# Ultralytics YOLO 🚀, AGPL-3.0 license

from ultralytics.solutions.solutions import BaseSolution
from ultralytics.utils.plotting import Annotator


class AIGym(BaseSolution):
    """
    A class to manage gym steps of people in a real-time video stream based on their poses.

    This class extends BaseSolution to monitor workouts using YOLO pose estimation models. It tracks and counts
    repetitions of exercises based on predefined angle thresholds for up and down positions.

    Attributes:
        count (List[int]): Repetition counts for each detected person.
        angle (List[float]): Current angle of the tracked body part for each person.
        stage (List[str]): Current exercise stage ('up', 'down', or '-') for each person.
        initial_stage (str | None): Initial stage of the exercise.
        up_angle (float): Angle threshold for considering the 'up' position of an exercise.
        down_angle (float): Angle threshold for considering the 'down' position of an exercise.
        kpts (List[int]): Indices of keypoints used for angle calculation.
        annotator (Annotator): Object for drawing annotations on the image.

    Methods:
        monitor: Processes a frame to detect poses, calculate angles, and count repetitions.

    Examples:
        >>> gym = AIGym(model="yolov8n-pose.pt")
        >>> image = cv2.imread("gym_scene.jpg")
        >>> processed_image = gym.monitor(image)
        >>> cv2.imshow("Processed Image", processed_image)
        >>> cv2.waitKey(0)
    """

    def __init__(self, **kwargs):
        """Initializes AIGym for workout monitoring using pose estimation and predefined angles."""
        # Check if the model name ends with '-pose'
        if "model" in kwargs and "-pose" not in kwargs["model"]:
            kwargs["model"] = "yolo11n-pose.pt"
        elif "model" not in kwargs:
            kwargs["model"] = "yolo11n-pose.pt"

        super().__init__(**kwargs)
        self.count = []  # List for counts, necessary where there are multiple objects in frame
        self.angle = []  # List for angle, necessary where there are multiple objects in frame
        self.stage = []  # List for stage, necessary where there are multiple objects in frame

        # Extract details from CFG single time for usage later
        self.initial_stage = None
        self.up_angle = float(self.CFG["up_angle"])  # Pose up predefined angle to consider up pose
        self.down_angle = float(self.CFG["down_angle"])  # Pose down predefined angle to consider down pose
        self.kpts = self.CFG["kpts"]  # User selected kpts of workouts storage for further usage

    def monitor(self, im0):
        """
        Monitors workouts using Ultralytics YOLO Pose Model.

        This function processes an input image to track and analyze human poses for workout monitoring. It uses
        the YOLO Pose model to detect keypoints, estimate angles, and count repetitions based on predefined
        angle thresholds.

        Args:
            im0 (ndarray): Input image for processing.

        Returns:
            (ndarray): Processed image with annotations for workout monitoring.

        Examples:
            >>> gym = AIGym()
            >>> image = cv2.imread("workout.jpg")
            >>> processed_image = gym.monitor(image)
        """
        # Extract tracks
        tracks = self.model.track(source=im0, persist=True, classes=self.CFG["classes"], **self.track_add_args)[0]

        if tracks.boxes.id is not None:
            # Extract and check keypoints
            if len(tracks) > len(self.count):
                new_human = len(tracks) - len(self.count)
                self.angle += [0] * new_human
                self.count += [0] * new_human
                self.stage += ["-"] * new_human

            # Initialize annotator
            self.annotator = Annotator(im0, line_width=self.line_width)

            # Enumerate over keypoints
            for ind, k in enumerate(reversed(tracks.keypoints.data)):
                # Get keypoints and estimate the angle
                kpts = [k[int(self.kpts[i])].cpu() for i in range(3)]
                self.angle[ind] = self.annotator.estimate_pose_angle(*kpts)
                im0 = self.annotator.draw_specific_points(k, self.kpts, radius=self.line_width * 3)

                # Determine stage and count logic based on angle thresholds
                if self.angle[ind] < self.down_angle:
                    if self.stage[ind] == "up":
                        self.count[ind] += 1
                    self.stage[ind] = "down"
                elif self.angle[ind] > self.up_angle:
                    self.stage[ind] = "up"

                # Display angle, count, and stage text
                self.annotator.plot_angle_and_count_and_stage(
                    angle_text=self.angle[ind],  # angle text for display
                    count_text=self.count[ind],  # count text for workouts
                    stage_text=self.stage[ind],  # stage position text
                    center_kpt=k[int(self.kpts[1])],  # center keypoint for display
                )

        self.display_output(im0)  # Display output image, if environment support display
        return im0  # return an image for writing or further usage
