import json

import bmesh
import bpy
from bpy_extras.io_utils import ExportHelper
from bpy.props import StringProperty


def dump_mesh_to_json(context, filepath):
    if context.object.mode == 'OBJECT':
        bpy.ops.object.mode_set(mode='EDIT')

    m = context.object.data
    b = bmesh.from_edit_mesh(m)

    print("info:")

    data = {}
    data['vertices'] = [list(vert.co) for vert in b.verts]

    data['edges for vert'] = []
    for vert in b.verts:
        data['edges for vert'].append([e.index for e in vert.link_edges])
    data['faces for vert'] = []
    for vert in b.verts:
        data['faces for vert'].append([e.index for e in vert.link_faces])

    edges = []
    for edge in b.edges:
        edges.append([v.index for v in edge.verts])
    data['edges'] = edges

    data['faces for edge'] = []
    for edge in b.edges:
        data['faces for edge'].append([f.index for f in edge.link_faces])

    faces = []
    for face in b.faces:
        faces.append([v.index for v in face.verts])
    data['faces'] = faces

    data['edges for face'] = []
    for face in b.faces:
        data['edges for face'].append([e.index for e in face.edges])

    json.dump(data, open(filepath, 'w'))
    bpy.ops.object.mode_set(mode='OBJECT')


class DumpMesh(bpy.types.Operator, ExportHelper):
    '''dump mesh for surfaces'''
    bl_idname = 'object.dump_mesh'
    bl_label = 'Dump Mesh'
    filename_ext = ".json"

    filter_glob = StringProperty(
        default="*.json",
        options={'HIDDEN'},
    )

    @classmethod
    def poll(cls, context):
        return context.active_object is not None

    def execute(self, context):
        dump_mesh_to_json(context, self.filepath)
        return {'FINISHED'}


def register():
    bpy.utils.register_class(DumpMesh)


def unregister():
    bpy.utils.unregister_class(DumpMesh)