#!/usr/bin/env bash
set -uo pipefail

DEVICE="XX:XX:XX:XX:XX:XX"
DEVICE_US="${DEVICE//:/_}"   # pactl names use underscores
SINK_WAIT=10                 # seconds to wait for the sink after connecting

info() { bluetoothctl info "$DEVICE" 2>/dev/null; }

sink_present() {
  pactl list short sinks 2>/dev/null | grep -q "bluez_output.$DEVICE_US"
}

# Wait for the PipeWire sink to actually show up — bluetoothctl saying
# "Connected: yes" means nothing if WirePlumber never creates the sink.
wait_for_sink() {
  for _ in $(seq "$SINK_WAIT"); do
    if sink_present; then
      return 0
    fi
    sleep 1
  done
  return 1
}

ensure_a2dp() {
  # Card can appear stuck in profile "off" or headset-only; force A2DP if available.
  local card="bluez_card.$DEVICE_US"
  if pactl list cards short 2>/dev/null | grep -q "$card"; then
    pactl set-card-profile "$card" a2dp-sink 2>/dev/null \
      || pactl set-card-profile "$card" a2dp_sink 2>/dev/null \
      || true
  fi
}

try_connect() {
  bluetoothctl connect "$DEVICE"
  ensure_a2dp
  wait_for_sink
}

# Make the headphones the default output and move every running app stream over
switch_audio_to_headphones() {
  local sink
  sink=$(pactl list short sinks | grep "bluez_output.$DEVICE_US" | head -1 | cut -f2)
  if [ -z "$sink" ]; then
    echo "Warning: could not resolve sink name; leaving default output unchanged." >&2
    return 1
  fi
  pactl set-default-sink "$sink"
  local input
  for input in $(pactl list short sink-inputs | cut -f1); do
    pactl move-sink-input "$input" "$sink" 2>/dev/null || true
  done
  echo "Default output set to $sink; existing app streams moved."
}

echo "Connecting to Bluetooth headphones ($DEVICE)..."

# Ensure bluetooth is powered on
if ! bluetoothctl show | grep -q "Powered: yes"; then
  bluetoothctl power on
  sleep 1
fi

# Pair if not already paired
if ! info | grep -q "Paired: yes"; then
  bluetoothctl scan on &
  SCAN_PID=$!
  sleep 5
  bluetoothctl pair "$DEVICE"
  kill "$SCAN_PID" 2>/dev/null || true
fi

# Trust if not already trusted
if ! info | grep -q "Trusted: yes"; then
  bluetoothctl trust "$DEVICE"
fi

# "Already connected" only counts if the sink actually exists
if info | grep -q "Connected: yes"; then
  ensure_a2dp
  if sink_present; then
    echo "Already connected and audio sink is up."
    switch_audio_to_headphones
    exit 0
  fi
  echo "BlueZ claims connected but no audio sink exists — resetting connection."
  bluetoothctl disconnect "$DEVICE"
  sleep 2
fi

# Attempt 1: plain connect
echo "Attempt 1: connecting..."
if try_connect; then
  echo "Done. Sink is up: bluez_output.$DEVICE_US"
  switch_audio_to_headphones
  exit 0
fi

# Attempt 2: restart WirePlumber (recreates all PipeWire BT nodes), reconnect
echo "No sink appeared. Attempt 2: restarting WirePlumber and reconnecting..."
bluetoothctl disconnect "$DEVICE"
systemctl --user restart wireplumber
sleep 3
if try_connect; then
  echo "Done. Sink is up: bluez_output.$DEVICE_US"
  switch_audio_to_headphones
  exit 0
fi

# Attempt 3: power-cycle the adapter, restart WirePlumber, reconnect
echo "Still no sink. Attempt 3: power-cycling Bluetooth adapter..."
bluetoothctl disconnect "$DEVICE"
bluetoothctl power off
sleep 2
bluetoothctl power on
sleep 2
systemctl --user restart wireplumber
sleep 3
if try_connect; then
  echo "Done. Sink is up: bluez_output.$DEVICE_US"
  switch_audio_to_headphones
  exit 0
fi

echo "FAILED: headphones never produced an audio sink after 3 attempts." >&2
echo "Last resort: sudo systemctl restart bluetooth, then re-run this script." >&2
echo "If that fails too, the headphones themselves may need a power cycle." >&2
exit 1