import bpy
from ..core import common
from bpy.types import Operator, Context, Mesh, Armature, EditBone, PoseBone
from ..core.register import register_wrap
from .translations import t

@register_wrap
class AvatarToolkit_RemoveZeroWeightBones(Operator):
    bl_idname = "avatar_toolkit.remove_zero_weight_bones"
    bl_label = t("Tools.remove_zero_weight_bones.label")
    bl_description = t("Tools.remove_zero_weight_bones.desc")
    bl_options = {'REGISTER', 'UNDO'}

    threshold: bpy.props.FloatProperty(
        default=0.01,
        name=t("Tools.remove_zero_weight_bones.threshold.label"),
        description=t("Tools.remove_zero_weight_bones.threshold.desc"),
        min=0.0000001, 
        max=0.9999999)

    @classmethod
    def poll(cls, context: Context) -> bool:
        return common.get_selected_armature(context) is not None

    def execute(self, context: Context) -> set[str]:
        armature = common.get_selected_armature(context)
        if not common.is_valid_armature(armature):
            self.report({'ERROR'}, t("Tools.apply_transforms.invalid_armature"))
            return {'CANCELLED'}

        weighted_bones: list[str] = []


        bpy.ops.object.mode_set(mode='OBJECT')
        bpy.ops.object.select_all(action='DESELECT')

        armature.select_set(True)
        context.view_layer.objects.active = armature

        meshes = common.get_all_meshes(context)
        for mesh in meshes:
            mesh_data: Mesh = mesh.data
            for vertex in mesh_data.vertices:
                for group in vertex.groups:
                    if group.weight > self.threshold: 
                        weighted_bones.append(mesh.vertex_groups[group.group].name) #add bone name to list of bones that are greater than the weight threshold
        
        bpy.ops.object.mode_set(mode='EDIT')
        amature_data: Armature = armature.data
        unweighted_bones: list[str] = []

        #doing 2 loops to prevent modification of array during iteration
        for bone in amature_data.edit_bones:
            if bone.name not in weighted_bones:
                unweighted_bones.append(bone.name) #add bones that arent in the list of bones that have weight into the list of bones that don't

        for bone_name in unweighted_bones:
            for edit_bone in amature_data.edit_bones[bone_name].children: 
                edit_bone.use_connect = False #to fix randomly moving bones
                edit_bone.parent = amature_data.edit_bones[bone_name].parent #to fix unparented bones.
            amature_data.edit_bones.remove(amature_data.edit_bones[bone_name]) #delete list of unweighted bones from the armature

        self.report({'INFO'}, t("Tools.remove_zero_weight_bones.success"))
        return {'FINISHED'}