"""
FILE: modules/web_api/llm/db/db_chat.py
ROLE: Управление историей сообщений и очисткой эфемерного контекста.
"""
from typing import List, Dict, Any
from .connection import get_db_connection

def db_save_chat_message(session_id: str, role: str, content: str, is_ephemeral: int = 0) -> None:
    """Сохраняет сообщение в БД (is_ephemeral=1 для временных служебных шагов, 0 для постоянных)."""
    conn = get_db_connection(row_factory=True)
    cursor = conn.cursor()
    cursor.execute("""
        INSERT INTO chat_messages (session_id, role, content, is_ephemeral)
        VALUES (?, ?, ?, ?)
    """, (session_id, role, content, is_ephemeral))
    conn.commit()
    conn.close()


def db_get_chat_history(session_id: str, limit: int = 50) -> list:
    """Возвращает историю сообщений диалога для сессии."""
    with get_db_connection(row_factory=True) as conn:
        cursor = conn.cursor()
        cursor.execute("""
            SELECT role, content, is_ephemeral, created_at
            FROM chat_messages
            WHERE session_id = ?
            ORDER BY id DESC
            LIMIT ?
        """, (session_id, limit))
        rows = cursor.fetchall()
        return [{"role": r["role"], "content": r["content"], "is_ephemeral": r["is_ephemeral"]} for r in reversed(rows)]


def db_purge_ephemeral_messages(session_id: str) -> int:
    """
    Физически удаляет все временные служебные сообщения выбранной сессии
    после завершения сценария работы с инструментом.
    """
    conn = get_db_connection(row_factory=True)
    cursor = conn.cursor()
    cursor.execute("DELETE FROM chat_messages WHERE session_id = ? AND is_ephemeral = 1", (session_id,))
    deleted = cursor.rowcount
    conn.commit()
    conn.close()
    return deleted


def db_clear_chat_history(session_id: str) -> None:
    """Полная очистка всех сообщений сессии."""
    conn = get_db_connection(row_factory=True)
    cursor = conn.cursor()
    cursor.execute("DELETE FROM chat_messages WHERE session_id = ?", (session_id,))
    conn.commit()
    conn.close()

def db_clear_all_chat_context(session_id: str = None, purge_all: bool = False) -> int:
    """Удаляет сообщения чата и стейты сессий."""
    with get_db_connection(row_factory=True) as conn:
        cursor = conn.cursor()
        if purge_all:
            if session_id:
                cursor.execute("DELETE FROM chat_messages WHERE session_id = ?", (session_id,))
                cursor.execute("DELETE FROM session_states WHERE session_id = ?", (session_id,))
            else:
                cursor.execute("DELETE FROM chat_messages")
                cursor.execute("DELETE FROM session_states")
            cnt = cursor.rowcount
            conn.commit()
            return cnt

        query = """
            DELETE FROM chat_messages 
            WHERE is_ephemeral = 1 
               OR content LIKE '%Предпросмотр изменений%'
               OR content LIKE '%Удален пункт:%'
               OR content LIKE '%добавлен пункт:%'
        """
        if session_id:
            cursor.execute(query + " AND session_id = ?", (session_id,))
            cursor.execute("DELETE FROM session_states WHERE session_id = ?", (session_id,))
        else:
            cursor.execute(query)
            cursor.execute("DELETE FROM session_states")
        cnt = cursor.rowcount
        conn.commit()
        return cnt