#!/bin/bash
# Auto-route iPhone HFP calls (the bluez nodes exist only during a live call):
#   uplink (what far-end hears)  <- micgate.out  (GATED mic only -> no self-echo)
#   far-end voice (bluez_input)  -> callmix       (recorded digitally, clean)
# and remove WirePlumber's default callrec_mix->uplink auto-link (that mix carries
# the ungated mic AND the far-end, i.e. a digital echo loop = far-end hears itself).
# Far-end -> headset earpiece is WirePlumber's own default link, NOT ours; callmix
# is a pure recording sink with no output.
#
# v3 (2026-07-30): `pw-link -l <node>` DOES NOT FILTER. Given a node name it cannot
#   resolve as a port it prints the ENTIRE graph, which always contains micgate.out
#   and callmix -> every "is it already linked?" grep returned true, so v2 removed
#   callrec_mix->uplink and then linked nothing: the far end heard silence.
#   Link state is now parsed per PORT out of one graph dump (links_of).
# v2 (2026-07-30): port names are discovered, not hardcoded (HFP/mSBC is MONO, so
#   the ports are playback_MONO/capture_MONO, not input_FL/input_FR -- the old
#   hardcoded grep never matched at all), and every link is verified on EVERY pass.
#   The old one-shot guard meant that if the far-end node appeared a tick later than
#   the uplink node (WirePlumber does not create the HFP nodes atomically), the
#   far-end was never linked for the whole call.
export XDG_RUNTIME_DIR=/run/user/1000
MAC=B4_96_A5_42_BD_D6

ports_in()  { pw-link -i 2>/dev/null | grep -E "^$1"; }
ports_out() { pw-link -o 2>/dev/null | grep -E "^$1"; }

# links_of PORT -- the peers linked to exactly this port, one per line, read from
# $GRAPH. pw-link -l prints a port header at column 0 followed by indented
# "|-> peer" / "|<- peer" lines, so match the header exactly and strip the arrows.
links_of() {
  printf '%s\n' "$GRAPH" | awk -v p="$1" '
    /^[^ \t]/ { inblk = ($0 == p); next }
    inblk     { sub(/^[ \t]*\|[-<>]+[ \t]*/, ""); print }
  '
}

has_peer() {  # has_peer REGEX PEER... -> 0 if any peer matches
  local re=$1; shift
  printf '%s\n' "$@" | grep -qE "$re"
}

log_state=""
while true; do
  mapfile -t UP < <(ports_in "bluez_output\.${MAC}")
  if [ ${#UP[@]} -eq 0 ]; then
    log_state=""
    sleep 1
    continue
  fi

  GRAPH=$(pw-link -l 2>/dev/null)
  CH=()
  mapfile -t GATE < <(ports_out 'micgate\.out')

  # --- uplink: exactly one gated-mic source per uplink port, no ungated mix ---
  for ((i = 0; i < ${#UP[@]}; i++)); do
    port=${UP[i]}
    mapfile -t peers < <(links_of "$port")

    # ADD BEFORE REMOVE. One link per uplink port: a stereo gate into a mono HFP
    # port sends FL only, linking both would sum them into the same port (+6 dB).
    if [ ${#GATE[@]} -gt 0 ] && ! has_peer '^micgate\.out:' "${peers[@]}"; then
      pw-link "${GATE[i % ${#GATE[@]}]}" "$port" 2>/dev/null && CH+=(+micgate)
      GRAPH=$(pw-link -l 2>/dev/null)
      mapfile -t peers < <(links_of "$port")
    fi

    # WirePlumber's callrec_mix -> uplink is the echo path. Drop every instance;
    # re-checked each pass because WP can add it at any point during the call.
    # SAFETY INVARIANT: only ever remove it once the gated mic is CONFIRMED linked.
    # v2 removed it and then linked nothing (the state check was broken) -> the
    # uplink had no source at all and the far end heard pure silence. An echo is
    # bad; being inaudible is worse.
    if has_peer '^micgate\.out:' "${peers[@]}"; then
      for pe in "${peers[@]}"; do
        case $pe in
          callrec_mix:*) pw-link -d "$pe" "$port" 2>/dev/null && CH+=(-callrec_mix) ;;
        esac
      done
    else
      CH+=("!no-micgate-uplink-keeping-callrec_mix")
    fi
  done

  # --- far-end into the recording mix (this node often appears after the uplink) ---
  mapfile -t FAR < <(ports_out "bluez_input\.${MAC}")
  if [ ${#FAR[@]} -eq 0 ]; then
    CH+=("(no-far-end-node-yet)")
  else
    mapfile -t REC < <(ports_in 'callmix')
    for ((j = 0; j < ${#REC[@]}; j++)); do
      rport=${REC[j]}
      mapfile -t rpeers < <(links_of "$rport")
      if ! has_peer "^bluez_input\.${MAC}" "${rpeers[@]}"; then
        pw-link "${FAR[j % ${#FAR[@]}]}" "$rport" 2>/dev/null && CH+=(+far-end)
      fi
    done
  fi

  # collapse repeats (one entry per uplink/callmix channel) and log only on change.
  # An ARRAY, not a string: a whitespace-only string passes -n and would log on
  # every single pass once the call is fully routed.
  if [ ${#CH[@]} -gt 0 ]; then
    msg=$(printf '%s\n' "${CH[@]}" | awk '!seen[$0]++' | tr '\n' ' ')
    if [ "$msg" != "$log_state" ]; then
      logger -t aime-iphone-route "iPhone call ${UP[0]%%:*}: $msg"
      log_state="$msg"
    fi
  fi
  sleep 1
done