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

L4T_VERSION="${L4T_VERSION:-r36.4.4}"
L4T_DIR="${L4T_DIR:-/opt/nvidia/Linux_for_Tegra}"
ROOTFS_DIR="${ROOTFS_DIR:-${L4T_DIR}/rootfs}"

l4t_download_url() {
    local version="$1"
    local major minor patch
    IFS='.' read -r major minor patch <<< "${version#r}"
    echo "https://developer.nvidia.com/downloads/embedded/l4t/r${major}_release_v${minor}.${patch}/release/Jetson_Linux_${version}_aarch64.tbz2"
}

rootfs_download_url() {
    local version="$1"
    local major minor patch
    IFS='.' read -r major minor patch <<< "${version#r}"
    echo "https://developer.nvidia.com/downloads/embedded/l4t/r${major}_release_v${minor}.${patch}/release/Tegra_Linux_Sample-Root-Filesystem_${version}_aarch64.tbz2"
}

if [[ -f "$L4T_DIR/flash.sh" ]]; then
    echo "L4T BSP already installed at $L4T_DIR"
else
    echo "L4T BSP not found at $L4T_DIR"
    echo "Downloading and installing L4T $L4T_VERSION..."

    bsp_url="$(l4t_download_url "$L4T_VERSION")"
    rootfs_url="$(rootfs_download_url "$L4T_VERSION")"
    tmp_dir="$(mktemp -d)"

    echo "  Downloading BSP from $bsp_url ..."
    wget -q --show-progress -O "$tmp_dir/bsp.tbz2" "$bsp_url"

    echo "  Downloading Sample Root Filesystem from $rootfs_url ..."
    wget -q --show-progress -O "$tmp_dir/rootfs.tbz2" "$rootfs_url"

    echo "  Extracting BSP to $(dirname "$L4T_DIR")/ ..."
    sudo mkdir -p "$(dirname "$L4T_DIR")"
    sudo tar -xjf "$tmp_dir/bsp.tbz2" -C "$(dirname "$L4T_DIR")"

    echo "  Extracting rootfs to $L4T_DIR/rootfs/ ..."
    sudo tar -xjf "$tmp_dir/rootfs.tbz2" -C "$L4T_DIR/rootfs/"

    echo "  Running apply_binaries.sh ..."
    sudo "$L4T_DIR/apply_binaries.sh"

    rm -rf "$tmp_dir"
    echo "L4T $L4T_VERSION installed to $L4T_DIR"
fi

for tool in flash.sh odmfuse.sh; do
    if [[ ! -f "$L4T_DIR/$tool" ]]; then
        echo "ERROR: $L4T_DIR/$tool not found after L4T setup" >&2
        exit 1
    fi
done

NV_RELEASE="$L4T_DIR/rootfs/etc/nv_tegra_release"
if [[ -f "$NV_RELEASE" ]]; then
    echo "L4T release: $(head -1 "$NV_RELEASE")"
fi