Initial version of habits

habits.sh

@@ -0,0 +1,72 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+HABITS_FILE="${HABITS_FILE:-$HOME/.local/share/os/habits.md}"
+
+usage() {
+  cat <<'EOF'
+Usage: habits <command>
+
+Commands:
+  open    Open the habits file in $EDITOR
+  new     Add a new day to the habits file
+EOF
+}
+
+ensure_file() {
+  mkdir -p "$(dirname "$HABITS_FILE")"
+  touch "$HABITS_FILE"
+}
+
+open_habits() {
+  ensure_file
+  "${EDITOR:-vi}" "$HABITS_FILE"
+}
+
+new_day() {
+  ensure_file
+
+  local date
+  date="$(date +%F)"
+
+  if grep -q "^# $date$" "$HABITS_FILE"; then
+    echo "A habits entry for $date already exists: $HABITS_FILE" >&2
+    exit 1
+  fi
+
+  local tmp
+  tmp="$(mktemp)"
+
+  {
+    printf '# %s\n\n' "$date"
+    printf '## Habits\n\n'
+    while IFS= read -r habit; do
+      [ -n "$habit" ] && printf -- '- [ ] %s\n' "$habit"
+    done <<< "$HABITS"
+    printf '\n## Metrics \n\n'
+    while IFS= read -r metric; do
+      [ -n "$metric" ] && printf -- '- %s\n' "$metric" ":"
+    done <<< "$METRICS"
+    printf '\n'
+    cat "$HABITS_FILE"
+  } > "$tmp"
+
+  mv "$tmp" "$HABITS_FILE"
+  echo "Added $date to $HABITS_FILE"
+}
+
+case "${1:-}" in
+  open)
+    open_habits
+    ;;
+  new)
+    new_day
+    ;;
+  -h|--help|help)
+    usage
+    ;;
+  *)
+    usage >&2
+    exit 1
+    ;;
+esac