import sys
import os
import ctypes
import bpy
import numpy as np
from . import utils

class Session:
    def __init__(self):
        pass

def get_session():
    global session

    return session

def load_native_library():
    script_dir = os.path.dirname(os.path.realpath(__file__))

    if os.name == 'nt':
        lib_file_name = 'cpp_test.dll'
    else:
        lib_file_name = 'libcpp_test.so'

    lib = ctypes.CDLL(os.path.join(script_dir, lib_file_name))

    return lib

def unload_native_library(lib):
    if os.name == 'nt':
        kernel32 = ctypes.WinDLL('kernel32', use_last_error=True)
        kernel32.FreeLibrary.argtypes = [ctypes.c_void_p]
        kernel32.FreeLibrary(lib._handle)
    else:
        stdlib = ctypes.CDLL("")
        stdlib.dlclose.argtypes = [ctypes.c_void_p]
        stdlib.dlclose(lib._handle)

class CPP_TEST_OT_generate_image(bpy.types.Operator):
    """Generate a image"""
    bl_idname = "cpp_test.generate_image"
    bl_label = "Generate Image"
    bl_options = {'REGISTER', 'UNDO'}

    def execute(self, context):
        global session

        wm = context.window_manager

        native_lib = load_native_library()

        native_lib.CPPTEST_init()

        img = bpy.data.images.new('cpp_test', 1024, 1024, alpha=True)

        context.tool_settings.image_paint.canvas = img
        context.tool_settings.image_paint.mode = 'IMAGE'

        img_width, img_height = img.size

        pixels = utils.read_pixels_from_image(img)
        pixels_ctypes = pixels.ctypes.data_as(ctypes.POINTER(ctypes.c_float))

        native_lib.CPPTEST_setImageSize(img_width, img_height)
        native_lib.CPPTEST_setImagePixels(pixels_ctypes)

        native_lib.CPPTEST_process()

        utils.write_pixels_to_image(img, pixels)

        native_lib.CPPTEST_free()

        unload_native_library(native_lib)

        return {'FINISHED'}

class CPP_TEST_PT_panel(bpy.types.Panel):
    bl_label = "Cpp Test"
    bl_space_type = "IMAGE_EDITOR"
    bl_region_type = "UI"
    bl_category = "Cpp Test"

    @classmethod
    def poll(cls, context):
        return True

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

        row = layout.row()
        op = row.operator(CPP_TEST_OT_generate_image.bl_idname, text='Generate Image')

session = Session()