#!/bin/bash
# Installs Paperwall on this machine, in place. Standalone -- doesn't require
# InkyPi to be installed. If InkyPi (or anything else) happens to already be
# running against the same panel, this stops it, since two processes can't
# both drive the same SPI display.
#
# Run this ON the Pi, from wherever you copied the project folder to (e.g.
# via SFTP): `sudo bash install.sh`

set -euo pipefail

# Resolve the real directory this script lives in, even through symlinks.
SOURCE="${BASH_SOURCE[0]}"
while [ -h "$SOURCE" ]; do
  DIR=$(cd -P "$(dirname "$SOURCE")" >/dev/null 2>&1 && pwd)
  SOURCE=$(readlink "$SOURCE")
  [[ $SOURCE != /* ]] && SOURCE="$DIR/$SOURCE"
done
APP_DIR=$(cd -P "$(dirname "$SOURCE")" >/dev/null 2>&1 && pwd)

VENV_DIR="$APP_DIR/venv"
SERVICE_NAME="paperwall.service"
SERVICE_TARGET="/etc/systemd/system/$SERVICE_NAME"
CONFIG_TXT="/boot/firmware/config.txt"
[ -f "$CONFIG_TXT" ] || CONFIG_TXT="/boot/config.txt"

step() { echo -e "\n==> $1"; }

check_permissions() {
  if [ "$EUID" -ne 0 ]; then
    echo "ERROR: run with sudo (sudo bash install.sh)" >&2
    exit 1
  fi
}

install_system_dependencies() {
  step "Installing system dependencies (python3-venv, lgpio/spidev build deps)"
  apt-get update -qq
  apt-get install -y -qq python3-venv python3-pip python3-dev liblgpio-dev swig
}

enable_spi_i2c() {
  step "Enabling SPI/I2C in $CONFIG_TXT"
  if [ ! -f "$CONFIG_TXT" ]; then
    echo "  WARNING: $CONFIG_TXT not found -- enable SPI/I2C manually for your platform." >&2
    return
  fi

  if grep -qE '^\s*dtparam=spi=on' "$CONFIG_TXT"; then
    echo "  SPI already enabled."
  else
    sed -i -E 's/^#?\s*dtparam=spi=.*/dtparam=spi=on/' "$CONFIG_TXT"
    grep -qE '^\s*dtparam=spi=on' "$CONFIG_TXT" || echo "dtparam=spi=on" >> "$CONFIG_TXT"
    echo "  SPI enabled (reboot required)."
  fi

  # This panel uses both SPI chip-select lines.
  if ! grep -qE '^\s*dtoverlay=spi0-2cs' "$CONFIG_TXT"; then
    echo "dtoverlay=spi0-2cs" >> "$CONFIG_TXT"
    echo "  Added dtoverlay=spi0-2cs (reboot required)."
  fi

  if grep -qE '^\s*dtparam=i2c_arm=on' "$CONFIG_TXT"; then
    echo "  I2C already enabled."
  else
    sed -i -E 's/^#?\s*dtparam=i2c_arm=.*/dtparam=i2c_arm=on/' "$CONFIG_TXT"
    grep -qE '^\s*dtparam=i2c_arm=on' "$CONFIG_TXT" || echo "dtparam=i2c_arm=on" >> "$CONFIG_TXT"
    echo "  I2C enabled (reboot required)."
  fi
}

create_venv() {
  step "Creating Python virtual environment at $VENV_DIR"
  python3 -m venv "$VENV_DIR"
  "$VENV_DIR/bin/python" -m pip install --upgrade -q pip
  "$VENV_DIR/bin/python" -m pip install -q -r "$APP_DIR/requirements.txt" -r "$APP_DIR/requirements-pi.txt"
  echo "  done."
}

stop_conflicting_services() {
  step "Checking for other software already driving this panel"
  if systemctl list-unit-files inkypi.service >/dev/null 2>&1 && systemctl is-active --quiet inkypi.service; then
    systemctl disable --now inkypi.service
    echo "  Stopped and disabled inkypi.service (left installed, not removed)."
  else
    echo "  Nothing else running against the panel."
  fi
}

install_service() {
  step "Installing $SERVICE_NAME"
  sed \
    -e "s#{{APP_DIR}}#$APP_DIR#g" \
    -e "s#{{PYTHON}}#$VENV_DIR/bin/python3#g" \
    "$APP_DIR/paperwall.service.template" > "$SERVICE_TARGET"
  systemctl daemon-reload
  systemctl enable --now "$SERVICE_NAME"
  echo "  installed and started."
}

show_status() {
  step "Status"
  sleep 2
  systemctl status "$SERVICE_NAME" --no-pager -l | head -15 || true
  ip_address=$(hostname -I | awk '{print $1}')
  echo
  echo "Web UI: http://$ip_address:8080  (or http://$(hostname).local:8080)"
  echo "Logs:   journalctl -u $SERVICE_NAME -f"
  echo "Remove: sudo bash uninstall.sh"
  if grep -qE '^\s*dtoverlay=spi0-2cs' "$CONFIG_TXT" 2>/dev/null; then
    echo
    echo "NOTE: if SPI/I2C were just newly enabled above, reboot for that to take effect:"
    echo "      sudo reboot"
  fi
}

check_permissions
install_system_dependencies
enable_spi_i2c
create_venv
stop_conflicting_services
install_service
show_status