"""Управление пробелами в знаниях (research gaps).

Работает **только с PostgreSQL** — никакого веб-поиска. Поиск выполняет сама
модель встроенным инструментом \`web_search\` (SearXNG и автоматический
research-цикл убраны).

Жизненный цикл пробела:
    open → researching → resolved | dismissed

Поля:
    question  — что нужно исследовать (формулировка)
    reason    — почему пробел обнаружен
    priority  — 0.0 .. 1.0 (больше = важнее)
    status    — open | researching | resolved | dismissed
"""
from __future__ import annotations

VALID_REASONS = ("low_coverage", "low_confidence", "stale", "contested", "user_query")
VALID_STATUSES = ("open", "researching", "resolved", "dismissed")

_COLS = "id, question, reason, priority, status, created_at"


def list_gaps(conn, *, status: str | None = None, limit: int = 50) -> list[dict]:
    """Список пробелов. Без фильтра — сначала открытые, затем по приоритету."""
    limit = max(1, min(int(limit), 200))
    with conn.cursor() as cur:
        if status:
            if status not in VALID_STATUSES:
                raise ValueError(f"status must be one of {VALID_STATUSES}")
            cur.execute(
                f"SELECT {_COLS} FROM pm_research_gap WHERE status = %s "
                "ORDER BY priority DESC, id LIMIT %s",
                (status, limit),
            )
        else:
            cur.execute(
                f"SELECT {_COLS} FROM pm_research_gap "
                "ORDER BY (status = 'open') DESC, priority DESC, id LIMIT %s",
                (limit,),
            )
        return cur.fetchall()


def get_gap(conn, gap_id: int) -> dict | None:
    """Один пробел по id (или None)."""
    with conn.cursor() as cur:
        cur.execute(f"SELECT {_COLS} FROM pm_research_gap WHERE id = %s", (gap_id,))
        return cur.fetchone()


def add_gap(conn, question: str, reason: str = "user_query", priority: float = 0.5) -> int:
    """Зарегистрировать пробел. Возвращает id."""
    question = (question or "").strip()
    if not question:
        raise ValueError("question must not be empty")
    if reason not in VALID_REASONS:
        raise ValueError(f"reason must be one of {VALID_REASONS}")
    priority = max(0.0, min(1.0, float(priority)))
    with conn.cursor() as cur:
        cur.execute(
            "INSERT INTO pm_research_gap (question, reason, priority, status) "
            "VALUES (%s, %s, %s, 'open') RETURNING id",
            (question, reason, priority),
        )
        row = cur.fetchone()
    conn.commit()
    return row["id"]


def update_gap(conn, gap_id: int, *, question: str | None = None,
               reason: str | None = None, priority: float | None = None,
               status: str | None = None) -> bool:
    """Обновить поля пробела. Возвращает True, если запись найдена.

    Типичные переходы: status='researching' (взял в работу),
    status='resolved' (закрыт), status='dismissed' (не актуален).
    """
    sets: list[str] = []
    vals: list = []
    if question is not None:
        question = question.strip()
        if not question:
            raise ValueError("question must not be empty")
        sets.append("question = %s"); vals.append(question)
    if reason is not None:
        if reason not in VALID_REASONS:
            raise ValueError(f"reason must be one of {VALID_REASONS}")
        sets.append("reason = %s"); vals.append(reason)
    if priority is not None:
        sets.append("priority = %s"); vals.append(max(0.0, min(1.0, float(priority))))
    if status is not None:
        if status not in VALID_STATUSES:
            raise ValueError(f"status must be one of {VALID_STATUSES}")
        sets.append("status = %s"); vals.append(status)

    if not sets:
        return get_gap(conn, gap_id) is not None

    vals.append(gap_id)
    with conn.cursor() as cur:
        cur.execute(f"UPDATE pm_research_gap SET {', '.join(sets)} WHERE id = %s", vals)
        found = cur.rowcount > 0
    conn.commit()
    return found


def delete_gap(conn, gap_id: int) -> bool:
    """Удалить пробел. Возвращает True, если запись существовала."""
    with conn.cursor() as cur:
        cur.execute("DELETE FROM pm_research_gap WHERE id = %s", (gap_id,))
        found = cur.rowcount > 0
    conn.commit()
    return found