#!/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=""

# Single-instance coordination: the headless daemon and the interactive GUI
# must never run at once (they share the radar, SHM rings and locator port).
SERVICE_NAME="radar.service"
LOCK_FILE="/tmp/radar_system.lock"

SKIP_BUILD=0
BUILD_ONLY=0
CLEAN_SHM=0
AUTO_START=0
PRODUCER_ONLY=0
HEADLESS=0
# Acquisition device, detected from the active run config's radar.model. Drives
# device-specific provisioning, dependencies, and which collector binary to build
# — so every device launches the same way (no per-device flags).
RADAR_MODEL=""

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

Options:
  --profile PATH   Use a specific GUI/run config profile (device is auto-detected
                   from its radar.model)
  --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 "$1" in
            --skip-build)
                SKIP_BUILD=1
                ;;
            --build-only)
                BUILD_ONLY=1
                ;;
            --clean-shm)
                CLEAN_SHM=1
                ;;
            --profile)
                if (($# < 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 [[ -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
}

# Resolve the config that will actually be used (explicit --profile, else the
# active run_config.json) and read its radar.model. Best-effort: any failure
# falls back to 'librevna' (the full-provisioning superset), so detection can
# never make a launch less safe. Uses system python3 (the venv may not exist yet).
detect_radar_model() {
    local config_path="${PROFILE_PATH:-${PROJECT_ROOT}/run_config.json}"
    RADAR_MODEL="librevna"
    [[ -f "${config_path}" ]] || return
    local detected
    detected="$(python3 -c '
import json, sys
try:
    with open(sys.argv[1]) as handle:
        data = json.load(handle)
    radar = data.get("radar") if isinstance(data, dict) else {}
    model = radar.get("model") if isinstance(radar, dict) else None
    print(model or "librevna")
except Exception:
    print("librevna")
' "${config_path}" 2>/dev/null)" || detected=""
    [[ -n "${detected}" ]] && RADAR_MODEL="${detected}"
    echo "[start.sh] Detected radar model: ${RADAR_MODEL} (config: ${config_path})"
}

# Acquisition producer for the active model, mirroring the process supervisor's
# selection so --producer-only behaves identically to a full pipeline launch.
producer_command() {
    local config_path="$1"
    case "${RADAR_MODEL}" in
        kamil_adc)
            printf '%s\0' "${PYTHON_CMD}" -m python_app.scripts.kamil_adc_raw_producer --config "${config_path}" ;;
        librevna_multi|sn9000)
            printf '%s\0' "${PYTHON_CMD}" -m python_app.scripts.matrix_raw_producer --config "${config_path}" ;;
        *)
            printf '%s\0' "${PROJECT_ROOT}/build/bin/sweep_orchestrator" --config "${config_path}" ;;
    esac
}

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 [[ "${RADAR_MODEL}" == "kamil_adc" ]]; then
        # Kamil ADC has no VISA dependency (it talks to its own L-Card collector).
        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

    if ((HEADLESS == 1)); then
        # Headless = unattended (often offline) appliance: never attempt a network
        # pip install that could hang or crash-loop the service. Provisioning is a
        # one-time interactive step. Fail fast with a clear, actionable message.
        echo "Python dependencies are missing and headless mode does not provision them." >&2
        echo "Run an interactive './start.sh' once (online) to create the venv, then retry." >&2
        exit 1
    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() {
    local jobs
    jobs="${BUILD_JOBS:-$(nproc)}"
    # The Kamil ADC collector is an extra, device-specific binary built only for
    # that model; all models share the core pipeline binaries (`all`).
    local targets="all"
    if [[ "${RADAR_MODEL}" == "kamil_adc" ]]; then
        targets="all kamil_adc_collector"
    fi
    if make -C "${PROJECT_ROOT}" -q ${targets} >/dev/null 2>&1; then
        echo "[start.sh] C++ binaries are up to date; skipping build."
        return
    fi
    echo "[start.sh] Building C++ binaries (jobs=${jobs}, targets: ${targets})..."
    make -C "${PROJECT_ROOT}" -j"${jobs}" ${targets}
}

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
}

kill_stale_adc_collector() {
    # The L-Card ADC collector runs in its own session and can outlive a crashed
    # or force-killed run, holding the E-502 device and hanging the next start.
    # Kill any leftover hard before launching so acquisition always opens cleanly.
    if command -v pkill >/dev/null 2>&1; then
        if pkill -9 -f kamil_adc_collector 2>/dev/null; then
            echo "[start.sh] Killed leftover ADC collector process(es)."
        fi
    fi
}

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() {
    local config_path="${PROFILE_PATH:-${PROJECT_ROOT}/run_config.json}"
    if [[ ! -f "${config_path}" ]]; then
        echo "--producer-only needs a config (pass --profile, or create run_config.json)." >&2
        exit 1
    fi

    export PYTHONPATH="${PROJECT_ROOT}${PYTHONPATH:+:${PYTHONPATH}}"
    # Run the acquisition producer the supervisor would pick for this model.
    local -a command=()
    while IFS= read -r -d '' token; do
        command+=("${token}")
    done < <(producer_command "${config_path}")
    echo "[start.sh] Starting ${RADAR_MODEL} producer: ${command[*]}"
    exec "${command[@]}"
}

stop_headless_service() {
    # Stop the headless daemon (if running) so it releases the radar, SHM rings
    # and locator port before the interactive GUI/producer takes over. Relies on
    # the passwordless sudoers rule installed by deploy/install-daemon.sh. Safe
    # no-op when systemd or the unit is absent (is-active is false -> skip).
    command -v systemctl >/dev/null 2>&1 || return 0
    if systemctl is-active --quiet "${SERVICE_NAME}"; then
        echo "[start.sh] Stopping ${SERVICE_NAME} so the GUI can take over the hardware..."
        # Non-fatal: a sudo/systemctl failure must not abort the GUI launch under
        # `set -e`. The single-instance lock below still prevents a real conflict.
        if ! sudo systemctl stop "${SERVICE_NAME}"; then
            echo "[start.sh] WARNING: failed to stop ${SERVICE_NAME}; relying on the instance lock." >&2
        fi
    fi
}

verify_cpp_binaries() {
    # Guard the daemon's --skip-build path: refuse to run against a tree whose C++
    # binaries were never built, instead of failing obscurely at spawn time.
    local missing=0 bin
    local required_bins="data_processor data_preprocessor"
    # Kamil ADC also needs its acquisition collector; other models use the C++
    # sweep_orchestrator, which `all` always builds.
    if [[ "${RADAR_MODEL}" == "kamil_adc" ]]; then
        required_bins="${required_bins} kamil_adc_collector"
    fi
    for bin in ${required_bins}; do
        if [[ ! -x "${PROJECT_ROOT}/build/bin/${bin}" ]]; then
            echo "Required binary missing or not executable: build/bin/${bin}" >&2
            missing=1
        fi
    done
    if ((missing == 1)); then
        echo "Build the C++ binaries first: run ./start.sh without --skip-build, or 'make all'." >&2
        exit 1
    fi
}

acquire_single_instance_lock() {
    # Fail fast if another instance already owns the hardware, instead of
    # surfacing a cryptic 'shm ring busy' / 'port in use' later. fd 9 survives
    # the exec into Python, so the lock is held for the whole app lifetime.
    exec 9>"${LOCK_FILE}"
    if ! flock -n 9; then
        echo "[start.sh] Another radar instance already holds ${LOCK_FILE}; aborting." >&2
        echo "[start.sh] Stop it first: sudo systemctl stop ${SERVICE_NAME} (or close the other run)." >&2
        exit 1
    fi
}

main() {
    parse_args "$@"
    resolve_profile_path
    check_environment
    detect_radar_model
    # Skip first-time provisioning (build headers, USB udev rule) in headless
    # mode: the daemon runs unattended at boot as a non-root user and must not
    # block on sudo. A fresh machine is provisioned by one interactive launch.
    # Also skip it for non-LibreVNA devices (e.g. Kamil ADC), which neither use
    # libusb directly nor need the LibreVNA USB access rule.
    if [[ "${RADAR_MODEL}" != "kamil_adc" ]] && ((HEADLESS == 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

    verify_cpp_binaries

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

    # Interactive GUI/producer launch: stop the headless daemon first so it
    # frees the radar, SHM and locator port. The daemon itself runs --headless
    # and skips this, so it never stops itself.
    if ((HEADLESS == 0)); then
        stop_headless_service
    fi
    acquire_single_instance_lock
    # Clear any ADC collector wedged by a previous run before we launch a new one.
    kill_stale_adc_collector

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

    run_gui
}

main "$@"