# -*- coding: utf-8 -*-
"""
AsciiDoctor
===========

This plugin allows you to use AsciiDoctor to write your posts.
File extension should be ``.asc``, ``.adoc``, or ``asciidoc``.

This plugin is based on
https://github.com/getpelican/pelican-plugins/tree/master/asciidoc_reader
and
https://github.com/marienfressinaud/Pelidoc

"""

from pelican.readers import BaseReader
from pelican.generators import Generator
from pelican import signals
import os
import re
import subprocess
import sys
import logging
from subprocess import check_call, check_output

logger = logging.getLogger(__name__)
pattern = re.compile("Asciidoctor.*asciidoctor.org")

class AsciiDoctorReader(BaseReader):
    """ Reader for AsciiDoc files. """

    file_extensions = ['asc', 'adoc', 'asciidoc']

    def read(self, source_path):
        """Parse content and metadata of AsciiDoc files."""
        cmd = self.settings.get('ASCIIDOCTOR_CMD', 'asciidoctor')
        cmd_version = check_output(['asciidoctor', '--version']).decode('utf-8')
        if not pattern.match(cmd_version):
            logger.error("AsciiDoctorReader: {} is not asciidoctor executable".format(cmd))
            return

        content = ""
        if cmd:
            content = check_output(
                [cmd] + self.settings.get('ASCIIDOCTOR_EXTRA_OPTIONS', []) +
                ['--doctype=article'] + ['--no-header-footer'] +
                ['--out-file', '-', source_path]
            ).decode('utf-8')
        metadata = self._read_metadata(source_path)
        return content, metadata

    def _read_metadata(self, source_path):
        """Parses the AsciiDoc file at the given `source_path`
        and returns found metadata."""
        metadata = {}
        with open(source_path) as fi:
            prev = ""
            for line in fi.readlines():
                # Parse for doc title.
                if 'title' not in metadata.keys():
                    title = ""
                    if line.startswith("= "):
                        title = line[2:].strip()
                    elif line.count("=") == len(prev.strip()):
                        title = prev.strip()
                    if title:
                        metadata['title'] = self.process_metadata('title', title)

                regexp = re.compile(r"^:[\-A-z]+:\s*")
                if regexp.search(line):
                    toks = line.split(":", 2)
                    key = toks[1].strip().lower()
                    val = toks[2].strip()
                    metadata[key] = self.process_metadata(key, val)
                prev = line
        if (not 'summary' in metadata) or (metadata['summary'] is None):
            metadata['summary'] = ''
        return metadata


class AsciiDoctorPdfGenerator(Generator):
    """The AsciiDoctorPdf generator.
    """

    def guess_format(self, content):
        """Return the format used by a given content.
        """

        formats = {
            '.adoc': 'asciidoc',
            '.asciidoc': 'asciidoc',
            '.asc': 'asciidoc',
        }

        file_name, file_extension = os.path.splitext(content.source_path)

        return formats[file_extension]

    def check_output_dir(self, dir_):
        """Check and create if needed the given directory."""
        if not os.path.isdir(dir_):
            try:
                os.mkdir(dir_)
            except OSError:
                return False

        return True

    def generate_files(self, content):
        """Generates the list of files for a given content.

        :param content: the content to generate.
        :type content: pelican.contents.Content

        """

        cmd = self.settings.get('ASCIIDOCTOR_CMD', 'asciidoctor')
        cmd_version = check_output(['asciidoctor', '--version']).decode('utf-8')
        if not pattern.match(cmd_version):
            logger.error("AsciiDoctorPdfGenerator: {} is not asciidoctor executable".format(cmd))
            return

        if self.settings.get('PDF_PROCESSOR', False) == False:
            return

        try:
            from_format = self.guess_format(content)
        except KeyError:
            return

        list_outputs = self.settings.get('ASCIIDOCTOR_PDF_OUTPUT_DIR', 'pdf')
        output_dir = os.path.join(self.output_path, list_outputs)

        if not self.check_output_dir(output_dir):
            logger.error("Couldn't create the PDF output "
                         "folder in {dir}".format(dir=output_dir))
            return

        filename = "{id_file}.pdf".format(id_file=content.slug)
        filepath = os.path.join(output_dir, filename)

        check_call([cmd] + self.settings.get('ASCIIDOCTOR_EXTRA_OPTIONS', []) +
                   ['--require', 'asciidoctor-pdf', '--backend', 'pdf'] +
                   ['--doctype=article'] +
                   ['--out-file', filepath, content.source_path])

        logger.info("[ok] writing {filepath}".format(filepath=filepath))

    def generate_output(self, writer=None):
        """Generate files for each articles and pages.

        If ASCIIDOCTOR_EXPORT_ARTICLES is False, articles are not generated.
        If ASCIIDOCTOR_EXPORT_PAGES is False, pages are not generated.

        We don't use the writer passed as argument since we write our own
        files ((c) PDF plugin :)).

        """
        contents_to_export = []
        if self.settings.get('ASCIIDOCTOR_EXPORT_ARTICLES', True):
            contents_to_export += self.context['articles']

        if self.settings.get('ASCIIDOCTOR_EXPORT_PAGES', True):
            contents_to_export += self.context['pages']

        for content_to_export in contents_to_export:
            self.generate_files(content_to_export)


def add_reader(readers):
    for ext in AsciiDoctorReader.file_extensions:
        readers.reader_classes[ext] = AsciiDoctorReader


def get_generator(generator):
    return AsciiDoctorPdfGenerator


def register():
    signals.readers_init.connect(add_reader)
    signals.get_generators.connect(get_generator)