"""
Summary
-------

This plugin allows easy, variable length summaries directly embedded into the
body of your articles.
"""

from __future__ import unicode_literals
from pelican import signals
from pelican.generators import ArticlesGenerator, StaticGenerator, PagesGenerator

def initialized(pelican):
    from pelican.settings import DEFAULT_CONFIG
    DEFAULT_CONFIG.setdefault('SUMMARY_BEGIN_MARKER',
                              '<!-- PELICAN_BEGIN_SUMMARY -->')
    DEFAULT_CONFIG.setdefault('SUMMARY_END_MARKER',
                              '<!-- PELICAN_END_SUMMARY -->')
    DEFAULT_CONFIG.setdefault('SUMMARY_USE_FIRST_PARAGRAPH', False)
    if pelican:
        pelican.settings.setdefault('SUMMARY_BEGIN_MARKER',
                                    '<!-- PELICAN_BEGIN_SUMMARY -->')
        pelican.settings.setdefault('SUMMARY_END_MARKER',
                                    '<!-- PELICAN_END_SUMMARY -->')
        pelican.settings.setdefault('SUMMARY_USE_FIRST_PARAGRAPH', False)

def extract_summary(instance):
    # if summary is already specified, use it
    # if there is no content, there's nothing to do
    if hasattr(instance, '_summary'):
        instance.has_summary = True
        return

    if not instance._content:
        instance.has_summary = False
        return

    begin_marker = instance.settings['SUMMARY_BEGIN_MARKER']
    end_marker   = instance.settings['SUMMARY_END_MARKER']
    use_first_paragraph = instance.settings['SUMMARY_USE_FIRST_PARAGRAPH']
    remove_markers = True

    content = instance._content
    begin_summary = -1
    end_summary = -1
    if begin_marker:
        begin_summary = content.find(begin_marker)
    if end_marker:
        end_summary = content.find(end_marker)

    if begin_summary == -1 and end_summary == -1 and use_first_paragraph:
        begin_marker, end_marker = '<p>', '</p>'
        remove_markers = False
        begin_summary = content.find(begin_marker)
        end_summary = content.find(end_marker)

    if begin_summary == -1 and end_summary == -1:
        instance.has_summary = False
        return

    # skip over the begin marker, if present
    if begin_summary == -1:
        begin_summary = 0
    else:
        begin_summary = begin_summary + len(begin_marker)

    if end_summary == -1:
        end_summary = None

    summary = content[begin_summary:end_summary]

    if remove_markers:
        # remove the markers from the content
        if begin_summary:
            content = content.replace(begin_marker, '', 1)
        if end_summary:
            content = content.replace(end_marker, '', 1)

    instance._content = content
    instance._summary = summary
    instance.has_summary = True


def run_plugin(generators):
    for generator in generators:
        if isinstance(generator, ArticlesGenerator):
            for article in generator.articles:
                extract_summary(article)
        elif isinstance(generator, PagesGenerator):
            for page in generator.pages:
                extract_summary(page)


def register():
    signals.initialized.connect(initialized)
    try:
        signals.all_generators_finalized.connect(run_plugin)
    except AttributeError:
        # NOTE: This results in #314 so shouldn't really be relied on
        # https://github.com/getpelican/pelican-plugins/issues/314
        signals.content_object_init.connect(extract_summary)