"""Daily prep generator for the Journal.

Runs once per day per user (scheduled, or lazy on first journal-open of a
new day). Gathers raw data into a structured prep block that becomes the
first message of the day's journal Conversation.

The output shape lives on Message.msg_metadata as:
    { kind: 'daily_prep', sections: { tasks, events, weather,
      projects, recent_moments, open_threads } }

Deliberately deterministic — no LLM call here. The journal LLM weaves
narrative into the conversation later, when the user actually starts
talking. Generating prose at scheduled-prep time would burn model time
on something the user may never read.
"""
from __future__ import annotations

import datetime
import logging

from sqlalchemy import select

from fabledassistant.models import Conversation, Message, async_session
from fabledassistant.services.events import list_events
from fabledassistant.services.journal_search import search_journal
from fabledassistant.services.notes import list_notes
from fabledassistant.services.projects import list_projects
from fabledassistant.services.weather import get_cached_weather_rows

logger = logging.getLogger(__name__)


async def generate_daily_prep(
    *,
    user_id: int,
    day_date: datetime.date,
    user_timezone: str,
) -> dict:
    """Gather all daily-prep sections and return them as a dict."""
    sections: dict = {}

    try:
        tasks_today, _ = await list_notes(
            user_id=user_id,
            is_task=True,
            status=["todo", "in_progress"],
            due_before=day_date,
            limit=20,
            sort="due_date",
            order="asc",
        )
        sections["tasks"] = [
            {
                "id": t.id,
                "title": t.title,
                "status": t.status,
                "priority": t.priority,
                "due_date": t.due_date.isoformat() if t.due_date else None,
            }
            for t in tasks_today
        ]
    except Exception:
        logger.exception("daily_prep tasks section failed for user %d", user_id)
        sections["tasks"] = []

    try:
        day_start = datetime.datetime.combine(day_date, datetime.time.min)
        day_end = datetime.datetime.combine(day_date, datetime.time.max)
        # list_events already returns dicts.
        sections["events"] = await list_events(
            user_id=user_id,
            date_from=day_start,
            date_to=day_end,
        )
    except Exception:
        logger.exception("daily_prep events section failed for user %d", user_id)
        sections["events"] = []

    try:
        weather_rows = await get_cached_weather_rows(user_id)
        sections["weather"] = [w.to_dict() for w in weather_rows]
    except Exception:
        logger.exception("daily_prep weather section failed for user %d", user_id)
        sections["weather"] = []

    try:
        projects = await list_projects(user_id=user_id, status="active")
        sections["projects"] = [
            {
                "id": p.id,
                "title": p.title,
                "auto_summary": p.auto_summary,
            }
            for p in projects[:5]
        ]
    except Exception:
        logger.exception("daily_prep projects section failed for user %d", user_id)
        sections["projects"] = []

    try:
        sections["recent_moments"] = await search_journal(
            user_id=user_id,
            date_from=day_date - datetime.timedelta(days=3),
            date_to=day_date - datetime.timedelta(days=1),
            limit=10,
        )
    except Exception:
        logger.exception("daily_prep recent_moments section failed for user %d", user_id)
        sections["recent_moments"] = []

    try:
        sections["open_threads"] = await _open_threads(user_id=user_id, day_date=day_date)
    except Exception:
        logger.exception("daily_prep open_threads section failed for user %d", user_id)
        sections["open_threads"] = []

    return sections


async def _open_threads(*, user_id: int, day_date: datetime.date) -> list[dict]:
    """Heuristic: moments from the last 7 days that look unresolved.

    Treated as 'unresolved' when they have no linked tasks/notes and aren't
    pinned. Starting heuristic — refine empirically.
    """
    candidates = await search_journal(
        user_id=user_id,
        date_from=day_date - datetime.timedelta(days=7),
        date_to=day_date - datetime.timedelta(days=1),
        limit=50,
    )
    return [
        m for m in candidates
        if not m.get("task_ids")
        and not m.get("note_ids")
        and not m.get("pinned")
    ]


async def ensure_daily_prep_message(
    *,
    user_id: int,
    day_date: datetime.date,
    user_timezone: str,
    force: bool = False,
) -> Message:
    """Get or create today's journal Conversation, then ensure the prep message exists.

    With force=True, regenerate even if a prep message already exists today
    (used by the manual /api/journal/trigger-prep endpoint).
    """
    async with async_session() as session:
        result = await session.execute(
            select(Conversation).where(
                Conversation.user_id == user_id,
                Conversation.conversation_type == "journal",
                Conversation.day_date == day_date,
            )
        )
        conv = result.scalar_one_or_none()
        if conv is None:
            conv = Conversation(
                user_id=user_id,
                conversation_type="journal",
                day_date=day_date,
                title=day_date.isoformat(),
            )
            session.add(conv)
            await session.flush()

        prep_stmt = select(Message).where(
            Message.conversation_id == conv.id,
            Message.role == "system",
        )
        existing_prep = None
        for msg in (await session.execute(prep_stmt)).scalars():
            if msg.msg_metadata and msg.msg_metadata.get("kind") == "daily_prep":
                existing_prep = msg
                break

        if existing_prep and not force:
            return existing_prep

        sections = await generate_daily_prep(
            user_id=user_id, day_date=day_date, user_timezone=user_timezone
        )
        if existing_prep:
            existing_prep.msg_metadata = {"kind": "daily_prep", "sections": sections}
            await session.commit()
            return existing_prep

        prep_msg = Message(
            conversation_id=conv.id,
            role="system",
            content="",
            msg_metadata={"kind": "daily_prep", "sections": sections},
        )
        session.add(prep_msg)
        await session.commit()
        return prep_msg