# Copyright (c) 2018-present, Baidu, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
##############################################################################

"""Utility functions."""

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import math
import distutils.util
import numpy as np
import cv2
from pathlib import Path


def print_arguments(args):
    """Print argparse's arguments.

    Usage:

    .. code-block:: python

        parser = argparse.ArgumentParser()
        parser.add_argument("name", default="Jonh", type=str, help="User name.")
        args = parser.parse_args()
        print_arguments(args)

    :param args: Input argparse.Namespace for printing.
    :type args: argparse.Namespace
    """
    print("-----------  Configuration Arguments -----------")
    for arg, value in sorted(vars(args).iteritems()):
        print("%s: %s" % (arg, value))
    print("------------------------------------------------")


def add_arguments(argname, type, default, help, argparser, **kwargs):
    """Add argparse's argument.

    Usage:

    .. code-block:: python

        parser = argparse.ArgumentParser()
        add_argument("name", str, "Jonh", "User name.", parser)
        args = parser.parse_args()
    """
    type = distutils.util.strtobool if type == bool else type
    argparser.add_argument(
        "--" + argname,
        default=default,
        type=type,
        help=help + ' Default: %(default)s.',
        **kwargs)


def get_max_preds(batch_heatmaps):
    """Get predictions from score maps.
    heatmaps: numpy.ndarray([batch_size, num_joints, height, width])
    """
    assert isinstance(batch_heatmaps, np.ndarray), \
        'batch_heatmaps should be numpy.ndarray'
    assert batch_heatmaps.ndim == 4, 'batch_images should be 4-ndim'

    batch_size = batch_heatmaps.shape[0]
    num_joints = batch_heatmaps.shape[1]
    width = batch_heatmaps.shape[3]
    heatmaps_reshaped = batch_heatmaps.reshape((batch_size, num_joints, -1))
    idx = np.argmax(heatmaps_reshaped, 2)
    maxvals = np.amax(heatmaps_reshaped, 2)

    maxvals = maxvals.reshape((batch_size, num_joints, 1))
    idx = idx.reshape((batch_size, num_joints, 1))

    preds = np.tile(idx, (1, 1, 2)).astype(np.float32)

    preds[:, :, 0] = (preds[:, :, 0]) % width
    preds[:, :, 1] = np.floor((preds[:, :, 1]) / width)

    pred_mask = np.tile(np.greater(maxvals, 0.0), (1, 1, 2))
    pred_mask = pred_mask.astype(np.float32)

    preds *= pred_mask
    return preds, maxvals


def affine_transform(pt, t):
    new_pt = np.array([pt[0], pt[1], 1.]).T
    new_pt = np.dot(t, new_pt)
    return new_pt[:2]


def get_3rd_point(a, b):
    direct = a - b
    return b + np.array([-direct[1], direct[0]], dtype=np.float32)


def get_dir(src_point, rot_rad):
    sn, cs = np.sin(rot_rad), np.cos(rot_rad)

    src_result = [0, 0]
    src_result[0] = src_point[0] * cs - src_point[1] * sn
    src_result[1] = src_point[0] * sn + src_point[1] * cs

    return src_result


def crop(img, center, scale, output_size, rot=0):
    trans = get_affine_transform(center, scale, rot, output_size)

    dst_img = cv2.warpAffine(img,
                             trans,
                             (int(output_size[0]), int(output_size[1])),
                             flags=cv2.INTER_LINEAR)

    return dst_img


def get_affine_transform(center,
                         scale,
                         rot,
                         output_size,
                         shift=np.array([0, 0], dtype=np.float32),
                         inv=0):
    if not isinstance(scale, np.ndarray) and not isinstance(scale, list):
        print(scale)
        scale = np.array([scale, scale])

    scale_tmp = scale * 200.0
    src_w = scale_tmp[0]
    dst_w = output_size[0]
    dst_h = output_size[1]

    rot_rad = np.pi * rot / 180
    src_dir = get_dir([0, src_w * -0.5], rot_rad)
    dst_dir = np.array([0, dst_w * -0.5], np.float32)

    src = np.zeros((3, 2), dtype=np.float32)
    dst = np.zeros((3, 2), dtype=np.float32)
    src[0, :] = center + scale_tmp * shift
    src[1, :] = center + src_dir + scale_tmp * shift
    dst[0, :] = [dst_w * 0.5, dst_h * 0.5]
    dst[1, :] = np.array([dst_w * 0.5, dst_h * 0.5]) + dst_dir

    src[2:, :] = get_3rd_point(src[0, :], src[1, :])
    dst[2:, :] = get_3rd_point(dst[0, :], dst[1, :])

    if inv:
        trans = cv2.getAffineTransform(np.float32(dst), np.float32(src))
    else:
        trans = cv2.getAffineTransform(np.float32(src), np.float32(dst))

    return trans


def transform_preds(coords, center, scale, output_size):
    target_coords = np.zeros(coords.shape)
    trans = get_affine_transform(center, scale, 0, output_size, inv=1)
    for p in range(coords.shape[0]):
        target_coords[p, 0:2] = affine_transform(coords[p, 0:2], trans)
    return target_coords


def get_final_preds(args, batch_heatmaps, center, scale):
    coords, maxvals = get_max_preds(batch_heatmaps)

    heatmap_height = batch_heatmaps.shape[2]
    heatmap_width = batch_heatmaps.shape[3]

    # Post-processing
    if args.post_process:
        for n in range(coords.shape[0]):
            for p in range(coords.shape[1]):
                hm = batch_heatmaps[n][p]
                px = int(math.floor(coords[n][p][0] + 0.5))
                py = int(math.floor(coords[n][p][1] + 0.5))
                if 1 < px < heatmap_width-1 and 1 < py < heatmap_height-1:
                    diff = np.array([hm[py][px+1] - hm[py][px-1],
                                     hm[py+1][px]-hm[py-1][px]])
                    coords[n][p] += np.sign(diff) * .25

    preds = coords.copy()

    # Transform back
    for i in range(coords.shape[0]):
        preds[i] = transform_preds(coords[i], center[i], scale[i],
                                   [heatmap_width, heatmap_height])
    return preds, maxvals


def calc_dists(preds, target, normalize):
    preds = preds.astype(np.float32)
    target = target.astype(np.float32)
    dists = np.zeros((preds.shape[1], preds.shape[0]))
    for n in range(preds.shape[0]):
        for c in range(preds.shape[1]):
            if target[n, c, 0] > 1 and target[n, c, 1] > 1:
                normed_preds = preds[n, c, :] / normalize[n]
                normed_targets = target[n, c, :] / normalize[n]
                dists[c, n] = np.linalg.norm(normed_preds - normed_targets)
            else:
                dists[c, n] = -1
    return dists


def dist_acc(dists, thr=0.5):
    """Return percentage below threshold while ignoring values with a -1.
    """
    dist_cal = np.not_equal(dists, -1)
    num_dist_cal = dist_cal.sum()
    if num_dist_cal > 0:
        return np.less(dists[dist_cal], thr).sum() * 1.0 / num_dist_cal
    else:
        return -1


def accuracy(output, target, hm_type='gaussian', thr=0.5):
    """
    Calculate accuracy according to PCK,
    but uses ground truth heatmap rather than x,y locations
    First value to be returned is average accuracy across 'idxs',
    followed by individual accuracies
    """
    idx = list(range(output.shape[1]))
    norm = 1.0
    if hm_type == 'gaussian':
        pred, _ = get_max_preds(output)
        target, _ = get_max_preds(target)
        h = output.shape[2]
        w = output.shape[3]
        norm = np.ones((pred.shape[0], 2)) * np.array([h, w]) / 10
    dists = calc_dists(pred, target, norm)

    acc = np.zeros((len(idx) + 1))
    avg_acc = 0
    cnt = 0

    for i in range(len(idx)):
        acc[i + 1] = dist_acc(dists[idx[i]])
        if acc[i + 1] >= 0:
            avg_acc = avg_acc + acc[i + 1]
            cnt += 1

    avg_acc = avg_acc / cnt if cnt != 0 else 0
    if cnt != 0:
        acc[0] = avg_acc
    return acc, avg_acc, cnt, pred


def save_batch_heatmaps(batch_image, batch_heatmaps, file_name, normalize=True):
    """
    :param batch_image: [batch_size, channel, height, width]
    :param batch_heatmaps: ['batch_size, num_joints, height, width]
    :param file_name: saved file name
    """
    if normalize:
        min = np.array(batch_image.min(), dtype=np.float)
        max = np.array(batch_image.max(), dtype=np.float)

        batch_image = np.add(batch_image, -min)
        batch_image = np.divide(batch_image, max - min + 1e-5)

    batch_size, num_joints, \
            heatmap_height, heatmap_width = batch_heatmaps.shape

    grid_image = np.zeros((batch_size*heatmap_height,
                           (num_joints+1)*heatmap_width,
                           3),
                          dtype=np.uint8)

    preds, maxvals = get_max_preds(batch_heatmaps)

    for i in range(batch_size):
        image = batch_image[i] * 255
        image = image.clip(0, 255).astype(np.uint8)
        image = image.transpose(1, 2, 0)

        heatmaps = batch_heatmaps[i] * 255
        heatmaps = heatmaps.clip(0, 255).astype(np.uint8)

        resized_image = cv2.resize(image,
                                   (int(heatmap_width), int(heatmap_height)))
        height_begin = heatmap_height * i
        height_end = heatmap_height * (i + 1)
        for j in range(num_joints):
            cv2.circle(resized_image,
                       (int(preds[i][j][0]), int(preds[i][j][1])),
                       1, [0, 0, 255], 1)
            heatmap = heatmaps[j, :, :]
            colored_heatmap = cv2.applyColorMap(heatmap, cv2.COLORMAP_JET)
            masked_image = colored_heatmap*0.7 + resized_image*0.3
            cv2.circle(masked_image,
                       (int(preds[i][j][0]), int(preds[i][j][1])),
                       1, [0, 0, 255], 1)

            width_begin = heatmap_width * (j+1)
            width_end = heatmap_width * (j+2)
            grid_image[height_begin:height_end, width_begin:width_end, :] = \
                masked_image
        grid_image[height_begin:height_end, 0:heatmap_width, :] = resized_image

    cv2.imwrite(file_name, grid_image)


def save_predict_results(batch_image, batch_heatmaps, file_ids, fold_name, normalize=True):
    """
    :param batch_image: [batch_size, channel, height, width]
    :param batch_heatmaps: ['batch_size, num_joints, height, width]
    :param fold_name: saved files in this folder
    """
    save_dir = Path('./{}'.format(fold_name))
    try:
        save_dir.mkdir()
    except OSError:
        pass

    if normalize:
        min = np.array(batch_image.min(), dtype=np.float)
        max = np.array(batch_image.max(), dtype=np.float)

        batch_image = np.add(batch_image, -min)
        batch_image = np.divide(batch_image, max - min + 1e-5)

    batch_size, num_joints, \
            heatmap_height, heatmap_width = batch_heatmaps.shape

    # (32, 16, 2), (32, 16, 1))
    preds, maxvals = get_max_preds(batch_heatmaps)

    # Blue
    icolor = (255, 137, 0)
    ocolor = (138, 255, 0)

    for i in range(batch_size):
        image = batch_image[i] * 255
        image = image.clip(0, 255).astype(np.uint8)
        image = image.transpose(1, 2, 0)
        image = cv2.resize(image, (384, 384))

        file_id = file_ids[i]
        imgname = save_dir.joinpath('rendered_{}.png'.format(str(file_id).zfill(7)))

        for j in range(num_joints):
            x, y = preds[i][j]
            cv2.circle(image, (int(x * 4), int(y * 4)), 3, icolor, -1, 16)
            cv2.circle(image, (int(x * 4), int(y * 4)), 6, ocolor,  1, 16)

        cv2.imwrite(str(imgname), image)

# Clean format output
def print_name_value(name_value, full_arch_name):
    names = name_value.keys()
    values = name_value.values()
    num_values = len(name_value)

    results = []
    for value in values:
        results.append('| {:.3f}'.format(value))

    print(
        '| Arch ' +
        ' '.join(['| {}'.format(name) for name in names]) +
        ' |'
    )
    print('|---' * (num_values+1) + '|')
    print('| ' + 'SIMPLEBASE RESNET50 ' + ' '.join(results) + ' |')


class AverageMeter(object):
    """Computes and stores the average and current value.
    """
    def __init__(self):
        self.reset()

    def reset(self):
        self.val = 0
        self.avg = 0
        self.sum = 0
        self.count = 0

    def update(self, val, n=1):
        self.val = val
        self.sum += val * n
        self.count += n
        self.avg = self.sum / self.count if self.count != 0 else 0
