#!/bin/bash

# =================================================================
# Bushnell Northstar / Meade Autostar Telescope Control Script
# =================================================================
# Controls a telescope via serial port using Arrow Keys and Number Keys.
# Protocol: Meade LX200 / Autostar Generic
#
# CONTROLS:
#   Arrow Keys : Start moving (North/South/East/West)
#   Spacebar   : STOP Moving (Important!)
#   1-9        : Set Speed (1=Slowest/Guide, 9=Fastest/Slew)
#   q          : Quit the program
# =================================================================

# Default Serial Port (can be changed by user input)
SERIAL_PORT="/dev/ttyS0"

# Function to attempt to auto-detect the telescope
scan_ports() {
    echo "Scanning ports for telescope response (sending :GR#)..."
    FOUND_PORT=""

    # Check common serial device patterns
    for port in /dev/ttyUSB* /dev/ttyS[0-9]; do
        # Check if port exists
        if [ -e "$port" ]; then
            # Configure port temporarily for the check (timeout 1s)
            # 9600 baud, raw input
            if stty -F "$port" 9600 cs8 -cstopb -parenb raw -echo 2>/dev/null; then

                # Clear any existing data in buffer (background read with short timeout)
                timeout 0.2s cat "$port" >/dev/null 2>&1

                # Send "Get RA" command
                echo -ne ":GR#" > "$port" 2>/dev/null

                # Try to read response (up to 10 chars, 1 second timeout)
                # Meade/Northstar response format is typically "HH:MM.T#"
                # We pipe to 'tr -d \0' to remove null bytes that cause Bash warnings
                RESPONSE=$(timeout 1s head -c 10 "$port" 2>/dev/null | tr -d '\0')

                # Check if response contains typical telescope characters (# or digits)
                if [[ "$RESPONSE" == *"#"* ]] || [[ "$RESPONSE" =~ [0-9] ]]; then
                    echo "  [FOUND] Telescope detected on $port (Response: $RESPONSE)"
                    FOUND_PORT="$port"
                else
                    echo "  [ ... ] Checked $port - No valid response"
                fi
            else
                echo "  [ ERR ] Could not configure $port (Permission denied?)"
            fi
        fi
    done

    if [ ! -z "$FOUND_PORT" ]; then
        echo ""
        echo "Auto-selected likely port: $FOUND_PORT"
        SERIAL_PORT="$FOUND_PORT"
    else
        echo "Scan complete. No obvious telescope response found."
    fi
}

# -----------------------------------------------------------------
# 1. Setup Serial Port
# -----------------------------------------------------------------
echo "-----------------------------------------------------"
echo "  Telescope Control Interface (Bash)"
echo "-----------------------------------------------------"

# Run the scan function
scan_ports

echo "-----------------------------------------------------"
echo "Available Serial Ports:"
ls /dev/ttyS* /dev/ttyUSB* 2>/dev/null
echo ""
read -p "Enter Serial Port [default: $SERIAL_PORT]: " USER_PORT

if [ ! -z "$USER_PORT" ]; then
    SERIAL_PORT="$USER_PORT"
fi

if [ ! -e "$SERIAL_PORT" ]; then
    echo "Error: Port $SERIAL_PORT does not exist."
    exit 1
fi

# Configure the serial port using stty
# 9600 baud, 8N1 (Standard for Northstar/Autostar), raw mode to prevent buffering
stty -F "$SERIAL_PORT" 9600 cs8 -cstopb -parenb raw -echo

echo "Connected to $SERIAL_PORT at 9600 baud."
echo "Initializing..."

# Send a Stop command just in case
echo -ne ":Q#" > "$SERIAL_PORT"

# -----------------------------------------------------------------
# 2. Control Loop
# -----------------------------------------------------------------
CURRENT_SPEED="Max"

print_ui() {
    clear
    echo "====================================================="
    echo "  TELESCOPE CONTROL PANEL"
    echo "====================================================="
    echo "  Port: $SERIAL_PORT  |  Status: Ready"
    echo "-----------------------------------------------------"
    echo "  [ UP ]    Move North"
    echo "  [DOWN]    Move South"
    echo "  [LEFT]    Move West"
    echo "  [RGHT]    Move East"
    echo "  [SPACE]   STOP ALL MOTORS"
    echo "-----------------------------------------------------"
    echo "  Current Speed Setting: $CURRENT_SPEED"
    echo "  [1-2] Guide (Slowest/Nudge)"
    echo "  [3-5] Center (Slow)"
    echo "  [6-8] Find (Medium)"
    echo "  [9]   Slew (Max Speed)"
    echo "-----------------------------------------------------"
    echo "  Press 'q' to Quit Script"
    echo "====================================================="
}

print_ui

# Loop to capture keystrokes one by one
while true; do
    # Read 1 character silently (-s), 3 chars if it's an escape sequence
    read -rsn1 key

    # If key is empty (sometimes happens), skip
    if [[ -z "$key" ]]; then continue; fi

    # Handle Escape Sequences (Arrow Keys start with ESC)
    if [[ "$key" == $'\x1b' ]]; then
        read -rsn2 key # Read the next 2 characters
        case "$key" in
            '[A') # UP Arrow
                echo -ne ":Mn#" > "$SERIAL_PORT"
                ;;
            '[B') # DOWN Arrow
                echo -ne ":Ms#" > "$SERIAL_PORT"
                ;;
            '[D') # LEFT Arrow
                echo -ne ":Mw#" > "$SERIAL_PORT"
                ;;
            '[C') # RIGHT Arrow
                echo -ne ":Me#" > "$SERIAL_PORT"
                ;;
        esac
    else
        # Handle Standard Keys
        case "$key" in
            # SPACEBAR - The most important key! Stops the telescope.
            ' ')
                echo -ne ":Q#" > "$SERIAL_PORT"
                ;;

            # Speed Controls (Mapped to Meade Standard Rate Commands)
            '1'|'2')
                # Guide Rate (Very Slow / Nudge)
                echo -ne ":RG#" > "$SERIAL_PORT"
                CURRENT_SPEED="Guide (Slowest)"
                print_ui
                ;;
            '3'|'4'|'5')
                # Center Rate (Slow)
                echo -ne ":RC#" > "$SERIAL_PORT"
                CURRENT_SPEED="Center (Slow)"
                print_ui
                ;;
            '6'|'7'|'8')
                # Find Rate (Medium)
                echo -ne ":RM#" > "$SERIAL_PORT"
                CURRENT_SPEED="Find (Medium)"
                print_ui
                ;;
            '9')
                # Slew Rate (Fastest)
                echo -ne ":RS#" > "$SERIAL_PORT"
                CURRENT_SPEED="Slew (Max)"
                print_ui
                ;;

            # Quit Application
            'q')
                echo "Stopping telescope..."
                echo -ne ":Q#" > "$SERIAL_PORT"
                exit 0
                ;;
        esac
    fi
done