#!/usr/bin/env python3
# -*- coding:utf-8 -*-
# Author: kerlomz <kerlomz@gmail.com>
import os
import tensorflow as tf
tf.compat.v1.disable_v2_behavior()
from tensorflow.python.framework.errors_impl import NotFoundError
from config import ModelConfig

os.environ['TF_XLA_FLAGS'] = '--tf_xla_cpu_global_jit'
os.environ['CUDA_VISIBLE_DEVICES'] = '1'


class GraphSession(object):
    def __init__(self, model_conf: ModelConfig):
        self.model_conf = model_conf
        self.logger = self.model_conf.logger
        self.size_str = self.model_conf.size_string
        self.model_name = self.model_conf.model_name
        self.graph_name = self.model_conf.model_name
        self.version = self.model_conf.model_version
        self.graph = tf.compat.v1.Graph()
        self.sess = tf.compat.v1.Session(
            graph=self.graph,
            config=tf.compat.v1.ConfigProto(

                # allow_soft_placement=True,
                # log_device_placement=True,
                gpu_options=tf.compat.v1.GPUOptions(
                    # allocator_type='BFC',
                    allow_growth=True,  # it will cause fragmentation.
                    # per_process_gpu_memory_fraction=self.model_conf.device_usage
                    per_process_gpu_memory_fraction=0.1
                )
            )
        )
        self.graph_def = self.graph.as_graph_def()
        self.loaded = self.load_model()

    def load_model(self):
        # Here is for debugging, positioning error source use.
        # with self.graph.as_default():
        #     saver = tf.train.import_meta_graph('graph/***.meta')
        #     saver.restore(self.sess, tf.train.latest_checkpoint('graph'))
        if not self.model_conf.model_exists:
            self.destroy()
            return False
        try:
            with tf.io.gfile.GFile(self.model_conf.compile_model_path, "rb") as f:
                graph_def_file = f.read()
            self.graph_def.ParseFromString(graph_def_file)
            with self.graph.as_default():
                self.sess.run(tf.compat.v1.global_variables_initializer())
                _ = tf.import_graph_def(self.graph_def, name="")

            self.logger.info('TensorFlow Session {} Loaded.'.format(self.model_conf.model_name))
            return True
        except NotFoundError:
            self.logger.error('The system cannot find the model specified.')
            self.destroy()
            return False

    @property
    def session(self):
        return self.sess

    def destroy(self):
        self.sess.close()
        del self.sess