# Copyright 2020,2021 Sony Corporation.
# Copyright 2021 Sony Group Corporation.
#
# 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.


'''
This module contains some common routines used by other samples.
'''

# Python 2/3 compatibility
from __future__ import print_function
import sys
PY3 = sys.version_info[0] == 3

if PY3:
    from functools import reduce

import numpy as np
import cv2 as cv

# built-in modules
import os
import itertools as it
from contextlib import contextmanager

image_extensions = ['.bmp', '.jpg', '.jpeg',
                    '.png', '.tif', '.tiff', '.pbm', '.pgm', '.ppm']


class Bunch(object):
    def __init__(self, **kw):
        self.__dict__.update(kw)

    def __str__(self):
        return str(self.__dict__)


def splitfn(fn):
    path, fn = os.path.split(fn)
    name, ext = os.path.splitext(fn)
    return path, name, ext


def anorm2(a):
    return (a*a).sum(-1)


def anorm(a):
    return np.sqrt(anorm2(a))


def homotrans(H, x, y):
    xs = H[0, 0]*x + H[0, 1]*y + H[0, 2]
    ys = H[1, 0]*x + H[1, 1]*y + H[1, 2]
    s = H[2, 0]*x + H[2, 1]*y + H[2, 2]
    return xs/s, ys/s


def to_rect(a):
    a = np.ravel(a)
    if len(a) == 2:
        a = (0, 0, a[0], a[1])
    return np.array(a, np.float64).reshape(2, 2)


def METHOD_NAME(src, dst):
    src, dst = to_rect(src), to_rect(dst)
    cx, cy = (dst[1] - dst[0]) / (src[1] - src[0])
    tx, ty = dst[0] - src[0] * (cx, cy)
    M = np.float64([[cx, 0, tx],
                    [0, cy, ty],
                    [0, 0, 1]])
    return M


def lookat(eye, target, up=(0, 0, 1)):
    fwd = np.asarray(target, np.float64) - eye
    fwd /= anorm(fwd)
    right = np.cross(fwd, up)
    right /= anorm(right)
    down = np.cross(fwd, right)
    R = np.float64([right, down, fwd])
    tvec = -np.dot(R, eye)
    return R, tvec


def mtx2rvec(R):
    w, u, vt = cv.SVDecomp(R - np.eye(3))
    p = vt[0] + u[:, 0]*w[0]    # same as np.dot(R, vt[0])
    c = np.dot(vt[0], p)
    s = np.dot(vt[1], p)
    axis = np.cross(vt[0], vt[1])
    return axis * np.arctan2(s, c)


def draw_str(dst, target, s):
    x, y = target
    cv.putText(dst, s, (x+1, y+1), cv.FONT_HERSHEY_PLAIN, 1.0,
               (0, 0, 0), thickness=2, lineType=cv.LINE_AA)
    cv.putText(dst, s, (x, y), cv.FONT_HERSHEY_PLAIN,
               1.0, (255, 255, 255), lineType=cv.LINE_AA)


class Sketcher:
    def __init__(self, windowname, dests, colors_func):
        self.prev_pt = None
        self.windowname = windowname
        self.dests = dests
        self.colors_func = colors_func
        self.dirty = False
        self.show()
        cv.setMouseCallback(self.windowname, self.on_mouse)

    def show(self):
        cv.imshow(self.windowname, self.dests[0])

    def on_mouse(self, event, x, y, flags, param):
        pt = (x, y)
        if event == cv.EVENT_LBUTTONDOWN:
            self.prev_pt = pt
        elif event == cv.EVENT_LBUTTONUP:
            self.prev_pt = None

        if self.prev_pt and flags & cv.EVENT_FLAG_LBUTTON:
            for dst, color in zip(self.dests, self.colors_func()):
                cv.line(dst, self.prev_pt, pt, color, 5)
            self.dirty = True
            self.prev_pt = pt
            self.show()


# palette data from matplotlib/_cm.py
_jet_data = {'red': ((0., 0, 0), (0.35, 0, 0), (0.66, 1, 1), (0.89, 1, 1),
                     (1, 0.5, 0.5)),
             'green': ((0., 0, 0), (0.125, 0, 0), (0.375, 1, 1), (0.64, 1, 1),
                       (0.91, 0, 0), (1, 0, 0)),
             'blue': ((0., 0.5, 0.5), (0.11, 1, 1), (0.34, 1, 1), (0.65, 0, 0),
                      (1, 0, 0))}

cmap_data = {'jet': _jet_data}


def make_cmap(name, n=256):
    data = cmap_data[name]
    xs = np.linspace(0.0, 1.0, n)
    channels = []
    eps = 1e-6
    for ch_name in ['blue', 'green', 'red']:
        ch_data = data[ch_name]
        xp, yp = [], []
        for x, y1, y2 in ch_data:
            xp += [x, x+eps]
            yp += [y1, y2]
        ch = np.interp(xs, xp, yp)
        channels.append(ch)
    return np.uint8(np.array(channels).T*255)


def nothing(*arg, **kw):
    pass


def clock():
    return cv.getTickCount() / cv.getTickFrequency()


@contextmanager
def Timer(msg):
    print(msg, '...',)
    start = clock()
    try:
        yield
    finally:
        print("%.2f ms" % ((clock()-start)*1000))


class StatValue:
    def __init__(self, smooth_coef=0.5):
        self.value = None
        self.smooth_coef = smooth_coef

    def update(self, v):
        if self.value is None:
            self.value = v
        else:
            c = self.smooth_coef
            self.value = c * self.value + (1.0-c) * v


class RectSelector:
    def __init__(self, win, callback):
        self.win = win
        self.callback = callback
        cv.setMouseCallback(win, self.onmouse)
        self.drag_start = None
        self.drag_rect = None

    def onmouse(self, event, x, y, flags, param):
        x, y = np.int16([x, y])  # BUG
        if event == cv.EVENT_LBUTTONDOWN:
            self.drag_start = (x, y)
            return
        if self.drag_start:
            if flags & cv.EVENT_FLAG_LBUTTON:
                xo, yo = self.drag_start
                x0, y0 = np.minimum([xo, yo], [x, y])
                x1, y1 = np.maximum([xo, yo], [x, y])
                self.drag_rect = None
                if x1-x0 > 0 and y1-y0 > 0:
                    self.drag_rect = (x0, y0, x1, y1)
            else:
                rect = self.drag_rect
                self.drag_start = None
                self.drag_rect = None
                if rect:
                    self.callback(rect)

    def draw(self, vis):
        if not self.drag_rect:
            return False
        x0, y0, x1, y1 = self.drag_rect
        cv.rectangle(vis, (x0, y0), (x1, y1), (0, 255, 0), 2)
        return True

    @property
    def dragging(self):
        return self.drag_rect is not None


def grouper(n, iterable, fillvalue=None):
    '''grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx'''
    args = [iter(iterable)] * n
    if PY3:
        output = it.zip_longest(fillvalue=fillvalue, *args)
    else:
        output = it.izip_longest(fillvalue=fillvalue, *args)
    return output


def mosaic(w, imgs):
    '''Make a grid from images.

    w    -- number of grid columns
    imgs -- images (must have same size and format)
    '''
    imgs = iter(imgs)
    if PY3:
        img0 = next(imgs)
    else:
        img0 = imgs.next()
    pad = np.zeros_like(img0)
    imgs = it.chain([img0], imgs)
    rows = grouper(w, imgs, pad)
    return np.vstack(map(np.hstack, rows))


def getsize(img):
    h, w = img.shape[:2]
    return w, h


def mdot(*args):
    return reduce(np.dot, args)


def draw_keypoints(vis, keypoints, color=(0, 255, 255)):
    for kp in keypoints:
        x, y = kp.pt
        cv.circle(vis, (int(x), int(y)), 2, color)