from converters.markdown import ConverterMarkdown
from IPython.utils.text import indent
import io
import os
import itertools

class ConverterReveal(ConverterMarkdown):
    """Convert a notebook to a html slideshow.

    It generates a static html slideshow based in markdown and reveal.js.
    """

    def __init__(self, infile, highlight_source=False, show_prompts=True,
                 inline_prompt=True):
        super(ConverterMarkdown, self).__init__(infile)
        self.highlight_source = highlight_source
        self.show_prompts = show_prompts
        self.inline_prompt = inline_prompt

    def switch_meta(self, m_list):
        if len(m_list) > 1:
            if not (len(m_list) == 2 and m_list[1] == [u'new_fragment = True']):
                m_list[0], m_list[1] = m_list[1], m_list[0]
        return m_list

    def meta2str(self, meta):
        try:
            meta_tuple = meta[u'slideshow'].items()
        except KeyError as e:
            meta_tuple = ()
        meta_list = [[x + ' = ' + unicode(y)] for x, y in meta_tuple]
        meta_list = self.switch_meta(meta_list)
        return u'\n'.join(list(itertools.chain(*meta_list)))

    def render_heading(self, cell):
        return [self.meta2str(cell.metadata), '{0} {1}'.format('#' * cell.level, cell.source), '']

    def render_markdown(self, cell):
        return [self.meta2str(cell.metadata), cell.source, '']

    def render_raw(self, cell):
        if self.raw_as_verbatim:
            return [indent(self.meta2str(cell.metadata)), indent(cell.source), '']
        else:
            return [self.meta2str(cell.metadata), cell.source, '']

    def convert(self, cell_separator='\n'):
        """
        Generic method to converts notebook to a string representation.

        This is accomplished by dispatching on the cell_type, so subclasses of
        Convereter class do not need to re-implement this method, but just
        need implementation for the methods that will be dispatched.

        Parameters
        ----------
        cell_separator : string
          Character or string to join cells with. Default is "\n"

        Returns
        -------
        out : string
        """
        lines = []
        lines.extend(self.optional_header())
        begin = ['<div class="reveal"><div class="slides">']
        lines.extend(begin)
        slides_list = self.build_slides(cell_separator)
        lines.extend(slides_list)
        end = ['</div></div>']
        lines.extend(end)
        lines.extend(self.optional_footer())
        return u'\n'.join(lines)

    def build_slides(self, cell_separator='\n'):
        "build the slides from text list"
        text = self.main_body(cell_separator)
        text = [x for x in text if x != u'new_section = False'
            and x != u'new_subsection = False' 
            and x != u'new_fragment = False']
        left = '<section data-markdown><script type="text/template">'
        right = '</script></section>'
        slides = [list(x[1]) for x in itertools.groupby(text, lambda x: x==u'new_section = True') if not x[0]] 
        for slide in slides:
            slide.insert(0, u'')
            slide.insert(0,left)
            slide.append(right)
            if slide[2] == u'new_subsection = True':
                slide.pop(2)
                slide.insert(0,'<section>')
                slide.append('</section>')
                for i,j in enumerate(slide):
                    if j == u'new_subsection = True':
                        slide[i] = right + left
                        slide.insert(i + 1, u'')
            elif slide[4] == u'new_subsection = True':
                slide[4] = right
                slide.insert(5, u'')
                slide.insert(5,left)  
                slide.insert(5,'<section>')
                slide.append('</section>')
                for i,j in enumerate(slide):
                    if j == u'new_subsection = True':
                        slide[i] = right + left
                        slide.insert(i + 1, u'')
            for i,j in enumerate(slide):
                if j == u'new_fragment = True':
                    slide[i] = '<p class="fragment">'
                    slide[i + 2] = '</p>'
                    slide.insert(i + 3, u'')
        return list(itertools.chain(*slides))

    def save(self, outfile=None, encoding=None):
        "read and parse notebook into self.nb"
        if outfile is None:
            outfile = self.outbase + '_slides.' + 'html'
        if encoding is None:
            encoding = self.default_encoding
        with io.open(outfile, 'w', encoding=encoding) as f:
            f.write(self.output)
        return os.path.abspath(outfile)

    def template_read(self):
        "read the reveal_template.html"
        here = os.path.split(os.path.realpath(__file__))[0]
        reveal_template = os.path.join(here, '..', 'templates', 'reveal_base.html')
        with io.open(reveal_template, 'r', encoding='utf-8') as f:
            template = f.readlines()
        template = map(lambda s: s.strip(), template) # cosmetic one to get short html files
        return template

    def template_split(self):
        "split the reveal_template.html in header and footer lists"
        temp = self.template_read()
        splitted_temp = [list(x[1]) for x in itertools.groupby(temp, lambda x: x==u'%slides%') if not x[0]]
        return splitted_temp  

    def optional_header(self):
        optional_header_body = self.template_split()
        return optional_header_body[0]

    def optional_footer(self):
        optional_footer_body = self.template_split()
        return optional_footer_body[1]