#  Copyright (c) 2021 Arm Limited. All rights reserved.
#  SPDX-License-Identifier: Apache-2.0
#
#  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 script to convert a set of RGB images in a given location into
corresponding cpp files and a single hpp file referencing the vectors
from the cpp files.
"""
import datetime
import glob
import math
from pathlib import Path
from argparse import ArgumentParser

import numpy as np
from PIL import Image, UnidentifiedImageError
from jinja2 import Environment, FileSystemLoader

parser = ArgumentParser()
parser.add_argument("--image_path", type=str, help="path to images folder or image file  to convert.")
parser.add_argument("--source_folder_path", type=str, help="path to source folder to be generated.")
parser.add_argument("--header_folder_path", type=str, help="path to header folder to be generated.")
parser.add_argument("--image_size", type=int, nargs=2, help="Size (width and height) of the converted images.")
parser.add_argument("--license_template", type=str, help="Header template file",
                    default="header_template.txt")
args = parser.parse_args()

env = Environment(loader=FileSystemLoader(Path(__file__).parent / 'templates'),
                  trim_blocks=True,
                  lstrip_blocks=True)


def write_hpp_file(header_file_path, cc_file_path, header_template_file, num_images, image_filenames,
                   image_array_names, image_size):
    print(f"++ Generating {header_file_path}")
    header_template = env.get_template(header_template_file)
    hdr = header_template.render(script_name=Path(__file__).name,
                                 gen_time=datetime.datetime.now(),
                                 year=datetime.datetime.now().year)
    env.get_template('Images.hpp.template').stream(common_template_header=hdr,
                                                   imgs_count=num_images,
                                                   img_size=str(image_size[0] * image_size[1] * 3),
                                                   var_names=image_array_names) \
        .dump(str(header_file_path))

    env.get_template('Images.cc.template').stream(common_template_header=hdr,
                                                  var_names=image_array_names,
                                                  img_names=image_filenames) \
        .dump(str(cc_file_path))


def write_individual_img_cc_file(image_filename, cc_filename, header_template_file, original_image,
                                 image_size, array_name):
    print(f"++ Converting {image_filename} to {cc_filename.name}")

    header_template = env.get_template(header_template_file)
    hdr = header_template.render(script_name=Path(__file__).name,
                                 gen_time=datetime.datetime.now(),
                                 file_name=image_filename,
                                 year=datetime.datetime.now().year)
    # IFM size
    ifm_width = image_size[0]
    ifm_height = image_size[1]

    # Aspect ratio resize
    scale_ratio = (float)(max(ifm_width, ifm_height)) / (float)(min(original_image.size[0], original_image.size[1]))
    resized_width = (int)(original_image.size[0] * scale_ratio)
    resized_height = (int)(original_image.size[1] * scale_ratio)
    resized_image = original_image.resize([resized_width,resized_height], Image.BILINEAR)

    # Crop the center of the image
    resized_image = resized_image.crop((
        (resized_width - ifm_width) / 2,   # left
        (resized_height - ifm_height) / 2, # top
        (resized_width + ifm_width) / 2,   # right
        (resized_height + ifm_height) / 2  # bottom
        ))

    # Convert the image and write it to the cc file
    rgb_data = np.array(resized_image, dtype=np.uint8).flatten()
    hex_line_generator = (', '.join(map(hex, sub_arr))
                          for sub_arr in np.array_split(rgb_data, math.ceil(len(rgb_data) / 20)))
    env.get_template('image.cc.template').stream(common_template_header=hdr,
                                                 var_name=array_name,
                                                 img_data=hex_line_generator) \
        .dump(str(cc_filename))


def main(args):
    # Keep the count of the images converted
    image_idx = 0
    image_filenames = []
    image_array_names = []

    if Path(args.image_path).is_dir():
        filepaths = sorted(glob.glob(str(Path(args.image_path) / '**/*.*'), recursive=True))
    elif Path(args.image_path).is_file():
        filepaths = [args.image_path]
    else:
        raise OSError("Directory or file does not exist.")

    for filepath in filepaths:
        filename = Path(filepath).name

        try:
            original_image = Image.open(filepath).convert("RGB")
        except UnidentifiedImageError:
            print(f"-- Skipping file {filepath} due to unsupported image format.")
            continue

        image_filenames.append(filename)

        # Save the cc file
        cc_filename = Path(args.source_folder_path) / (Path(filename).stem.replace(" ", "_") + ".cc")
        array_name = "im" + str(image_idx)
        image_array_names.append(array_name)
        write_individual_img_cc_file(filename, cc_filename, args.license_template,
                                     original_image, args.image_size, array_name)

        # Increment image index
        image_idx = image_idx + 1

    header_filename = "InputFiles.hpp"
    header_filepath = Path(args.header_folder_path) / header_filename
    common_cc_filename = "InputFiles.cc"
    common_cc_filepath = Path(args.source_folder_path) / common_cc_filename

    if len(image_filenames) > 0:
        write_hpp_file(header_filepath, common_cc_filepath, args.license_template,
                    image_idx, image_filenames, image_array_names, args.image_size)
    else:
        raise FileNotFoundError("No valid images found.")


if __name__ == '__main__':
    main(args)