# copyright 2019 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
#
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb is free software: you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.

"""
Debug view for pyramid debug toolbar and others to help development
"""

import os
import logging
import inspect

from itertools import dropwhile

from pyramid.response import Response
from mako.template import Template

from cubicweb.misc.source_highlight import highlight_html, generate_css, has_pygments


DEBUG_DISPLAY_SOURCE_CODE_PATH = '_debug_display_source_code'

FILES_WHITE_LIST = set()


def _generate_link_to_source(file_path, start=None, end=None, tag_body="[source]"):
    if start:
        # step back a bit so we have a bit of top padding wen displaying the page
        # and the highlighted line isn't glued to top of the browser window
        line_anchor = max(0, start - 10)

        if end:
            return '<a href="../%s?file=%s&line=%s&end=%s#line-%s" target="_blank">%s</a>' % (
                DEBUG_DISPLAY_SOURCE_CODE_PATH, file_path, start, end, line_anchor, tag_body
            )
        else:
            return '<a href="../%s?file=%s&line=%s#line-%s" target="_blank">%s</a>' % (
                DEBUG_DISPLAY_SOURCE_CODE_PATH, file_path, start, line_anchor, tag_body
            )

    return '<a href="../%s?file=%s" target="_blank">%s</a>' % (
        DEBUG_DISPLAY_SOURCE_CODE_PATH, file_path, tag_body
    )


def source_code_url(object_or_class):
    if object_or_class is None:
        return ""

    if not inspect.isclass(object_or_class):
        object_or_class = object_or_class.__class__

    try:
        file_path = inspect.getsourcefile(object_or_class)
    except TypeError:
        logging.debug("Error while trying to source code of '%s'" % object_or_class)
        return ""

    FILES_WHITE_LIST.add(file_path)

    try:
        source_code, line = inspect.getsourcelines(object_or_class)
    except OSError:  # when we couldn't read the source code/line
        return _generate_link_to_source(file_path)

    return _generate_link_to_source(file_path, line, line + len(source_code))


def source_code_url_in_stack(stack, highlighted=False):
    new_stack = []

    if highlighted:
        for i in stack.split(" File "):
            # expecting this format:
            # '<span class="nb">&quot;/path/to/file.py&quot;</span>,
            # line <span class="m">885</span>,...'
            if not i.startswith('<span class="nb">'):
                new_stack.append(i)
                continue

            # this will give:
            # ['<span class="nb">', '/file/to/path.py', '</span>, ...']
            tag, file_path, rest = i.split("&quot;", 2)

            # "rest" is like that: '</span>, line <span class="m">885</span>, ...'
            # we want to extrait "885" here
            line_number = int("".join(dropwhile(lambda x: not x.isdigit(), rest)).split("<")[0])

            new_stack.append("%s%s%s" % (
                tag,
                _generate_link_to_source(file_path, start=line_number,
                                         tag_body="&quot;%s&quot;" % file_path),
                rest,
            ))

            FILES_WHITE_LIST.add(file_path)

        new_stack = " File ".join(new_stack)

    # no syntax
    else:
        for i in stack.split("\n"):
            # expecting this format:
            # File "/path/to/file.py", line 885, in stuf\n  some_code\nFile "/stuff.py", line...
            if not i.startswith("  File "):
                new_stack.append(i)
                continue

            # this will give:
            # ['File "', '/path/to/file.py', '", line 885, in stuf']
            beginning, file_path, rest = i.split('"', 2)
            line_number = int("".join(dropwhile(lambda x: not x.isdigit(), rest)).split(",")[0])

            new_stack.append("%s%s%s" % (
                beginning,
                _generate_link_to_source(file_path, start=line_number,
                                         tag_body='"%s"' % file_path),
                rest,
            ))

            FILES_WHITE_LIST.add(file_path)

        new_stack = "\n".join(new_stack)

    return new_stack


def debug_display_source_code(request):
    """
    This view display a python source file content for making debugging easier.

    It is only activated on debug mode (-D) for pyramid during development.

    It will uses pygment if installed to colorize the source code.
    """

    if "file" not in request.params:
        return Response('Error: you should have end up on this page following a link in the '
                        'pyramid debug toolbar with the correct parameters.')

    source_code_file = request.params["file"]

    if not os.path.exists(source_code_file):
        return Response("Error: file '%s' doesn't exist on the filesystem." % source_code_file)

    # security
    if source_code_file not in FILES_WHITE_LIST:
        return Response("Error: access to file is not authorized")

    try:
        content = open(source_code_file, "r").read()
    except Exception as e:
        return Response("Error: while opening file '%s' got the error: %s" % (source_code_file, e))

    lines = []
    line_begin = request.params.get("line", None)
    if line_begin:
        line_end = request.params.get("end", line_begin)
        lines = list(range(int(line_begin), int(line_end) + 1))

    this_file_directory = os.path.split(os.path.realpath(__file__))[0]
    template_filename = os.path.join(this_file_directory,
                                     "debug_toolbar_templates/debug_source_code.mako")

    html = Template(filename=template_filename).render(
        file_path=source_code_file,
        content=content,
        has_pygments=has_pygments,
        highlight_html=highlight_html,
        css=generate_css(),
        lines=lines,
    )

    return Response(html)