if context_elements:
        blocks.append({"type": "context", "elements": context_elements})

    for index, question in enumerate(question_set.questions, start=1):
        blocks.append(
            {
                "type": "section",
                "text": {"type": "mrkdwn", "text": f"*{index}.* {question}"},
            }
        )

    blocks.append(
        {
            "type": "context",
            "elements": [
                {"type": "mrkdwn", "text": f"_Reply in this thread by {deadline}._"}
            ],
        }
    )
    return blocks


def _join_answer_actions(actions: Sequence[Mapping[str, Any]]) -> Any:
    """Reduce one-or-more interactive actions to a single answer value.

    A button click yields one action; a multi-select yields several. A single
    action collapses to its scalar value; multiple actions return the ordered
    list of values so the responder records every selection.
    """
    values = [_action_value(action) for action in actions]
    if len(values) == 1:
        return values[0]
    return values


def _action_value(action: Mapping[str, Any]) -> Any:
    """Extract the answer value from one Slack ``block_actions`` action."""
    if "value" in action and action["value"] is not None:
        return action["value"]
    selected = action.get("selected_option")
    if isinstance(selected, Mapping):
        return selected.get("value")
    selected_options = action.get("selected_options")
    if isinstance(selected_options, Sequence) and not isinstance(
        selected_options, (str, bytes)
    ):
        return [
            opt.get("value") for opt in selected_options if isinstance(opt, Mapping)
        ]
    selected_user = action.get("selected_user")
    if selected_user is not None:
        return selected_user
    # Fall back to the action_id so a payload without an explicit value still
    # maps to *some* deterministic answer rather than ``None``.
    return action.get("action_id")


class SlackTransport(Transport):
    """Concrete Slack Block Kit :class:`Transport` (§3.3.1, P1 — Slack first).

    ``channel`` is the target Slack channel id. ``poster`` is the injected
    network seam (defaults to a non-networking poster that raises, so the
    foundation ships nothing live). ``thread_ts`` mode is implicit: when a
    ``QuestionSet`` is delivered the adapter posts a top-level message and uses
    its ``ts`` as the ``channel_ref``; answers arrive as thread replies or
    interactive callbacks carrying the embedded ``question_id``.
    """

    def __init__(
        self,
        channel: str,
        poster: SlackPoster | None = None,
    ) -> None:
        self.channel = channel
        self._poster: SlackPoster = poster if poster is not None else _default_poster

    def post_question(
        self,
        *,
        thread_id: str,
        question_id: str,
        turn: int,
        question_set: QuestionSet,
        deadline: str,
    ) -> str:
        """Render + post the question-set; return the Slack ``ts`` channel_ref.

        Embeds ``question_id`` in the message ``callback_id`` so an inbound
        answer maps back (§3.3.1). On any poster failure raises
        :class:`SlackPostError` so the ledger row stays ``open`` for reconcile.
        """
        blocks = build_question_blocks(question_set, deadline)
        message: dict[str, Any] = {
            "channel": self.channel,
            "callback_id": build_callback_id(question_id),
            "text": (
                f"Agent-team needs input on task {thread_id} "
                f"(turn {turn}); reply by {deadline}."
            ),
            "blocks": blocks,
            "metadata": {
                "event_type": "agent_team_question",
                "event_payload": {
                    "thread_id": thread_id,
                    "question_id": question_id,
                    "turn": turn,
                },
            },
        }

        try:
            response = self._poster(message)
        except SlackPostError:
            raise
        except Exception as exc:  # noqa: BLE001 — normalize any poster failure
            raise SlackPostError(f"Slack post failed: {exc}") from exc

        channel_ref = _extract_ts(response)
        if not channel_ref:
            raise SlackPostError(
                "Slack post response missing message 'ts'; cannot record "
                f"channel_ref (response keys: {sorted(response.keys())})"
            )
        return channel_ref

    def parse_answer(self, raw: Any) -> tuple[str, Any, str]:
        """Normalize an inbound Slack payload to ``(question_id, answer, via)``.

        Handles the two inbound shapes for P1:

        * an interactive ``block_actions`` payload — ``callback_id`` carries the
          ``question_id`` and ``actions[*]`` carry the answer value(s);
        * a plain text / slash reply — ``callback_id`` (or ``question_id``)
          carries the id and ``text`` / ``answer`` carries the value.

        Raises :class:`ValueError` on a payload with no recoverable
        ``question_id`` so a malformed answer is rejected loudly rather than
        mis-attributed.
        """
        if not isinstance(raw, Mapping):
            raise ValueError(f"Slack payload must be a mapping, got {type(raw)!r}")

        question_id = _extract_question_id(raw)
        answer = _extract_answer(raw)
        normalized = NormalizedAnswer(
            question_id=question_id, answer=answer, via=VIA_SLACK
        )
        return normalized.question_id, normalized.answer, normalized.via


def _extract_ts(response: Mapping[str, Any]) -> str | None:
    """Pull the message ``ts`` from a ``chat.postMessage`` response.

    Slack returns the timestamp at the top level (``{"ts": ...}``) and also
    nested under ``message`` (``{"message": {"ts": ...}}``); accept either.
    """
    ts = response.get("ts")
    if ts:
        return str(ts)
    message = response.get("message")
    if isinstance(message, Mapping) and message.get("ts"):
        return str(message["ts"])
    return None


def _extract_question_id(raw: Mapping[str, Any]) -> str:
    """Recover the ledger ``question_id`` from any supported inbound payload."""
    callback_id = raw.get("callback_id")
    if callback_id:
        return parse_callback_id(str(callback_id))

    # Interactive payloads nest the callback metadata under ``view`` / ``message``.
    view = raw.get("view")
    if isinstance(view, Mapping) and view.get("callback_id"):
        return parse_callback_id(str(view["callback_id"]))
    message = raw.get("message")
    if isinstance(message, Mapping):
        metadata = message.get("metadata")
        if isinstance(metadata, Mapping):
            payload = metadata.get("event_payload")
            if isinstance(payload, Mapping) and payload.get("question_id"):
                return str(payload["question_id"])

    question_id = raw.get("question_id")
    if question_id:
        return str(question_id)

    raise ValueError("Slack payload carries no recoverable question_id")


def _extract_answer(raw: Mapping[str, Any]) -> Any:
    """Recover the answer value from any supported inbound payload."""
    actions = raw.get("actions")
    if (
        isinstance(actions, Sequence)
        and not isinstance(actions, (str, bytes))
        and actions
    ):
        return _join_answer_actions(
            [action for action in actions if isinstance(action, Mapping)]
        )

    if "answer" in raw:
        return raw["answer"]
    if "text" in raw:
        return raw["text"]
    if "value" in raw:
        return raw["value"]

    raise ValueError("Slack payload carries no recoverable answer")