#!/usr/bin/env bash
# cxos/vendor/busybox/build.sh — build a static busybox + install into rootfs.
#
# Usage:
#   build.sh                              # x86_64, install into dist/cxos/rootfs
#   build.sh --arch aarch64
#   build.sh --rootfs /path/to/rootfs
#   build.sh --dry
#
# After install:
#   <rootfs>/bin/busybox      static binary (~1 MB)
#   <rootfs>/bin/* ./sbin/*   symlinks to busybox (one per applet)
set -euo pipefail

ARCH="x86_64"
DRY=0
ROOTFS=""
for ((i=1; i<=$#; i++)); do
    case "${!i}" in
        --arch)   ((i++)); ARCH="${!i}" ;;
        --rootfs) ((i++)); ROOTFS="${!i}" ;;
        --dry)    DRY=1 ;;
        -h|--help) sed -n '2,12p' "$0" | sed 's/^# \{0,1\}//'; exit 0 ;;
        *) echo "build.sh: unknown arg: ${!i}" >&2; exit 2 ;;
    esac
done

HERE="$(cd "$(dirname "$0")" && pwd)"
REPO_ROOT="$(cd "$HERE/../../.." && pwd)"
PINNED="$HERE/PINNED.json"
FRAGMENT="$HERE/cxos.config.fragment"

VERSION="$(python3 -c 'import json,sys;print(json.load(open(sys.argv[1]))["version"])' "$PINNED")"
EXTRACTED_DIR="$(python3 -c 'import json,sys;print(json.load(open(sys.argv[1]))["extracted_dir"])' "$PINNED")"
SRC="$HERE/src/$EXTRACTED_DIR"
ROOTFS="${ROOTFS:-$REPO_ROOT/dist/cxos/rootfs}"

case "$ARCH" in
    x86_64)  CROSS="" ;;
    aarch64) CROSS="${CROSS_COMPILE:-aarch64-linux-gnu-}" ;;
    *) echo "build.sh: unsupported arch: $ARCH" >&2; exit 2 ;;
esac

JOBS="${JOBS:-$(nproc 2>/dev/null || echo 2)}"

echo "==> busybox ${VERSION} (${ARCH}) -> ${ROOTFS}"
echo "    src     : ${SRC}"
echo "    fragment: ${FRAGMENT}"
echo "    cross   : ${CROSS:-<native>}"
echo "    jobs    : ${JOBS}"

if [[ "$DRY" == "1" ]]; then
    echo "==> dry-run; not compiling"
    exit 0
fi

[[ -d "$SRC" ]] || { echo "build.sh: source not extracted; run fetch.sh first" >&2; exit 1; }

cd "$SRC"
make CROSS_COMPILE="$CROSS" defconfig

# Apply fragment overrides line-by-line. Lines that start with '#' or are
# blank are skipped. KEY=VALUE lines replace any existing KEY= line, or are
# appended if absent.
while IFS= read -r line; do
    [[ -z "$line" || "$line" == \#* ]] && continue
    key="${line%%=*}"
    if grep -qE "^# ${key} is not set$|^${key}=" .config; then
        sed -i -E "s|^# ${key} is not set\$|${line}|; s|^${key}=.*|${line}|" .config
    else
        printf '%s\n' "$line" >> .config
    fi
done < "$FRAGMENT"

make CROSS_COMPILE="$CROSS" oldconfig
make CROSS_COMPILE="$CROSS" -j"$JOBS" busybox

mkdir -p "$ROOTFS"
make CROSS_COMPILE="$CROSS" CONFIG_PREFIX="$ROOTFS" install

# busybox install creates /linuxrc symlink — pointless on initramfs (we have
# our own /init).  Drop it.
rm -f "$ROOTFS/linuxrc"

echo "==> installed: $(find "$ROOTFS/bin" "$ROOTFS/sbin" -maxdepth 1 -mindepth 1 2>/dev/null | wc -l) applets"