"""Action ↔ Recurring bridge for unified schedules (ADP v0.1 Slice 2)."""

from __future__ import annotations

from typing import Any, Optional

from psycopg2.extras import RealDictCursor

from db import get_connection
from services.audit import log_audit
from services.cadence_instance import ensure_open_instance
from services.recurring import (
    create_recurring_element,
    get_recurring_element,
    update_recurring_element,
)
from services.schedule import (
    create_schedule,
    get_schedule,
    initial_due_at,
    update_schedule,
)


def _get_action_row(*, tenant_id: str, action_id: str) -> dict[str, Any]:
    conn = get_connection()
    try:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute(
                """
                SELECT id, tenant_id, initiative_id, project_id, roadmap_item_id, schedule_id,
                       title, description
                FROM actions
                WHERE id = %s AND tenant_id = %s
                """,
                (action_id, tenant_id),
            )
            row = cur.fetchone()
            if not row:
                raise ValueError("Arbeitspaket nicht gefunden")
            result = dict(row)
            for key in (
                "id",
                "tenant_id",
                "initiative_id",
                "project_id",
                "roadmap_item_id",
                "schedule_id",
            ):
                if result.get(key):
                    result[key] = str(result[key])
            return result
    finally:
        conn.close()


def _find_recurring_for_action(*, tenant_id: str, action_id: str) -> Optional[dict[str, Any]]:
    conn = get_connection()
    try:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute(
                """
                SELECT id
                FROM recurring_elements
                WHERE tenant_id = %s AND action_id = %s
                LIMIT 1
                """,
                (tenant_id, action_id),
            )
            row = cur.fetchone()
            if not row:
                return None
            return get_recurring_element(tenant_id=tenant_id, recurring_id=str(row["id"]))
    finally:
        conn.close()


def attach_action_schedule_fields(
    action: dict[str, Any], *, tenant_id: str
) -> dict[str, Any]:
    schedule = None
    if action.get("schedule_id"):
        schedule = get_schedule(tenant_id=tenant_id, schedule_id=str(action["schedule_id"]))
    bridge = _find_recurring_for_action(tenant_id=tenant_id, action_id=str(action["id"]))
    copy = dict(action)
    copy["schedule"] = schedule
    copy["recurring_id"] = bridge["id"] if bridge else None
    return copy


def get_action_schedule_bundle(*, tenant_id: str, action_id: str) -> dict[str, Any]:
    action = _get_action_row(tenant_id=tenant_id, action_id=action_id)
    enriched = attach_action_schedule_fields(action, tenant_id=tenant_id)
    bridge = _find_recurring_for_action(tenant_id=tenant_id, action_id=action_id)
    return {
        "action_id": action_id,
        "schedule": enriched.get("schedule"),
        "recurring_id": enriched.get("recurring_id"),
        "recurring": bridge,
    }


def upsert_action_schedule(
    *,
    tenant_id: str,
    action_id: str,
    user_id: Optional[str] = None,
    schedule_kind: str = "interval",
    interval_days: Optional[int] = 1,
    weekday_mask: int = 0,
    pause_until=None,
) -> dict[str, Any]:
    action = _get_action_row(tenant_id=tenant_id, action_id=action_id)
    existing_schedule_id = action.get("schedule_id")
    if existing_schedule_id:
        schedule = update_schedule(
            tenant_id=tenant_id,
            schedule_id=str(existing_schedule_id),
            schedule_kind=schedule_kind,  # type: ignore[arg-type]
            interval_days=interval_days,
            weekday_mask=weekday_mask,
            pause_until=pause_until,
            clear_pause_until=pause_until is None,
        )
    else:
        schedule = create_schedule(
            tenant_id=tenant_id,
            schedule_kind=schedule_kind,  # type: ignore[arg-type]
            interval_days=interval_days,
            weekday_mask=weekday_mask,
            pause_until=pause_until,
        )

    if not schedule:
        raise ValueError("Schedule konnte nicht gespeichert werden")

    next_due = initial_due_at(schedule=schedule)
    interval = schedule.get("interval_days") or 1

    conn = get_connection()
    try:
        with conn.cursor() as cur:
            cur.execute(
                """
                UPDATE actions
                SET schedule_id = %s, updated_at = NOW()
                WHERE id = %s AND tenant_id = %s
                """,
                (schedule["id"], action_id, tenant_id),
            )
        conn.commit()
    finally:
        conn.close()

    bridge = _find_recurring_for_action(tenant_id=tenant_id, action_id=action_id)
    if bridge:
        update_recurring_element(
            tenant_id=tenant_id,
            recurring_id=bridge["id"],
            user_id=user_id,
            status="active",
            interval_days=int(interval),
            next_due_at=next_due,
        )
        conn = get_connection()
        try:
            with conn.cursor() as cur:
                cur.execute(
                    """
                    UPDATE recurring_elements
                    SET schedule_id = %s, updated_at = NOW()
                    WHERE id = %s AND tenant_id = %s
                    """,
                    (schedule["id"], bridge["id"], tenant_id),
                )
            conn.commit()
        finally:
            conn.close()
        recurring = get_recurring_element(tenant_id=tenant_id, recurring_id=bridge["id"])
    else:
        recurring = create_recurring_element(
            tenant_id=tenant_id,
            initiative_id=str(action["initiative_id"]),
            title=action["title"],
            description=action.get("description") or "",
            status="active",
            interval_days=int(interval),
            next_due_at=next_due,
            roadmap_item_id=action.get("roadmap_item_id"),
            project_id=action.get("project_id"),
            schedule_id=str(schedule["id"]),
            user_id=user_id,
        )
        conn = get_connection()
        try:
            with conn.cursor() as cur:
                cur.execute(
                    """
                    UPDATE recurring_elements
                    SET action_id = %s
                    WHERE id = %s AND tenant_id = %s
                    """,
                    (action_id, recurring["id"], tenant_id),
                )
            conn.commit()
        finally:
            conn.close()

    ensure_open_instance(
        tenant_id=tenant_id,
        recurring_element_id=recurring["id"],
        due_at=next_due,
    )

    log_audit(
        "action.schedule_set",
        user_id=user_id,
        tenant_id=tenant_id,
        details={"action_id": action_id, "schedule_id": schedule["id"]},
    )

    return get_action_schedule_bundle(tenant_id=tenant_id, action_id=action_id)


def clear_action_schedule(
    *,
    tenant_id: str,
    action_id: str,
    user_id: Optional[str] = None,
) -> dict[str, Any]:
    bundle = get_action_schedule_bundle(tenant_id=tenant_id, action_id=action_id)
    bridge = bundle.get("recurring")
    if bridge:
        update_recurring_element(
            tenant_id=tenant_id,
            recurring_id=bridge["id"],
            user_id=user_id,
            status="ended",
        )

    conn = get_connection()
    try:
        with conn.cursor() as cur:
            cur.execute(
                """
                UPDATE actions
                SET schedule_id = NULL, updated_at = NOW()
                WHERE id = %s AND tenant_id = %s
                """,
                (action_id, tenant_id),
            )
        conn.commit()
    finally:
        conn.close()

    log_audit(
        "action.schedule_cleared",
        user_id=user_id,
        tenant_id=tenant_id,
        details={"action_id": action_id},
    )
    return {"action_id": action_id, "schedule": None, "recurring_id": None}


def create_scheduled_action_at_gate(
    *,
    tenant_id: str,
    initiative_id: str,
    gate_id: str,
    title: str,
    description: str = "",
    user_id: Optional[str] = None,
    schedule_kind: str = "weekdays",
    interval_days: Optional[int] = 1,
    weekday_mask: int = 0,
    pause_until=None,
) -> dict[str, Any]:
    """Plan a repeating AP at a work-gate. RecurringElement is the cadence bridge."""
    from datetime import date

    from services.actions import create_action
    from services.schedule import weekday_mask_for_date

    if schedule_kind == "weekdays" and weekday_mask <= 0:
        weekday_mask = weekday_mask_for_date(date.today())

    action = create_action(
        tenant_id=tenant_id,
        initiative_id=initiative_id,
        title=title,
        description=description,
        status="open",
        roadmap_item_id=gate_id,
        user_id=user_id,
    )
    bundle = upsert_action_schedule(
        tenant_id=tenant_id,
        action_id=str(action["id"]),
        user_id=user_id,
        schedule_kind=schedule_kind,
        interval_days=interval_days,
        weekday_mask=weekday_mask,
        pause_until=pause_until,
    )
    recurring = bundle.get("recurring")
    if not recurring:
        raise ValueError("Cadence-Brücke für Arbeitspaket fehlt")
    return recurring