# Ultralytics YOLO 🚀, GPL-3.0 license

import os
import sys
from multiprocessing.pool import ThreadPool
from pathlib import Path

import numpy as np
import torch
import torch.nn.functional as F

from ultralytics.yolo.utils import DEFAULT_CFG, NUM_THREADS, ops
from ultralytics.yolo.utils.checks import check_requirements
from ultralytics.yolo.utils.metrics import ConfusionMatrix, SegmentMetrics, box_iou, mask_iou
from ultralytics.yolo.utils.plotting import output_to_target, plot_images
from ultralytics.yolo.v8.detect import DetectionValidator


class SegmentationValidator(DetectionValidator):

    def __init__(self, dataloader=None, save_dir=None, pbar=None, logger=None, args=None):
        super().__init__(dataloader, save_dir, pbar, logger, args)
        self.args.task = 'segment'
        self.metrics = SegmentMetrics(save_dir=self.save_dir)

    def preprocess(self, batch):
        batch = super().preprocess(batch)
        batch["masks"] = batch["masks"].to(self.device).float()
        return batch

    def init_metrics(self, model):
        head = model.model[-1] if self.training else model.model.model[-1]
        val = self.data.get('val', '')  # validation path
        self.is_coco = isinstance(val, str) and val.endswith(f'coco{os.sep}val2017.txt')  # is COCO dataset
        self.class_map = ops.coco80_to_coco91_class() if self.is_coco else list(range(1000))
        self.args.save_json |= self.is_coco and not self.training  # run on final val if training COCO
        self.nc = head.nc
        self.nm = head.nm if hasattr(head, "nm") else 32
        self.names = model.names
        self.metrics.names = self.names
        self.metrics.plot = self.args.plots
        self.confusion_matrix = ConfusionMatrix(nc=self.nc)
        self.plot_masks = []
        self.seen = 0
        self.jdict = []
        self.stats = []
        if self.args.save_json:
            check_requirements('pycocotools>=2.0.6')
            self.process = ops.process_mask_upsample  # more accurate
        else:
            self.process = ops.process_mask  # faster

    def get_desc(self):
        return ('%22s' + '%11s' * 10) % ('Class', 'Images', 'Instances', 'Box(P', "R", "mAP50", "mAP50-95)", "Mask(P",
                                         "R", "mAP50", "mAP50-95)")

    def postprocess(self, preds):
        p = ops.non_max_suppression(preds[0],
                                    self.args.conf,
                                    self.args.iou,
                                    labels=self.lb,
                                    multi_label=True,
                                    agnostic=self.args.single_cls,
                                    max_det=self.args.max_det,
                                    nm=self.nm)
        return p, preds[1][-1]

    def update_metrics(self, preds, batch):
        # Metrics
        for si, (pred, proto) in enumerate(zip(preds[0], preds[1])):
            idx = batch["batch_idx"] == si
            cls = batch["cls"][idx]
            bbox = batch["bboxes"][idx]
            nl, npr = cls.shape[0], pred.shape[0]  # number of labels, predictions
            shape = batch["ori_shape"][si]
            correct_masks = torch.zeros(npr, self.niou, dtype=torch.bool, device=self.device)  # init
            correct_bboxes = torch.zeros(npr, self.niou, dtype=torch.bool, device=self.device)  # init
            self.seen += 1

            if npr == 0:
                if nl:
                    self.stats.append((correct_masks, correct_bboxes, *torch.zeros(
                        (2, 0), device=self.device), cls.squeeze(-1)))
                    if self.args.plots:
                        self.confusion_matrix.process_batch(detections=None, labels=cls.squeeze(-1))
                continue

            # Masks
            midx = [si] if self.args.overlap_mask else idx
            gt_masks = batch["masks"][midx]
            pred_masks = self.process(proto, pred[:, 6:], pred[:, :4], shape=batch["img"][si].shape[1:])

            # Predictions
            if self.args.single_cls:
                pred[:, 5] = 0
            predn = pred.clone()
            ops.scale_boxes(batch["img"][si].shape[1:], predn[:, :4], shape,
                            ratio_pad=batch["ratio_pad"][si])  # native-space pred

            # Evaluate
            if nl:
                height, width = batch["img"].shape[2:]
                tbox = ops.xywh2xyxy(bbox) * torch.tensor(
                    (width, height, width, height), device=self.device)  # target boxes
                ops.scale_boxes(batch["img"][si].shape[1:], tbox, shape,
                                ratio_pad=batch["ratio_pad"][si])  # native-space labels
                labelsn = torch.cat((cls, tbox), 1)  # native-space labels
                correct_bboxes = self._process_batch(predn, labelsn)
                # TODO: maybe remove these `self.` arguments as they already are member variable
                correct_masks = self._process_batch(predn,
                                                    labelsn,
                                                    pred_masks,
                                                    gt_masks,
                                                    overlap=self.args.overlap_mask,
                                                    masks=True)
                if self.args.plots:
                    self.confusion_matrix.process_batch(predn, labelsn)

            # Append correct_masks, correct_boxes, pconf, pcls, tcls
            self.stats.append((correct_masks, correct_bboxes, pred[:, 4], pred[:, 5], cls.squeeze(-1)))

            pred_masks = torch.as_tensor(pred_masks, dtype=torch.uint8)
            if self.args.plots and self.batch_i < 3:
                self.plot_masks.append(pred_masks[:15].cpu())  # filter top 15 to plot

            # Save
            if self.args.save_json:
                pred_masks = ops.scale_image(batch["img"][si].shape[1:],
                                             pred_masks.permute(1, 2, 0).contiguous().cpu().numpy(),
                                             shape,
                                             ratio_pad=batch["ratio_pad"][si])
                self.pred_to_json(predn, batch["im_file"][si], pred_masks)
            # if self.args.save_txt:
            #    save_one_txt(predn, save_conf, shape, file=save_dir / 'labels' / f'{path.stem}.txt')

    def _process_batch(self, detections, labels, pred_masks=None, gt_masks=None, overlap=False, masks=False):
        """
        Return correct prediction matrix
        Arguments:
            detections (array[N, 6]), x1, y1, x2, y2, conf, class
            labels (array[M, 5]), class, x1, y1, x2, y2
        Returns:
            correct (array[N, 10]), for 10 IoU levels
        """
        if masks:
            if overlap:
                nl = len(labels)
                index = torch.arange(nl, device=gt_masks.device).view(nl, 1, 1) + 1
                gt_masks = gt_masks.repeat(nl, 1, 1)  # shape(1,640,640) -> (n,640,640)
                gt_masks = torch.where(gt_masks == index, 1.0, 0.0)
            if gt_masks.shape[1:] != pred_masks.shape[1:]:
                gt_masks = F.interpolate(gt_masks[None], pred_masks.shape[1:], mode="bilinear", align_corners=False)[0]
                gt_masks = gt_masks.gt_(0.5)
            iou = mask_iou(gt_masks.view(gt_masks.shape[0], -1), pred_masks.view(pred_masks.shape[0], -1))
        else:  # boxes
            iou = box_iou(labels[:, 1:], detections[:, :4])

        correct = np.zeros((detections.shape[0], self.iouv.shape[0])).astype(bool)
        correct_class = labels[:, 0:1] == detections[:, 5]
        for i in range(len(self.iouv)):
            x = torch.where((iou >= self.iouv[i]) & correct_class)  # IoU > threshold and classes match
            if x[0].shape[0]:
                matches = torch.cat((torch.stack(x, 1), iou[x[0], x[1]][:, None]),
                                    1).cpu().numpy()  # [label, detect, iou]
                if x[0].shape[0] > 1:
                    matches = matches[matches[:, 2].argsort()[::-1]]
                    matches = matches[np.unique(matches[:, 1], return_index=True)[1]]
                    # matches = matches[matches[:, 2].argsort()[::-1]]
                    matches = matches[np.unique(matches[:, 0], return_index=True)[1]]
                correct[matches[:, 1].astype(int), i] = True
        return torch.tensor(correct, dtype=torch.bool, device=detections.device)

    def plot_val_samples(self, batch, ni):
        plot_images(batch["img"],
                    batch["batch_idx"],
                    batch["cls"].squeeze(-1),
                    batch["bboxes"],
                    batch["masks"],
                    paths=batch["im_file"],
                    fname=self.save_dir / f"val_batch{ni}_labels.jpg",
                    names=self.names)

    def plot_predictions(self, batch, preds, ni):
        plot_images(batch["img"],
                    *output_to_target(preds[0], max_det=15),
                    torch.cat(self.plot_masks, dim=0) if len(self.plot_masks) else self.plot_masks,
                    paths=batch["im_file"],
                    fname=self.save_dir / f'val_batch{ni}_pred.jpg',
                    names=self.names)  # pred
        self.plot_masks.clear()

    def pred_to_json(self, predn, filename, pred_masks):
        # Save one JSON result
        # Example result = {"image_id": 42, "category_id": 18, "bbox": [258.15, 41.29, 348.26, 243.78], "score": 0.236}
        from pycocotools.mask import encode  # noqa

        def single_encode(x):
            rle = encode(np.asarray(x[:, :, None], order="F", dtype="uint8"))[0]
            rle["counts"] = rle["counts"].decode("utf-8")
            return rle

        stem = Path(filename).stem
        image_id = int(stem) if stem.isnumeric() else stem
        box = ops.xyxy2xywh(predn[:, :4])  # xywh
        box[:, :2] -= box[:, 2:] / 2  # xy center to top-left corner
        pred_masks = np.transpose(pred_masks, (2, 0, 1))
        with ThreadPool(NUM_THREADS) as pool:
            rles = pool.map(single_encode, pred_masks)
        for i, (p, b) in enumerate(zip(predn.tolist(), box.tolist())):
            self.jdict.append({
                'image_id': image_id,
                'category_id': self.class_map[int(p[5])],
                'bbox': [round(x, 3) for x in b],
                'score': round(p[4], 5),
                'segmentation': rles[i]})

    def eval_json(self, stats):
        if self.args.save_json and self.is_coco and len(self.jdict):
            anno_json = self.data['path'] / "annotations/instances_val2017.json"  # annotations
            pred_json = self.save_dir / "predictions.json"  # predictions
            self.logger.info(f'\nEvaluating pycocotools mAP using {pred_json} and {anno_json}...')
            try:  # https://github.com/cocodataset/cocoapi/blob/master/PythonAPI/pycocoEvalDemo.ipynb
                check_requirements('pycocotools>=2.0.6')
                from pycocotools.coco import COCO  # noqa
                from pycocotools.cocoeval import COCOeval  # noqa

                for x in anno_json, pred_json:
                    assert x.is_file(), f"{x} file not found"
                anno = COCO(str(anno_json))  # init annotations api
                pred = anno.loadRes(str(pred_json))  # init predictions api (must pass string, not Path)
                for i, eval in enumerate([COCOeval(anno, pred, 'bbox'), COCOeval(anno, pred, 'segm')]):
                    if self.is_coco:
                        eval.params.imgIds = [int(Path(x).stem)
                                              for x in self.dataloader.dataset.im_files]  # images to eval
                    eval.evaluate()
                    eval.accumulate()
                    eval.summarize()
                    idx = i * 4 + 2
                    stats[self.metrics.keys[idx + 1]], stats[
                        self.metrics.keys[idx]] = eval.stats[:2]  # update mAP50-95 and mAP50
            except Exception as e:
                self.logger.warning(f'pycocotools unable to run: {e}')
        return stats


def val(cfg=DEFAULT_CFG, use_python=False):
    model = cfg.model or "yolov8n-seg.pt"
    data = cfg.data or "coco128-seg.yaml"

    args = dict(model=model, data=data, verbose=True)
    if use_python:
        from ultralytics import YOLO
        YOLO(model).val(**args)
    else:
        validator = SegmentationValidator(args=args)
        validator(model=args['model'])


if __name__ == "__main__":
    val()
