"""Place shared calculation sources beside their peripheral distribution channels."""


def place_shared_sources(bodies, peripheral_nodes, positions, sizes, *, gap):
    """Place consumer regions first, then keep their producers outside and to the left."""
    ordinary = [box for members, box in bodies if not members & peripheral_nodes]
    if not ordinary:
        ordinary = [(x, x + sizes[node].width, y, y - sizes[node].height)
                    for node, (x, y) in positions.items() if node not in peripheral_nodes]
    ceiling = max(box[2] for box in ordinary)
    floor = min(box[3] for box in ordinary)
    for index, (members, (left, right, top, bottom)) in enumerate(bodies):
        if not members & peripheral_nodes:
            continue
        links = [link for node in members for socket in node.outputs for link in socket.links
                 if link.to_node not in members and link.to_node in positions]
        if not links:
            continue
        height = top - bottom
        candidates = (ceiling + gap * 2 + height, floor - gap * 2)
        new_top = min(candidates, key=lambda level: (sum(
            abs(positions[link.to_node][1] - level + height / 2) for link in links), -level))
        dy = new_top - top
        new_left = float("inf")
        for link in links:
            source, target = link.from_node, link.to_node
            source_y = positions[source][1] + dy - sizes[source].sockets[link.from_socket]
            target_y = positions[target][1] - sizes[target].sockets[link.to_socket]
            runway = (abs(source_y - target_y) + height * 2) * 0.8 + gap * 3
            new_left = min(new_left, positions[target][0] - runway
                           - (positions[source][0] - left) - sizes[source].width)
        dx = new_left - left
        for node in members:
            x, y = positions[node]
            positions[node] = (x + dx, y + dy)
        bodies[index] = (members, (left + dx, right + dx, top + dy, bottom + dy))
        ceiling = max(ceiling, top + dy)
        floor = min(floor, bottom + dy)