#!/bin/bash
# extract-kernel-config.sh — Pull kernel config from Tiny Core rootfs
# Usage: ./hack/extract-kernel-config.sh [path-to-core.gz]
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
ROOTFS_DIR="${ROOTFS_DIR:-$PROJECT_ROOT/build/rootfs-work}"

COREGZ="${1:-$ROOTFS_DIR/rootfs}"
OUTPUT="$PROJECT_ROOT/build/cache/kernel-config"

if [ -d "$COREGZ" ]; then
    # Rootfs already extracted
    ROOTFS="$COREGZ"
elif [ -f "$COREGZ" ]; then
    # Extract core.gz
    TMPDIR=$(mktemp -d)
    cd "$TMPDIR"
    zcat "$COREGZ" | cpio -idm 2>/dev/null
    ROOTFS="$TMPDIR"
fi

# Try /proc/config.gz in rootfs
if [ -f "$ROOTFS/proc/config.gz" ]; then
    zcat "$ROOTFS/proc/config.gz" > "$OUTPUT"
    echo "==> Extracted kernel config to: $OUTPUT"
    "$PROJECT_ROOT/build/config/kernel-audit.sh" "$OUTPUT"
else
    echo "Kernel config not found in rootfs /proc/config.gz"
    echo ""
    echo "Alternative: Boot the Tiny Core ISO in QEMU and run:"
    echo "  zcat /proc/config.gz > /tmp/kernel-config"
    echo "  # Then copy it out"
    echo ""
    echo "Or check if /boot/config-* exists in the ISO"

    # Try looking in /boot
    for f in "$ROOTFS"/boot/config-*; do
        [ -f "$f" ] || continue
        cp "$f" "$OUTPUT"
        echo "==> Found boot config: $f → $OUTPUT"
        "$PROJECT_ROOT/build/config/kernel-audit.sh" "$OUTPUT"
        exit 0
    done
fi

[ -d "${TMPDIR:-}" ] && rm -rf "$TMPDIR"