from pathlib import Path
import math

import cv2
import numpy as np
import onnxruntime as ort
from numpy import ndarray
from pydantic import BaseModel


class BoundingBox(BaseModel):
    x1: int
    y1: int
    x2: int
    y2: int
    cls_id: int
    conf: float


class TVFrameResult(BaseModel):
    frame_id: int
    boxes: list[BoundingBox]
    keypoints: list[tuple[int, int]]


class Miner:
    """
    ONNX-backed version of the petrol-tracking miner.

    This class is responsible for:
    - Loading the ONNX model via onnxruntime.
    - Running predictions on images.
    - Parsing ONNX outputs into structured results (TVFrameResult).

    It must have the following to be compatible with the chute:
        - be named `Miner`
        - have a `predict_batch` function with the inputs and outputs specified
        - be stored in a file called `miner.py` which lives in the root of the
          HFHub repo (rename/copy this file to `miner.py` before deploying)
    """

    def __init__(self, path_hf_repo: Path) -> None:
        model_path = path_hf_repo / "weights.onnx"

        # Class order as exported from the training pt: must match model.names
        self.class_names = ["petrol hose", "petrol pump", "price board", "roof canopy"]

        print("ORT version:", ort.__version__)

        try:
            ort.preload_dlls()
            print("✅ onnxruntime.preload_dlls() success")
        except Exception as e:
            print(f"⚠️ preload_dlls failed: {e}")

        print("ORT available providers BEFORE session:", ort.get_available_providers())

        sess_options = ort.SessionOptions()
        sess_options.graph_optimization_level = ort.GraphOptimizationLevel.ORT_ENABLE_ALL

        try:
            self.session = ort.InferenceSession(
                str(model_path),
                sess_options=sess_options,
                providers=["CUDAExecutionProvider", "CPUExecutionProvider"],
            )
            print("✅ Created ORT session with preferred CUDA provider list")
        except Exception as e:
            print(f"⚠️ CUDA session creation failed, falling back to CPU: {e}")
            self.session = ort.InferenceSession(
                str(model_path),
                sess_options=sess_options,
                providers=["CPUExecutionProvider"],
            )

        print("ORT session providers:", self.session.get_providers())

        for inp in self.session.get_inputs():
            print("INPUT:", inp.name, inp.shape, inp.type)

        for out in self.session.get_outputs():
            print("OUTPUT:", out.name, out.shape, out.type)

        self.input_name = self.session.get_inputs()[0].name
        self.output_names = [output.name for output in self.session.get_outputs()]
        self.input_shape = self.session.get_inputs()[0].shape

        self.input_height = self._safe_dim(self.input_shape[2], default=640)
        self.input_width = self._safe_dim(self.input_shape[3], default=640)

        # Thresholds
        self.conf_thres = 0.4
        self.iou_thres = 0.50
        self.max_det = 300

        print(f"✅ Petrol ONNX model loaded from: {model_path}")
        print(f"✅ ONNX providers: {self.session.get_providers()}")
        print(f"✅ ONNX input: name={self.input_name}, shape={self.input_shape}")

    def __repr__(self) -> str:
        return (
            f"Petrol ONNXRuntime(session={type(self.session).__name__}, "
            f"providers={self.session.get_providers()})"
        )

    @staticmethod
    def _safe_dim(value, default: int) -> int:
        return value if isinstance(value, int) and value > 0 else default

    def _letterbox(
        self,
        image: ndarray,
        new_shape: tuple[int, int],
        color=(114, 114, 114),
    ) -> tuple[ndarray, float, tuple[float, float]]:
        h, w = image.shape[:2]
        new_w, new_h = new_shape

        ratio = min(new_w / w, new_h / h)
        resized_w = int(round(w * ratio))
        resized_h = int(round(h * ratio))

        if (resized_w, resized_h) != (w, h):
            interp = cv2.INTER_CUBIC if ratio > 1.0 else cv2.INTER_LINEAR
            image = cv2.resize(image, (resized_w, resized_h), interpolation=interp)

        dw = new_w - resized_w
        dh = new_h - resized_h
        dw /= 2.0
        dh /= 2.0

        left = int(round(dw - 0.1))
        right = int(round(dw + 0.1))
        top = int(round(dh - 0.1))
        bottom = int(round(dh + 0.1))

        padded = cv2.copyMakeBorder(
            image,
            top,
            bottom,
            left,
            right,
            borderType=cv2.BORDER_CONSTANT,
            value=color,
        )
        return padded, ratio, (dw, dh)

    def _preprocess(
        self, image: ndarray
    ) -> tuple[np.ndarray, float, tuple[float, float], tuple[int, int]]:
        orig_h, orig_w = image.shape[:2]

        img, ratio, pad = self._letterbox(
            image, (self.input_width, self.input_height)
        )
        img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
        img = img.astype(np.float32) / 255.0
        img = np.transpose(img, (2, 0, 1))[None, ...]
        img = np.ascontiguousarray(img, dtype=np.float32)

        return img, ratio, pad, (orig_w, orig_h)

    @staticmethod
    def _clip_boxes(boxes: np.ndarray, image_size: tuple[int, int]) -> np.ndarray:
        w, h = image_size
        boxes[:, 0] = np.clip(boxes[:, 0], 0, w - 1)
        boxes[:, 1] = np.clip(boxes[:, 1], 0, h - 1)
        boxes[:, 2] = np.clip(boxes[:, 2], 0, w - 1)
        boxes[:, 3] = np.clip(boxes[:, 3], 0, h - 1)
        return boxes

    @staticmethod
    def _xywh_to_xyxy(boxes: np.ndarray) -> np.ndarray:
        out = np.empty_like(boxes)
        out[:, 0] = boxes[:, 0] - boxes[:, 2] / 2.0
        out[:, 1] = boxes[:, 1] - boxes[:, 3] / 2.0
        out[:, 2] = boxes[:, 0] + boxes[:, 2] / 2.0
        out[:, 3] = boxes[:, 1] + boxes[:, 3] / 2.0
        return out

    @staticmethod
    def _hard_nms(
        boxes: np.ndarray,
        scores: np.ndarray,
        iou_thresh: float,
    ) -> np.ndarray:
        if len(boxes) == 0:
            return np.array([], dtype=np.intp)

        boxes = np.asarray(boxes, dtype=np.float32)
        scores = np.asarray(scores, dtype=np.float32)
        order = np.argsort(scores)[::-1]
        keep = []

        while len(order) > 0:
            i = order[0]
            keep.append(i)
            if len(order) == 1:
                break

            rest = order[1:]

            xx1 = np.maximum(boxes[i, 0], boxes[rest, 0])
            yy1 = np.maximum(boxes[i, 1], boxes[rest, 1])
            xx2 = np.minimum(boxes[i, 2], boxes[rest, 2])
            yy2 = np.minimum(boxes[i, 3], boxes[rest, 3])

            inter = np.maximum(0.0, xx2 - xx1) * np.maximum(0.0, yy2 - yy1)

            area_i = max(0.0, (boxes[i, 2] - boxes[i, 0])) * max(0.0, (boxes[i, 3] - boxes[i, 1]))
            area_r = np.maximum(0.0, boxes[rest, 2] - boxes[rest, 0]) * np.maximum(0.0, boxes[rest, 3] - boxes[rest, 1])

            iou = inter / (area_i + area_r - inter + 1e-7)
            order = rest[iou <= iou_thresh]

        return np.array(keep, dtype=np.intp)

    @classmethod
    def _nms_per_class(
        cls,
        boxes: np.ndarray,
        scores: np.ndarray,
        cls_ids: np.ndarray,
        iou_thresh: float,
        max_det: int,
    ) -> np.ndarray:
        if len(boxes) == 0:
            return np.array([], dtype=np.intp)
        keep_all: list[int] = []
        for c in np.unique(cls_ids):
            idxs = np.nonzero(cls_ids == c)[0]
            if len(idxs) == 0:
                continue
            local_keep = cls._hard_nms(boxes[idxs], scores[idxs], iou_thresh)
            keep_all.extend(idxs[local_keep].tolist())
        keep_all_arr = np.array(keep_all, dtype=np.intp)
        order = np.argsort(scores[keep_all_arr])[::-1]
        return keep_all_arr[order[:max_det]]

    def _decode_yolov8(
        self,
        preds: np.ndarray,
        ratio: float,
        pad: tuple[float, float],
        orig_size: tuple[int, int],
    ) -> list[BoundingBox]:
        """
        Decode a raw YOLOv8-style ONNX detection output.

        Expected shape: [1, 4 + nc, num_boxes] (no objectness channel).
        Some exporters emit [1, num_boxes, 4 + nc]; both are handled.
        """
        if preds.ndim != 3 or preds.shape[0] != 1:
            raise ValueError(f"Unexpected ONNX output shape: {preds.shape}")

        preds = preds[0]

        # Normalize to [N, C] where C = 4 + nc
        nc = len(self.class_names)
        expected_c = 4 + nc
        if preds.shape[0] == expected_c:
            preds = preds.T
        elif preds.shape[1] != expected_c:
            # Fall back: treat smaller dim as channels
            if preds.shape[0] < preds.shape[1]:
                preds = preds.T

        if preds.ndim != 2 or preds.shape[1] < 5:
            raise ValueError(f"Unexpected normalized output shape: {preds.shape}")

        boxes_xywh = preds[:, :4].astype(np.float32)
        class_probs = preds[:, 4:].astype(np.float32)

        cls_ids = np.argmax(class_probs, axis=1).astype(np.int32)
        scores = class_probs[np.arange(len(class_probs)), cls_ids]

        keep = scores >= self.conf_thres
        boxes_xywh = boxes_xywh[keep]
        scores = scores[keep]
        cls_ids = cls_ids[keep]

        if len(boxes_xywh) == 0:
            return []

        boxes = self._xywh_to_xyxy(boxes_xywh)

        pad_w, pad_h = pad
        orig_w, orig_h = orig_size

        boxes[:, [0, 2]] -= pad_w
        boxes[:, [1, 3]] -= pad_h
        boxes /= ratio
        boxes = self._clip_boxes(boxes, (orig_w, orig_h))

        keep_idx = self._nms_per_class(
            boxes, scores, cls_ids, self.iou_thres, self.max_det
        )

        boxes = boxes[keep_idx]
        scores = scores[keep_idx]
        cls_ids = cls_ids[keep_idx]

        return [
            BoundingBox(
                x1=int(math.floor(box[0])),
                y1=int(math.floor(box[1])),
                x2=int(math.ceil(box[2])),
                y2=int(math.ceil(box[3])),
                cls_id=int(cls_id),
                conf=float(conf),
            )
            for box, conf, cls_id in zip(boxes, scores, cls_ids)
            if box[2] > box[0] and box[3] > box[1]
        ]

    def _predict_single(self, image: np.ndarray) -> list[BoundingBox]:
        if image is None:
            raise ValueError("Input image is None")
        if not isinstance(image, np.ndarray):
            raise TypeError(f"Input is not numpy array: {type(image)}")
        if image.ndim != 3:
            raise ValueError(f"Expected HWC image, got shape={image.shape}")
        if image.shape[0] <= 0 or image.shape[1] <= 0:
            raise ValueError(f"Invalid image shape={image.shape}")
        if image.shape[2] != 3:
            raise ValueError(f"Expected 3 channels, got shape={image.shape}")

        if image.dtype != np.uint8:
            image = image.astype(np.uint8)

        input_tensor, ratio, pad, orig_size = self._preprocess(image)

        expected_shape = (1, 3, self.input_height, self.input_width)
        if input_tensor.shape != expected_shape:
            raise ValueError(
                f"Bad input tensor shape={input_tensor.shape}, expected={expected_shape}"
            )

        outputs = self.session.run(self.output_names, {self.input_name: input_tensor})
        det_output = outputs[0]
        return self._decode_yolov8(det_output, ratio, pad, orig_size)

    def predict_batch(
        self,
        batch_images: list[ndarray],
        offset: int,
        n_keypoints: int,
    ) -> list[TVFrameResult]:
        """
        Miner prediction for a batch of images using ONNX Runtime.

        The petrol detector is a plain object-detection model (no pose),
        so keypoints are returned as `n_keypoints` padding entries of (0, 0)
        to keep the TVFrameResult schema stable across challenge types.
        """
        results: list[TVFrameResult] = []
        n_kp = max(0, int(n_keypoints))

        for frame_number_in_batch, image in enumerate(batch_images):
            frame_idx = offset + frame_number_in_batch
            try:
                boxes = self._predict_single(image)
            except Exception as e:
                print(f"⚠️ Inference failed for frame {frame_idx}: {e}")
                boxes = []

            results.append(
                TVFrameResult(
                    frame_id=frame_idx,
                    boxes=boxes,
                    keypoints=[(0, 0) for _ in range(n_kp)],
                )
            )

        print("✅ Petrol ONNX predictions complete")
        return results


def main() -> None:
    """
    Example runner for the ONNX Miner class.

    Loads `weights.onnx` from the current directory and runs `predict_batch`
    on one or more image files.

    Usage:
        python miner_onnx.py                         # dummy blank image
        python miner_onnx.py image1.jpg              # single image
        python miner_onnx.py image1.jpg image2.jpg   # batch of images
    """
    import sys

    import numpy as np

    repo_path = Path(__file__).parent
    print(f"Loading miner from: {repo_path}")
    miner = Miner(path_hf_repo=repo_path)
    print(repr(miner))

    batch_images: list[np.ndarray] = []

    if len(sys.argv) > 1:
        for image_path in sys.argv[1:]:
            image = cv2.imread(image_path)
            if image is None:
                raise ValueError(f"Cannot read image: {image_path}")
            batch_images.append(image)
        print(f"Loaded {len(batch_images)} image(s)")
    else:
        batch_images = [np.zeros((640, 640, 3), dtype=np.uint8)]
        print("No image provided — running on a single blank dummy frame")

    results = miner.predict_batch(
        batch_images=batch_images,
        offset=0,
        n_keypoints=32,
    )

    output_dir = repo_path / "predictions"
    output_dir.mkdir(exist_ok=True)

    class_names = {i: n for i, n in enumerate(miner.class_names)}

    def color_for_class(cls_id: int) -> tuple[int, int, int]:
        hue = (cls_id * 47) % 180
        hsv = np.uint8([[[hue, 220, 255]]])
        bgr = cv2.cvtColor(hsv, cv2.COLOR_HSV2BGR)[0, 0]
        return int(bgr[0]), int(bgr[1]), int(bgr[2])

    for image, r in zip(batch_images, results):
        print(
            f"frame={r.frame_id} "
            f"boxes={len(r.boxes)} "
            f"keypoints={len(r.keypoints)}"
        )

        vis = image.copy()
        for box in r.boxes:
            name = class_names.get(box.cls_id, str(box.cls_id))
            color = color_for_class(box.cls_id)
            print(
                f"  box cls={box.cls_id}({name}) conf={box.conf:.2f} "
                f"[{box.x1},{box.y1},{box.x2},{box.y2}]"
            )
            cv2.rectangle(vis, (box.x1, box.y1), (box.x2, box.y2), color, 2)
            label = f"{name} {box.conf:.2f}"
            (tw, th), baseline = cv2.getTextSize(
                label, cv2.FONT_HERSHEY_SIMPLEX, 0.5, 1
            )
            top = max(box.y1 - th - baseline, 0)
            cv2.rectangle(
                vis, (box.x1, top), (box.x1 + tw, top + th + baseline), color, -1
            )
            cv2.putText(
                vis, label, (box.x1, top + th),
                cv2.FONT_HERSHEY_SIMPLEX, 0.5, (0, 0, 0), 1, cv2.LINE_AA,
            )

        for x, y in r.keypoints:
            if x == 0 and y == 0:
                continue
            cv2.circle(vis, (x, y), 3, (0, 0, 255), -1)

        out_path = output_dir / f"frame_{r.frame_id:04d}.jpg"
        cv2.imwrite(str(out_path), vis)
        print(f"  saved: {out_path}")


if __name__ == "__main__":
    main()