from .db_logging import log_change
from .entity import ensure_entity_active


def _get_entity_type(cursor, entity_id):
    cursor.execute("SELECT type FROM entity WHERE id = %s", (entity_id,))
    row = cursor.fetchone()
    return row["type"] if row else None


def _validate_role(role):
    if not isinstance(role, str):
        raise TypeError("role must be a string")
    r = role.strip()
    if not r:
        raise ValueError("role must be a non-empty string")
    if len(r) > 10:
        raise ValueError("role must be at most 10 characters")
    return r


def add_group_member(cursor, group_id, member_id, role):
    """Add a member to a group.

    Rules:
      - group_id must reference an active entity of type 'group'
      - member_id must reference an active entity (person/device/group)
      - role must be a non-empty string with max length 10
      - duplicates are rejected
    """
    ensure_entity_active(cursor, group_id)
    ensure_entity_active(cursor, member_id)

    if _get_entity_type(cursor, group_id) != "group":
        raise ValueError("group_id must reference an entity of type 'group'")

    r = _validate_role(role)

    cursor.execute(
        "SELECT 1 FROM group_member WHERE group_id = %s AND member_id = %s",
        (group_id, member_id),
    )
    if cursor.fetchone() is not None:
        raise ValueError("Member is already in the group")

    cursor.execute(
        """
        INSERT INTO group_member (group_id, member_id, role)
        VALUES (%s, %s, %s)
        """,
        (group_id, member_id, r),
    )

    log_change(cursor, f"Added member {member_id} to group {group_id} as {r}")


def get_members_of_group(cursor, group_id):
    ensure_entity_active(cursor, group_id)
    cursor.execute(
        """
        SELECT member_id, role
        FROM group_member
        WHERE group_id = %s
        ORDER BY member_id
        """,
        (group_id,),
    )
    return cursor.fetchall()