# This file is part of the Indico plugins.
# Copyright (C) 2002 - 2021 CERN
#
# The Indico plugins are free software; you can redistribute
# them and/or modify them under the terms of the MIT License;
# see the LICENSE file for more details.

import mimetypes

from flask import render_template
from pygments import highlight
from pygments.formatters import HtmlFormatter
from pygments.lexers import CppLexer, JavaLexer, PhpLexer, RubyLexer, get_lexer_for_mimetype

from indico.core import signals
from indico.core.plugins import IndicoPlugin
from indico.modules.attachments.preview import Previewer


def register_custom_mimetypes():
    mimetypes.add_type('text/x-csharp', '.cs')


register_custom_mimetypes()


class PygmentsPreviewer(Previewer):
    # All supported MIME types
    MIMETYPES = ('text/css', 'text/x-python', 'text/x-ruby-script', 'text/x-java-source', 'text/x-c',
                 'application/javascript', 'application/x-javascript', 'text/x-fortran', 'text/x-csharp', 'text/php',
                 'text/x-php')

    # Python's mimetypes lib and Pygments do not quite agree on some MIME types
    CUSTOM_LEXERS = {
        'text/x-c': CppLexer(),
        'text/x-java-source': JavaLexer(),
        'text/x-ruby-script': RubyLexer(),
        'text/php': PhpLexer()
    }

    @classmethod
    def can_preview(cls, attachment_file):
        return attachment_file.content_type in cls.MIMETYPES

    @classmethod
    def generate_content(cls, attachment):
        mime_type = attachment.file.content_type

        lexer = cls.CUSTOM_LEXERS.get(mime_type)
        if lexer is None:
            lexer = get_lexer_for_mimetype(mime_type)

        with attachment.file.open() as f:
            html_formatter = HtmlFormatter(style='tango', linenos='inline', prestyles='mono')
            html_code = highlight(f.read(), lexer, html_formatter)

        css_code = html_formatter.get_style_defs('.highlight')

        return render_template('previewer_code:pygments_preview.html', attachment=attachment,
                               html_code=html_code, css_code=css_code)


class CodePreviewerPlugin(IndicoPlugin):
    """Syntax highlighter (Pygments)"""

    configurable = False

    def init(self):
        super().init()
        self.connect(signals.attachments.get_file_previewers, self._get_file_previewers)

    def _get_file_previewers(self, sender, **kwargs):
        yield PygmentsPreviewer