#!/bin/sh -e

post_title="${POST_TITLE:-}"

is_in_list=0
is_in_link_block=0
is_in_preformatted_block=0
is_in_blockquote=0

if_in_list_then_close()
{
  if [ $is_in_list -ne 0 ]
  then
    echo "</ul>"
    is_in_list=0
  fi
}

if_in_link_block_then_close()
{
  if [ $is_in_link_block -ne 0 ]
  then
    echo "</p>"
    is_in_link_block=0
  fi
}

if_in_preformatted_block_then_close()
{
  if [ $is_in_preformatted_block -ne 0 ]
  then
    echo "</pre>"
    is_in_preformatted_block=0
  fi
}

if_in_blockquote_then_close()
{
  if [ $is_in_blockquote -ne 0 ]
  then
    echo "</blockquote>"
    is_in_blockquote=0
  fi
}

close_all_open_blocks()
{
  if_in_list_then_close
  if_in_link_block_then_close
  if_in_preformatted_block_then_close
  if_in_blockquote_then_close
}

escape_upphtml()
{
  echo "$1" \
    | sed "s/&/\\&amp;/g" \
    | sed "s/</\\&lt;/g" \
    | sed "s/>/\\&gt;/g" \
    | sed "s/\"/\\&quot;/g" \
    | sed "s/'/\\&#x27;/g" \
    | sed "s/\`/\\&#x60;/g" \
    | sed "s/\\\$/\\\\\$/g"
}

close_all_open_blocks_except()
{
  except="$1"
  if [ "$except" != "list" ]
  then
    if_in_list_then_close
  fi
  if [ "$except" != "link" ]
  then
    if_in_link_block_then_close
  fi
  if [ "$except" != "pre" ]
  then
    if_in_preformatted_block_then_close
  fi
  if [ "$except" != "blockquote" ]
  then
    if_in_blockquote_then_close
  fi
}

if [ -z "$post_title" ]
then
  read first_line
  if [ "$(echo "$first_line" | cut -c1-2)" != "# " ]
  then
    echo >&2 "Error: no [post_title] argument provided and no top-level heading at top of the document."
    exit 1
  fi
  post_title="${first_line### }"
fi

echo "#!
export TITLE=\"${post_title} | joeac's blog\"
export DESCRIPTION=\"${post_title} | joeac's blog\"
pp \"\${SHARE}\"/components/meta.upphtml
#!"

while read line
do
  if [ "$(echo $line | sed "s/[[:space:]]//g")" = "" ]
  then
    continue
  fi

  if [ "$(echo $line | cut -c1)" = "#" ]
  then
    title="$(escape_upphtml "${line#*# }")"
    heading="${line%%$title}"
    heading="${heading%% }"
    heading_level="${#heading}"
    if [ "$(echo "$line" | cut -c$(( $heading_level + 1 )) )" = " " ]
    then
      close_all_open_blocks
      echo "<h${heading_level}>${title}</h${heading_level}>"
      continue
    fi
  fi

  if [ "$(echo "$line" | cut -c1-2)" = "=>" ]
  then
    close_all_open_blocks_except link
    href="$(escape_upphtml "$(echo "$line" | sed "s/^=>[[:space:]]\+//" | sed "s/[[:space:]]\+.*//")")"
    title="$(escape_upphtml "${line#=> *${href}}")"
    title="${title:-${href}}"
    if [ $is_in_link_block -eq 0 ]
    then
      echo "<p>"
    else
      echo "<br/>"
    fi
    is_in_link_block=1
    echo "=> <a href='${href}'>${title}</a>"
    continue
  fi

  if [ "$( echo "$line" | cut -c1-2)" = "* " ]
  then
    close_all_open_blocks_except list
    if [ $is_in_list -eq 0 ]
    then
      echo "<ul>"
    fi
    is_in_list=1
    echo "<li>$(escape_upphtml "$(echo "$line" | cut -c3-)")</li>"
    continue
  fi

  if [ "$(echo "$line" | cut -c1)" = ">" ]
  then
    close_all_open_blocks_except blockquote
    if [ $is_in_blockquote -eq 0 ]
    then
      echo "<blockquote>"
    fi
    is_in_blockquote=1
    echo "<p>$(escape_upphtml "$(echo "$line" | cut -c2-)")</p>"
    continue
  fi

  if [ "$(echo "$line" | cut -c1-3)" = "\`\`\`" ]
  then
    close_all_open_blocks_except pre
    if [ $is_in_preformatted_block -eq 0 ]
    then
      echo "<pre>"
    else
      echo -e "\n"
    fi
    is_in_preformatted_block=1
    echo "$(escape_upphtml "$(echo "$line" | cut -c4-)")"
    continue
  fi

  close_all_open_blocks
  echo "<p>$(escape_upphtml "${line}")</p>"
done

close_all_open_blocks