# Copyright (C) 2010 Google Inc. All rights reserved.
# Copyright (C) 2010 Gabor Rapcsanyi <rgabor@inf.u-szeged.hu>, University of Szeged
# Copyright (C) 2011, 2012 Apple Inc. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#     * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
#     * Neither the Google name nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

"""WebKit implementations of the Port interface."""

import logging
import re
import time

from webkitcorepy import BytesIO, string_utils

_log = logging.getLogger(__name__)


class ImageDiffResult(object):
    def __init__(self, passed, diff_image, difference, tolerance=0, fuzzy_data=None, error_string=None):
        self.passed = passed
        self.diff_image = diff_image
        self.diff_percent = difference
        self.fuzzy_data = fuzzy_data
        self.tolerance = tolerance
        self.error_string = error_string

    def __eq__(self, other):
        if isinstance(other, self.__class__):
            return (self.passed == other.passed and
                    self.diff_image == other.diff_image and
                    self.diff_percent == other.diff_percent and
                    self.fuzzy_data == other.fuzzy_data and
                    self.tolerance == other.tolerance and
                    self.error_string == other.error_string)

        return False

    def __ne__(self, other):
        return not self.__eq__(other)

    def __repr__(self):
        return 'ImageDiffResult(Passed {} {} diff {} tolerance {} fuzzy data {} {})'.format(self.passed, self.diff_image, self.diff_percent, self.tolerance, self.fuzzy_data, self.error_string)

class ImageDiffer(object):
    def __init__(self, port):
        self._port = port
        self._tolerance = None
        self._process = None

    def diff_image(self, expected_contents, actual_contents, tolerance):
        if (self._process and self._process.has_available_stdout()):
            self.stop()
        try:
            assert(expected_contents)
            assert(actual_contents)
            assert(tolerance is not None)

            if not self._process:
                self._start(tolerance)
            # Note that although we are handed 'old', 'new', ImageDiff wants 'new', 'old'.
            buffer = BytesIO()
            buffer.write(string_utils.encode('Content-Length: {}\n'.format(len(actual_contents))))
            buffer.write(actual_contents)
            buffer.write(string_utils.encode('Content-Length: {}\n'.format(len(expected_contents))))
            buffer.write(expected_contents)
            self._process.write(buffer.getvalue())
            return self._read()
        except IOError as exception:
            return (None, 0, "Failed to compute an image diff: %s" % str(exception))

    def _start(self, tolerance):
        command = [self._port._path_to_image_diff(), '--difference']
        if self._port._should_use_jhbuild():
            command = self._port._jhbuild_wrapper + command
        environment = self._port.setup_environ_for_server('ImageDiff')
        self._process = self._port._server_process_constructor(self._port, 'ImageDiff', command, environment, crash_message='Test marked as failed, ImageDiff crashed')
        self._process.start()
        self._tolerance = tolerance

    def _read(self):
        deadline = time.time() + 2.0
        output_image = None
        diff_output = None
        fuzzy_data = None

        while not self._process.timed_out and not self._process.has_crashed():
            output = self._process.read_stdout_line(deadline)
            if self._process.timed_out or self._process.has_crashed() or not output:
                break

            if output.startswith(b'#EOF'):
                break

            if output.startswith(b'diff:'):
                diff_output = output

            if output.startswith(b'maxDifference='):
                fuzzy_data = output

            if output.startswith(b'Content-Length'):
                m = re.match(br'Content-Length: (\d+)', output)
                content_length = int(string_utils.decode(m.group(1), target_type=str))
                output_image = self._process.read_stdout(deadline, content_length)

        stderr = string_utils.decode(self._process.pop_all_buffered_stderr(), target_type=str)
        err_str = ''
        if stderr:
            err_str += "ImageDiff produced stderr output:\n" + stderr
        if self._process.timed_out:
            err_str += "ImageDiff timed out\n"
        if self._process.has_crashed():
            err_str += "ImageDiff crashed\n"

        if not diff_output or not fuzzy_data:
            return ImageDiffResult(passed=False, diff_image=None, difference=0, tolerance=self._tolerance, fuzzy_data=None, error_string=err_str or "Failed to read ImageDiff output")

        m = re.match(b'diff: (.+)%', diff_output)
        if not m:
            return ImageDiffResult(passed=False, diff_image=None, difference=0, tolerance=self._tolerance, fuzzy_data=None, error_string=err_str or 'Failed to match ImageDiff diff output {}'.format(diff_output))

        diff_percent = float(string_utils.decode(m.group(1), target_type=str))

        m = re.match(br'maxDifference=(\d+); totalPixels=(\d+)', fuzzy_data)
        if not m:
            return ImageDiffResult(passed=False, diff_image=None, difference=0, tolerance=self._tolerance, fuzzy_data=None, error_string=err_str or 'Failed to match ImageDiff fuzzy data output {}'.format(fuzzy_data))

        max_difference = int(string_utils.decode(m.group(1), target_type=str))
        total_pixels = int(string_utils.decode(m.group(2), target_type=str))

        passed = diff_percent <= self._tolerance
        return ImageDiffResult(passed=passed, diff_image=output_image, difference=diff_percent, tolerance=self._tolerance, fuzzy_data={'max_difference': max_difference, 'total_pixels': total_pixels}, error_string=err_str or None)

    def stop(self):
        if self._process:
            self._process.stop()
            self._process = None