"""Frame complex field calculations by their consuming inputs."""

from .flow import origin_socket

FRAME_PADDING = 32
FRAME_HEADING = 48
FRAME_MIN_NODES = 12


def remove_field_frames(node_group):
    """Detach generated containers before calculating absolute positions again."""
    frames = {node for node in node_group.nodes if node.get("arrangement_frame")}
    for node in node_group.nodes:
        if node.parent in frames:
            position = tuple(node.location_absolute)
            node.parent = None
            node.location = position
    for frame in frames:
        node_group.nodes.remove(frame)


def create_field_frames(node_group, bodies, core):
    """Keep a complex calculation and its internal wire passages in one frame."""
    for members, (left, right, top, bottom) in bodies:
        if sum(node.bl_idname not in {"NodeGroupInput", "NodeReroute"} for node in members) < FRAME_MIN_NODES:
            continue
        members = set(members)
        outlets = [link for node in members for socket in node.outputs for link in socket.links
                   if link.to_node not in members]
        targets = []
        pending = list(outlets)
        visited = set()
        while pending:
            link = pending.pop()
            if link.to_node in core:
                targets.append(link)
            elif link.to_node not in visited:
                visited.add(link.to_node)
                pending.extend(edge for socket in link.to_node.outputs for edge in socket.links)
        target = min(targets, key=lambda link: (link.to_node.location_absolute.x,
                                               link.to_node.name, link.to_socket.name), default=None)
        pending = {node for node in node_group.nodes if node.bl_idname == "NodeReroute"
                   and node.get("arrangement_branch") and origin_socket(node.outputs[0]).node in members}
        while ready := {node for node in pending if all(link.to_node in members for link in node.outputs[0].links)}:
            members.update(ready)
            pending.difference_update(ready)
        frame = node_group.nodes.new("NodeFrame")
        frame["arrangement_frame"] = True
        frame.name = f"{target.to_node.name} · {target.to_socket.name}" if target else "Field Calculation"
        frame.label = frame.name
        frame.shrink = False
        frame.location = (left - FRAME_PADDING, top + FRAME_HEADING)
        frame.width = right - left + FRAME_PADDING * 2
        frame.height = top - bottom + FRAME_HEADING + FRAME_PADDING
        frame.use_custom_color = True
        frame.color = (0.12, 0.16, 0.18)
        for node in members:
            node.parent = frame