#vim: set colorcolumn=81 ft=sh:hi ColorColumn ctermbg=224
# Due to ambiguity in the markup format, you probably intended to
# go to a link labeled "$/build.sh". This is really a link to
# "$/build.sh.txt" in the unformatted post. Here is a proper
# link: $/build.sh.txt. This was
# fixed in this document through a hack I'm not particularly
# proud of.

txt2html() {
  # cut off the modeline and title
  tail -n +3 |

  # convert lines starting with `##` to comments
  sed 's|^\(##.*\)$|\1|' |

  # convert <,> to HTML-compatible format
  sed 's|<|\<|g' |
  sed 's|>|\>|g' |

  # convert ` ` italics to html
  sed 's|\||g' |
  sed 's|}\*||g' |

  # convert bold to html
  sed 's|||g' |
  sed 's|||g' |

  # convert ` 
 code 
 ` codeblocks into css-ified codeblocks
  sed 's|``[`]{|
|' |
  sed 's|}[`]``|
|' |
  # convert ` code ` inline codeblocks into css-ified codeblocks
  sed 's|`[{]||g' |
  sed 's|[}]`||g' |

  # See next comment. $/url -> /url.html
  sed 's|\([$]/\)\([^ \)]*\)[.]txt\([,.]\)|\1\2\3|g' |
  sed 's|\([$]/\)\([^ \)<>]*\)[.]txt|\1\2|g' |
  # convert `$/url` to html links relative to root domain
  #sed 's|\([$]/\)\([^ \)]*\)\([,.]\)|\1\2\3|g' |
  sed 's!^\([$]/\)\([^ \)<>]*\)!\1\2!g;s!\([^>]\)\([$]/\)\([^ \)<>]*\)!\1\2\3!g' |

  # See next comment. %/url -> url.html
  sed 's|\(%/\)\([^ \)]*\)[.]txt\([,.]\)|\1\2\3|g' |
  sed 's|\(%/\)\([^ \)<>]*\)[.]txt|\1\2|g' |
  # convert `%/url` to html links relative to current directory
  sed 's!^\(%/\)\([^ \)<>]*\)!\1\2!g;s!\([^>]\)\(%/\)\([^ \)<>]*\)!\1\2\3!g' |
  # convert `#/url` to html links
  sed 's|\([#]/\)\([^ )]*\)\([,.)] \)|\1\2\3|g' |
  sed 's|\([#]/\)\([^ )<>]*\)|\1\2|g' |

  # convert `-[0-9]` into IDs
  sed 's|^\([ -]*\)\[\([0-9.][0-9.]*\)\]|\1[\2]|g' |
  # convert `[0-9]` into references to IDs
  sed 's|\([^\"#]\)\[\([0-9.][0-9.]*\)\]|\1[\2]|g' |

  # convert `-{0-9 into references to footnotes
  sed 's|^\(- [^{]*\){\([0-9]*\)}|\1{\2}|g' |
  # convert 0-9 into footnotes
  sed 's|{\([0-9]*\)}|{\1}|g' |

  # set content
  sed '/%%CONTENT%%/r /dev/stdin' html_template |
  sed '/%%CONTENT%%/d' |
  # set title
  sed "s|#Site build script|${1:-Index}|"
}
{
  # process arguments if available, else all *.txt
  [ $# -eq 0 ] && find . -name '*.txt' | grep -ve 'robots.txt$' | tee /dev/stderr
  while [ ! $# -eq 0 ]; do
    case "$1" in
      sitemap*)
        shift
        break
        ;;
    esac
    printf '%s\n' "$1"
    shift
  done
} | while read -r PAGE; do
  title=$(sed '2p;d' "$PAGE")
  printf 'txt2html %s\n' "$title"
  txt2html "$title" < "$PAGE" > "${PAGE%%.txt}.html"
  [ "$PAGE" = ./build.sh.txt ] && sed -i 's|<|<|g;s|>|>|g' "${PAGE%%.txt}.html"
done
printf 'txt2html Sitemap\n'
find . -name '*.html' | cut -d/ -f2- | grep -v ^sitemap.html\$ | while read -r PAGE; do
  printf '>$/%s\n' "$PAGE" "$(sed '2p;d' "${PAGE%%.html}.txt")"
done |
  sed '/%%CONTENT%%/r /dev/stdin' html_template |
  sed '/%%CONTENT%%/d' |
  sed 's|#Site build script|Sitemap|' > sitemap.html