# -*- coding: utf-8 -*-
#
# diffoscope: in-depth comparison of files, archives, and directories
#
# Copyright © 2015 Chris Lamb <lamby@debian.org>
#
# diffoscope is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# diffoscope is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with diffoscope.  If not, see <https://www.gnu.org/licenses/>.

import re
import base64
import logging
import subprocess

from diffoscope.config import Config
from diffoscope.tools import tool_required
from diffoscope.tempfiles import get_named_temporary_file
from diffoscope.difference import Difference, VisualDifference

from .utils.file import File
from .utils.command import Command

re_ansi_escapes = re.compile(r'\x1b[^m]*m')

logger = logging.getLogger(__name__)


class Img2Txt(Command):
    @tool_required('img2txt')
    def cmdline(self):
        return [
            'img2txt',
            '--width', '60',
            '--format', 'utf8',
            self.path,
        ]

    def filter(self, line):
        # Strip ANSI escapes
        return re_ansi_escapes.sub('', line.decode('utf-8')).encode('utf-8')


class Identify(Command):
    ATTRIBUTES = (
        'Image format: %m',
        'File size: %b',
        'Height: %[height]',
        'Width: %[width]',
        'Orientation: %[orientation]',
        'Compression type: %[compression]',
        'Compression quality: %[quality]',
        'Colorspace: %[colorspace]',
        'Channels: %[channels]',
        'Depth: %[depth]',
        'Interlace mode: %[interlace]',
        'Rendering intent: %[rendering-intent]',
        'X resolution: %[resolution.x]',
        'Y resolution: %[resolution.y]',
        'Resolution units: %[units]',
        'Transparency channel enabled: %A',
        'Gamma: %[gamma]',
        'Number of unique colors: %[colors]',
        'Comment: %c',
        'EXIF data: %[EXIF:*]',
    )

    @tool_required('identify')
    def cmdline(self):
        return [
            'identify',
            '-format',
            '\n'.join(self.ATTRIBUTES),
            self.path,
        ]


@tool_required('compare')
def pixel_difference(image1_path, image2_path):
    compared_filename = get_named_temporary_file(suffix='.png').name

    try:
        subprocess.check_call((
            'compare',
            image1_path,
            image2_path,
            '-compose', 'src',
            compared_filename,
        ))
    except subprocess.CalledProcessError as e:
        # ImageMagick's `compare` will return 1 if images are different
        if e.returncode == 1:
            pass

    with open(compared_filename, 'rb') as f:
        content = base64.b64encode(f.read()).decode('utf8')

    return VisualDifference('image/png;base64', content, "Pixel difference")


@tool_required('convert')
def flicker_difference(image1_path, image2_path):
    compared_filename = get_named_temporary_file(suffix='.gif').name

    subprocess.check_call((
        'convert',
        '-delay', '50',
        image1_path,
        image2_path,
        '-loop', '0',
        '-compose', 'difference',
        compared_filename,
    ))

    with open(compared_filename, 'rb') as f:
        content = base64.b64encode(f.read()).decode('utf8')

    return VisualDifference('image/gif;base64', content, "Flicker difference")


@tool_required('identify')
def get_image_size(image_path):
    return subprocess.check_output((
        'identify',
        '-format', '%[h]x%[w]',
        image_path,
    ))


def same_size(image1, image2):
    try:
        return get_image_size(image1.path) == get_image_size(image2.path)
    except subprocess.CalledProcessError:  # noqa
        return False


class JPEGImageFile(File):
    DESCRIPTION = "JPEG images"
    FILE_TYPE_RE = re.compile(r'\bJPEG image data\b')

    def compare_details(self, other, source=None):
        content_diff = Difference.from_command(
            Img2Txt,
            self.path,
            other.path,
            source="Image content",
        )
        if content_diff is not None and Config().compute_visual_diffs and \
                same_size(self, other):
            try:
                logger.debug(
                    "Generating visual difference for %s and %s",
                    self.path,
                    other.path,
                )
                content_diff.add_visuals([
                    pixel_difference(self.path, other.path),
                    flicker_difference(self.path, other.path),
                ])
            except subprocess.CalledProcessError:  # noqa
                pass
        return [
            content_diff,
            Difference.from_command(
                Identify,
                self.path,
                other.path,
                source="Image metadata",
            ),
        ]


class ICOImageFile(File):
    DESCRIPTION = "Microsoft Windows icon files"
    FILE_TYPE_RE = re.compile(r'\bMS Windows icon resource\b')

    def compare_details(self, other, source=None):
        differences = []

        # img2txt does not support .ico files directly so convert to .PNG.
        try:
            png_a, png_b = [ICOImageFile.convert(x) for x in (self, other)]
        except subprocess.CalledProcessError:  # noqa
            pass
        else:
            content_diff = Difference.from_command(
                Img2Txt,
                png_a,
                png_b,
                source="Image content",
            )
            if content_diff is not None and Config().compute_visual_diffs and \
                    same_size(self, other):
                if get_image_size(self.path) == get_image_size(other.path):
                    logger.debug(
                        "Generating visual difference for %s and %s",
                        self.path,
                        other.path,
                    )
                    content_diff.add_visuals([
                        pixel_difference(self.path, other.path),
                        flicker_difference(self.path, other.path),
                    ])
            differences.append(content_diff)

        differences.append(Difference.from_command(
            Identify,
            self.path,
            other.path,
            source="Image metadata",
        ))

        return differences

    @staticmethod
    @tool_required('convert')
    def convert(file):
        result = get_named_temporary_file(suffix='.png').name

        subprocess.check_call(('convert', file.path, result))

        return result
