import os
import numpy as np
import pandas as pd
import matplotlib.pylab as plt

PATH_IMAGE_REF = 'Rat_Kidney_HE.jpg'
PATH_IMAGE_MOVE = 'Rat_Kidney_PanCytokeratin.jpg'
PATH_IMAGE_WARP = 'Rat_Kidney_PanCytokeratin_warped.jpg'
PATH_POINTS_MOVE = 'Rat_Kidney_PanCytokeratin.csv'
PATH_POINTS_WARP = 'Rat_Kidney_PanCytokeratin_warp.csv'
PATH_TRANSFORM = 'transform_raw.txt'

def save_landmarks_csv(path_file, landmarks):
    """ save landmarks into a csv file

    :param str path_file: path to the output file
    :param landmarks: np.array<np_points, dim>
    """
    df = pd.DataFrame(landmarks, columns=['X', 'Y'])
    df.to_csv(path_file)


def load_landmarks_csv(path_file):
    """ load file with landmarks in cdv format

    :param str path_file: path to the input file
    :return: np.array<np_points, dim>
    """
    assert os.path.exists(path_file)
    df = pd.DataFrame.from_csv(path_file)
    points = df[['X', 'Y']].values
    return points


def load_parse_bunwarpj_displacement_axis(fp, size, points):
    """ given pointer in the file aiming to the beginning of displacement
     parse all lines and if in the particular line is a point from list
     get its new position

    :param fp: file pointer
    :param (int, int) size: width, height of the image
    :param points: np.array<nb_points, 2>
    :return list: list of new positions on given axis (x/y) for related points
    """
    width, height = size
    points = np.round(points)
    selected_lines = points[:, 1].tolist()
    pos_new = [0] * len(points)

    # walk thor all lined of this displacement field
    for i in range(height):
        line = fp.readline()
        # if the any point is listed in this line
        if i in selected_lines :
            pos = line.rstrip().split()
            # pos = [float(e) for e in pos if len(e)>0]
            assert len(pos) == width
            # find all points in this line
            for j, point in enumerate(points):
                if point[1] == i:
                    pos_new[j] = float(pos[point[0]])
    return pos_new


def load_parse_bunwarpj(path_file, points):
    """ load and parse displacement field for both X and Y coordinated
    and return new position of selected points

    :param str path_file:
    :param points: np.array<nb_points, 2>
    :return: np.array<nb_points, 2>
    """
    fp = open(path_file, "r")
    width = int(fp.readline().split('=')[1])
    height = int(fp.readline().split('=')[1])
    size = (width, height)
    assert all(np.max(points, axis=0) <= size)

    fp.readline(), fp.readline()
    # read X Trans
    points_x = load_parse_bunwarpj_displacement_axis(fp, size, points)

    fp.readline(), fp.readline()
    # read Y Trans
    points_y = load_parse_bunwarpj_displacement_axis (fp, size, points)
    fp.close()

    points_new = np.array(zip(points_x, points_y))
    return points_new

if __name__ == '__main__':
    img_ref = plt.imread(PATH_IMAGE_REF)
    img_move = plt.imread(PATH_IMAGE_MOVE)
    img_warp = plt.imread(PATH_IMAGE_WARP)
    points_move = load_landmarks_csv(PATH_POINTS_MOVE)
    points_warp = load_parse_bunwarpj(PATH_TRANSFORM, points_move)
    save_landmarks_csv(PATH_POINTS_WARP, points_warp)

    plt.figure()
    plt.imshow(img_ref, alpha=0.5)
    plt.imshow(img_warp, alpha=0.5)

    plt.figure()
    plt.imshow(img_move)
    plt.plot(points_move[:, 0], points_move[:, 1], 'go')

    plt.figure()
    plt.imshow(img_warp)
    plt.plot(points_warp[:, 0], points_warp[:, 1], 'go')

    plt.show()


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