"""Materialise schedule_type special slots into per-agent time_slots rows.

A ScheduleTypeSpecialSlot is a template — it lives on the schedule_type.
For an agent on that schedule_type to actually be woken, the system must
emit a row in `time_slots` with `slot_type=system`, `is_admin_locked=true`,
`special_slot_id=<template_id>` for the agent's `user_id` on the target
date. This module is the single materialisation point.

Called from:
  * GET /calendar/day — before returning slots, materialise today's special
    slots for the calling user.
  * GET /calendar/sync — before returning per-claw schedules, materialise
    today's special slots for every agent on this claw whose schedule_type
    has any active special slot template.

Idempotent: re-running on the same (agent, date, special_slot_template)
is a no-op — uniqueness is enforced via SELECT-then-insert. We do not add
a DB-level unique constraint because the time_slots table is already
indexed by (user_id, date) and an extra composite index is overkill for
the low cardinality of (agents × special-slot-templates) per day.
"""

from __future__ import annotations

from datetime import date as date_type, time as time_type
from typing import Iterable

from sqlalchemy.orm import Session

from app.models.agent import Agent
from app.models.calendar import TimeSlot, SlotType, SlotStatus, EventType
from app.models.schedule_type import ScheduleType
from app.models.schedule_type_special_slot import ScheduleTypeSpecialSlot


def materialise_special_slots_for_user(
    db: Session,
    user_id: int,
    target_date: date_type,
    commit: bool = True,
) -> list[TimeSlot]:
    """Materialise today's special slots for one agent (identified by user_id).

    Returns the list of newly created rows (may be empty if all already exist
    or the agent has no schedule_type / no active templates).
    """
    agent = db.query(Agent).filter(Agent.user_id == user_id).first()
    if not agent or not agent.schedule_type_id:
        return []

    return _materialise_for_agent(db, agent, target_date, commit=commit)


def materialise_special_slots_for_claw(
    db: Session,
    claw_identifier: str,
    target_date: date_type,
    commit: bool = True,
) -> list[TimeSlot]:
    """Materialise today's special slots for every agent on a claw instance.

    Used by the multi-agent `/calendar/sync` endpoint so plugin-driven
    `runSync` cycles see the special slots without each agent having to
    hit `/calendar/day` first.
    """
    agents = (
        db.query(Agent)
        .filter(
            Agent.claw_identifier == claw_identifier,
            Agent.schedule_type_id.isnot(None),
        )
        .all()
    )
    created: list[TimeSlot] = []
    for agent in agents:
        created.extend(_materialise_for_agent(db, agent, target_date, commit=False))
    if commit and created:
        db.commit()
    return created


def _materialise_for_agent(
    db: Session,
    agent: Agent,
    target_date: date_type,
    commit: bool,
) -> list[TimeSlot]:
    st: ScheduleType | None = (
        db.query(ScheduleType).filter(ScheduleType.id == agent.schedule_type_id).first()
    )
    if not st:
        return []

    templates: Iterable[ScheduleTypeSpecialSlot] = (
        db.query(ScheduleTypeSpecialSlot)
        .filter(
            ScheduleTypeSpecialSlot.schedule_type_id == st.id,
            ScheduleTypeSpecialSlot.is_active.is_(True),
        )
        .all()
    )

    created: list[TimeSlot] = []
    for tpl in templates:
        if _already_materialised(db, agent.user_id, target_date, tpl.id):
            continue
        slot = _build_time_slot_from_template(
            user_id=agent.user_id,
            target_date=target_date,
            schedule_type=st,
            template=tpl,
        )
        db.add(slot)
        created.append(slot)

    if commit and created:
        db.commit()
        for slot in created:
            db.refresh(slot)
    return created


def _already_materialised(
    db: Session,
    user_id: int,
    target_date: date_type,
    template_id: int,
) -> bool:
    return (
        db.query(TimeSlot.id)
        .filter(
            TimeSlot.user_id == user_id,
            TimeSlot.date == target_date,
            TimeSlot.special_slot_id == template_id,
        )
        .first()
        is not None
    )


def _build_time_slot_from_template(
    *,
    user_id: int,
    target_date: date_type,
    schedule_type: ScheduleType,
    template: ScheduleTypeSpecialSlot,
) -> TimeSlot:
    scheduled_at = time_type(
        hour=schedule_type.maintenance_from,
        minute=template.minute_in_window,
        second=0,
    )
    # Merge admin-supplied event_data with bookkeeping pointers so the
    # agent (and ARD) can identify the template at wake time.
    merged_event_data = dict(template.event_data or {})
    merged_event_data.setdefault("source", "schedule_type_special_slot")
    merged_event_data["special_slot_id"] = template.id
    merged_event_data["special_slot_name"] = template.name
    merged_event_data["schedule_type_id"] = schedule_type.id
    merged_event_data["schedule_type_name"] = schedule_type.name

    return TimeSlot(
        user_id=user_id,
        date=target_date,
        slot_type=SlotType.SYSTEM,
        estimated_duration=template.estimated_duration,
        scheduled_at=scheduled_at,
        attended=False,
        event_type=EventType.SYSTEM_EVENT,
        event_data=merged_event_data,
        priority=template.priority,
        status=SlotStatus.NOT_STARTED,
        is_admin_locked=True,
        special_slot_id=template.id,
    )