import logging

import numpy as np
import trimesh

from src.common import compute_iou
# from scipy.spatial import cKDTree
from src.utils.libkdtree import KDTree
from src.utils.libmesh import check_mesh_contains

# Maximum values for bounding box [-0.5, 0.5]^3
EMPTY_PCL_DICT = {
    'completeness': np.sqrt(3),
    'accuracy': np.sqrt(3),
    'completeness2': 3,
    'accuracy2': 3,
    'chamfer': 6,
}

EMPTY_PCL_DICT_NORMALS = {
    'normals completeness': -1.,
    'normals accuracy': -1.,
    'normals': -1.,
}

logger = logging.getLogger(__name__)


class MeshEvaluator(object):
    """ Mesh evaluation class.

    It handles the mesh evaluation process.

    Args:
        n_points (int): number of points to be used for evaluation
    """

    def __init__(self, n_points=100000):
        self.n_points = n_points

    def eval_mesh(self,
                  mesh,
                  pointcloud_tgt,
                  normals_tgt,
                  points_iou,
                  occ_tgt,
                  remove_wall=False):
        """ Evaluates a mesh.

        Args:
            mesh (trimesh): mesh which should be evaluated
            pointcloud_tgt (numpy array): target point cloud
            normals_tgt (numpy array): target normals
            points_iou (numpy_array): points tensor for IoU evaluation
            occ_tgt (numpy_array): GT occupancy values for IoU points
        """
        if len(mesh.vertices) != 0 and len(mesh.faces) != 0:
            if remove_wall:  # ! Remove walls and floors
                pointcloud, idx = mesh.sample(2 * self.n_points, return_index=True)
                eps = 0.007
                x_max, x_min = pointcloud_tgt[:, 0].max(), pointcloud_tgt[:, 0].min()
                y_max, y_min = pointcloud_tgt[:, 1].max(), pointcloud_tgt[:, 1].min()
                z_max, z_min = pointcloud_tgt[:, 2].max(), pointcloud_tgt[:, 2].min()

                # add small offsets
                x_max, x_min = x_max + eps, x_min - eps
                y_max, y_min = y_max + eps, y_min - eps
                z_max, z_min = z_max + eps, z_min - eps

                mask_x = (pointcloud[:, 0] <= x_max) & (pointcloud[:, 0] >= x_min)
                mask_y = (pointcloud[:, 1] >= y_min)  # floor
                mask_z = (pointcloud[:, 2] <= z_max) & (pointcloud[:, 2] >= z_min)

                mask = mask_x & mask_y & mask_z
                pointcloud_new = pointcloud[mask]
                # Subsample 
                idx_new = np.random.randint(pointcloud_new.shape[0], size=self.n_points)
                pointcloud = pointcloud_new[idx_new]
                idx = idx[mask][idx_new]
            else:
                pointcloud, idx = mesh.sample(self.n_points, return_index=True)

            pointcloud = pointcloud.astype(np.float32)
            normals = mesh.face_normals[idx]
        else:
            pointcloud = np.empty((0, 3))
            normals = np.empty((0, 3))

        out_dict = self.eval_pointcloud(pointcloud, pointcloud_tgt, normals, normals_tgt)

        if len(mesh.vertices) != 0 and len(mesh.faces) != 0:
            occ = check_mesh_contains(mesh, points_iou)

            if occ_tgt.min() < 0:
                occ_tgt = (occ_tgt <= 0).astype(np.float32)

            out_dict['iou'] = compute_iou(occ, occ_tgt)
        else:
            out_dict['iou'] = 0.

        return out_dict

    @staticmethod
    def eval_pointcloud(pointcloud,
                        pointcloud_tgt,
                        normals=None,
                        normals_tgt=None,
                        thresholds=np.linspace(1. / 1000, 1, 1000)):
        """ Evaluates a point cloud.

        Args:
            pointcloud (numpy array): predicted point cloud
            pointcloud_tgt (numpy array): target point cloud
            normals (numpy array): predicted normals
            normals_tgt (numpy array): target normals
            thresholds (numpy array): threshold values for the F-score calculation
        """
        # Return maximum losses if pointcloud is empty
        if pointcloud.shape[0] == 0:
            logger.warning('Empty pointcloud / mesh detected!')
            out_dict = EMPTY_PCL_DICT.copy()
            if normals is not None and normals_tgt is not None:
                out_dict.update(EMPTY_PCL_DICT_NORMALS)
            return out_dict

        pointcloud = np.asarray(pointcloud)
        pointcloud_tgt = np.asarray(pointcloud_tgt)

        # Completeness: how far are the points of the target point cloud from the predicted point cloud
        completeness, completeness_normals = distance_p2p(pointcloud_tgt, normals_tgt, pointcloud, normals)
        recall = get_threshold_percentage(completeness, thresholds)
        completeness2 = completeness ** 2

        completeness = completeness.mean()
        completeness2 = completeness2.mean()
        completeness_normals = completeness_normals.mean()

        # Accuracy: how far are the points of the predicted pointcloud from the target pointcloud
        accuracy, accuracy_normals = distance_p2p(pointcloud, normals, pointcloud_tgt, normals_tgt)
        precision = get_threshold_percentage(accuracy, thresholds)
        accuracy2 = accuracy ** 2

        accuracy = accuracy.mean()
        accuracy2 = accuracy2.mean()
        accuracy_normals = accuracy_normals.mean()

        # Chamfer distance
        chamferL2 = 0.5 * (completeness2 + accuracy2)
        normals_correctness = (0.5 * completeness_normals + 0.5 * accuracy_normals)
        chamferL1 = 0.5 * (completeness + accuracy)

        # F-Score
        F = [2 * precision[i] * recall[i] / (precision[i] + recall[i]) for i in range(len(precision))]

        out_dict = {
            'completeness': completeness,
            'accuracy': accuracy,
            'normals completeness': completeness_normals,
            'normals accuracy': accuracy_normals,
            'normals': normals_correctness,
            'completeness2': completeness2,
            'accuracy2': accuracy2,
            'chamfer-L2': chamferL2,
            'chamfer-L1': chamferL1,
            'f-score': F[9],  # threshold = 1.0%
            'f-score-15': F[14],  # threshold = 1.5%
            'f-score-20': F[19],  # threshold = 2.0%
        }

        return out_dict


def distance_p2p(points_src, normals_src, points_tgt, normals_tgt):
    """ Computes minimal distances of each point in points_src to points_tgt.

    Args:
        points_src (numpy array): source points
        normals_src (numpy array): source normals
        points_tgt (numpy array): target points
        normals_tgt (numpy array): target normals
    """
    kdtree = KDTree(points_tgt)
    dist, idx = kdtree.query(points_src)

    if normals_src is not None and normals_tgt is not None:
        normals_src = normals_src / np.linalg.norm(normals_src, axis=-1, keepdims=True)
        normals_tgt = normals_tgt / np.linalg.norm(normals_tgt, axis=-1, keepdims=True)

        normals_dot_product = (normals_tgt[idx] * normals_src).sum(axis=-1)
        # Handle normals that point into wrong direction gracefully (mostly due to method not caring about this in generation)
        normals_dot_product = np.abs(normals_dot_product)
    else:
        normals_dot_product = np.array([np.nan] * points_src.shape[0], dtype=np.float32)
    return dist, normals_dot_product


def distance_p2m(points, mesh):
    """ Compute minimal distances of each point in points to mesh.

    Args:
        points (numpy array): points array
        mesh (trimesh): mesh

    """
    _, dist, _ = trimesh.proximity.closest_point(mesh, points)
    return dist


def get_threshold_percentage(dist, thresholds):
    """ Evaluates a point cloud.

    Args:
        dist (numpy array): calculated distance
        thresholds (numpy array): threshold values for the F-score calculation
    """
    in_threshold = [(dist <= t).mean() for t in thresholds]
    return in_threshold
