#!/usr/bin/env bash
#
# scripts/boot.sh — quick direct boot in QEMU (dev loop)
#
# Fastest iteration: boots the kernel directly as BOOTX64.EFI via QEMU's
# FAT driver, skipping the bootloader entirely.
#
# Usage:
#   ./scripts/boot.sh [--gui] [--debug] [--release] [--mem 512M] [--smp 2]
#
# Boot chain:  firmware → rsnix (direct)
# Full chain:  use ./scripts/boot-image.sh (firmware → rsboot → rsnix)
#
# Keybindings:
#   Ctrl-A X   — quit
#   Ctrl-A C   — QEMU monitor
#
# Environment:
#   OVMF    path to OVMF firmware (default: /usr/share/edk2/x64/OVMF.4m.fd)
#   MEM     memory size (default: 256M)
#   SMP     CPU count (default: 1)
#   DISK_IMG raw disk image attached as the SATA data disk (default: /tmp/disk.img)
#
# The data disk is pinned to AHCI port 0 (ide.0) and the ESP to port 1
# (ide.1); the implicit `-drive file=fat:rw:esp` would otherwise grab
# port 0 and the kernel would find the ESP where it expects a FAT32 disk.
#
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
PROJECT_DIR="$(dirname "$SCRIPT_DIR")"

cd "$PROJECT_DIR"

ESP_DIR="$PROJECT_DIR/esp"

# ---- config ----
OVMF="${OVMF:-/usr/share/edk2/x64/OVMF.4m.fd}"
MEM="${MEM:-256M}"
SMP="${SMP:-1}"
DISK_IMG="${DISK_IMG:-/tmp/disk.img}"
PROFILE="debug"
CARGO_FLAGS=""
GUI=""
DEBUG=""

# ---- args ----
while [ $# -gt 0 ]; do
	case "$1" in
	--gui | -g) GUI="-vga std" ;;
	--debug | -d) DEBUG="-s -S" ;;
	--release | -r)
		PROFILE="release"
		CARGO_FLAGS="--release"
		;;
	--mem)
		shift
		MEM="$1"
		;;
	--smp)
		shift
		SMP="$1"
		;;
	--help | -h)
		head -20 "$0" | grep "^#" | sed 's/^# //'
		exit 0
		;;
	*)
		echo "unknown: $1"
		exit 1
		;;
	esac
	shift
done

OUT_DIR="target/x86_64-unknown-uefi/$PROFILE"
KERNEL="$OUT_DIR/rsdos.efi"

# ---- build ----
echo "=== Building kernel ($PROFILE) ==="
cargo build --package rsdos --target x86_64-unknown-uefi $CARGO_FLAGS

# ---- deploy ----
mkdir -p "$ESP_DIR/EFI/BOOT"
cp "$KERNEL" "$ESP_DIR/EFI/BOOT/BOOTX64.EFI"
echo "  kernel: $(ls -lh "$KERNEL" | awk '{print $5}')"

# ---- boot ----
echo ""
echo "=== Booting (direct: firmware → rsnix) ==="
echo "  ovmf:  $OVMF"
echo "  mem:   $MEM   smp: $SMP"
echo "  disk:  $([ -f "$DISK_IMG" ] && echo "$DISK_IMG" || echo "none ($DISK_IMG missing)")"
echo "  gui:   $([ -n "$GUI" ] && echo yes || echo no)"
echo "  gdb:   $([ -n "$DEBUG" ] && echo ':1234' || echo off)"
echo ""

if [ ! -f "$DISK_IMG" ]; then
	echo "  (creating missing disk image: $DISK_IMG)"
	"$SCRIPT_DIR/mkdisk.sh" "$DISK_IMG"
fi

if [ -f "$DISK_IMG" ]; then
	DISK_ARGS=(
		-drive "file=$DISK_IMG,format=raw,if=none,id=disk"
		-device ide-hd,drive=disk,bus=ide.0
	)
else
	DISK_ARGS=()
fi

exec qemu-system-x86_64 \
	-bios "$OVMF" \
	"${DISK_ARGS[@]}" \
	-drive file=fat:rw:"$ESP_DIR",format=raw,if=none,id=esp \
	-device ide-hd,drive=esp,bus=ide.1 \
	-serial stdio \
	-m "$MEM" \
	-machine q35 \
	-cpu qemu64 \
	-no-reboot \
	-smp "$SMP" \
	$GUI $DEBUG