Add an optional log to the now_playing segment

segments/now_playing.sh

@@ -9,6 +9,8 @@ TMUX_POWERLINE_SEG_NOW_PLAYING_TRIM_METHOD_DEFAULT="trim"
 TMUX_POWERLINE_SEG_NOW_PLAYING_ROLL_SPEED_DEFAULT="2"
 TMUX_POWERLINE_SEG_NOW_PLAYING_ROLL_MODE="${TMUX_POWERLINE_SEG_NOW_PLAYING_ROLL_MODE:-repeat}"
 TMUX_POWERLINE_SEG_NOW_PLAYING_ROLL_SEPARATOR="${TMUX_POWERLINE_SEG_NOW_PLAYING_ROLL_SEPARATOR:-   }"
+TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_FILEPATH_DEFAULT="\${HOME}/.now_playing.log"
+TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_MAX_ENTRIES_DEFAULT="100"
 TMUX_POWERLINE_SEG_NOW_PLAYING_MPD_HOST_DEFAULT="localhost"
 TMUX_POWERLINE_SEG_NOW_PLAYING_MPD_PORT_DEFAULT="6600"
 TMUX_POWERLINE_SEG_NOW_PLAYING_LASTFM_UPDATE_PERIOD_DEFAULT="30"
@@ -35,6 +37,10 @@ export TMUX_POWERLINE_SEG_NOW_PLAYING_ROLL_SPEED="${TMUX_POWERLINE_SEG_NOW_PLAYI
 # export TMUX_POWERLINE_SEG_NOW_PLAYING_ROLL_MODE="${TMUX_POWERLINE_SEG_NOW_PLAYING_ROLL_MODE}"
 # Separator for "repeat" roll mode
 # export TMUX_POWERLINE_SEG_NOW_PLAYING_ROLL_SEPARATOR="${TMUX_POWERLINE_SEG_NOW_PLAYING_ROLL_SEPARATOR}"
+# If set to a non-empty string, played tracks will be logged to the following file.
+# export TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_FILEPATH="${TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_FILEPATH_DEFAULT}"
+# Maximum number of logged song entries. Set to "unlimited" for unlimited entries.
+# export TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_MAX_ENTRIES="${TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_MAX_ENTRIES_DEFAULT}"
 
 # Hostname for MPD server in the format "[password@]host"
 export TMUX_POWERLINE_SEG_NOW_PLAYING_MPD_HOST="${TMUX_POWERLINE_SEG_NOW_PLAYING_MPD_HOST_DEFAULT}"
@@ -120,6 +126,30 @@ run_segment() {
 		return ${exitcode}
 	fi
 	if [ -n "$np" ]; then
+		if [[ -n "$TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_FILEPATH" && -n "$TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_MAX_ENTRIES" ]]; then
+			local last_track=$( \
+				awk -F': ' 'END { for (i = 2; i <= NF; ++i) printf("%s%s", $i, (i < NF) ? FS : "") }' \
+				<"$TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_FILEPATH" 2>/dev/null \
+			)
+			if [[ "$np" != "$last_track" ]]; then
+				local next_entry="$(date +"%Y-%m-%d %H:%M:%S"): ${np}"
+				if [[ "${TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_MAX_ENTRIES}" == "unlimited" ]]; then
+					echo "$next_entry" >> "$TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_FILEPATH"
+				else
+					local tmp_log_file="$(mktemp)" && \
+					{
+						tail -n $(( TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_MAX_ENTRIES - 1 )) \
+							"$TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_FILEPATH" 2>/dev/null
+						echo "$next_entry"
+					} > "$tmp_log_file" && \
+					if [[ -f "$tmp_log_file" ]]; then
+						# Use `cat` to preserve destination file attributes rather than source file attributes
+						cat "$tmp_log_file" >"$TMUX_POWERLINE_SEG_NOW_PLAYING_TRACK_LOG_FILEPATH"
+						rm "$tmp_log_file"
+					fi
+				fi
+			fi
+		fi
 		case "$TMUX_POWERLINE_SEG_NOW_PLAYING_TRIM_METHOD" in
 		"roll")
 			np=$(roll_text "${np}" "${TMUX_POWERLINE_SEG_NOW_PLAYING_MAX_LEN}" "${TMUX_POWERLINE_SEG_NOW_PLAYING_ROLL_SPEED_DEFAULT}" "${TMUX_POWERLINE_SEG_NOW_PLAYING_ROLL_MODE}" "${TMUX_POWERLINE_SEG_NOW_PLAYING_ROLL_SEPARATOR}")