"""
WhatsApp Learning Service — ruta de aprendizaje para piezas no resueltas.

Registra sesiones donde el bot no pudo identificar una pieza, y las resuelve
asíncronamente cuando el cliente realiza una compra futura.
"""

import json


def register_unresolved_search(phone, customer_id, description, offered_parts, tenant_conn):
    """Registrar una sesión no resuelta para aprendizaje futuro."""
    if not tenant_conn or not phone or not description:
        return None
    cur = tenant_conn.cursor()
    cur.execute("""
        INSERT INTO wa_learning_sessions (phone, customer_id, description, offered_parts, status, created_at)
        VALUES (%s, %s, %s, %s, 'pending', NOW())
        RETURNING id
    """, (phone, customer_id, description, json.dumps(offered_parts or [])))
    sid = cur.fetchone()[0]
    tenant_conn.commit()
    cur.close()
    return sid


def find_pending_sessions(phone, tenant_conn):
    """Buscar sesiones pendientes de aprendizaje para un número WA."""
    if not tenant_conn or not phone:
        return []
    cur = tenant_conn.cursor()
    cur.execute("""
        SELECT id, description, offered_parts, created_at
        FROM wa_learning_sessions
        WHERE phone = %s AND status = 'pending'
        ORDER BY created_at DESC
    """, (phone,))
    rows = cur.fetchall()
    cur.close()
    return [{'id': r[0], 'description': r[1], 'offered_parts': r[2], 'created_at': str(r[3])} for r in rows]


def find_pending_sessions_by_customer(customer_id, tenant_conn):
    """Buscar sesiones pendientes por customer_id."""
    if not tenant_conn or not customer_id:
        return []
    cur = tenant_conn.cursor()
    cur.execute("""
        SELECT id, phone, description, offered_parts, created_at
        FROM wa_learning_sessions
        WHERE customer_id = %s AND status = 'pending'
        ORDER BY created_at DESC
    """, (customer_id,))
    rows = cur.fetchall()
    cur.close()
    return [{'id': r[0], 'phone': r[1], 'description': r[2], 'offered_parts': r[3], 'created_at': str(r[4])} for r in rows]


def resolve_session(session_id, resolved_part_id, sale_id, tenant_conn):
    """Marcar sesión como resuelta con la pieza comprada."""
    if not tenant_conn or not session_id:
        return
    cur = tenant_conn.cursor()
    cur.execute("""
        UPDATE wa_learning_sessions
        SET status = 'learned', resolved_part_id = %s, resolution_sale_id = %s, resolved_at = NOW()
        WHERE id = %s
    """, (resolved_part_id, sale_id, session_id))
    tenant_conn.commit()
    cur.close()


def get_learning_pairs_for_training(tenant_conn, limit=100):
    """Obtener pares (descripción del cliente → pieza real) para entrenamiento."""
    if not tenant_conn:
        return []
    cur = tenant_conn.cursor()
    cur.execute("""
        SELECT l.description, i.name, i.part_number, i.brand
        FROM wa_learning_sessions l
        JOIN inventory i ON i.id = l.resolved_part_id
        WHERE l.status = 'learned' AND l.resolved_at > NOW() - INTERVAL '90 days'
        ORDER BY l.resolved_at DESC
        LIMIT %s
    """, (limit,))
    rows = cur.fetchall()
    cur.close()
    return [{'description': r[0], 'part_name': r[1], 'part_number': r[2], 'brand': r[3]} for r in rows]


def check_learning_resolution(sale_id, customer_id, tenant_conn):
    """
    Hook para llamar después de completar una venta.
    Verifica si esta venta resuelve una sesión de aprendizaje pendiente.
    """
    if not tenant_conn or not customer_id:
        return

    sessions = find_pending_sessions_by_customer(customer_id, tenant_conn)
    if not sessions:
        return

    # Obtener items de esta venta
    cur = tenant_conn.cursor()
    cur.execute("""
        SELECT si.inventory_id, i.name, i.part_number
        FROM sale_items si
        JOIN inventory i ON i.id = si.inventory_id
        WHERE si.sale_id = %s
    """, (sale_id,))
    sale_items = cur.fetchall()
    cur.close()

    if not sale_items:
        return

    # Matching heurístico
    for sess in sessions:
        desc_words = set(sess['description'].lower().split())
        for inv_id, item_name, part_number in sale_items:
            item_words = set(item_name.lower().split())
            # Intersección de palabras significativas
            common = desc_words & item_words - {'de', 'la', 'el', 'para', 'un', 'una', 'con', 'y', 'o', 'en', 'al', 'del', 'los', 'las'}
            if len(common) >= 2:
                resolve_session(sess['id'], inv_id, sale_id, tenant_conn)
                print(f"[WA-LEARN] Resolved session {sess['id']} with sale {sale_id}, item {inv_id}")
                break