# coding=utf-8
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import os
import ast
import argparse
from collections import OrderedDict
from functools import partial
from math import ceil

import numpy as np
import paddle.fluid as fluid
import paddlehub as hub
from paddlehub.module.module import moduleinfo, runnable, serving
from paddle.fluid.core import PaddleTensor, AnalysisConfig, create_paddle_predictor
from paddlehub.io.parser import txt_parser
from paddlehub.common.paddle_helper import add_vars_prefix

from faster_rcnn_resnet50_fpn_coco2017.processor import load_label_info, postprocess, base64_to_cv2
from faster_rcnn_resnet50_fpn_coco2017.data_feed import test_reader, padding_minibatch
from faster_rcnn_resnet50_fpn_coco2017.fpn import FPN
from faster_rcnn_resnet50_fpn_coco2017.resnet import ResNet
from faster_rcnn_resnet50_fpn_coco2017.rpn_head import AnchorGenerator, RPNTargetAssign, GenerateProposals, FPNRPNHead
from faster_rcnn_resnet50_fpn_coco2017.bbox_head import MultiClassNMS, BBoxHead, TwoFCHead
from faster_rcnn_resnet50_fpn_coco2017.bbox_assigner import BBoxAssigner
from faster_rcnn_resnet50_fpn_coco2017.roi_extractor import FPNRoIAlign


@moduleinfo(
    name="faster_rcnn_resnet50_fpn_coco2017",
    version="1.0.0",
    type="cv/object_detection",
    summary=
    "Baidu's Faster-RCNN model for object detection, whose backbone is ResNet50, processed with Feature Pyramid Networks",
    author="paddlepaddle",
    author_email="paddle-dev@baidu.com")
class FasterRCNNResNet50RPN(hub.Module):
    def _initialize(self):
        # default pretrained model, Faster-RCNN with backbone ResNet50, shape of input tensor is [3, 800, 1333]
        self.default_pretrained_model_path = os.path.join(self.directory, "faster_rcnn_resnet50_fpn_model")
        self.label_names = load_label_info(os.path.join(self.directory, "label_file.txt"))
        self._set_config()

    def _set_config(self):
        """
        predictor config setting
        """
        cpu_config = AnalysisConfig(self.default_pretrained_model_path)
        cpu_config.disable_glog_info()
        cpu_config.disable_gpu()
        self.cpu_predictor = create_paddle_predictor(cpu_config)

        try:
            _places = os.environ["CUDA_VISIBLE_DEVICES"]
            int(_places[0])
            use_gpu = True
        except:
            use_gpu = False
        if use_gpu:
            gpu_config = AnalysisConfig(self.default_pretrained_model_path)
            gpu_config.disable_glog_info()
            gpu_config.enable_use_gpu(memory_pool_init_size_mb=500, device_id=0)
            self.gpu_predictor = create_paddle_predictor(gpu_config)

    def context(self, num_classes=81, trainable=True, pretrained=True, phase='train'):
        """
        Distill the Head Features, so as to perform transfer learning.

        Args:
            num_classes (int): number of categories
            trainable (bool): whether to set parameters trainable.
            pretrained (bool): whether to load default pretrained model.
            phase (str): optional choices are 'train' and 'predict'.

        Returns:
             inputs (dict): the input variables.
             outputs (dict): the output variables.
             context_prog (Program): the program to execute transfer learning.
        """
        context_prog = fluid.Program()
        startup_program = fluid.Program()
        with fluid.program_guard(context_prog, startup_program):
            with fluid.unique_name.guard():
                image = fluid.layers.data(name='image', shape=[-1, 3, -1, -1], dtype='float32')
                # backbone
                backbone = ResNet(norm_type='affine_channel', depth=50, feature_maps=[2, 3, 4, 5], freeze_at=2)
                body_feats = backbone(image)
                # fpn
                fpn = FPN(max_level=6, min_level=2, num_chan=256, spatial_scale=[0.03125, 0.0625, 0.125, 0.25])
                var_prefix = '@HUB_{}@'.format(self.name)
                im_info = fluid.layers.data(name='im_info', shape=[3], dtype='float32', lod_level=0)
                im_shape = fluid.layers.data(name='im_shape', shape=[3], dtype='float32', lod_level=0)
                body_feat_names = list(body_feats.keys())
                body_feats, spatial_scale = fpn.get_output(body_feats)
                # rpn_head: RPNHead
                rpn_head = self.rpn_head()
                rois = rpn_head.get_proposals(body_feats, im_info, mode=phase)
                # train
                if phase == 'train':
                    gt_bbox = fluid.layers.data(name='gt_bbox', shape=[4], dtype='float32', lod_level=1)
                    is_crowd = fluid.layers.data(name='is_crowd', shape=[1], dtype='int32', lod_level=1)
                    gt_class = fluid.layers.data(name='gt_class', shape=[1], dtype='int32', lod_level=1)
                    rpn_loss = rpn_head.get_loss(im_info, gt_bbox, is_crowd)
                    # bbox_assigner: BBoxAssigner
                    bbox_assigner = self.bbox_assigner(num_classes)
                    outs = fluid.layers.generate_proposal_labels(
                        rpn_rois=rois,
                        gt_classes=gt_class,
                        is_crowd=is_crowd,
                        gt_boxes=gt_bbox,
                        im_info=im_info,
                        batch_size_per_im=bbox_assigner.batch_size_per_im,
                        fg_fraction=bbox_assigner.fg_fraction,
                        fg_thresh=bbox_assigner.fg_thresh,
                        bg_thresh_hi=bbox_assigner.bg_thresh_hi,
                        bg_thresh_lo=bbox_assigner.bg_thresh_lo,
                        bbox_reg_weights=bbox_assigner.bbox_reg_weights,
                        class_nums=bbox_assigner.class_nums,
                        use_random=bbox_assigner.use_random)
                    rois = outs[0]

                roi_extractor = self.roi_extractor()
                roi_feat = roi_extractor(head_inputs=body_feats, rois=rois, spatial_scale=spatial_scale)
                # head_feat
                bbox_head = self.bbox_head(num_classes)
                head_feat = bbox_head.head(roi_feat)
                if isinstance(head_feat, OrderedDict):
                    head_feat = list(head_feat.values())[0]
                if phase == 'train':
                    inputs = {
                        'image': var_prefix + image.name,
                        'im_info': var_prefix + im_info.name,
                        'im_shape': var_prefix + im_shape.name,
                        'gt_class': var_prefix + gt_class.name,
                        'gt_bbox': var_prefix + gt_bbox.name,
                        'is_crowd': var_prefix + is_crowd.name
                    }
                    outputs = {
                        'head_features': var_prefix + head_feat.name,
                        'rpn_cls_loss': var_prefix + rpn_loss['rpn_cls_loss'].name,
                        'rpn_reg_loss': var_prefix + rpn_loss['rpn_reg_loss'].name,
                        'generate_proposal_labels': [var_prefix + var.name for var in outs]
                    }
                elif phase == 'predict':
                    pred = bbox_head.get_prediction(roi_feat, rois, im_info, im_shape)
                    inputs = {
                        'image': var_prefix + image.name,
                        'im_info': var_prefix + im_info.name,
                        'im_shape': var_prefix + im_shape.name
                    }
                    outputs = {
                        'head_features': var_prefix + head_feat.name,
                        'rois': var_prefix + rois.name,
                        'bbox_out': var_prefix + pred.name
                    }
                add_vars_prefix(context_prog, var_prefix)
                add_vars_prefix(startup_program, var_prefix)

                global_vars = context_prog.global_block().vars
                inputs = {key: global_vars[value] for key, value in inputs.items()}
                outputs = {
                    key: global_vars[value] if not isinstance(value, list) else [global_vars[var] for var in value]
                    for key, value in outputs.items()
                }

                for param in context_prog.global_block().iter_parameters():
                    param.trainable = trainable

                place = fluid.CPUPlace()
                exe = fluid.Executor(place)
                exe.run(startup_program)
                if pretrained:

                    def _if_exist(var):
                        if num_classes != 81:
                            if 'bbox_pred' in var.name or 'cls_score' in var.name:
                                return False
                        return os.path.exists(os.path.join(self.default_pretrained_model_path, var.name))

                    fluid.io.load_vars(exe, self.default_pretrained_model_path, predicate=_if_exist)
                return inputs, outputs, context_prog

    def rpn_head(self):
        return FPNRPNHead(
            anchor_generator=AnchorGenerator(
                anchor_sizes=[32, 64, 128, 256, 512],
                aspect_ratios=[0.5, 1.0, 2.0],
                stride=[16.0, 16.0],
                variance=[1.0, 1.0, 1.0, 1.0]),
            rpn_target_assign=RPNTargetAssign(
                rpn_batch_size_per_im=256,
                rpn_fg_fraction=0.5,
                rpn_negative_overlap=0.3,
                rpn_positive_overlap=0.7,
                rpn_straddle_thresh=0.0),
            train_proposal=GenerateProposals(min_size=0.0, nms_thresh=0.7, post_nms_top_n=2000, pre_nms_top_n=2000),
            test_proposal=GenerateProposals(min_size=0.0, nms_thresh=0.7, post_nms_top_n=1000, pre_nms_top_n=1000),
            anchor_start_size=32,
            num_chan=256,
            min_level=2,
            max_level=6)

    def roi_extractor(self):
        return FPNRoIAlign(
            canconical_level=4, canonical_size=224, max_level=5, min_level=2, box_resolution=7, sampling_ratio=2)

    def bbox_head(self, num_classes):
        return BBoxHead(
            head=TwoFCHead(mlp_dim=1024),
            nms=MultiClassNMS(keep_top_k=100, nms_threshold=0.5, score_threshold=0.05),
            num_classes=num_classes)

    def bbox_assigner(self, num_classes):
        return BBoxAssigner(
            batch_size_per_im=512,
            bbox_reg_weights=[0.1, 0.1, 0.2, 0.2],
            bg_thresh_hi=0.5,
            bg_thresh_lo=0.0,
            fg_fraction=0.25,
            fg_thresh=0.5,
            class_nums=num_classes)

    def save_inference_model(self, dirname, model_filename=None, params_filename=None, combined=True):
        if combined:
            model_filename = "__model__" if not model_filename else model_filename
            params_filename = "__params__" if not params_filename else params_filename
        place = fluid.CPUPlace()
        exe = fluid.Executor(place)

        program, feeded_var_names, target_vars = fluid.io.load_inference_model(
            dirname=self.default_pretrained_model_path, executor=exe)

        fluid.io.save_inference_model(
            dirname=dirname,
            main_program=program,
            executor=exe,
            feeded_var_names=feeded_var_names,
            target_vars=target_vars,
            model_filename=model_filename,
            params_filename=params_filename)

    def object_detection(self,
                         paths=None,
                         images=None,
                         data=None,
                         use_gpu=False,
                         batch_size=1,
                         output_dir='detection_result',
                         score_thresh=0.5,
                         visualization=True):
        """API of Object Detection.

        Args:
            paths (list[str]): The paths of images.
            images (list(numpy.ndarray)): images data, shape of each is [H, W, C]
            batch_size (int): batch size.
            use_gpu (bool): Whether to use gpu.
            output_dir (str): The path to store output images.
            visualization (bool): Whether to save image or not.
            score_thresh (float): threshold for object detecion.

        Returns:
            res (list[dict]): The result of coco2017 detecion. keys include 'data', 'save_path', the corresponding value is:
                data (dict): the result of object detection, keys include 'left', 'top', 'right', 'bottom', 'label', 'confidence', the corresponding value is:
                    left (float): The X coordinate of the upper left corner of the bounding box;
                    top (float): The Y coordinate of the upper left corner of the bounding box;
                    right (float): The X coordinate of the lower right corner of the bounding box;
                    bottom (float): The Y coordinate of the lower right corner of the bounding box;
                    label (str): The label of detection result;
                    confidence (float): The confidence of detection result.
                save_path (str, optional): The path to save output images.
        """
        if use_gpu:
            try:
                _places = os.environ["CUDA_VISIBLE_DEVICES"]
                int(_places[0])
            except:
                raise RuntimeError(
                    "Environment Variable CUDA_VISIBLE_DEVICES is not set correctly. If you wanna use gpu, please set CUDA_VISIBLE_DEVICES as cuda_device_id."
                )

        paths = paths if paths else list()
        if data and 'image' in data:
            paths += data['image']

        all_images = list()
        for yield_data in test_reader(paths, images):
            all_images.append(yield_data)

        images_num = len(all_images)
        loop_num = ceil(images_num / batch_size)
        res = []

        for iter_id in range(loop_num):
            batch_data = []
            handle_id = iter_id * batch_size

            for image_id in range(batch_size):
                try:
                    batch_data.append(all_images[handle_id + image_id])
                except:
                    pass

            padding_image, padding_info, padding_shape = padding_minibatch(
                batch_data, coarsest_stride=32, use_padded_im_info=True)
            padding_image_tensor = PaddleTensor(padding_image.copy())
            padding_info_tensor = PaddleTensor(padding_info.copy())
            padding_shape_tensor = PaddleTensor(padding_shape.copy())
            feed_list = [padding_image_tensor, padding_info_tensor, padding_shape_tensor]

            if use_gpu:
                data_out = self.gpu_predictor.run(feed_list)
            else:
                data_out = self.cpu_predictor.run(feed_list)

            output = postprocess(
                paths=paths,
                images=images,
                data_out=data_out,
                score_thresh=score_thresh,
                label_names=self.label_names,
                output_dir=output_dir,
                handle_id=handle_id,
                visualization=visualization)
            res += output

        return res

    def add_module_config_arg(self):
        """
        Add the command config options
        """
        self.arg_config_group.add_argument(
            '--use_gpu', type=ast.literal_eval, default=False, help="whether use GPU or not")

        self.arg_config_group.add_argument('--batch_size', type=int, default=1, help="batch size for prediction")

    def add_module_input_arg(self):
        """
        Add the command input options
        """
        self.arg_input_group.add_argument('--input_path', type=str, default=None, help="input data")

        self.arg_input_group.add_argument('--input_file', type=str, default=None, help="file contain input data")

    def check_input_data(self, args):
        input_data = []
        if args.input_path:
            input_data = [args.input_path]
        elif args.input_file:
            if not os.path.exists(args.input_file):
                raise RuntimeError("File %s is not exist." % args.input_file)
            else:
                input_data = txt_parser.parse(args.input_file, use_strip=True)
        return input_data

    @serving
    def serving_method(self, images, **kwargs):
        """
        Run as a service.
        """
        images_decode = [base64_to_cv2(image) for image in images]
        results = self.object_detection(images=images_decode, **kwargs)
        return results

    @runnable
    def run_cmd(self, argvs):
        self.parser = argparse.ArgumentParser(
            description="Run the {}".format(self.name),
            prog="hub run {}".format(self.name),
            usage='%(prog)s',
            add_help=True)
        self.arg_input_group = self.parser.add_argument_group(title="Input options", description="Input data. Required")
        self.arg_config_group = self.parser.add_argument_group(
            title="Config options", description="Run configuration for controlling module behavior, not required.")
        self.add_module_config_arg()

        self.add_module_input_arg()
        args = self.parser.parse_args(argvs)
        input_data = self.check_input_data(args)
        if len(input_data) == 0:
            self.parser.print_help()
            exit(1)
        else:
            for image_path in input_data:
                if not os.path.exists(image_path):
                    raise RuntimeError("File %s or %s is not exist." % image_path)
        return self.object_detection(paths=input_data, use_gpu=args.use_gpu, batch_size=args.batch_size)
