#!/bin/bash
#
# Drives the firmware's calibration patterns from the PC over ALSA MIDI.
# See "Calibration" in README.md for the procedure.
#
# Usage:
#   tools/calibrate.sh list                 list MIDI ports
#   tools/calibrate.sh ends                 pixel 0 (red) and last pixel (green)
#   tools/calibrate.sh octaves              every C, middle C in red
#   tools/calibrate.sh keys                 every key, white green / black blue
#   tools/calibrate.sh walk <n>             light pixel n only
#   tools/calibrate.sh sweep [ms]           walk every pixel in turn
#   tools/calibrate.sh all                  every pixel, for voltage droop
#   tools/calibrate.sh off                  back to normal operation
#   tools/calibrate.sh note <n> [vel]       play one MIDI note
#   tools/calibrate.sh chromatic [ms]       play every key, low to high
#
# Set PORT to the device's ALSA port (e.g. PORT=24:0). If unset, the script
# picks the first port whose name matches PORT_MATCH.
#
set -e

PORT_MATCH=${PORT_MATCH:-Piano LED}

CC_PATTERN=20
CC_INDEX_HI=21
CC_INDEX_LO=22

PAT_OFF=0; PAT_ENDS=1; PAT_OCTAVES=2; PAT_KEYS=3; PAT_WALK=4; PAT_ALL=5

need() {
	command -v "$1" >/dev/null 2>&1 || {
		echo "error: $1 not found (install alsa-utils)" >&2; exit 1; }
}

find_port() {
	if [ -n "$PORT" ]; then echo "$PORT"; return; fi
	local p
	p=$(aconnect -l | awk -v m="$PORT_MATCH" '
		/^client /{ cl=$2; sub(":","",cl); name=$0 }
		/^ +[0-9]+ / { if (name ~ m) { port=$1; print cl ":" port; exit } }')
	if [ -z "$p" ]; then
		echo "error: no MIDI port matching \"$PORT_MATCH\"." >&2
		echo "       Run '$0 list', then set PORT=client:port" >&2
		exit 1
	fi
	echo "$p"
}

# Send raw MIDI bytes to the port.
send() {
	need amidi
	local hex="$*"
	amidi -p "$(alsa_rawmidi_port)" -S "$hex" 2>/dev/null && return 0
	# amidi needs a rawmidi device; fall back to the sequencer via aplaymidi
	echo "error: could not send. Set PORT and ensure the device is connected." >&2
	exit 1
}

# amidi addresses rawmidi (hw:X,Y), not sequencer ports.
alsa_rawmidi_port() {
	if [ -n "$RAWMIDI" ]; then echo "$RAWMIDI"; return; fi
	need amidi
	local p
	p=$(amidi -l | awk -v m="$PORT_MATCH" '$0 ~ m { print $2; exit }')
	if [ -z "$p" ]; then
		echo "error: no rawmidi device matching \"$PORT_MATCH\"." >&2
		echo "       Run 'amidi -l', then set RAWMIDI=hw:X,Y" >&2
		exit 1
	fi
	echo "$p"
}

cc() { printf 'B0 %02X %02X' "$1" "$2"; }

pattern() { send "$(cc $CC_PATTERN $1)"; }

walk() {
	local n=$1
	send "$(cc $CC_PATTERN $PAT_WALK) $(cc $CC_INDEX_HI $((n >> 7))) $(cc $CC_INDEX_LO $((n & 127)))"
}

case "${1:-}" in
list)
	echo "--- sequencer ports (aconnect -l) ---"; aconnect -l || true
	echo; echo "--- rawmidi devices (amidi -l) ---"; amidi -l || true
	;;
ends)		pattern $PAT_ENDS;    echo "pattern: ends" ;;
octaves)	pattern $PAT_OCTAVES; echo "pattern: octaves" ;;
keys)		pattern $PAT_KEYS;    echo "pattern: keys" ;;
all)		pattern $PAT_ALL;     echo "pattern: all (watch the far end for warm colour)" ;;
off)		pattern $PAT_OFF;     echo "pattern: off" ;;
walk)
	[ -n "${2:-}" ] || { echo "usage: $0 walk <pixel>" >&2; exit 1; }
	walk "$2"; echo "pixel $2"
	;;
sweep)
	MS=${2:-120}
	COUNT=${LED_COUNT:-176}
	echo "sweeping 0..$((COUNT-1)); Ctrl-C to stop"
	for ((i=0; i<COUNT; i++)); do
		walk "$i"; printf '\rpixel %3d' "$i"; sleep "$(echo "$MS/1000" | bc -l)"
	done
	echo
	;;
note)
	[ -n "${2:-}" ] || { echo "usage: $0 note <midi-note> [velocity]" >&2; exit 1; }
	V=${3:-100}
	send "$(printf '90 %02X %02X' "$2" "$V")"
	echo "note $2 on (velocity $V); '$0 off' or send note-off to clear"
	;;
chromatic)
	MS=${2:-150}
	echo "playing notes 21..108; Ctrl-C to stop"
	for ((n=21; n<=108; n++)); do
		send "$(printf '90 %02X 64' "$n")"
		printf '\rnote %3d' "$n"
		sleep "$(echo "$MS/1000" | bc -l)"
		send "$(printf '80 %02X 00' "$n")"
	done
	echo
	;;
*)
	 sed -n "2,/^# Set PORT/p" "$0" | sed 's/^# \{0,1\}//'
	exit 1
	;;
esac