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

SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="${SCRIPT_DIR}"
VENV_PYTHON="${PROJECT_ROOT}/.venv/bin/python"
VENV_PIP="${PROJECT_ROOT}/.venv/bin/pip"
GUI_ENTRY="${PROJECT_ROOT}/python_app/gui/main.py"
REQUIREMENTS_FILE="${PROJECT_ROOT}/requirements.txt"
PYTHON_CMD=""
PROFILE_PATH=""

SKIP_BUILD=0
BUILD_ONLY=0
CLEAN_SHM=0
KAMIL_ADC_MODE=0
AUTO_START=0
PRODUCER_ONLY=0
HEADLESS=0

print_usage() {
    cat <<'EOF'
Usage: ./start.sh [options]

Options:
  --kamil-adc      Use the Raspberry Pi Kamil ADC profile
  --profile PATH   Use a specific GUI/run config profile
  --auto-start     Start the GUI pipeline automatically after launch
  --headless       Run without a display (Qt offscreen platform) and apply
                   the active radar config, then start the pipeline. Suitable
                   for unattended Raspberry Pi deployments. Implies
                   --auto-start.
  --producer-only  Run only the raw producer selected by the profile
  --skip-build     Skip C++ build step
  --build-only     Build C++ binaries and exit
  --clean-shm      Remove known radar shared-memory segments before start
  -h, --help       Show this help
EOF
}

parse_args() {
    while (($# > 0)); do
        case "$1" in
            --skip-build)
                SKIP_BUILD=1
                ;;
            --build-only)
                BUILD_ONLY=1
                ;;
            --clean-shm)
                CLEAN_SHM=1
                ;;
            --kamil-adc)
                KAMIL_ADC_MODE=1
                ;;
            --profile)
                if (($# < 2)); then
                    echo "--profile requires a path argument." >&2
                    exit 1
                fi
                PROFILE_PATH="$2"
                shift
                ;;
            --auto-start)
                AUTO_START=1
                ;;
            --headless)
                HEADLESS=1
                AUTO_START=1
                ;;
            --producer-only)
                PRODUCER_ONLY=1
                ;;
            -h|--help)
                print_usage
                exit 0
                ;;
            *)
                echo "Unknown argument: $1" >&2
                print_usage
                exit 1
                ;;
        esac
        shift
    done
}

absolute_path() {
    local path="$1"
    if [[ "${path}" = /* ]]; then
        printf '%s\n' "${path}"
        return
    fi
    printf '%s\n' "${PROJECT_ROOT}/${path}"
}

resolve_profile_path() {
    if ((KAMIL_ADC_MODE == 1)); then
        if [[ -z "${PROFILE_PATH}" ]]; then
            if [[ -f "${PROJECT_ROOT}/run_config_kamil_adc.pi.json" ]]; then
                PROFILE_PATH="${PROJECT_ROOT}/run_config_kamil_adc.pi.json"
            else
                PROFILE_PATH="${PROJECT_ROOT}/run_config_kamil_adc.example.json"
            fi
        fi
    fi

    if [[ -n "${PROFILE_PATH}" ]]; then
        PROFILE_PATH="$(absolute_path "${PROFILE_PATH}")"
        if [[ ! -f "${PROFILE_PATH}" ]]; then
            echo "Config profile not found: ${PROFILE_PATH}" >&2
            exit 1
        fi
    fi
}

check_environment() {
    if ! command -v python3 >/dev/null 2>&1; then
        echo "python3 is not installed or not found in PATH." >&2
        exit 1
    fi

    if [[ ! -f "${REQUIREMENTS_FILE}" ]]; then
        echo "Requirements file not found: ${REQUIREMENTS_FILE}" >&2
        exit 1
    fi

    if [[ ! -f "${GUI_ENTRY}" ]]; then
        echo "GUI entry not found: ${GUI_ENTRY}" >&2
        exit 1
    fi
}

ensure_python_dependencies() {
    local dependency_check
    if ((KAMIL_ADC_MODE == 1)); then
        dependency_check='import numpy, serial, PyQt6, pyqtgraph, usb1'
    else
        dependency_check='import numpy, serial, PyQt6, pyqtgraph, usb1, pyvisa'
    fi

    if [[ ! -x "${VENV_PYTHON}" ]]; then
        echo "[start.sh] Creating virtual environment..."
        python3 -m venv "${PROJECT_ROOT}/.venv"
    fi

    if [[ ! -x "${VENV_PIP}" ]]; then
        echo "pip is missing in virtual environment: ${VENV_PIP}" >&2
        exit 1
    fi

    if "${VENV_PYTHON}" -c "${dependency_check}" >/dev/null 2>&1; then
        PYTHON_CMD="${VENV_PYTHON}"
        return
    fi

    echo "[start.sh] Installing Python dependencies into virtual environment..."
    "${VENV_PIP}" install --upgrade pip
    "${VENV_PIP}" install -r "${REQUIREMENTS_FILE}"

    if ! "${VENV_PYTHON}" -c "${dependency_check}" >/dev/null 2>&1; then
        echo "Required Python dependencies are still unavailable in virtual environment: ${PROJECT_ROOT}/.venv" >&2
        exit 1
    fi

    PYTHON_CMD="${VENV_PYTHON}"
    echo "[start.sh] Using virtual environment: ${PYTHON_CMD}"
}

run_privileged() {
    if [[ "${EUID}" -eq 0 ]]; then
        "$@"
        return
    fi
    if command -v sudo >/dev/null 2>&1; then
        sudo "$@"
        return
    fi
    echo "Need elevated privileges to run: $*" >&2
    echo "Run as root or install 'sudo'." >&2
    exit 1
}

ensure_system_dependencies() {
    if command -v pkg-config >/dev/null 2>&1 && pkg-config --exists libusb-1.0; then
        return
    fi

    echo "[start.sh] Installing system dependency: libusb-1.0 dev headers..."
    if command -v apt-get >/dev/null 2>&1; then
        run_privileged apt-get update
        run_privileged apt-get install -y pkg-config libusb-1.0-0-dev
    elif command -v dnf >/dev/null 2>&1; then
        run_privileged dnf install -y pkgconf-pkg-config libusb1-devel
    elif command -v yum >/dev/null 2>&1; then
        run_privileged yum install -y pkgconfig libusb1-devel
    elif command -v pacman >/dev/null 2>&1; then
        run_privileged pacman -Sy --needed pkgconf libusb
    elif command -v zypper >/dev/null 2>&1; then
        run_privileged zypper --non-interactive install pkg-config libusb-1_0-devel
    elif command -v brew >/dev/null 2>&1; then
        brew install pkg-config libusb
    else
        echo "Could not detect supported package manager." >&2
        echo "Install manually: pkg-config and libusb development package." >&2
        exit 1
    fi

    if ! command -v pkg-config >/dev/null 2>&1 || ! pkg-config --exists libusb-1.0; then
        echo "libusb-1.0 development package is still unavailable after install attempt." >&2
        exit 1
    fi
}

ensure_usb_access_rules() {
    if [[ "$(uname -s)" != "Linux" ]]; then
        return
    fi
    if ! command -v udevadm >/dev/null 2>&1; then
        return
    fi

    local rule_file="/etc/udev/rules.d/99-radar-librevna.rules"
    local tmp_rule
    tmp_rule="$(mktemp)"

    cat > "${tmp_rule}" <<'EOF'
# LibreVNA USB access for non-root users
SUBSYSTEM=="usb", ATTR{idVendor}=="0483", ATTR{idProduct}=="564e", GROUP="plugdev", MODE="0660", TAG+="uaccess"
SUBSYSTEM=="usb", ATTR{idVendor}=="0483", ATTR{idProduct}=="4121", GROUP="plugdev", MODE="0660", TAG+="uaccess"
SUBSYSTEM=="usb", ATTR{idVendor}=="1209", ATTR{idProduct}=="4121", GROUP="plugdev", MODE="0660", TAG+="uaccess"
EOF

    if [[ -f "${rule_file}" ]] && cmp -s "${tmp_rule}" "${rule_file}"; then
        rm -f "${tmp_rule}"
        return
    fi

    echo "[start.sh] Installing udev rule for LibreVNA USB access..."
    run_privileged install -m 0644 "${tmp_rule}" "${rule_file}"
    rm -f "${tmp_rule}"

    run_privileged udevadm control --reload-rules
    run_privileged udevadm trigger
    echo "[start.sh] udev rules updated. Reconnect USB device if it is already plugged in."
}

build_cpp_binaries() {
    if make -C "${PROJECT_ROOT}" -q all >/dev/null 2>&1; then
        echo "[start.sh] C++ binaries are up to date; skipping build."
        return
    fi
    local jobs
    jobs="${BUILD_JOBS:-$(nproc)}"
    echo "[start.sh] Building C++ binaries (jobs=${jobs})..."
    make -C "${PROJECT_ROOT}" -j"${jobs}" all
}

cleanup_known_shm() {
    echo "[start.sh] Cleaning known shared-memory segments..."
    rm -f \
        /dev/shm/radar_raw \
        /dev/shm/radar_raw_tap \
        /dev/shm/radar_preprocessed \
        /dev/shm/radar_preprocessed_tap \
        /dev/shm/radar_results \
        /dev/shm/radar_raw_kamil_adc \
        /dev/shm/radar_raw_tap_kamil_adc \
        /dev/shm/radar_preprocessed_kamil_adc \
        /dev/shm/radar_preprocessed_tap_kamil_adc \
        /dev/shm/radar_results_kamil_adc \
        || true
}

run_gui() {
    if [[ -n "${PROFILE_PATH}" ]]; then
        export RADAR_SYSTEM_PROFILE="${PROFILE_PATH}"
        echo "[start.sh] Using config profile: ${PROFILE_PATH}"
    fi
    if ((AUTO_START == 1)); then
        export RADAR_SYSTEM_AUTO_START=1
        echo "[start.sh] GUI auto-start is enabled."
    fi
    if ((HEADLESS == 1)); then
        # Qt offscreen platform lets the GUI controller and its event loop run
        # on a machine with no display (typical Raspberry Pi deployment). All
        # backend services — supervisor, Python device drivers, SHM readers,
        # locator client (vlc) handling — continue to work unchanged.
        export QT_QPA_PLATFORM=offscreen
        export RADAR_SYSTEM_HEADLESS=1
        export RADAR_SYSTEM_AUTO_APPLY_RADAR=1
        echo "[start.sh] Headless mode: Qt offscreen + auto apply-radar + auto-start."
    fi

    echo "[start.sh] Launching GUI..."
    exec "${PYTHON_CMD}" "${GUI_ENTRY}"
}

run_producer_only() {
    if ((KAMIL_ADC_MODE != 1)); then
        echo "--producer-only currently requires --kamil-adc." >&2
        exit 1
    fi
    if [[ -z "${PROFILE_PATH}" ]]; then
        echo "--producer-only requires a resolved config profile." >&2
        exit 1
    fi

    export PYTHONPATH="${PROJECT_ROOT}${PYTHONPATH:+:${PYTHONPATH}}"
    echo "[start.sh] Starting Kamil ADC raw producer with profile: ${PROFILE_PATH}"
    exec "${PYTHON_CMD}" -m python_app.scripts.kamil_adc_raw_producer --config "${PROFILE_PATH}"
}

main() {
    parse_args "$@"
    resolve_profile_path
    check_environment
    if ((KAMIL_ADC_MODE == 0)); then
        ensure_system_dependencies
        ensure_usb_access_rules
    fi
    ensure_python_dependencies

    if ((CLEAN_SHM == 1)); then
        cleanup_known_shm
    fi

    if ((SKIP_BUILD == 0)); then
        build_cpp_binaries
    fi

    if ((BUILD_ONLY == 1)); then
        echo "[start.sh] Build completed."
        exit 0
    fi

    if ((PRODUCER_ONLY == 1)); then
        run_producer_only
    fi

    run_gui
}

main "$@"