#!/bin/bash
# qemu-helpers.sh — Shared functions for QEMU-based tests
# Source this file from test scripts: . "$(dirname "$0")/../lib/qemu-helpers.sh"

# extract_kernel_from_iso <iso-path> <extract-dir>
# Sets VMLINUZ and INITRAMFS variables on success
# Falls back to build/rootfs-work/ if available
extract_kernel_from_iso() {
    local iso="$1"
    local extract_dir="$2"
    local project_root="${PROJECT_ROOT:-$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)}"
    local rootfs_dir="${ROOTFS_DIR:-$project_root/build/rootfs-work}"

    VMLINUZ=""
    INITRAMFS=""

    # Prefer build artifacts (no extraction needed)
    if [ -f "$rootfs_dir/vmlinuz" ] && [ -f "$rootfs_dir/kubesolo-os.gz" ]; then
        VMLINUZ="$rootfs_dir/vmlinuz"
        INITRAMFS="$rootfs_dir/kubesolo-os.gz"
        echo "    Using kernel/initramfs from build directory"
        return 0
    fi

    local extracted=0

    echo "    Extracting kernel/initramfs from ISO..."

    # Method 1: bsdtar (ships with macOS, libarchive-tools on Linux)
    if [ $extracted -eq 0 ] && command -v bsdtar >/dev/null 2>&1; then
        if bsdtar -xf "$iso" -C "$extract_dir" boot/vmlinuz boot/kubesolo-os.gz 2>/dev/null; then
            echo "    Extracted via bsdtar"
            extracted=1
        fi
    fi

    # Method 2: isoinfo (genisoimage/cdrtools)
    if [ $extracted -eq 0 ] && command -v isoinfo >/dev/null 2>&1; then
        mkdir -p "$extract_dir/boot"
        isoinfo -i "$iso" -x "/BOOT/VMLINUZ;1" > "$extract_dir/boot/vmlinuz" 2>/dev/null || true
        isoinfo -i "$iso" -x "/BOOT/KUBESOLO-OS.GZ;1" > "$extract_dir/boot/kubesolo-os.gz" 2>/dev/null || true
        if [ -s "$extract_dir/boot/vmlinuz" ] && [ -s "$extract_dir/boot/kubesolo-os.gz" ]; then
            echo "    Extracted via isoinfo"
            extracted=1
        else
            rm -f "$extract_dir/boot/vmlinuz" "$extract_dir/boot/kubesolo-os.gz"
        fi
    fi

    # Method 3: loop mount (Linux only, may need root)
    if [ $extracted -eq 0 ] && [ "$(uname)" = "Linux" ]; then
        local iso_mount="$extract_dir/mnt"
        mkdir -p "$iso_mount"
        if mount -o loop,ro "$iso" "$iso_mount" 2>/dev/null; then
            mkdir -p "$extract_dir/boot"
            cp "$iso_mount/boot/vmlinuz" "$extract_dir/boot/" 2>/dev/null || true
            cp "$iso_mount/boot/kubesolo-os.gz" "$extract_dir/boot/" 2>/dev/null || true
            umount "$iso_mount" 2>/dev/null || true
            if [ -f "$extract_dir/boot/vmlinuz" ] && [ -f "$extract_dir/boot/kubesolo-os.gz" ]; then
                echo "    Extracted via loop mount"
                extracted=1
            fi
        fi
    fi

    if [ $extracted -eq 0 ]; then
        echo "ERROR: Failed to extract kernel/initramfs from ISO."
        echo "  Install one of: bsdtar (libarchive-tools), isoinfo (genisoimage), or run as root for loop mount."
        return 1
    fi

    VMLINUZ="$extract_dir/boot/vmlinuz"
    INITRAMFS="$extract_dir/boot/kubesolo-os.gz"
    return 0
}

# detect_kvm — prints "-enable-kvm" if KVM available, empty string otherwise
detect_kvm() {
    if [ -w /dev/kvm ] 2>/dev/null; then
        echo "-enable-kvm"
    fi
}