"""Kanban triage specifier — flesh out a one-liner into a real spec.

Used by ``hermes kanban specify [task_id | --all]``. Takes a task that
lives in the Triage column (a rough idea, typically only a title), calls
the auxiliary LLM to produce:

  * A tightened title (optional — only replaces if the model proposes a
    materially different one)
  * A concrete body: goal, proposed approach, acceptance criteria

and then flips the task ``triage -> todo`` via
``kanban_db.specify_triage_task``. The dispatcher promotes it to
``ready`` on its next tick (or immediately if there are no open parents).

Design notes
------------

* This module intentionally mirrors ``hermes_cli/goals.py`` — same aux
  client pattern, same "empty config => skip, don't crash" tolerance.
  Keeps the surface area tiny and the failure modes predictable.

* The prompt is a short system + user pair. We ask for JSON with
  ``{title, body}``; if parsing fails, we fall back to treating the
  whole response as the body and leave the title untouched. No
  retry loop — one shot, keep cost bounded.

* Structured output / JSON mode is not requested explicitly so the
  specifier works on providers that don't implement it. The parse
  is lenient (tolerates markdown code fences around the JSON).
"""

from __future__ import annotations

import json
import logging
import os
import re
from dataclasses import dataclass
from typing import Optional

from hermes_cli import kanban_db as kb

HERMES_KANBAN_SPECIFY_MAX_TOKENS = max(
    1500,
    int(os.getenv("HERMES_KANBAN_SPECIFY_MAX_TOKENS", "6000")),
)

logger = logging.getLogger(__name__)


_SYSTEM_PROMPT = """You are the Kanban triage specifier for the Hermes Agent board.
A user dropped a rough idea into the Triage column. Your job is to turn it
into a concrete, actionable task spec that an autonomous worker can pick up
and execute without further clarification.

Output a single JSON object with exactly two keys:

  {
    "title": "<tightened task title, <= 80 chars, imperative voice>",
    "body":  "<multi-line spec, see structure below>"
  }

The body MUST include these sections, each prefixed with a bold markdown
heading, in this order:

  **Goal** — one sentence, user-facing outcome.
  **Approach** — 2-5 bullets on how a worker should tackle it.
  **Acceptance criteria** — checklist of concrete, verifiable conditions.
  **Out of scope** — short list of things NOT to touch (omit if nothing
      obvious; never invent scope creep).

Rules:
  - Keep the tightened title close in meaning to the original idea — do
    NOT invent a different project.
  - If the original idea is already detailed, preserve its substance and
    just reformat into the sections above.
  - Never add invented requirements the user didn't hint at.
  - No preamble, no closing remarks, no code fences around the JSON.
  - Output only the JSON object and nothing else.
"""


_USER_TEMPLATE = """Task id: {task_id}
Current title: {title}
Current body:
{body}
"""


@dataclass
class SpecifyOutcome:
    """Result of specifying a single triage task."""

    task_id: str
    ok: bool
    reason: str = ""
    new_title: Optional[str] = None


def _truncate(text: str, limit: int) -> str:
    if len(text) <= limit:
        return text
    return text[: limit - 1] + "…"


_FENCE_RE = re.compile(r"^\s*```(?:json)?\s*|\s*```\s*$", re.IGNORECASE)


def _extract_json_blob(raw: str) -> Optional[dict]:
    """Lenient JSON extraction — tolerates fenced code blocks and
    leading/trailing whitespace. Returns None if nothing parses."""
    if not raw:
        return None
    stripped = _FENCE_RE.sub("", raw.strip())
    # Greedy: find the first `{` and last `}` and try that slice.
    first = stripped.find("{")
    last = stripped.rfind("}")
    if first == -1 or last == -1 or last <= first:
        return None
    candidate = stripped[first : last + 1]
    try:
        val = json.loads(candidate)
    except (ValueError, json.JSONDecodeError):
        return None
    if not isinstance(val, dict):
        return None
    return val


def _profile_author() -> str:
    """Mirror of ``hermes_cli.kanban._profile_author``. Kept local to
    avoid a circular import when kanban.py imports this module."""
    return (
        os.environ.get("HERMES_PROFILE")
        or os.environ.get("USER")
        or "specifier"
    )


def specify_task(
    task_id: str,
    *,
    author: Optional[str] = None,
    timeout: Optional[int] = None,
) -> SpecifyOutcome:
    """Specify a single triage task and promote it to ``todo``.

    Returns an outcome describing what happened. Never raises for expected
    failure modes (task not in triage, no aux client configured, API
    error, malformed response) — those surface via ``ok=False`` so the
    ``--all`` sweep can continue past individual failures.
    """
    with kb.connect_closing() as conn:
        task = kb.get_task(conn, task_id)
    if task is None:
        return SpecifyOutcome(task_id, False, "unknown task id")
    if task.status != "triage":
        return SpecifyOutcome(
            task_id, False, f"task is not in triage (status={task.status!r})"
        )

    try:
        from agent.auxiliary_client import get_auxiliary_extra_body, get_text_auxiliary_client
    except Exception as exc:  # pragma: no cover — import smoke test
        logger.debug("specify: auxiliary client import failed: %s", exc)
        return SpecifyOutcome(task_id, False, "auxiliary client unavailable")

    try:
        client, model = get_text_auxiliary_client("triage_specifier")
    except Exception as exc:
        logger.debug("specify: get_text_auxiliary_client failed: %s", exc)
        return SpecifyOutcome(task_id, False, "auxiliary client unavailable")

    if client is None or not model:
        return SpecifyOutcome(
            task_id, False, "no auxiliary client configured"
        )

    user_msg = _USER_TEMPLATE.format(
        task_id=task.id,
        title=_truncate(task.title or "", 400),
        body=_truncate(task.body or "(no body)", 4000),
    )

    try:
        resp = client.chat.completions.create(
            model=model,
            messages=[
                {"role": "system", "content": _SYSTEM_PROMPT},
                {"role": "user", "content": user_msg},
            ],
            temperature=0.3,
            max_tokens=HERMES_KANBAN_SPECIFY_MAX_TOKENS,
            timeout=timeout or 120,
            extra_body=get_auxiliary_extra_body() or None,
        )
    except Exception as exc:
        logger.info(
            "specify: API call failed for %s (%s) — skipping",
            task_id, exc,
        )
        return SpecifyOutcome(
            task_id, False, f"LLM error: {type(exc).__name__}"
        )

    try:
        raw = (resp.choices[0].message.content or "").strip()
    except Exception:
        raw = ""

    parsed = _extract_json_blob(raw)

    new_title: Optional[str]
    new_body: Optional[str]
    if parsed is None:
        # Fall back: treat the whole reply as the body, leave title as-is.
        # Worst case the user edits afterward — still better than stranding
        # the task in triage on a malformed LLM reply.
        stripped_raw = raw.strip()
        if not stripped_raw:
            return SpecifyOutcome(
                task_id, False, "LLM returned an empty response"
            )
        new_title = None
        new_body = stripped_raw
    else:
        title_val = parsed.get("title")
        body_val = parsed.get("body")
        new_title = (
            title_val.strip()
            if isinstance(title_val, str) and title_val.strip()
            else None
        )
        new_body = (
            body_val if isinstance(body_val, str) and body_val.strip() else None
        )
        if new_body is None and new_title is None:
            return SpecifyOutcome(
                task_id, False, "LLM response missing title and body"
            )

    with kb.connect_closing() as conn:
        ok = kb.specify_triage_task(
            conn,
            task_id,
            title=new_title,
            body=new_body,
            author=author or _profile_author(),
        )
    if not ok:
        # Race: someone else promoted / archived the task between our
        # read above and the write. Report, don't crash.
        return SpecifyOutcome(
            task_id, False, "task moved out of triage before promotion"
        )
    return SpecifyOutcome(task_id, True, "specified", new_title=new_title)


def list_triage_ids(*, tenant: Optional[str] = None) -> list[str]:
    """Return task ids currently in the triage column.

    ``tenant`` narrows the sweep; ``None`` returns every triage task.
    """
    with kb.connect_closing() as conn:
        tasks = kb.list_tasks(
            conn,
            status="triage",
            tenant=tenant,
            include_archived=False,
        )
    return [t.id for t in tasks]
