import os
from os.path import join
import re
import glob
import simplejson as json
import mistune
from jinja2 import Environment, FileSystemLoader, select_autoescape

import app.settings.app_cfg as cfg
import app.site.s3 as s3

renderer = mistune.Renderer(escape=False)
markdown = mistune.Markdown(renderer=renderer)

includes_env = Environment(
  loader=FileSystemLoader(cfg.DIR_SITE_INCLUDES),
  autoescape=select_autoescape([])
)

footnote_count = 0

def parse_markdown(metadata, sections, s3_path, skip_h1=False):
  """
  parse page into sections, preprocess the markdown to handle our modifications
  """
  groups = []
  current_group = []
  footnotes = []
  in_stats = False
  in_columns = False
  in_footnotes = False
  ignoring = False

  if 'desc' in metadata and 'subdesc' in metadata:
    groups.append(intro_section(metadata, s3_path))

  for section in sections:
    if skip_h1 and section.startswith('# '):
      continue
    elif section.strip().startswith('---'):
      continue
    elif section.lower().strip().startswith('ignore text'):
      ignoring = True
      continue
    elif section.strip().startswith('### Footnotes'):
      groups.append(format_section(current_group, s3_path))
      current_group = []
      footnotes = []
      in_footnotes = True
    elif in_footnotes:
      footnotes.append(section)
    elif ignoring:
      continue

    elif '### statistics' in section.lower() or '### sidebar' in section.lower():
      if len(current_group):
        groups.append(format_section(current_group, s3_path))
      current_group = [format_include("{% include 'sidebar.html' %}", metadata)]
      if 'sidebar' not in section.lower():
        current_group.append(section)
      in_stats = True
      if 'end sidebar' in section.lower():
        current_group = [format_section(current_group, s3_path, 'right-sidebar', tag='div')]
        in_stats = False
    elif in_stats and not section.strip().startswith('## ') and 'end sidebar' not in section.lower():
      current_group.append(section)
    elif in_stats and section.strip().startswith('## ') or 'end sidebar' in section.lower():
      current_group = [format_section(current_group, s3_path, 'right-sidebar', tag='div')]
      if 'end sidebar' not in section.lower():
        current_group.append(section)
      in_stats = False

    elif '=== columns' in section.lower():
      if len(current_group):
        groups.append(format_section(current_group, s3_path))
      current_group = []
      in_columns = True
      column_partz = section.split(' ')
      if len(column_partz) == 3:
        column_count = column_partz[2]
      else:
        column_count = "N"
      groups.append("<section><div class='columns columns-{}'>".format(column_count))
    elif in_columns is True and '===' in section:
      groups.append(format_section(current_group, s3_path, type='column', tag='div'))
      current_group = []
      if 'end columns' in section:
        groups.append("</div></section>")
        in_columns = False
        current_group = []

    elif section.strip().startswith('{% include'):
      groups.append(format_section(current_group, s3_path))
      current_group = []
      current_group.append(section)
      if section.strip().endswith(' %}'):
        groups.append(format_include("\n\n".join(current_group), metadata))
        current_group = []
    elif section.strip().startswith('```'):
      groups.append(format_section(current_group, s3_path))
      current_group = []
      current_group.append(section)
      if section.strip().endswith('```'):
        groups.append(format_applet("\n\n".join(current_group), s3_path))
        current_group = []
    elif section.strip().endswith('```'):
      current_group.append(section)
      groups.append(format_applet("\n\n".join(current_group), s3_path))
      current_group = []
    elif section.startswith('+ '):
      groups.append(format_section(current_group, s3_path))
      groups.append('<section>' + format_metadata(section) + '<section>')
      current_group = []
    elif '![fullwidth:' in section:
      groups.append(format_section(current_group, s3_path))
      groups.append(format_section([section], s3_path, type='fullwidth'))
      current_group = []
    elif '![wide:' in section:
      groups.append(format_section(current_group, s3_path))
      groups.append(format_section([section], s3_path, type='wide'))
      current_group = []
    elif '![' in section:
      groups.append(format_section(current_group, s3_path))
      groups.append(format_section([section], s3_path, type='images'))
      current_group = []
    else:
      current_group.append(section)
  groups.append(format_section(current_group, s3_path))

  footnote_txt = ''
  footnote_lookup = {}

  if len(footnotes):
    footnote_txt, footnote_lookup = format_footnotes(footnotes, s3_path)

  content = "".join(groups)

  if footnote_lookup:
    for key, index in footnote_lookup.items():
      global footnote_count
      footnote_count = 0
      letters = "abcdefghijklmnopqrstuvwxyz"
      footnote_backlinks = []
      def footnote_tag(match):
        global footnote_count
        footnote_count += 1
        footnote_backlinks.append('<a href="#{}_{}">{}</a>'.format(key, footnote_count, letters[footnote_count-1]))
        return '<a class="footnote_shim" name="{}_{}"> </a><a href="#{}" class="footnote" title="Footnote {}">{}</a>'.format(key, footnote_count, key, index, index)
      key_regex = re.compile(key.replace('[', '\\[').replace('^', '\\^').replace(']', '\\]'))
      content = key_regex.sub(footnote_tag, content)
      footnote_txt = footnote_txt.replace("{}_BACKLINKS".format(key), "".join(footnote_backlinks))
    content += '<section>'
    content += '<h3>References</h3>'
    content += footnote_txt
    content += '</section>'
  return content


def intro_section(metadata, s3_path):
  """
  Build the intro section for datasets
  """

  section = "<section class='intro_section' style='background-image: url({})'>".format(s3_path + metadata['image'])
  section += "<div class='inner'>"

  parts = []
  if 'desc' in metadata:
    desc = metadata['desc']
    # colorize the first instance of the database name in the header
    if 'color' in metadata and metadata['title'] in desc:
      desc = desc.replace(metadata['title'], "<span style='color: {}'>{}</span>".format(metadata['color'], metadata['title']), 1)
    section += "<div class='hero_desc'><span class='bgpad'>{}</span></div>".format(desc, desc)

  if 'subdesc' in metadata:
    subdesc = markdown(metadata['subdesc']).replace('<p>', '').replace('</p>', '')
    section += "<div class='hero_subdesc'><span class='bgpad'>{}</span></div>".format(subdesc, subdesc)

  section += "</div>"
  section += "</section>"

  if 'caption' in metadata:
    section += "<section><div class='image'><div class='intro-caption caption'>{}</div></div></section>".format(metadata['caption'])

  return section


def fix_images(lines, s3_path):
  """
  do our own transformation of the markdown around images to handle wide images etc
  lines: markdown lines
  """
  real_lines = []
  block = "\n\n".join(lines)
  for line in block.split("\n"):
    if "![" in line:
      line = line.replace('![', '')
      alt_text, tail = line.split('](', 1)
      url, tail = tail.split(')', 1)
      tag = ''
      if ':' in alt_text:
        tag, alt_text = alt_text.split(':', 1)
      img_tag = "<img src='{}' alt='{}'>".format(s3_path + url, alt_text.replace("'", ""))
      if 'sideimage' in tag:
        line = "<div class='sideimage'>{}<div>{}</div></div>".format(img_tag, markdown(tail))
      elif len(alt_text):
        line = "<div class='image'>{}<div class='caption'>{}</div></div>".format(img_tag, alt_text)
      else:
        line = "<div class='image'>{}</div>".format(img_tag, alt_text)
    real_lines.append(line)
  return "\n".join(real_lines)


def format_section(lines, s3_path, type='', tag='section'):
  """
  format a normal markdown section
  """
  if len(lines):
    lines = fix_meta(lines)
    lines = fix_images(lines, s3_path)
    if type:
      return "<{} class='{}'>{}</{}>".format(tag, type, markdown(lines), tag)
    else:
      return "<{}>{}</{}>".format(tag, markdown(lines), tag)
  return ""

def fix_meta(lines):
  """
  Format metadata sections before passing to markdown
  """
  new_lines = []
  for line in lines:
    if line.startswith('+ '):
      line = format_metadata(line)
    new_lines.append(line)
  return new_lines

def format_metadata(section):
  """
  format a metadata section (+ key: value pairs)
  """
  meta = []
  for line in section.split('\n'):
    if ': ' not in line:
      continue
    key, value = line[2:].split(': ', 1)
    meta.append("<div><div class='gray'>{}</div><div>{}</div></div>".format(key, value))
  return "<div class='meta'>{}</div>".format(''.join(meta)) 

def format_footnotes(footnotes, s3_path):
  """
  Format the footnotes section separately and produce a lookup we can use to update the main site
  """
  footnotes = '\n'.join(footnotes).split('\n')
  index = 1
  footnote_index_lookup = {}
  footnote_list = []
  for footnote in footnotes:
    if not len(footnote) or '[^' not in footnote:
      continue
    key, note = footnote.split(': ', 1)
    footnote_index_lookup[key] = index
    note_markup = markdown(note).replace('<p>', '', 1).replace('</p>', '', 1)
    footnote_list.append('{} <a name="{}" class="footnote_shim"></a><span class="backlinks">{}_BACKLINKS</span>'.format(index, key, key) + note_markup)
    index += 1

  footnote_txt = '<section><ul class="footnotes"><li>' + '</li><li>'.join(footnote_list) + '</li></ul></section>'
  return footnote_txt, footnote_index_lookup

def format_include(section, metadata):
  """
  Include html template
  """
  include_fn = section.strip().strip('\n').strip().strip('{%').strip().strip('%}').strip()
  include_fn = include_fn.strip('include').strip().strip('"').strip().strip("'").strip()
  return includes_env.get_template(include_fn).render(metadata=metadata)

def format_applet(section, s3_path):
  """
  Format the applets, which load javascript modules like the map and CSVs
  """
  # print(section)
  payload = section.strip('```').strip().strip('```').strip().split('\n')
  applet = {}
  # print(payload)
  if ': ' in payload[0]:
    command, opt = payload[0].split(': ', 1)
  else:
    command = payload[0]
    opt = None
  print(command)
  if command == 'python' or command == 'javascript' or command == 'code':
    return format_section([ section ], s3_path)
  if command == '':
    return ''

  applet['command'] = command
  if opt:
    applet['opt'] = opt
  if command == 'load_file':
    if opt[0:4] != 'http':
      applet['opt'] = s3_path + opt
  if len(payload) > 1:
    applet['fields'] = payload[1:]
  return "<section class='applet_container'><div class='applet' data-payload='{}'></div></section>".format(json.dumps(applet))


def parse_research_index(research_posts):
  """
  Generate an index file for the research pages
  """
  content = "<div class='research_index'>"
  for post in research_posts:
    print(post)
    if 'path' not in post:
      print("No path attribute for post")
      return ""
    s3_path = s3.make_s3_path(cfg.S3_SITE_PATH, post['path'])
    if 'image' in post:
      post_image = s3_path + post['image']
    else:
      post_image = 'data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw=='
    row = "<a href='{}'><section class='wide'><img src='{}' alt='Research post' /><section><h1>{}</h1><h2>{}</h2></section></section></a>".format(
      post['path'],
      post_image,
      post['title'],
      post['tagline'])
    content += row
  content += '</div>'
  return content