import colorsys
import imghdr
import os
import random
from keras import backend as K
import numpy as np
from PIL import Image, ImageDraw, ImageFont

def read_classes(classes_path):
    with open(classes_path) as f:
        class_names = f.readlines()
    class_names = [c.strip() for c in class_names]
    return class_names

def read_anchors(anchors_path):
    with open(anchors_path) as f:
        anchors = f.readline()
        anchors = [float(x) for x in anchors.split(',')]
        anchors = np.array(anchors).reshape(-1, 2)
    return anchors

def generate_colors(class_names):
    hsv_tuples = [(x / len(class_names), 1., 1.) for x in range(len(class_names))]
    colors = list(map(lambda x: colorsys.hsv_to_rgb(*x), hsv_tuples))
    colors = list(map(lambda x: (int(x[0] * 255), int(x[1] * 255), int(x[2] * 255)), colors))
    random.seed(10101)  # Fixed seed for consistent colors across runs.
    random.shuffle(colors)  # Shuffle colors to decorrelate adjacent classes.
    random.seed(None)  # Reset seed to default.
    return colors

def scale_boxes(boxes, image_shape):
    """ Scales the predicted boxes in order to be drawable on the image"""
    height = image_shape[0]
    width = image_shape[1]
    image_dims = K.stack([height, width, height, width])
    image_dims = K.reshape(image_dims, [1, 4])
    boxes = boxes * image_dims
    return boxes

def preprocess_image(image, model_image_size):
    # image = Image.open(img_path)
    resized_image = image.resize(tuple(reversed(model_image_size)), Image.BICUBIC)
    image_data = np.array(resized_image, dtype='float32')
    image_data /= 255.
    image_data = np.expand_dims(image_data, 0)  # Add batch dimension.
    return image, image_data


def draw_boxes(image, out_scores, out_boxes, out_classes, class_names, colors, printlabel):
    
    font = ImageFont.truetype(font='font/FiraMono-Medium.otf',size=np.floor(3e-2 * image.size[1] + 0.5).astype('int32'))
    thickness = (image.size[0] + image.size[1]) // 300

    for i, c in reversed(list(enumerate(out_classes))):
        predicted_class = class_names[c]
        box = out_boxes[i]
        score = out_scores[i]

        label = '{} {:.2f}'.format(predicted_class, score)

        draw = ImageDraw.Draw(image)
        label_size = draw.textsize(label, font)

        top, left, bottom, right = box
        top = max(0, np.floor(top + 0.5).astype('int32'))
        left = max(0, np.floor(left + 0.5).astype('int32'))
        bottom = min(image.size[1], np.floor(bottom + 0.5).astype('int32'))
        right = min(image.size[0], np.floor(right + 0.5).astype('int32'))
        if printlabel == True:
            print(label, (left, top), (right, bottom))

        if top - label_size[1] >= 0:
            text_origin = np.array([left, top - label_size[1]])
        else:
            text_origin = np.array([left, top + 1])

        # My kingdom for a good redistributable image drawing library.
        for i in range(thickness):
            draw.rectangle([left + i, top + i, right - i, bottom - i], outline=colors[c])
        draw.rectangle([tuple(text_origin), tuple(text_origin + label_size)], fill=colors[c])
        draw.text(text_origin, label, fill=(0, 0, 0), font=font)
        del draw

def yolo_boxes_to_corners(box_xy, box_wh):
    """Convert YOLO box predictions to bounding box corners."""
    box_mins = box_xy - (box_wh / 2.)
    box_maxes = box_xy + (box_wh / 2.)

    return K.concatenate([
        box_mins[..., 1:2],  # y_min
        box_mins[..., 0:1],  # x_min
        box_maxes[..., 1:2],  # y_max
        box_maxes[..., 0:1]  # x_max
    ])

def yolo_head(feats, anchors, num_classes):
    """Convert final layer features to bounding box parameters.

    Parameters
    ----------
    feats : tensor
        Final convolutional layer features.
    anchors : array-like
        Anchor box widths and heights.
    num_classes : int
        Number of target classes.

    Returns
    -------
    box_xy : tensor
        x, y box predictions adjusted by spatial location in conv layer.
    box_wh : tensor
        w, h box predictions adjusted by anchors and conv spatial resolution.
    box_conf : tensor
        Probability estimate for whether each box contains any object.
    box_class_pred : tensor
        Probability distribution estimate for each box over class labels.
    """
    num_anchors = len(anchors)
    # Reshape to batch, height, width, num_anchors, box_params.
    anchors_tensor = K.reshape(K.variable(anchors), [1, 1, 1, num_anchors, 2])

    # Static implementation for fixed models.
    # TODO: Remove or add option for static implementation.
    # _, conv_height, conv_width, _ = K.int_shape(feats)
    # conv_dims = K.variable([conv_width, conv_height])

    # Dynamic implementation of conv dims for fully convolutional model.
    conv_dims = K.shape(feats)[1:3]  # assuming channels last
    # In YOLO the height index is the inner most iteration.
    conv_height_index = K.arange(0, stop=conv_dims[0])
    conv_width_index = K.arange(0, stop=conv_dims[1])
    conv_height_index = K.tile(conv_height_index, [conv_dims[1]])

    # TODO: Repeat_elements and tf.split doesn't support dynamic splits.
    # conv_width_index = K.repeat_elements(conv_width_index, conv_dims[1], axis=0)
    conv_width_index = K.tile(
        K.expand_dims(conv_width_index, 0), [conv_dims[0], 1])
    conv_width_index = K.flatten(K.transpose(conv_width_index))
    conv_index = K.transpose(K.stack([conv_height_index, conv_width_index]))
    conv_index = K.reshape(conv_index, [1, conv_dims[0], conv_dims[1], 1, 2])
    conv_index = K.cast(conv_index, K.dtype(feats))

    feats = K.reshape(
        feats, [-1, conv_dims[0], conv_dims[1], num_anchors, num_classes + 5])
    conv_dims = K.cast(K.reshape(conv_dims, [1, 1, 1, 1, 2]), K.dtype(feats))

    # Static generation of conv_index:
    # conv_index = np.array([_ for _ in np.ndindex(conv_width, conv_height)])
    # conv_index = conv_index[:, [1, 0]]  # swap columns for YOLO ordering.
    # conv_index = K.variable(
    #     conv_index.reshape(1, conv_height, conv_width, 1, 2))
    # feats = Reshape(
    #     (conv_dims[0], conv_dims[1], num_anchors, num_classes + 5))(feats)

    box_xy = K.sigmoid(feats[..., :2])
    box_wh = K.exp(feats[..., 2:4])
    box_confidence = K.sigmoid(feats[..., 4:5])
    box_class_probs = K.softmax(feats[..., 5:])

    # Adjust preditions to each spatial grid point and anchor size.
    # Note: YOLO iterates over height index before width index.
    box_xy = (box_xy + conv_index) / conv_dims
    box_wh = box_wh * anchors_tensor / conv_dims

    return box_xy, box_wh, box_confidence, box_class_probs

def get_colors_for_classes(num_classes):
    """Return list of random colors for number of classes given."""
    # Use previously generated colors if num_classes is the same.
    if (hasattr(get_colors_for_classes, "colors") and
            len(get_colors_for_classes.colors) == num_classes):
        return get_colors_for_classes.colors

    hsv_tuples = [(x / num_classes, 1., 1.) for x in range(num_classes)]
    colors = list(map(lambda x: colorsys.hsv_to_rgb(*x), hsv_tuples))
    colors = list(
        map(lambda x: (int(x[0] * 255), int(x[1] * 255), int(x[2] * 255)),
            colors))
    random.seed(10101)  # Fixed seed for consistent colors across runs.
    random.shuffle(colors)  # Shuffle colors to decorrelate adjacent classes.
    random.seed(None)  # Reset seed to default.
    get_colors_for_classes.colors = colors  # Save colors for future calls.
    return colors