#!/bin/bash
# dev-vm.sh — Launch a QEMU VM for development and testing
# Usage: ./hack/dev-vm.sh [path-to-iso-or-img] [--shell] [--debug]
#
# Works on both Linux (with KVM) and macOS (TCG emulation).
# On macOS/Apple Silicon, x86_64 guests run under TCG (~5-15x slower than KVM).
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
VERSION="$(cat "$PROJECT_ROOT/VERSION")"
ROOTFS_DIR="${ROOTFS_DIR:-$PROJECT_ROOT/build/rootfs-work}"
DEFAULT_ISO="$PROJECT_ROOT/output/kubesolo-os-${VERSION}.iso"
DEFAULT_IMG="$PROJECT_ROOT/output/kubesolo-os-${VERSION}.img"

IMAGE=""
EXTRA_APPEND=""

# Parse all arguments — flags and optional image path
for arg in "$@"; do
    case "$arg" in
        --shell)         EXTRA_APPEND="$EXTRA_APPEND kubesolo.shell" ;;
        --debug)         EXTRA_APPEND="$EXTRA_APPEND kubesolo.debug" ;;
        --edge-id=*)     EXTRA_APPEND="$EXTRA_APPEND kubesolo.edge_id=${arg#--edge-id=}" ;;
        --edge-key=*)    EXTRA_APPEND="$EXTRA_APPEND kubesolo.edge_key=${arg#--edge-key=}" ;;
        *)               IMAGE="$arg" ;;
    esac
done

# Auto-detect image
if [ -z "$IMAGE" ]; then
    if [ -f "$DEFAULT_ISO" ]; then
        IMAGE="$DEFAULT_ISO"
    elif [ -f "$DEFAULT_IMG" ]; then
        IMAGE="$DEFAULT_IMG"
    else
        echo "ERROR: No image found. Run 'make iso' or 'make disk-image' first."
        echo "  Or specify path: $0 <path-to-iso-or-img>"
        exit 1
    fi
fi

echo "==> Launching QEMU with: $IMAGE"
echo "    Press Ctrl+A, X to exit"
echo ""

DATA_APPEND=""
DATA_DISK=""

# Find mkfs.ext4 (Homebrew on macOS installs to a non-PATH location)
MKFS_EXT4=""
if command -v mkfs.ext4 >/dev/null 2>&1; then
    MKFS_EXT4="mkfs.ext4"
elif [ -x "/opt/homebrew/opt/e2fsprogs/sbin/mkfs.ext4" ]; then
    MKFS_EXT4="/opt/homebrew/opt/e2fsprogs/sbin/mkfs.ext4"
elif [ -x "/usr/local/opt/e2fsprogs/sbin/mkfs.ext4" ]; then
    MKFS_EXT4="/usr/local/opt/e2fsprogs/sbin/mkfs.ext4"
fi

# Create and attach a formatted data disk for persistent K8s state.
if [ -n "$MKFS_EXT4" ]; then
    DATA_DISK="$(mktemp /tmp/kubesolo-data-XXXXXX).img"
    dd if=/dev/zero of="$DATA_DISK" bs=1M count=2048 2>/dev/null
    "$MKFS_EXT4" -q -L KSOLODATA "$DATA_DISK" 2>/dev/null
    DATA_APPEND="kubesolo.data=/dev/vda"
    echo "    Data disk: 2 GB ext4 (persistent)"
else
    echo "ERROR: mkfs.ext4 not found. Install e2fsprogs:"
    echo "  brew install e2fsprogs"
    exit 1
fi

EXTRACT_DIR=""

cleanup() {
    [ -n "$DATA_DISK" ] && rm -f "$DATA_DISK" "${DATA_DISK%.img}"
    [ -n "$EXTRACT_DIR" ] && rm -rf "$EXTRACT_DIR"
}
trap cleanup EXIT

# Build QEMU command
QEMU_ARGS=(-m 2048 -smp 2 -nographic -cpu max)
QEMU_ARGS+=(-net nic,model=virtio)
QEMU_ARGS+=(-net user,hostfwd=tcp::6443-:6443,hostfwd=tcp::2222-:22,hostfwd=tcp::8080-:8080)

if [ -n "$DATA_DISK" ]; then
    QEMU_ARGS+=(-drive "file=$DATA_DISK,format=raw,if=virtio")
fi

# Enable KVM on Linux, fall back to TCG everywhere else
if [ -w /dev/kvm ] 2>/dev/null; then
    QEMU_ARGS+=(-accel kvm)
    echo "    KVM acceleration: enabled"
else
    QEMU_ARGS+=(-accel tcg)
    echo "    TCG emulation (no KVM — expect slower boot)"
fi

case "$IMAGE" in
    *.iso)
        # -append only works with -kernel, not -cdrom.
        # Extract kernel + initramfs and use direct kernel boot.
        VMLINUZ=""
        INITRAMFS=""

        # Prefer build artifacts if present (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"
        else
            # Extract from ISO using bsdtar (works on macOS + Linux, no mount needed)
            EXTRACT_DIR="$(mktemp -d /tmp/kubesolo-extract-XXXXXX)"

            echo "    Extracting kernel/initramfs from ISO..."
            bsdtar -xf "$IMAGE" -C "$EXTRACT_DIR" boot/vmlinuz boot/kubesolo-os.gz 2>/dev/null || {
                echo "ERROR: Failed to extract kernel/initramfs from ISO."
                echo "  Ensure bsdtar is available (ships with macOS, install libarchive on Linux)."
                echo "  Or run 'make rootfs initramfs' to produce build artifacts."
                exit 1
            }

            VMLINUZ="$EXTRACT_DIR/boot/vmlinuz"
            INITRAMFS="$EXTRACT_DIR/boot/kubesolo-os.gz"

            if [ ! -f "$VMLINUZ" ] || [ ! -f "$INITRAMFS" ]; then
                echo "ERROR: ISO does not contain expected boot/vmlinuz and boot/kubesolo-os.gz"
                echo "  ISO contents:"
                bsdtar -tf "$IMAGE" 2>/dev/null || true
                exit 1
            fi
            echo "    Extracted kernel/initramfs from ISO"
        fi

        qemu-system-x86_64 \
            "${QEMU_ARGS[@]}" \
            -kernel "$VMLINUZ" \
            -initrd "$INITRAMFS" \
            -append "console=ttyS0,115200n8 $DATA_APPEND $EXTRA_APPEND"
        ;;
    *.img)
        qemu-system-x86_64 \
            "${QEMU_ARGS[@]}" \
            -drive "file=$IMAGE,format=raw,if=virtio"
        ;;
    *)
        echo "ERROR: Unrecognized image format: $IMAGE"
        exit 1
        ;;
esac