[script] Add simple due script for bibtex file

Scrapes a bibtex file for 'due' field, and outputs all found entries
with their priority and sorted for date.

bibtex/.local/bin/bib-due

@@ -0,0 +1,147 @@
+#!/usr/bin/env sh
+# shows due entries of bibtex file passed in
+# HACK: brittle! will break on various bibfile abnormities (even just on due date w/o priority)
+# FIXME: reimplementation with real library needed
+#
+
+OPTIND=1 # Reset in case getopts has been used previously in the shell.
+fields="due|priority|\bauthor\b|\btitle\b"
+filterby="due"
+file="${BIBFILE}"
+until=""
+
+show_help() {
+  printf "%s\n" \
+    "" \
+    " bib-due       Show due readings from bibtex file." \
+    "" \
+    " Usage: bib-due [-hv] -i input.bib -r 'due|priority|\bauthor|\btitle' -l 'due' -u '2020-05-12'" \
+    "" \
+    " Options:" \
+    "" \
+    "     -i [bibtex-file]                    Input bibtex file to scrape and get items from." \
+    "" \
+    "     -r [fields]                         Field values to read in file." \
+    "" \
+    "     -l [filter]                         Field to use as filter entity." \
+    "                                         This field is required for the scraper to pick entries up." \
+    "" \
+    "     help    | -h | --help               Print out this help." \
+    "" \
+    " Invoked without arguments, bib-due will scrape the file defined in BIBFILE environment variable, " \
+    " filtering entries with the 'due' field, and getting the values for 'due', 'priority', 'author', " \
+    " and 'title' fields. It will then print the entries to stdout." \
+    "" \
+    " Example output line:" \
+    "" \
+    ' 2020-06-25 (1): Sergei Gerasymchuk -- “Ze” time in Ukraine (Gerasymchuk2019) ' \
+    ""
+}
+
+filter_until() {
+  # filter for dates, with line numbers
+  filtered=$(echo "$entries" | grep -noE '[[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}')
+
+  # redirect entries to fifo pipe
+  mkfifo filteredentries
+  finish() {
+    rm filteredentries
+  }
+  trap finish EXIT
+  echo "$filtered" >filteredentries &
+
+  # find first date past until filter
+  lastline=""
+  while IFS= read -r line; do
+    cond=$(printf '%s' "$line" | cut -d: -f2)
+    cond=$(date -d "$cond" +%s)
+    if [ "$cond" -gt "$until" ]; then
+      lastline=$(printf '%s' "$line" | cut -d: -f1)
+      break
+    fi
+  done <filteredentries
+
+  # special cases all in filter, or none in filter
+  if [ -z "$lastline" ]; then
+    return
+  elif [ "$lastline" -eq 1 ]; then
+    entries=""
+  # filter
+  else
+    # remove lines below found
+    lastprinted="$((lastline - 1))"
+    entries=$(echo "$entries" | sed -n "1,${lastprinted}p;${lastline}q")
+  fi
+}
+
+filter_priority() {
+  priority="$1"
+  # filter for dates, with line numbers
+  # filtered=$(echo "$entries" | grep -noE '[[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}')
+  filtered=""
+  while [ "$priority" -gt 0 ]; do
+    current=$(echo "$entries" | grep -E "\($priority\)")
+
+    # append found to filtered entries
+    filtered=$(printf "%s\n%s" "$filtered" "$current")
+
+    # go to next 'higher' priority
+    priority="$((priority - 1))"
+  done
+  # sort them chronologically again, remove empty lines
+  entries="$(echo "$filtered" | sed -e '/^$/d' | sort)"
+}
+
+main() {
+  if [ -z "$file" ]; then
+    echo "Requires a bibtex file as argument."
+    exit 1
+  fi
+
+  # filter all entries for those containing filterby field (default: due)
+  # retain values of all fields mentioned in fields variable
+  entries=$(grep -E "^@|$fields" "$file" | awk 1 ORS=' ' | sed -E 's/@\w+\{/\n/g' | grep "$filterby" | tail -n +2 | sed -E 's/(,\s+(\w+)\s+=\s+|,\s*$)/\t/g' | awk -F'\t' '{ print $4 "\t" $5 "\t" $2 "\t" $3 "\t" $1 }')
+
+  # prettify and sort the entries for display (remove {}, order by date,prio,author,title)
+  entries=$(echo "$entries" | awk -F'\t' '{ gsub(/{/,""); gsub(/}/,""); gsub(/prio/,"",$2) } { print $1 " (" $2 "): " $3 " -- " $4 " (" $5 ")"}' | sort)
+
+  if [ -n "$until" ]; then
+    filter_until
+  fi
+  if [ -n "$priority" ]; then
+    filter_priority "$priority"
+  fi
+
+  echo "$entries"
+}
+
+while getopts "h?i:u:r:l:p:" opt; do
+  case "$opt" in
+  h | \?)
+    show_help
+    exit 0
+    ;;
+    # v)  verbose=1
+    # ;;
+  r)
+    fields="$OPTARG"
+    ;;
+  l)
+    filterby="$OPTARG"
+    ;;
+  i)
+    file="$OPTARG"
+    ;;
+  u)
+    until="$(date -d "$OPTARG" +%s)"
+    ;;
+  p)
+    priority="$OPTARG"
+    ;;
+  esac
+done
+shift $((OPTIND - 1))
+
+[ "${1:-}" = "--" ] && shift
+
+main "$@"

bibtex/.local/bin/rofi-bib-due

@@ -0,0 +1,29 @@
+#!/usr/bin/env sh
+
+exist rofi normal
+
+_rofi() {
+  rofi -dmenu -no-auto-select -i -theme themes/dropdown -p "papers" -l 25 -yoffset 20 -columns 1 -u "$urgent"
+}
+
+# call for whatever file is passed in
+results="$(bib-due "$@")"
+
+# mark priority 1 items as urgent in rofi
+urgent="$(
+  # find all lines with priority 1, (marked as `(1):` );
+  # print them on 1 line, -1 since dmenu is 0 indexed
+  echo "$results" | grep -n '(1):' | cut -d: -f1 | awk '{ $0=$0-1; print $0 }' ORS=','
+)"
+
+# get user choice, exit if nothing selected
+choice=$(echo "$results" | _rofi)
+[ -z "$choice" ] && exit 0
+
+key=$(echo "$choice" | sed -E 's/.*\((\w+)\)$/\1/')
+
+# get library pdf folder (only searches for default ./pdf path)
+library="$(dirname "$(realpath "$BIBFILE")")/pdf"
+
+# find and open the key-associated pdf file
+${FILEREADER:-xdg-open} "$(find "$library" -type f -name "$key *.pdf")"