"""Simple interface for GeoCalib model."""

from pathlib import Path
from typing import Dict, Optional

import torch
import torch.nn as nn
from torch.nn.functional import interpolate

from siclib.geometry.base_camera import BaseCamera
from siclib.models.networks.geocalib import GeoCalib as Model
from siclib.utils.image import ImagePreprocessor, load_image


class GeoCalib(nn.Module):
    """Simple interface for GeoCalib model."""

    def __init__(self, weights: str = "pinhole"):
        """Initialize the model with optional config overrides.

        Args:
            weights (str, optional): Weights to load. Defaults to "pinhole".
        """
        super().__init__()
        if weights not in {"pinhole", "distorted"}:
            raise ValueError(f"Unknown weights: {weights}")
        url = f"https://github.com/cvg/GeoCalib/releases/download/v1.0/geocalib-{weights}.tar"

        # load checkpoint
        model_dir = f"{torch.hub.get_dir()}/geocalib"
        state_dict = torch.hub.load_state_dict_from_url(
            url, model_dir, map_location="cpu", file_name=f"{weights}.tar"
        )

        self.model = Model({})
        self.model.flexible_load(state_dict["model"])
        self.model.eval()

        self.image_processor = ImagePreprocessor({"resize": 320, "edge_divisible_by": 32})

    def load_image(self, path: Path) -> torch.Tensor:
        """Load image from path."""
        return load_image(path)

    def _post_process(
        self, camera: BaseCamera, img_data: dict[str, torch.Tensor], out: dict[str, torch.Tensor]
    ) -> tuple[BaseCamera, dict[str, torch.Tensor]]:
        """Post-process model output by undoing scaling and cropping."""
        camera = camera.undo_scale_crop(img_data)

        w, h = camera.size.unbind(-1)
        h = h[0].round().int().item()
        w = w[0].round().int().item()

        for k in ["latitude_field", "up_field"]:
            out[k] = interpolate(out[k], size=(h, w), mode="bilinear")
        for k in ["up_confidence", "latitude_confidence"]:
            out[k] = interpolate(out[k][:, None], size=(h, w), mode="bilinear")[:, 0]

        inverse_scales = 1.0 / img_data["scales"]
        zero = camera.new_zeros(camera.f.shape[0])
        out["focal_uncertainty"] = out.get("focal_uncertainty", zero) * inverse_scales[1]
        return camera, out

    @torch.no_grad()
    def calibrate(
        self,
        img: torch.Tensor,
        camera_model: str = "pinhole",
        priors: Optional[Dict[str, torch.Tensor]] = None,
        shared_intrinsics: bool = False,
    ) -> Dict[str, torch.Tensor]:
        """Perform calibration with online resizing.

        Assumes input image is in range [0, 1] and in RGB format.

        Args:
            img (torch.Tensor): Input image, shape (C, H, W) or (1, C, H, W)
            camera_model (str, optional): Camera model. Defaults to "pinhole".
            priors (Dict[str, torch.Tensor], optional): Prior parameters. Defaults to {}.
            shared_intrinsics (bool, optional): Whether to share intrinsics. Defaults to False.

        Returns:
            Dict[str, torch.Tensor]: camera and gravity vectors and uncertainties.
        """
        if len(img.shape) == 3:
            img = img[None]  # add batch dim
        if not shared_intrinsics:
            assert len(img.shape) == 4 and img.shape[0] == 1

        img_data = self.image_processor(img)

        if priors is None:
            priors = {}

        prior_values = {}
        if prior_focal := priors.get("focal"):
            prior_focal = prior_focal[None] if len(prior_focal.shape) == 0 else prior_focal
            prior_values["prior_focal"] = prior_focal * img_data["scales"][1]

        if "gravity" in priors:
            prior_gravity = priors["gravity"]
            prior_gravity = prior_gravity[None] if len(prior_gravity.shape) == 0 else prior_gravity
            prior_values["prior_gravity"] = prior_gravity

        self.model.optimizer.set_camera_model(camera_model)
        self.model.optimizer.shared_intrinsics = shared_intrinsics

        out = self.model(img_data | prior_values)

        camera, gravity = out["camera"], out["gravity"]
        camera, out = self._post_process(camera, img_data, out)

        return {
            "camera": camera,
            "gravity": gravity,
            "covariance": out["covariance"],
            **{k: out[k] for k in out.keys() if "field" in k},
            **{k: out[k] for k in out.keys() if "confidence" in k},
            **{k: out[k] for k in out.keys() if "uncertainty" in k},
        }