#!/bin/bash
# ============================================================================
# run_qemu.sh — Launch QEMU with UEFI firmware
#
# Usage: run_qemu.sh <arch> <disk_image>
#
# Requirements:
#   x86_64:  OVMF firmware (usually in /usr/share/OVMF/ or /usr/share/edk2/)
#   aarch64: AAVMF firmware (usually in /usr/share/AAVMF/ or qemu-efi-aarch64)
# ============================================================================

set -e

ARCH="$1"
DISK="$2"

if [ -z "$ARCH" ] || [ -z "$DISK" ]; then
    echo "Usage: $0 <arch> <disk_image>"
    exit 1
fi

# ── Find UEFI firmware ─────────────────────────────────────────────────────

find_firmware() {
    local candidates=("$@")
    for path in "${candidates[@]}"; do
        if [ -f "$path" ]; then
            echo "$path"
            return 0
        fi
    done
    return 1
}

if [ "$ARCH" = "x86_64" ]; then
    QEMU=qemu-system-x86_64

    # Common OVMF paths across distros
    OVMF=$(find_firmware \
        /usr/share/OVMF/OVMF_CODE.fd \
        /usr/share/edk2/ovmf/OVMF_CODE.fd \
        /usr/share/edk2-ovmf/x64/OVMF_CODE.fd \
        /usr/share/qemu/OVMF_CODE.fd \
        /usr/share/OVMF/OVMF_CODE_4M.fd \
    ) || {
        echo "ERROR: Cannot find OVMF firmware."
        echo "Install it: apt install ovmf  OR  dnf install edk2-ovmf"
        exit 1
    }

    echo "Using OVMF: $OVMF"
    echo "Starting QEMU x86_64..."
    echo "Press Ctrl+A, X to exit QEMU"
    echo "─────────────────────────────────────"

    exec $QEMU \
        -machine q35 \
        -cpu qemu64 \
        -m 256M \
        -drive if=pflash,format=raw,readonly=on,file="$OVMF" \
        -drive format=raw,file="$DISK" \
        -serial stdio \
        -no-reboot \
        -no-shutdown \
        -d int,cpu_reset \
        -D qemu_log.txt

elif [ "$ARCH" = "aarch64" ]; then
    QEMU=qemu-system-aarch64

    # Common AAVMF / EDK2 paths
    AAVMF=$(find_firmware \
        /usr/share/AAVMF/AAVMF_CODE.fd \
        /usr/share/qemu-efi-aarch64/QEMU_EFI.fd \
        /usr/share/edk2/aarch64/QEMU_EFI.fd \
        /usr/share/edk2-aarch64/QEMU_EFI.fd \
    ) || {
        echo "ERROR: Cannot find AAVMF firmware."
        echo "Install it: apt install qemu-efi-aarch64  OR  dnf install edk2-aarch64"
        exit 1
    }

    echo "Using AAVMF: $AAVMF"
    echo "Starting QEMU aarch64..."
    echo "Press Ctrl+A, X to exit QEMU"
    echo "─────────────────────────────────────"

    # Create a pflash variable store (AAVMF needs separate code + vars)
    VARS_FILE="${DISK}.vars.fd"
    if [ ! -f "$VARS_FILE" ]; then
        dd if=/dev/zero of="$VARS_FILE" bs=1M count=64 status=none
    fi

    exec $QEMU \
        -machine virt \
        -cpu cortex-a72 \
        -m 256M \
        -drive if=pflash,format=raw,readonly=on,file="$AAVMF" \
        -drive if=pflash,format=raw,file="$VARS_FILE" \
        -drive format=raw,file="$DISK" \
        -serial stdio \
        -no-reboot \
        -no-shutdown \
        -d int,cpu_reset \
        -D qemu_log.txt

else
    echo "Unknown architecture: $ARCH"
    exit 1
fi