#!/usr/bin/env bash
#
# Open the TranspOtter serial console.
#
#   ./console.sh                 minicom, port auto-detected
#   ./console.sh /dev/ttyACM1    force a port
#   ./console.sh -m              use `pio device monitor` instead
#   ./console.sh -r              raw stty/cat fallback, no terminal program
#   ./console.sh -l              list candidate ports and exit
#
# Exit minicom with Ctrl-A X.
set -euo pipefail

PROFILE_NAME=transpotter
PROFILE="$HOME/.minirc.$PROFILE_NAME"
BAUD=115200
MODE=minicom
PORT="${TRANSPOTTER_PORT:-}"

# Print the comment block at the top of this file, stopping at the first line
# of actual code, so the help text cannot drift out of sync with it.
usage() { awk 'NR>2 && /^#/ { sub(/^# ?/, ""); print; next } NR>2 { exit }' "$0"; }

while [ $# -gt 0 ]; do
  case "$1" in
    -m|--monitor) MODE=monitor ;;
    -r|--raw)     MODE=raw ;;
    -l|--list)    MODE=list ;;
    -h|--help)    usage; exit 0 ;;
    -*)           echo "unknown option: $1" >&2; usage >&2; exit 2 ;;
    *)            PORT="$1" ;;
  esac
  shift
done

# --- find the board ----------------------------------------------------------
# by-id first: the name is stable across replugs and unambiguous when several
# USB serial devices are attached. Falls back to matching Espressif's USB vendor
# id (0x303a) in sysfs, then to the usual device node.
list_ports() {
  local found=0
  for l in /dev/serial/by-id/*Espressif*; do
    [ -e "$l" ] && { echo "$l"; found=1; }
  done
  for d in /sys/class/tty/ttyACM* /sys/class/tty/ttyUSB*; do
    [ -e "$d" ] || continue
    [ "$(cat "$d/device/../idVendor" 2>/dev/null)" = "303a" ] || continue
    echo "/dev/$(basename "$d")"; found=1
  done
  [ "$found" -eq 0 ] && [ -e /dev/ttyACM0 ] && echo /dev/ttyACM0
  return 0
}

if [ "$MODE" = list ]; then
  echo "candidate ports:"; list_ports | sort -u | sed 's/^/  /'
  exit 0
fi

if [ -z "$PORT" ]; then
  PORT="$(list_ports | head -1 || true)"
fi

if [ -z "$PORT" ] || [ ! -e "$PORT" ]; then
  echo "error: no serial port found." >&2
  echo "       Plug the ESP32 in, or pass one explicitly: $0 /dev/ttyACM0" >&2
  echo "       '$0 -l' lists candidates." >&2
  exit 1
fi

if [ ! -w "$PORT" ]; then
  echo "error: $PORT is not writable. You likely need to be in the 'plugdev'" >&2
  echo "       or 'dialout' group: sudo usermod -aG plugdev \$USER (then re-login)." >&2
  exit 1
fi

# A second reader steals half the bytes and makes the console look broken — and
# blocks `pio run -t upload` outright. fuser/lsof are often not installed, so
# walk /proc instead: our own processes' fds are always readable.
port_holders() {
  local target pid
  target="$(readlink -f "$1" 2>/dev/null)" || return 0
  for l in /proc/[0-9]*/fd/*; do
    [ -e "$l" ] || continue
    [ "$(readlink -f "$l" 2>/dev/null)" = "$target" ] || continue
    pid="${l#/proc/}"; pid="${pid%%/*}"
    [ "$pid" = "$$" ] && continue
    echo "$pid $(tr '\0' ' ' < "/proc/$pid/cmdline" 2>/dev/null)"
  done | sort -u
}

HOLDERS="$(port_holders "$PORT")"
if [ -n "$HOLDERS" ]; then
  echo "warning: something else already has $PORT open:" >&2
  printf '%s\n' "$HOLDERS" | sed 's/^/         /' >&2
  echo "         close it first — two readers split the bytes between them," >&2
  echo "         and an upload cannot open the port at all." >&2
fi

# --- alternate modes ---------------------------------------------------------
case "$MODE" in
  monitor)
    exec pio device monitor -p "$PORT" -b "$BAUD"
    ;;
  raw)
    echo "raw mode on $PORT — type a command and press Enter, Ctrl-C to quit."
    stty -F "$PORT" "$BAUD" raw -echo -crtscts
    cat "$PORT" &
    CATPID=$!
    trap 'kill $CATPID 2>/dev/null || true' EXIT
    while IFS= read -r line; do printf '%s\n' "$line" > "$PORT"; done
    exit 0
    ;;
esac

# --- minicom -----------------------------------------------------------------
command -v minicom >/dev/null 2>&1 || {
  echo "error: minicom is not installed. Try '$0 -m' (pio device monitor)" >&2
  echo "       or '$0 -r' (raw), or: sudo apt install minicom" >&2
  exit 1
}

# Three minicom defaults make this board awkward, so the profile is written
# rather than assumed:
#   rtscts No     - the C3's USB CDC never asserts CTS, and minicom defaults
#                   hardware flow control ON, silently blocking every keystroke.
#   localecho     - the firmware does not echo, so without this nothing appears
#                   as you type and the terminal seems unresponsive.
#   addcarreturn  - turns a bare LF into CR+LF on the way in. Firmware that
#                   prints "\n" without "\r" otherwise staircases off the right
#                   of the screen. Harmless when the firmware already sends
#                   CR+LF, so it is on regardless.
WANT=$(cat <<PROFILE_EOF
# Written by $(basename "$0") — see that script for why these matter.
pu port             $PORT
pu baudrate         $BAUD
pu bits             8
pu parity           N
pu stopbits         1
pu rtscts           No
pu xonxoff          No
pu localecho        Yes
pu addcarreturn     Yes
PROFILE_EOF
)
# Rewrite whenever it differs, so a stale profile cannot quietly reintroduce
# any of the problems above.
if [ ! -f "$PROFILE" ] || [ "$(cat "$PROFILE")" != "$WANT" ]; then
  printf '%s\n' "$WANT" > "$PROFILE"
  echo "wrote $PROFILE"
fi

echo "connecting to $PORT at $BAUD  (Ctrl-A X to quit, Ctrl-A Z for help)"
echo "note: opening the port resets the ESP32 — expect the boot banner."
exec minicom "$PROFILE_NAME" -D "$PORT"