# Ultralytics YOLOv5 🚀, AGPL-3.0 license
"""Model validation metrics."""

import numpy as np

from ..metrics import ap_per_class


def fitness(x):
    """Evaluates model fitness by a weighted sum of 8 metrics, `x`: [N,8] array, weights: [0.1, 0.9] for mAP and F1."""
    w = [0.0, 0.0, 0.1, 0.9, 0.0, 0.0, 0.1, 0.9]
    return (x[:, :8] * w).sum(1)


def ap_per_class_box_and_mask(
    tp_m,
    tp_b,
    conf,
    pred_cls,
    target_cls,
    plot=False,
    save_dir=".",
    names=(),
):
    """
    Args:
        tp_b: tp of boxes.
        tp_m: tp of masks.
        other arguments see `func: ap_per_class`.
    """
    results_boxes = ap_per_class(
        tp_b, conf, pred_cls, target_cls, plot=plot, save_dir=save_dir, names=names, prefix="Box"
    )[2:]
    results_masks = ap_per_class(
        tp_m, conf, pred_cls, target_cls, plot=plot, save_dir=save_dir, names=names, prefix="Mask"
    )[2:]

    return {
        "boxes": {
            "p": results_boxes[0],
            "r": results_boxes[1],
            "ap": results_boxes[3],
            "f1": results_boxes[2],
            "ap_class": results_boxes[4],
        },
        "masks": {
            "p": results_masks[0],
            "r": results_masks[1],
            "ap": results_masks[3],
            "f1": results_masks[2],
            "ap_class": results_masks[4],
        },
    }


class Metric:
    """Computes performance metrics like precision, recall, F1 score, and average precision for model evaluation."""

    def __init__(self) -> None:
        """Initializes performance metric attributes for precision, recall, F1 score, average precision, and class
        indices.
        """
        self.p = []  # (nc, )
        self.r = []  # (nc, )
        self.f1 = []  # (nc, )
        self.all_ap = []  # (nc, 10)
        self.ap_class_index = []  # (nc, )

    @property
    def ap50(self):
        """
        AP@0.5 of all classes.

        Return:
            (nc, ) or [].
        """
        return self.all_ap[:, 0] if len(self.all_ap) else []

    @property
    def ap(self):
        """AP@0.5:0.95
        Return:
            (nc, ) or [].
        """
        return self.all_ap.mean(1) if len(self.all_ap) else []

    @property
    def mp(self):
        """
        Mean precision of all classes.

        Return:
            float.
        """
        return self.p.mean() if len(self.p) else 0.0

    @property
    def mr(self):
        """
        Mean recall of all classes.

        Return:
            float.
        """
        return self.r.mean() if len(self.r) else 0.0

    @property
    def map50(self):
        """
        Mean AP@0.5 of all classes.

        Return:
            float.
        """
        return self.all_ap[:, 0].mean() if len(self.all_ap) else 0.0

    @property
    def map(self):
        """
        Mean AP@0.5:0.95 of all classes.

        Return:
            float.
        """
        return self.all_ap.mean() if len(self.all_ap) else 0.0

    def mean_results(self):
        """Mean of results, return mp, mr, map50, map."""
        return (self.mp, self.mr, self.map50, self.map)

    def class_result(self, i):
        """Class-aware result, return p[i], r[i], ap50[i], ap[i]."""
        return (self.p[i], self.r[i], self.ap50[i], self.ap[i])

    def get_maps(self, nc):
        """Calculates and returns mean Average Precision (mAP) for each class given number of classes `nc`."""
        maps = np.zeros(nc) + self.map
        for i, c in enumerate(self.ap_class_index):
            maps[c] = self.ap[i]
        return maps

    def update(self, results):
        """
        Args:
            results: tuple(p, r, ap, f1, ap_class).
        """
        p, r, all_ap, f1, ap_class_index = results
        self.p = p
        self.r = r
        self.all_ap = all_ap
        self.f1 = f1
        self.ap_class_index = ap_class_index


class Metrics:
    """Metric for boxes and masks."""

    def __init__(self) -> None:
        """Initializes Metric objects for bounding boxes and masks to compute performance metrics in the Metrics
        class.
        """
        self.metric_box = Metric()
        self.metric_mask = Metric()

    def update(self, results):
        """
        Args:
            results: Dict{'boxes': Dict{}, 'masks': Dict{}}.
        """
        self.metric_box.update(list(results["boxes"].values()))
        self.metric_mask.update(list(results["masks"].values()))

    def mean_results(self):
        """Computes and returns the mean results for both box and mask metrics by summing their individual means."""
        return self.metric_box.mean_results() + self.metric_mask.mean_results()

    def class_result(self, i):
        """Returns the sum of box and mask metric results for a specified class index `i`."""
        return self.metric_box.class_result(i) + self.metric_mask.class_result(i)

    def get_maps(self, nc):
        """Calculates and returns the sum of mean average precisions (mAPs) for both box and mask metrics for `nc`
        classes.
        """
        return self.metric_box.get_maps(nc) + self.metric_mask.get_maps(nc)

    @property
    def ap_class_index(self):
        """Returns the class index for average precision, shared by both box and mask metrics."""
        return self.metric_box.ap_class_index


KEYS = [
    "train/box_loss",
    "train/seg_loss",  # train loss
    "train/obj_loss",
    "train/cls_loss",
    "metrics/precision(B)",
    "metrics/recall(B)",
    "metrics/mAP_0.5(B)",
    "metrics/mAP_0.5:0.95(B)",  # metrics
    "metrics/precision(M)",
    "metrics/recall(M)",
    "metrics/mAP_0.5(M)",
    "metrics/mAP_0.5:0.95(M)",  # metrics
    "val/box_loss",
    "val/seg_loss",  # val loss
    "val/obj_loss",
    "val/cls_loss",
    "x/lr0",
    "x/lr1",
    "x/lr2",
]

BEST_KEYS = [
    "best/epoch",
    "best/precision(B)",
    "best/recall(B)",
    "best/mAP_0.5(B)",
    "best/mAP_0.5:0.95(B)",
    "best/precision(M)",
    "best/recall(M)",
    "best/mAP_0.5(M)",
    "best/mAP_0.5:0.95(M)",
]