node_wrangler.py

        min=0, max=1, step=1, precision=3,
        subtype='COLOR_GAMMA', size=3
    )

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        selected = []
        for node in nodes:
            if node.select == True:
                selected.append(node)

        bpy.ops.node.add_node(type='NodeFrame')
        frm = nodes.active
        frm.label = self.label_prop
        frm.use_custom_color = True
        frm.color = self.color_prop

        for node in selected:
            node.parent = frm

        return {'FINISHED'}


class NWReloadImages(Operator, NWBase):
    bl_idname = "node.nw_reload_images"
    bl_label = "Reload Images"
    bl_description = "Update all the image nodes to match their files on disk"

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        image_types = ["IMAGE", "TEX_IMAGE", "TEX_ENVIRONMENT", "TEXTURE"]
        num_reloaded = 0
        for node in nodes:
            if node.type in image_types:
                if node.type == "TEXTURE":
                    if node.texture:  # node has texture assigned
                        if node.texture.type in ['IMAGE', 'ENVIRONMENT_MAP']:
                            if node.texture.image:  # texture has image assigned
                                node.texture.image.reload()
                                num_reloaded += 1
                else:
                    if node.image:
                        node.image.reload()
                        num_reloaded += 1

        if num_reloaded:
            self.report({'INFO'}, "Reloaded images")
            print("Reloaded " + str(num_reloaded) + " images")
            force_update(context)
            return {'FINISHED'}
        else:
            self.report({'WARNING'}, "No images found to reload in this node tree")
            return {'CANCELLED'}


class NWSwitchNodeType(Operator, NWBase):
    """Switch type of selected nodes """
    bl_idname = "node.nw_swtch_node_type"
    bl_label = "Switch Node Type"
    bl_options = {'REGISTER', 'UNDO'}

    to_type: EnumProperty(
        name="Switch to type",
        items=list(shaders_input_nodes_props) +
        list(shaders_output_nodes_props) +
        list(shaders_shader_nodes_props) +
        list(shaders_texture_nodes_props) +
        list(shaders_color_nodes_props) +
        list(shaders_vector_nodes_props) +
        list(shaders_converter_nodes_props) +
        list(shaders_layout_nodes_props) +
        list(compo_input_nodes_props) +
        list(compo_output_nodes_props) +
        list(compo_color_nodes_props) +
        list(compo_converter_nodes_props) +
        list(compo_filter_nodes_props) +
        list(compo_vector_nodes_props) +
        list(compo_matte_nodes_props) +
        list(compo_distort_nodes_props) +
        list(compo_layout_nodes_props) +
        list(blender_mat_input_nodes_props) +
        list(blender_mat_output_nodes_props) +
        list(blender_mat_color_nodes_props) +
        list(blender_mat_vector_nodes_props) +
        list(blender_mat_converter_nodes_props) +
        list(blender_mat_layout_nodes_props) +
        list(texture_input_nodes_props) +
        list(texture_output_nodes_props) +
        list(texture_color_nodes_props) +
        list(texture_pattern_nodes_props) +
        list(texture_textures_nodes_props) +
        list(texture_converter_nodes_props) +
        list(texture_distort_nodes_props) +
        list(texture_layout_nodes_props)
    )

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        to_type = self.to_type
        # Those types of nodes will not swap.
        src_excludes = ('NodeFrame')
        # Those attributes of nodes will be copied if possible
        attrs_to_pass = ('color', 'hide', 'label', 'mute', 'parent',
                         'show_options', 'show_preview', 'show_texture',
                         'use_alpha', 'use_clamp', 'use_custom_color', 'location'
                         )
        selected = [n for n in nodes if n.select]
        reselect = []
        for node in [n for n in selected if
                     n.rna_type.identifier not in src_excludes and
                     n.rna_type.identifier != to_type]:
            new_node = nodes.new(to_type)
            for attr in attrs_to_pass:
                if hasattr(node, attr) and hasattr(new_node, attr):
                    setattr(new_node, attr, getattr(node, attr))
            # set image datablock of dst to image of src
            if hasattr(node, 'image') and hasattr(new_node, 'image'):
                if node.image:
                    new_node.image = node.image
            # Special cases
            if new_node.type == 'SWITCH':
                new_node.hide = True
            # Dictionaries: src_sockets and dst_sockets:
            # 'INPUTS': input sockets ordered by type (entry 'MAIN' main type of inputs).
            # 'OUTPUTS': output sockets ordered by type (entry 'MAIN' main type of outputs).
            # in 'INPUTS' and 'OUTPUTS':
            # 'SHADER', 'RGBA', 'VECTOR', 'VALUE' - sockets of those types.
            # socket entry:
            # (index_in_type, socket_index, socket_name, socket_default_value, socket_links)
            src_sockets = {
                'INPUTS': {'SHADER': [], 'RGBA': [], 'VECTOR': [], 'VALUE': [], 'MAIN': None},
                'OUTPUTS': {'SHADER': [], 'RGBA': [], 'VECTOR': [], 'VALUE': [], 'MAIN': None},
            }
            dst_sockets = {
                'INPUTS': {'SHADER': [], 'RGBA': [], 'VECTOR': [], 'VALUE': [], 'MAIN': None},
                'OUTPUTS': {'SHADER': [], 'RGBA': [], 'VECTOR': [], 'VALUE': [], 'MAIN': None},
            }
            types_order_one = 'SHADER', 'RGBA', 'VECTOR', 'VALUE'
            types_order_two = 'SHADER', 'VECTOR', 'RGBA', 'VALUE'
            # check src node to set src_sockets values and dst node to set dst_sockets dict values
            for sockets, nd in ((src_sockets, node), (dst_sockets, new_node)):
                # Check node's inputs and outputs and fill proper entries in "sockets" dict
                for in_out, in_out_name in ((nd.inputs, 'INPUTS'), (nd.outputs, 'OUTPUTS')):
                    # enumerate in inputs, then in outputs
                    # find name, default value and links of socket
                    for i, socket in enumerate(in_out):
                        the_name = socket.name
                        dval = None
                        # Not every socket, especially in outputs has "default_value"
                        if hasattr(socket, 'default_value'):
                            dval = socket.default_value
                        socket_links = []
                        for lnk in socket.links:
                            socket_links.append(lnk)
                        # check type of socket to fill proper keys.
                        for the_type in types_order_one:
                            if socket.type == the_type:
                                # create values for sockets['INPUTS'][the_type] and sockets['OUTPUTS'][the_type]
                                # entry structure: (index_in_type, socket_index, socket_name, socket_default_value, socket_links)
                                sockets[in_out_name][the_type].append((len(sockets[in_out_name][the_type]), i, the_name, dval, socket_links))
                    # Check which of the types in inputs/outputs is considered to be "main".
                    # Set values of sockets['INPUTS']['MAIN'] and sockets['OUTPUTS']['MAIN']
                    for type_check in types_order_one:
                        if sockets[in_out_name][type_check]:
                            sockets[in_out_name]['MAIN'] = type_check
                            break

            matches = {
                'INPUTS': {'SHADER': [], 'RGBA': [], 'VECTOR': [], 'VALUE_NAME': [], 'VALUE': [], 'MAIN': []},
                'OUTPUTS': {'SHADER': [], 'RGBA': [], 'VECTOR': [], 'VALUE_NAME': [], 'VALUE': [], 'MAIN': []},
            }

            for inout, soctype in (
                    ('INPUTS', 'MAIN',),
                    ('INPUTS', 'SHADER',),
                    ('INPUTS', 'RGBA',),
                    ('INPUTS', 'VECTOR',),
                    ('INPUTS', 'VALUE',),
                    ('OUTPUTS', 'MAIN',),
                    ('OUTPUTS', 'SHADER',),
                    ('OUTPUTS', 'RGBA',),
                    ('OUTPUTS', 'VECTOR',),
                    ('OUTPUTS', 'VALUE',),
            ):
                if src_sockets[inout][soctype] and dst_sockets[inout][soctype]:
                    if soctype == 'MAIN':
                        sc = src_sockets[inout][src_sockets[inout]['MAIN']]
                        dt = dst_sockets[inout][dst_sockets[inout]['MAIN']]
                    else:
                        sc = src_sockets[inout][soctype]
                        dt = dst_sockets[inout][soctype]
                    # start with 'dt' to determine number of possibilities.
                    for i, soc in enumerate(dt):
                        # if src main has enough entries - match them with dst main sockets by indexes.
                        if len(sc) > i:
                            matches[inout][soctype].append(((sc[i][1], sc[i][3]), (soc[1], soc[3])))
                        # add 'VALUE_NAME' criterion to inputs.
                        if inout == 'INPUTS' and soctype == 'VALUE':
                            for s in sc:
                                if s[2] == soc[2]:  # if names match
                                    # append src (index, dval), dst (index, dval)
                                    matches['INPUTS']['VALUE_NAME'].append(((s[1], s[3]), (soc[1], soc[3])))

            # When src ['INPUTS']['MAIN'] is 'VECTOR' replace 'MAIN' with matches VECTOR if possible.
            # This creates better links when relinking textures.
            if src_sockets['INPUTS']['MAIN'] == 'VECTOR' and matches['INPUTS']['VECTOR']:
                matches['INPUTS']['MAIN'] = matches['INPUTS']['VECTOR']

            # Pass default values and RELINK:
            for tp in ('MAIN', 'SHADER', 'RGBA', 'VECTOR', 'VALUE_NAME', 'VALUE'):
                # INPUTS: Base on matches in proper order.
                for (src_i, src_dval), (dst_i, dst_dval) in matches['INPUTS'][tp]:
                    # pass dvals
                    if src_dval and dst_dval and tp in {'RGBA', 'VALUE_NAME'}:
                        new_node.inputs[dst_i].default_value = src_dval
                    # Special case: switch to math
                    if node.type in {'MIX_RGB', 'ALPHAOVER', 'ZCOMBINE'} and\
                            new_node.type == 'MATH' and\
                            tp == 'MAIN':
                        new_dst_dval = max(src_dval[0], src_dval[1], src_dval[2])
                        new_node.inputs[dst_i].default_value = new_dst_dval
                        if node.type == 'MIX_RGB':
                            if node.blend_type in [o[0] for o in operations]:
                                new_node.operation = node.blend_type
                    # Special case: switch from math to some types
                    if node.type == 'MATH' and\
                            new_node.type in {'MIX_RGB', 'ALPHAOVER', 'ZCOMBINE'} and\
                            tp == 'MAIN':
                        for i in range(3):
                            new_node.inputs[dst_i].default_value[i] = src_dval
                        if new_node.type == 'MIX_RGB':
                            if node.operation in [t[0] for t in blend_types]:
                                new_node.blend_type = node.operation
                            # Set Fac of MIX_RGB to 1.0
                            new_node.inputs[0].default_value = 1.0
                    # make link only when dst matching input is not linked already.
                    if node.inputs[src_i].links and not new_node.inputs[dst_i].links:
                        in_src_link = node.inputs[src_i].links[0]
                        in_dst_socket = new_node.inputs[dst_i]
                        links.new(in_src_link.from_socket, in_dst_socket)
                        links.remove(in_src_link)
                # OUTPUTS: Base on matches in proper order.
                for (src_i, src_dval), (dst_i, dst_dval) in matches['OUTPUTS'][tp]:
                    for out_src_link in node.outputs[src_i].links:
                        out_dst_socket = new_node.outputs[dst_i]
                        links.new(out_dst_socket, out_src_link.to_socket)
            # relink rest inputs if possible, no criteria
            for src_inp in node.inputs:
                for dst_inp in new_node.inputs:
                    if src_inp.links and not dst_inp.links:
                        src_link = src_inp.links[0]
                        links.new(src_link.from_socket, dst_inp)
                        links.remove(src_link)
            # relink rest outputs if possible, base on node kind if any left.
            for src_o in node.outputs:
                for out_src_link in src_o.links:
                    for dst_o in new_node.outputs:
                        if src_o.type == dst_o.type:
                            links.new(dst_o, out_src_link.to_socket)
            # relink rest outputs no criteria if any left. Link all from first output.
            for src_o in node.outputs:
                for out_src_link in src_o.links:
                    if new_node.outputs:
                        links.new(new_node.outputs[0], out_src_link.to_socket)
            nodes.remove(node)
        force_update(context)
        return {'FINISHED'}


class NWMergeNodes(Operator, NWBase):
    bl_idname = "node.nw_merge_nodes"
    bl_label = "Merge Nodes"
    bl_description = "Merge Selected Nodes"
    bl_options = {'REGISTER', 'UNDO'}

    mode: EnumProperty(
        name="mode",
        description="All possible blend types and math operations",
        items=blend_types + [op for op in operations if op not in blend_types],
    )
    merge_type: EnumProperty(
        name="merge type",
        description="Type of Merge to be used",
        items=(
            ('AUTO', 'Auto', 'Automatic Output Type Detection'),
            ('SHADER', 'Shader', 'Merge using ADD or MIX Shader'),
            ('MIX', 'Mix Node', 'Merge using Mix Nodes'),
            ('MATH', 'Math Node', 'Merge using Math Nodes'),
            ('ZCOMBINE', 'Z-Combine Node', 'Merge using Z-Combine Nodes'),
            ('ALPHAOVER', 'Alpha Over Node', 'Merge using Alpha Over Nodes'),
        ),
    )

    def execute(self, context):
        settings = context.preferences.addons[__name__].preferences
        merge_hide = settings.merge_hide
        merge_position = settings.merge_position  # 'center' or 'bottom'

        do_hide = False
        do_hide_shader = False
        if merge_hide == 'ALWAYS':
            do_hide = True
            do_hide_shader = True
        elif merge_hide == 'NON_SHADER':
            do_hide = True

        tree_type = context.space_data.node_tree.type
        if tree_type == 'COMPOSITING':
            node_type = 'CompositorNode'
        elif tree_type == 'SHADER':
            node_type = 'ShaderNode'
        elif tree_type == 'TEXTURE':
            node_type = 'TextureNode'
        nodes, links = get_nodes_links(context)
        mode = self.mode
        merge_type = self.merge_type
        # Prevent trying to add Z-Combine in not 'COMPOSITING' node tree.
        # 'ZCOMBINE' works only if mode == 'MIX'
        # Setting mode to None prevents trying to add 'ZCOMBINE' node.
        if (merge_type == 'ZCOMBINE' or merge_type == 'ALPHAOVER') and tree_type != 'COMPOSITING':
            merge_type = 'MIX'
            mode = 'MIX'
        selected_mix = []  # entry = [index, loc]
        selected_shader = []  # entry = [index, loc]
        selected_math = []  # entry = [index, loc]
        selected_z = []  # entry = [index, loc]
        selected_alphaover = []  # entry = [index, loc]

        for i, node in enumerate(nodes):
            if node.select and node.outputs:
                if merge_type == 'AUTO':
                    for (type, types_list, dst) in (
                            ('SHADER', ('MIX', 'ADD'), selected_shader),
                            ('RGBA', [t[0] for t in blend_types], selected_mix),
                            ('VALUE', [t[0] for t in operations], selected_math),
                    ):
                        output_type = node.outputs[0].type
                        valid_mode = mode in types_list
                        # When mode is 'MIX' use mix node for both 'RGBA' and 'VALUE' output types.
                        # Cheat that output type is 'RGBA',
                        # and that 'MIX' exists in math operations list.
                        # This way when selected_mix list is analyzed:
                        # Node data will be appended even though it doesn't meet requirements.
                        if output_type != 'SHADER' and mode == 'MIX':
                            output_type = 'RGBA'
                            valid_mode = True
                        if output_type == type and valid_mode:
                            dst.append([i, node.location.x, node.location.y, node.dimensions.x, node.hide])
                else:
                    for (type, types_list, dst) in (
                            ('SHADER', ('MIX', 'ADD'), selected_shader),
                            ('MIX', [t[0] for t in blend_types], selected_mix),
                            ('MATH', [t[0] for t in operations], selected_math),
                            ('ZCOMBINE', ('MIX', ), selected_z),
                            ('ALPHAOVER', ('MIX', ), selected_alphaover),
                    ):
                        if merge_type == type and mode in types_list:
                            dst.append([i, node.location.x, node.location.y, node.dimensions.x, node.hide])
        # When nodes with output kinds 'RGBA' and 'VALUE' are selected at the same time
        # use only 'Mix' nodes for merging.
        # For that we add selected_math list to selected_mix list and clear selected_math.
        if selected_mix and selected_math and merge_type == 'AUTO':
            selected_mix += selected_math
            selected_math = []

        for nodes_list in [selected_mix, selected_shader, selected_math, selected_z, selected_alphaover]:
            if nodes_list:
                count_before = len(nodes)
                # sort list by loc_x - reversed
                nodes_list.sort(key=lambda k: k[1], reverse=True)
                # get maximum loc_x
                loc_x = nodes_list[0][1] + nodes_list[0][3] + 70
                nodes_list.sort(key=lambda k: k[2], reverse=True)
                if merge_position == 'CENTER':
                    loc_y = ((nodes_list[len(nodes_list) - 1][2]) + (nodes_list[len(nodes_list) - 2][2])) / 2  # average yloc of last two nodes (lowest two)
                    if nodes_list[len(nodes_list) - 1][-1] == True:  # if last node is hidden, mix should be shifted up a bit
                        if do_hide:
                            loc_y += 40
                        else:
                            loc_y += 80
                else:
                    loc_y = nodes_list[len(nodes_list) - 1][2]
                offset_y = 100
                if not do_hide:
                    offset_y = 200
                if nodes_list == selected_shader and not do_hide_shader:
                    offset_y = 150.0
                the_range = len(nodes_list) - 1
                if len(nodes_list) == 1:
                    the_range = 1
                for i in range(the_range):
                    if nodes_list == selected_mix:
                        add_type = node_type + 'MixRGB'
                        add = nodes.new(add_type)
                        add.blend_type = mode
                        if mode != 'MIX':
                            add.inputs[0].default_value = 1.0
                        add.show_preview = False
                        add.hide = do_hide
                        if do_hide:
                            loc_y = loc_y - 50
                        first = 1
                        second = 2
                        add.width_hidden = 100.0
                    elif nodes_list == selected_math:
                        add_type = node_type + 'Math'
                        add = nodes.new(add_type)
                        add.operation = mode
                        add.hide = do_hide
                        if do_hide:
                            loc_y = loc_y - 50
                        first = 0
                        second = 1
                        add.width_hidden = 100.0
                    elif nodes_list == selected_shader:
                        if mode == 'MIX':
                            add_type = node_type + 'MixShader'
                            add = nodes.new(add_type)
                            add.hide = do_hide_shader
                            if do_hide_shader:
                                loc_y = loc_y - 50
                            first = 1
                            second = 2
                            add.width_hidden = 100.0
                        elif mode == 'ADD':
                            add_type = node_type + 'AddShader'
                            add = nodes.new(add_type)
                            add.hide = do_hide_shader
                            if do_hide_shader:
                                loc_y = loc_y - 50
                            first = 0
                            second = 1
                            add.width_hidden = 100.0
                    elif nodes_list == selected_z:
                        add = nodes.new('CompositorNodeZcombine')
                        add.show_preview = False
                        add.hide = do_hide
                        if do_hide:
                            loc_y = loc_y - 50
                        first = 0
                        second = 2
                        add.width_hidden = 100.0
                    elif nodes_list == selected_alphaover:
                        add = nodes.new('CompositorNodeAlphaOver')
                        add.show_preview = False
                        add.hide = do_hide
                        if do_hide:
                            loc_y = loc_y - 50
                        first = 1
                        second = 2
                        add.width_hidden = 100.0
                    add.location = loc_x, loc_y
                    loc_y += offset_y
                    add.select = True
                count_adds = i + 1
                count_after = len(nodes)
                index = count_after - 1
                first_selected = nodes[nodes_list[0][0]]
                # "last" node has been added as first, so its index is count_before.
                last_add = nodes[count_before]
                # Special case:
                # Two nodes were selected and first selected has no output links, second selected has output links.
                # Then add links from last add to all links 'to_socket' of out links of second selected.
                if len(nodes_list) == 2:
                    if not first_selected.outputs[0].links:
                        second_selected = nodes[nodes_list[1][0]]
                        for ss_link in second_selected.outputs[0].links:
                            # Prevent cyclic dependencies when nodes to be marged are linked to one another.
                            # Create list of invalid indexes.
                            invalid_i = [n[0] for n in (selected_mix + selected_math + selected_shader + selected_z)]
                            # Link only if "to_node" index not in invalid indexes list.
                            if ss_link.to_node not in [nodes[i] for i in invalid_i]:
                                links.new(last_add.outputs[0], ss_link.to_socket)
                # add links from last_add to all links 'to_socket' of out links of first selected.
                for fs_link in first_selected.outputs[0].links:
                    # Prevent cyclic dependencies when nodes to be marged are linked to one another.
                    # Create list of invalid indexes.
                    invalid_i = [n[0] for n in (selected_mix + selected_math + selected_shader + selected_z)]
                    # Link only if "to_node" index not in invalid indexes list.
                    if fs_link.to_node not in [nodes[i] for i in invalid_i]:
                        links.new(last_add.outputs[0], fs_link.to_socket)
                # add link from "first" selected and "first" add node
                node_to = nodes[count_after - 1]
                links.new(first_selected.outputs[0], node_to.inputs[first])
                if node_to.type == 'ZCOMBINE':
                    for fs_out in first_selected.outputs:
                        if fs_out != first_selected.outputs[0] and fs_out.name in ('Z', 'Depth'):
                            links.new(fs_out, node_to.inputs[1])
                            break
                # add links between added ADD nodes and between selected and ADD nodes
                for i in range(count_adds):
                    if i < count_adds - 1:
                        node_from = nodes[index]
                        node_to = nodes[index - 1]
                        node_to_input_i = first
                        node_to_z_i = 1  # if z combine - link z to first z input
                        links.new(node_from.outputs[0], node_to.inputs[node_to_input_i])
                        if node_to.type == 'ZCOMBINE':
                            for from_out in node_from.outputs:
                                if from_out != node_from.outputs[0] and from_out.name in ('Z', 'Depth'):
                                    links.new(from_out, node_to.inputs[node_to_z_i])
                    if len(nodes_list) > 1:
                        node_from = nodes[nodes_list[i + 1][0]]
                        node_to = nodes[index]
                        node_to_input_i = second
                        node_to_z_i = 3  # if z combine - link z to second z input
                        links.new(node_from.outputs[0], node_to.inputs[node_to_input_i])
                        if node_to.type == 'ZCOMBINE':
                            for from_out in node_from.outputs:
                                if from_out != node_from.outputs[0] and from_out.name in ('Z', 'Depth'):
                                    links.new(from_out, node_to.inputs[node_to_z_i])
                    index -= 1
                # set "last" of added nodes as active
                nodes.active = last_add
                for i, x, y, dx, h in nodes_list:
                    nodes[i].select = False

        return {'FINISHED'}


class NWBatchChangeNodes(Operator, NWBase):
    bl_idname = "node.nw_batch_change"
    bl_label = "Batch Change"
    bl_description = "Batch Change Blend Type and Math Operation"
    bl_options = {'REGISTER', 'UNDO'}

    blend_type: EnumProperty(
        name="Blend Type",
        items=blend_types + navs,
    )
    operation: EnumProperty(
        name="Operation",
        items=operations + navs,
    )

    def execute(self, context):

        nodes, links = get_nodes_links(context)
        blend_type = self.blend_type
        operation = self.operation
        for node in context.selected_nodes:
            if node.type == 'MIX_RGB':
                if not blend_type in [nav[0] for nav in navs]:
                    node.blend_type = blend_type
                else:
                    if blend_type == 'NEXT':
                        index = [i for i, entry in enumerate(blend_types) if node.blend_type in entry][0]
                        #index = blend_types.index(node.blend_type)
                        if index == len(blend_types) - 1:
                            node.blend_type = blend_types[0][0]
                        else:
                            node.blend_type = blend_types[index + 1][0]

                    if blend_type == 'PREV':
                        index = [i for i, entry in enumerate(blend_types) if node.blend_type in entry][0]
                        if index == 0:
                            node.blend_type = blend_types[len(blend_types) - 1][0]
                        else:
                            node.blend_type = blend_types[index - 1][0]

            if node.type == 'MATH':
                if not operation in [nav[0] for nav in navs]:
                    node.operation = operation
                else:
                    if operation == 'NEXT':
                        index = [i for i, entry in enumerate(operations) if node.operation in entry][0]
                        #index = operations.index(node.operation)
                        if index == len(operations) - 1:
                            node.operation = operations[0][0]
                        else:
                            node.operation = operations[index + 1][0]

                    if operation == 'PREV':
                        index = [i for i, entry in enumerate(operations) if node.operation in entry][0]
                        #index = operations.index(node.operation)
                        if index == 0:
                            node.operation = operations[len(operations) - 1][0]
                        else:
                            node.operation = operations[index - 1][0]

        return {'FINISHED'}


class NWChangeMixFactor(Operator, NWBase):
    bl_idname = "node.nw_factor"
    bl_label = "Change Factor"
    bl_description = "Change Factors of Mix Nodes and Mix Shader Nodes"
    bl_options = {'REGISTER', 'UNDO'}

    # option: Change factor.
    # If option is 1.0 or 0.0 - set to 1.0 or 0.0
    # Else - change factor by option value.
    option: FloatProperty()

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        option = self.option
        selected = []  # entry = index
        for si, node in enumerate(nodes):
            if node.select:
                if node.type in {'MIX_RGB', 'MIX_SHADER'}:
                    selected.append(si)

        for si in selected:
            fac = nodes[si].inputs[0]
            nodes[si].hide = False
            if option in {0.0, 1.0}:
                fac.default_value = option
            else:
                fac.default_value += option

        return {'FINISHED'}


class NWCopySettings(Operator, NWBase):
    bl_idname = "node.nw_copy_settings"
    bl_label = "Copy Settings"
    bl_description = "Copy Settings of Active Node to Selected Nodes"
    bl_options = {'REGISTER', 'UNDO'}

    @classmethod
    def poll(cls, context):
        valid = False
        if nw_check(context):
            if (
                    context.active_node is not None and
                    context.active_node.type != 'FRAME'
            ):
                valid = True
        return valid

    def execute(self, context):
        node_active = context.active_node
        node_selected = context.selected_nodes

        # Error handling
        if not (len(node_selected) > 1):
            self.report({'ERROR'}, "2 nodes must be selected at least")
            return {'CANCELLED'}

        # Check if active node is in the selection
        selected_node_names = [n.name for n in node_selected]
        if node_active.name not in selected_node_names:
            self.report({'ERROR'}, "No active node")
            return {'CANCELLED'}

        # Get nodes in selection by type
        valid_nodes = [n for n in node_selected if n.type == node_active.type]

        if not (len(valid_nodes) > 1) and node_active:
            self.report({'ERROR'}, "Selected nodes are not of the same type as {}".format(node_active.name))
            return {'CANCELLED'}

        if len(valid_nodes) != len(node_selected):
            # Report nodes that are not valid
            valid_node_names = [n.name for n in valid_nodes]
            not_valid_names = list(set(selected_node_names) - set(valid_node_names))
            self.report({'INFO'}, "Ignored {} (not of the same type as {})".format(", ".join(not_valid_names), node_active.name))

        # Reference original
        orig = node_active
        #node_selected_names = [n.name for n in node_selected]

        # Output list
        success_names = []

        # Deselect all nodes
        for i in node_selected:
            i.select = False

        # Code by zeffii from http://blender.stackexchange.com/a/42338/3710
        # Run through all other nodes
        for node in valid_nodes[1:]:

            # Check for frame node
            parent = node.parent if node.parent else None
            node_loc = [node.location.x, node.location.y]

            # Select original to duplicate
            orig.select = True

            # Duplicate selected node
            bpy.ops.node.duplicate()
            new_node = context.selected_nodes[0]

            # Deselect copy
            new_node.select = False

            # Properties to copy
            node_tree = node.id_data
            props_to_copy = 'bl_idname name location height width'.split(' ')

            # Input and outputs
            reconnections = []
            mappings = chain.from_iterable([node.inputs, node.outputs])
            for i in (i for i in mappings if i.is_linked):
                for L in i.links:
                    reconnections.append([L.from_socket.path_from_id(), L.to_socket.path_from_id()])

            # Properties
            props = {j: getattr(node, j) for j in props_to_copy}
            props_to_copy.pop(0)

            for prop in props_to_copy:
                setattr(new_node, prop, props[prop])

            # Get the node tree to remove the old node
            nodes = node_tree.nodes
            nodes.remove(node)
            new_node.name = props['name']

            if parent:
                new_node.parent = parent
                new_node.location = node_loc

            for str_from, str_to in reconnections:
                node_tree.links.new(eval(str_from), eval(str_to))

            success_names.append(new_node.name)

        orig.select = True
        node_tree.nodes.active = orig
        self.report({'INFO'}, "Successfully copied attributes from {} to: {}".format(orig.name, ", ".join(success_names)))
        return {'FINISHED'}


class NWCopyLabel(Operator, NWBase):
    bl_idname = "node.nw_copy_label"
    bl_label = "Copy Label"
    bl_options = {'REGISTER', 'UNDO'}

    option: EnumProperty(
        name="option",
        description="Source of name of label",
        items=(
            ('FROM_ACTIVE', 'from active', 'from active node',),
            ('FROM_NODE', 'from node', 'from node linked to selected node'),
            ('FROM_SOCKET', 'from socket', 'from socket linked to selected node'),
        )
    )

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        option = self.option
        active = nodes.active
        if option == 'FROM_ACTIVE':
            if active:
                src_label = active.label
                for node in [n for n in nodes if n.select and nodes.active != n]:
                    node.label = src_label
        elif option == 'FROM_NODE':
            selected = [n for n in nodes if n.select]
            for node in selected:
                for input in node.inputs:
                    if input.links:
                        src = input.links[0].from_node
                        node.label = src.label
                        break
        elif option == 'FROM_SOCKET':
            selected = [n for n in nodes if n.select]
            for node in selected:
                for input in node.inputs:
                    if input.links:
                        src = input.links[0].from_socket
                        node.label = src.name
                        break

        return {'FINISHED'}


class NWClearLabel(Operator, NWBase):
    bl_idname = "node.nw_clear_label"
    bl_label = "Clear Label"
    bl_options = {'REGISTER', 'UNDO'}

    option: BoolProperty()

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        for node in [n for n in nodes if n.select]:
            node.label = ''

        return {'FINISHED'}

    def invoke(self, context, event):
        if self.option:
            return self.execute(context)
        else:
            return context.window_manager.invoke_confirm(self, event)


class NWModifyLabels(Operator, NWBase):
    """Modify Labels of all selected nodes"""
    bl_idname = "node.nw_modify_labels"
    bl_label = "Modify Labels"
    bl_options = {'REGISTER', 'UNDO'}

    prepend: StringProperty(
        name="Add to Beginning"
    )
    append: StringProperty(
        name="Add to End"
    )
    replace_from: StringProperty(
        name="Text to Replace"
    )
    replace_to: StringProperty(
        name="Replace with"
    )

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        for node in [n for n in nodes if n.select]:
            node.label = self.prepend + node.label.replace(self.replace_from, self.replace_to) + self.append

        return {'FINISHED'}

    def invoke(self, context, event):
        self.prepend = ""
        self.append = ""
        self.remove = ""
        return context.window_manager.invoke_props_dialog(self)


class NWAddTextureSetup(Operator, NWBase):
    bl_idname = "node.nw_add_texture"
    bl_label = "Texture Setup"
    bl_description = "Add Texture Node Setup to Selected Shaders"
    bl_options = {'REGISTER', 'UNDO'}

    add_mapping: BoolProperty(name="Add Mapping Nodes", description="Create coordinate and mapping nodes for the texture (ignored for selected texture nodes)", default=True)

    @classmethod
    def poll(cls, context):
        valid = False
        if nw_check(context):
            space = context.space_data
            if space.tree_type == 'ShaderNodeTree':
                valid = True
        return valid

    def execute(self, context):
        nodes, links = get_nodes_links(context)
        shader_types = [x[1] for x in shaders_shader_nodes_props if x[1] not in {'MIX_SHADER', 'ADD_SHADER'}]
        texture_types = [x[1] for x in shaders_texture_nodes_props]
        selected_nodes = [n for n in nodes if n.select]
        for t_node in selected_nodes:
            valid = False
            input_index = 0
            if t_node.inputs:
                for index, i in enumerate(t_node.inputs):
                    if not i.is_linked:
                        valid = True
                        input_index = index
                        break
            if valid:
                locx = t_node.location.x
                locy = t_node.location.y - t_node.dimensions.y/2

                xoffset = [500, 700]
                is_texture = False
                if t_node.type in texture_types + ['MAPPING']:
                    xoffset = [290, 500]
                    is_texture = True

                coordout = 2
                image_type = 'ShaderNodeTexImage'

                if (t_node.type in texture_types and t_node.type != 'TEX_IMAGE') or (t_node.type == 'BACKGROUND'):
                    coordout = 0  # image texture uses UVs, procedural textures and Background shader use Generated
                    if t_node.type == 'BACKGROUND':
                        image_type = 'ShaderNodeTexEnvironment'

                if not is_texture:
                    tex = nodes.new(image_type)
                    tex.location = [locx - 200, locy + 112]
                    nodes.active = tex
                    links.new(tex.outputs[0], t_node.inputs[input_index])

                t_node.select = False
                if self.add_mapping or is_texture:
                    if t_node.type != 'MAPPING':
                        m = nodes.new('ShaderNodeMapping')
                        m.location = [locx - xoffset[0], locy + 141]
                        m.width = 240
                    else:
                        m = t_node
                    coord = nodes.new('ShaderNodeTexCoord')
                    coord.location = [locx - (200 if t_node.type == 'MAPPING' else xoffset[1]), locy + 124]

                    if not is_texture:
                        links.new(m.outputs[0], tex.inputs[0])
                        links.new(coord.outputs[coordout], m.inputs[0])
                    else:
                        nodes.active = m
                        links.new(m.outputs[0], t_node.inputs[input_index])
                        links.new(coord.outputs[coordout], m.inputs[0])
            else:
                self.report({'WARNING'}, "No free inputs for node: "+t_node.name)
        return {'FINISHED'}


class NWAddPrincipledSetup(Operator, NWBase, ImportHelper):
    bl_idname = "node.nw_add_textures_for_principled"
    bl_label = "Principled Texture Setup"
    bl_description = "Add Texture Node Setup for Principled BSDF"
    bl_options = {'REGISTER', 'UNDO'}

    directory: StringProperty(
        name='Directory',
        subtype='DIR_PATH',
        default='',
        description='Folder to search in for image files'
    )
    files: CollectionProperty(
        type=bpy.types.OperatorFileListElement,
        options={'HIDDEN', 'SKIP_SAVE'}
    )

    relative_path: BoolProperty(
        name='Relative Path',
        description='Select the file relative to the blend file',
        default=True
    )

    order = [
        "filepath",
        "files",
    ]

    def draw(self, context):
        layout = self.layout
        layout.alignment = 'LEFT'

        layout.prop(self, 'relative_path')

    @classmethod
    def poll(cls, context):
        valid = False
        if nw_check(context):
            space = context.space_data
            if space.tree_type == 'ShaderNodeTree':
                valid = True
        return valid

    def execute(self, context):
        # Check if everything is ok
        if not self.directory:
            self.report({'INFO'}, 'No Folder Selected')
            return {'CANCELLED'}
        if not self.files[:]:
            self.report({'INFO'}, 'No Files Selected')
            return {'CANCELLED'}

        nodes, links = get_nodes_links(context)
        active_node = nodes.active
        if not (active_node and active_node.bl_idname == 'ShaderNodeBsdfPrincipled'):
            self.report({'INFO'}, 'Select Principled BSDF')
            return {'CANCELLED'}

        # Helper_functions
        def split_into__components(fname):
            # Split filename into components
            # 'WallTexture_diff_2k.002.jpg' -> ['Wall', 'Texture', 'diff', 'k']
            # Remove extension
            fname = path.splitext(fname)[0]
            # Remove digits
            fname = ''.join(i for i in fname if not i.isdigit())
            # Separate CamelCase by space
            fname = re.sub("([a-z])([A-Z])","\g<1> \g<2>",fname)
            # Replace common separators with SPACE
            seperators = ['_', '.', '-', '__', '--', '#']
            for sep in seperators:
                fname = fname.replace(sep, ' ')

            components = fname.split(' ')
            components = [c.lower() for c in components]
            return components

        # Filter textures names for texturetypes in filenames
        # [Socket Name, [abbreviations and keyword list], Filename placeholder]
        tags = context.preferences.addons[__name__].preferences.principled_tags
        normal_abbr = tags.normal.split(' ')
        bump_abbr = tags.bump.split(' ')
        gloss_abbr = tags.gloss.split(' ')
        rough_abbr = tags.rough.split(' ')
        socketnames = [
        ['Displacement', tags.displacement.split(' '), None],
        ['Base Color', tags.base_color.split(' '), None],
        ['Subsurface Color', tags.sss_color.split(' '), None],
        ['Metallic', tags.metallic.split(' '), None],
        ['Specular', tags.specular.split(' '), None],
        ['Roughness', rough_abbr + gloss_abbr, None],
        ['Normal', normal_abbr + bump_abbr, None],
        ]

        # Look through texture_types and set value as filename of first matched file
        def match_files_to_socket_names():
            for sname in socketnames:
                for file in self.files: