#!/usr/bin/python
# -*- coding: utf-8 -*-

# thumbor imaging service
# https://github.com/thumbor/thumbor/wiki

# Licensed under the MIT license:
# http://www.opensource.org/licenses/mit-license
# Copyright (c) 2011 globo.com thumbor@googlegroups.com

from __future__ import absolute_import

import os
from tempfile import mkstemp
from subprocess import Popen, PIPE
from io import BytesIO

from PIL import Image, ImageFile, ImageDraw, ImageSequence, JpegImagePlugin, ImageFilter

from thumbor.engines import BaseEngine
from thumbor.engines.extensions.pil import GifWriter
from thumbor.utils import logger, deprecated

try:
    from thumbor.ext.filters import _composite

    FILTERS_AVAILABLE = True
except ImportError:
    FILTERS_AVAILABLE = False

FORMATS = {
    '.tif': 'PNG',  # serve tif as png
    '.jpg': 'JPEG',
    '.jpeg': 'JPEG',
    '.gif': 'GIF',
    '.png': 'PNG',
    '.webp': 'WEBP'
}

ImageFile.MAXBLOCK = 2 ** 25
ImageFile.LOAD_TRUNCATED_IMAGES = True

DecompressionBombExceptions = (Image.DecompressionBombWarning,)
if hasattr(Image, 'DecompressionBombError'):
    DecompressionBombExceptions += (Image.DecompressionBombError,)


class Engine(BaseEngine):
    def __init__(self, context):
        super(Engine, self).__init__(context)
        self.subsampling = None
        self.qtables = None
        self.original_mode = None

        try:
            if self.context.config.MAX_PIXELS is None or int(self.context.config.MAX_PIXELS):
                Image.MAX_IMAGE_PIXELS = self.context.config.MAX_PIXELS
        except (AttributeError, TypeError, ValueError):  # invalid type
            logger.info('MAX_PIXELS config variable set to invalid type. Has to be int on None')

    def gen_image(self, size, color):
        if color == 'transparent':
            color = None
        img = Image.new("RGBA", size, color)
        return img

    def create_image(self, buffer):
        try:
            img = Image.open(BytesIO(buffer))
        except DecompressionBombExceptions as e:
            logger.warning("[PILEngine] create_image failed: {0}".format(e))
            return None
        self.icc_profile = img.info.get('icc_profile')
        self.exif = img.info.get('exif')
        self.original_mode = img.mode

        self.subsampling = JpegImagePlugin.get_sampling(img)
        if (self.subsampling == -1):  # n/a for this file
            self.subsampling = None
        self.qtables = getattr(img, 'quantization', None)

        if self.context.config.ALLOW_ANIMATED_GIFS and self.extension == '.gif':
            frames = []
            for frame in ImageSequence.Iterator(img):
                frames.append(frame.convert('P'))
            img.seek(0)
            self.frame_count = len(frames)
            return frames

        return img

    def get_resize_filter(self):
        config = self.context.config
        resample = config.PILLOW_RESAMPLING_FILTER if config.PILLOW_RESAMPLING_FILTER is not None else 'LANCZOS'

        available = {
            'LANCZOS': Image.LANCZOS,
            'NEAREST': Image.NEAREST,
            'BILINEAR': Image.BILINEAR,
            'BICUBIC': Image.BICUBIC,
        }

        if hasattr(Image, 'HAMMING'):
            available['HAMMING'] = Image.HAMMING

        return available.get(resample.upper(), Image.LANCZOS)

    def draw_rectangle(self, x, y, width, height):
        # Nasty retry if the image is loaded for the first time and it's truncated
        try:
            d = ImageDraw.Draw(self.image)
        except IOError:
            d = ImageDraw.Draw(self.image)
        d.rectangle([x, y, x + width, y + height])

        del d

    def resize(self, width, height):
        # Indexed color modes (such as 1 and P) will be forced to use a
        # nearest neighbor resampling algorithm. So we convert them to
        # RGB(A) mode before resizing to avoid nasty scaling artifacts.
        if self.image.mode in ['1', 'P']:
            logger.debug('converting image from 8-bit/1-bit palette to 32-bit RGB(A) for resize')
            if self.image.mode == '1':
                target_mode = 'RGB'
            else:
                # convert() figures out RGB or RGBA based on palette used
                target_mode = None
            self.image = self.image.convert(mode=target_mode)

        size = (int(width), int(height))
        # Tell image loader what target size we want (only JPG for a moment)
        self.image.draft(None, size)

        resample = self.get_resize_filter()
        self.image = self.image.resize(size, resample)

    def crop(self, left, top, right, bottom):
        self.image = self.image.crop((
            int(left),
            int(top),
            int(right),
            int(bottom)
        ))

    def rotate(self, degrees):
        # PIL rotates counter clockwise
        if degrees == 90:
            self.image = self.image.transpose(Image.ROTATE_90)
        elif degrees == 180:
            self.image = self.image.transpose(Image.ROTATE_180)
        elif degrees == 270:
            self.image = self.image.transpose(Image.ROTATE_270)
        else:
            self.image = self.image.rotate(degrees, expand=1)

    def flip_vertically(self):
        self.image = self.image.transpose(Image.FLIP_TOP_BOTTOM)

    def flip_horizontally(self):
        self.image = self.image.transpose(Image.FLIP_LEFT_RIGHT)

    def get_default_extension(self):
        # extension is not present => force JPEG or PNG
        if self.image.mode in ['P', 'RGBA', 'LA']:
            return '.png'
        else:
            return '.jpeg'

    def read(self, extension=None, quality=None):  # NOQA
        # returns image buffer in byte format.

        img_buffer = BytesIO()
        requested_extension = extension or self.extension

        # 1 and P mode images will be much smaller if converted back to
        # their original mode. So let's do that after resizing. Get $$.
        if self.context.config.PILLOW_PRESERVE_INDEXED_MODE and requested_extension in [None, '.png', '.gif'] \
                and self.original_mode in ['P', '1'] and self.original_mode != self.image.mode:
            if self.original_mode == '1':
                self.image = self.image.convert('1')
            else:
                # libimagequant might not be enabled on compile time
                # but it's better than default octree for RGBA images, so worth a try
                quantize_default = True
                try:
                    # Option available since Pillow 3.3.0
                    if hasattr(Image, 'LIBIMAGEQUANT'):
                        self.image = self.image.quantize(method=Image.LIBIMAGEQUANT)
                        quantize_default = False
                except ValueError as ex:
                    if 'dependency' not in str(ex).lower():
                        raise

                if quantize_default:
                    self.image = self.image.quantize()

        ext = requested_extension or self.get_default_extension()

        options = {
            'quality': quality
        }
        if ext == '.jpg' or ext == '.jpeg':
            options['optimize'] = True
            if self.context.config.PROGRESSIVE_JPEG:
                # Can't simply set options['progressive'] to the value
                # of self.context.config.PROGRESSIVE_JPEG because save
                # operates on the presence of the key in **options, not
                # the value of that setting.
                options['progressive'] = True

            if self.image.mode != 'RGB':
                self.image = self.image.convert('RGB')
            else:
                subsampling_config = self.context.config.PILLOW_JPEG_SUBSAMPLING
                qtables_config = self.context.config.PILLOW_JPEG_QTABLES

                if subsampling_config is not None or qtables_config is not None:
                    options['quality'] = 0  # can't use 'keep' here as Pillow would try to extract qtables/subsampling and fail
                    orig_subsampling = self.subsampling
                    orig_qtables = self.qtables

                    if (subsampling_config == 'keep' or subsampling_config is None) and (orig_subsampling is not None):
                        options['subsampling'] = orig_subsampling
                    else:
                        options['subsampling'] = subsampling_config

                    if (qtables_config == 'keep' or qtables_config is None) and (orig_qtables and 2 <= len(orig_qtables) <= 4):
                        options['qtables'] = orig_qtables
                    else:
                        options['qtables'] = qtables_config

        if ext == '.png' and self.context.config.PNG_COMPRESSION_LEVEL is not None:
            options['compress_level'] = self.context.config.PNG_COMPRESSION_LEVEL

        if options['quality'] is None:
            options['quality'] = self.context.config.QUALITY

        if self.icc_profile is not None:
            options['icc_profile'] = self.icc_profile

        if self.context.config.PRESERVE_EXIF_INFO:
            if self.exif is not None:
                options['exif'] = self.exif

        try:
            if ext == '.webp':
                if options['quality'] == 100:
                    logger.debug("webp quality is 100, using lossless instead")
                    options['lossless'] = True
                    options.pop('quality')
                if self.image.mode not in ['RGB', 'RGBA']:
                    if self.image.mode == 'P':
                        mode = 'RGBA'
                    else:
                        mode = 'RGBA' if self.image.mode[-1] == 'A' else 'RGB'
                    self.image = self.image.convert(mode)

            if ext in ['.png', '.gif'] and self.image.mode == 'CMYK':
                self.image = self.image.convert('RGBA')

            self.image.format = FORMATS.get(ext, FORMATS[self.get_default_extension()])
            self.image.save(img_buffer, self.image.format, **options)
        except IOError:
            logger.exception('Could not save as improved image, consider to increase ImageFile.MAXBLOCK')
            self.image.save(img_buffer, FORMATS[ext])

        results = img_buffer.getvalue()
        img_buffer.close()
        self.extension = ext
        return results

    def read_multiple(self, images, extension=None):
        gif_writer = GifWriter()
        img_buffer = BytesIO()

        duration = []
        converted_images = []
        xy = []
        dispose = []

        for im in images:
            duration.append(float(im.info.get('duration', 80)) / 1000)
            converted_images.append(im.convert("RGB"))
            xy.append((0, 0))
            dispose.append(1)

        loop = int(self.image.info.get('loop', 1))

        images = gif_writer.convertImagesToPIL(converted_images, False, None)
        gif_writer.writeGifToFile(img_buffer, images, duration, loop, xy, dispose)

        results = img_buffer.getvalue()
        img_buffer.close()

        tmp_fd, tmp_file_path = mkstemp()
        f = os.fdopen(tmp_fd, "w")
        f.write(results)
        f.close()

        command = [
            'gifsicle',
            '--colors',
            '256',
            tmp_file_path
        ]

        popen = Popen(command, stdout=PIPE)
        pipe = popen.stdout
        pipe_output = pipe.read()
        pipe.close()

        if popen.wait() == 0:
            results = pipe_output

        os.remove(tmp_file_path)

        return results

    @deprecated("Use image_data_as_rgb instead.")
    def get_image_data(self):
        return self.image.tobytes()

    def set_image_data(self, data):
        self.image.frombytes(data)

    @deprecated("Use image_data_as_rgb instead.")
    def get_image_mode(self):
        return self.image.mode

    def image_data_as_rgb(self, update_image=True):
        converted_image = self.image
        if converted_image.mode not in ['RGB', 'RGBA']:
            if 'A' in converted_image.mode:
                converted_image = converted_image.convert('RGBA')
            elif converted_image.mode == 'P':
                # convert() figures out RGB or RGBA based on palette used
                converted_image = converted_image.convert(None)
            else:
                converted_image = converted_image.convert('RGB')
        if update_image:
            self.image = converted_image
        return converted_image.mode, converted_image.tobytes()

    def convert_to_grayscale(self, update_image=True, with_alpha=True):
        if 'A' in self.image.mode and with_alpha:
            image = self.image.convert('LA')
        else:
            image = self.image.convert('L')
        if update_image:
            self.image = image
        return image

    def has_transparency(self):
        has_transparency = 'A' in self.image.mode or 'transparency' in self.image.info
        if has_transparency:
            # If the image has alpha channel,
            # we check for any pixels that are not opaque (255)
            has_transparency = min(self.image.convert('RGBA').getchannel('A').getextrema()) < 255
        return has_transparency

    def paste(self, other_engine, pos, merge=True):
        if merge and not FILTERS_AVAILABLE:
            raise RuntimeError(
                'You need filters enabled to use paste with merge. Please reinstall ' +
                'thumbor with proper compilation of its filters.')

        self.enable_alpha()
        other_engine.enable_alpha()

        image = self.image
        other_image = other_engine.image

        if merge:
            sz = self.size
            other_size = other_engine.size
            mode, data = self.image_data_as_rgb()
            other_mode, other_data = other_engine.image_data_as_rgb()
            imgdata = _composite.apply(
                mode, data, sz[0], sz[1],
                other_data, other_size[0], other_size[1], pos[0], pos[1])
            self.set_image_data(imgdata)
        else:
            image.paste(other_image, pos)

    def enable_alpha(self):
        if self.image.mode != 'RGBA':
            self.image = self.image.convert('RGBA')

    def strip_icc(self):
        self.icc_profile = None

    def strip_exif(self):
        self.exif = None

    def blur(self, radius):
        self.image = self.image.filter(ImageFilter.GaussianBlur(radius))
