#!/usr/bin/env bash

# mkbootimg is the property of The Android Open Source Project and licensed under the Apache License, Version 2.0
# You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0

CMDLINE="root=PARTLABEL=linux loglevel=3"

VMLINUZ="/boot/efi/vmlinuz-6.1.10-nabu"
DTB="/boot/efi/dtb-6.1.10-nabu"

function log() {
    printf "\e[1m\e[92m==>\e[0m \e[1m%s\e[0m\n" "$*"
}

function log_err() {
    printf "\e[1m\e[31m==>\e[0m \e[1m%s\e[0m\n" "$*"
}

function sigterm_handler() {
  printf "\e[1m\e[31m>\e[0m \e[1m%s\e[0m\n" "Shutdown signal received."
  exit 1
}

trap 'trap " " SIGINT SIGTERM SIGHUP; kill 0; wait; sigterm_handler' SIGINT SIGTERM SIGHUP

which base64 > /dev/null 2>&1 || {
  log_err "base64 not found"
  exit 1
}

which curl > /dev/null 2>&1 || {
  log_err "curl not found"
  exit 1
}

if which python3 > /dev/null 2>&1; then
  PYTHON="python3"
elif which python > /dev/null 2>&1 && [[ "$(python -V)" =~ "Python 3" ]]; then
  PYTHON="python"
else
  log_err "python 3 not found"
  exit 1
fi

if which doas > /dev/null 2>&1; then
  SUDO=doas
elif which sudo > /dev/null 2>&1; then
  SUDO=sudo
elif [ "$(id -u)" -eq "0" ]; then
  SUDO=""
else
  log_err "sudo/doas not found"
fi


# Begin script

if [ $# -eq 2 ]; then
  VMLINUZ="$1"
  DTB="$2"
else
  log "Using default vmlinuz and dtb path"
  log "vmlinuz: $VMLINUZ"
  log "dtb: $DTB"
fi

[ -f "$VMLINUZ" ] || {
  log_err "vmlinuz not found at $VMLINUZ"
  exit 1
}

[ -f "$DTB" ] || {
  log_err "dtb not found at $DTB"
  exit 1
}

[ -r "$VMLINUZ" ] && [ -r "$DTB" ] && SUDO=""

{ [ -f ./mkbootimg.py ] && [ -f ./generate_gki_certificate.py ]; } || {
  log "Downloading mkbootimg from google"
  curl -s "https://android.googlesource.com/platform/system/tools/mkbootimg/+/refs/heads/main/mkbootimg.py?format=text" \
    | base64 -d \
    | sed "s/from gki.generate_gki_certificate import generate_gki_certificate/from generate_gki_certificate import generate_gki_certificate/g" \
    > mkbootimg.py || ERR="1"
  curl -s "https://android.googlesource.com/platform/system/tools/mkbootimg/+/refs/heads/main/gki/generate_gki_certificate.py?format=text" \
    | base64 -d \
    > generate_gki_certificate.py || ERR="1"
  [[ "$ERR" -eq "1" ]] && {
    log_err "Failed to download mkbootimg"
    exit 1
  }
}

$SUDO cat "$VMLINUZ" "$DTB" > zImage || {
  log_err "Failed to create zImage"
  exit 1
}
$PYTHON mkbootimg.py --kernel zImage --cmdline "$CMDLINE" --base 0x00000000 --kernel_offset 0x00008000 --tags_offset 0x00000100 --pagesize 4096 --id -o linux.boot.img > /dev/null || {
  log_err "Failed to create boot image"
  rm ./zImage
  exit 1
}
rm ./zImage
rm -r ./__pycache__
log "Created ./linux.boot.img"