def get_selected_movie_proxy_recursive_unique(strips):
    buildable = {s.filepath: s for s in strips if s.type =='MOVIE' and s.use_proxy}
    metas = [s for s in strips if s.type == 'META' and s.use_proxy]

    for meta in metas:
        buildable = {**buildable, **get_selected_movie_proxy_recursive_unique(meta.strips)}

    return buildable

def get_selected_image_proxy_recursive_unique(strips):
    images = [s for s in strips if s.type =='IMAGE' and s.use_proxy]
    metas = [s for s in strips if s.type == 'META' and s.use_proxy]
    buildable = set()

    for image in images:
        buildable |= set([image.directory + s.filename for s in image.elements])

    for meta in metas:
        buildable |= get_selected_image_proxy_recursive_unique(meta.strips)

    return buildable


def draw_selection_info(layout, context):
    movies = get_selected_movie_proxy_recursive_unique(context.selected_sequences)
    images = get_selected_image_proxy_recursive_unique(context.selected_sequences)
    total_len = 0

    for movie in movies.values():
        total_len += movie.frame_final_duration
        total_len += movie.animation_offset_start
        total_len += movie.animation_offset_end
        total_len += movie.frame_offset_start
        total_len += movie.frame_offset_end

    total_len += len(images)

    text_num = str(len(context.selected_sequences)) + " Selected"
    time = bpy.utils.smpte_from_frame(total_len)
    text_time = time + " Total time to rebuild"

    layout.label(text=text_num)
    layout.label(text=text_time)


class SEQUENCER_PT_proxy_settings(SequencerButtonsPanel, Panel):
    bl_label = "Proxy settings"
    bl_category = "Proxy"
    @classmethod
    def poll(cls, context):
        return cls.has_sequencer(context)

    def draw(self, context):
        layout = self.layout

        ed = context.scene.sequence_editor

        flow = layout.column_flow()
        flow.prop(ed, "proxy_storage", text="Storage")
        if ed.proxy_storage == 'PROJECT':
            flow.prop(ed, "proxy_dir", text="Directory")

        col = layout.column()
        draw_selection_info(col, context)
        col.operator("sequencer.enable_proxies")
        col.operator("sequencer.rebuild_proxy")