#!/bin/bash

function BasebandDetect {
    Firmware=resources/firmware/$ProductType
    BasebandURL=$(cat $Firmware/13G37/url 2>/dev/null) # iOS 9.3.6
    if [ $ProductType == iPad2,2 ]; then
        BasebandURL=$(cat $Firmware/13G36/url) # iOS 9.3.5
        Baseband=ICE3_04.12.09_BOOT_02.13.Release.bbfw
        BasebandSHA1=e6f54acc5d5652d39a0ef9af5589681df39e0aca
    elif [ $ProductType == iPad2,3 ]; then
        Baseband=Phoenix-3.6.03.Release.bbfw
        BasebandSHA1=8d4efb2214344ea8e7c9305392068ab0a7168ba4
    elif [ $ProductType == iPad2,6 ] || [ $ProductType == iPad2,7 ]; then
        Baseband=Mav5-11.80.00.Release.bbfw
        BasebandSHA1=aa52cf75b82fc686f94772e216008345b6a2a750
    elif [ $ProductType == iPad3,2 ] || [ $ProductType == iPad3,3 ]; then
        Baseband=Mav4-6.7.00.Release.bbfw
        BasebandSHA1=a5d6978ecead8d9c056250ad4622db4d6c71d15e
    elif [ $ProductType == iPhone4,1 ]; then
        Baseband=Trek-6.7.00.Release.bbfw
        BasebandSHA1=22a35425a3cdf8fa1458b5116cfb199448eecf49
    elif [ $ProductType == iPad3,5 ] || [ $ProductType == iPad3,6 ] ||
         [ $ProductType == iPhone5,1 ] || [ $ProductType == iPhone5,2 ]; then
        BasebandURL=$(cat $Firmware/14G61/url) # iOS 10.3.4
        Baseband=Mav5-11.80.00.Release.bbfw
        BasebandSHA1=8951cf09f16029c5c0533e951eb4c06609d0ba7f
    else # For Wi-Fi only devices
        Baseband=0
    fi
}

function Clean {
    rm -rf iP*/ tmp/ $(ls *_${ProductType}_${OSVer}-*.shsh2 2>/dev/null) $(ls *.bbfw 2>/dev/null) BuildManifest.plist
}

function Log {
    echo "[Log] $1"
}

function Error {
    echo "[Error] $1"
    [[ ! -z $2 ]] && echo $2
    exit
}

function MainMenu {    
    if [ $(lsusb | grep -c '1227') == 1 ]; then
        read -p "[Input] Device in DFU mode detected. Is the device in kDFU mode? (y/N) " kDFUManual
        if [[ $kDFUManual == y ]] || [[ $kDFUManual == Y ]]; then
            read -p "[Input] Enter ProductType (eg. iPad2,1): " ProductType
            read -p "[Input] Enter UniqueChipID (ECID): " UniqueChipID
            BasebandDetect
            Log "Downgrading device $ProductType in kDFU mode..."
            Mode='Downgrade'
            SelectVersion
        else
            Error "Please put the device in normal mode and jailbroken before proceeding."
        fi
    elif [ ! $ProductType ]; then
        Error "Please plug the device in and trust this computer before proceeding."
    fi
    BasebandDetect
    
    echo "Main Menu"
    echo
    echo "HardwareModel: ${HWModel}ap"
    echo "ProductType: $ProductType"
    echo "ProductVersion: $ProductVer"
    echo "UniqueChipID (ECID): $UniqueChipID"
    echo
    echo "[Input] Select an option:"
    select opt in "Downgrade device" "Save OTA blobs" "Just put device in kDFU mode" "(Re-)Install Dependencies" "(Any other key to exit)"; do
        case $opt in
            "Downgrade device" ) Mode='Downgrade'; break;;
            "Save OTA blobs" ) Mode='SaveOTABlobs'; break;;
            "Just put device in kDFU mode" ) Mode='kDFU'; break;;
            "(Re-)Install Dependencies" ) InstallDependencies; exit;;
            * ) exit;;
        esac
    done
    SelectVersion
}

function SelectVersion {
    Selection=("iOS 8.4.1")
    if [[ $Mode == 'kDFU' ]]; then
        Action
    elif [ $ProductType == iPad2,1 ] || [ $ProductType == iPad2,2 ] ||
         [ $ProductType == iPad2,3 ] || [ $ProductType == iPhone4,1 ]; then
        Selection+=("iOS 6.1.3")
    fi
    [[ $Mode == 'Downgrade' ]] && Selection+=("Other")
    Selection+=("Back")
    echo "[Input] Select iOS version:"
    select opt in "${Selection[@]}"; do
        case $opt in
            "iOS 8.4.1" ) OSVer='8.4.1'; BuildVer='12H321'; break;;
            "iOS 6.1.3" ) OSVer='6.1.3'; BuildVer='10B329'; break;;
            "Other" ) OSVer='Other'; break;;
            "Back" ) MainMenu; break;;
            *) SelectVersion;;
        esac
    done
    Action
}

function Action {    
    Log "iOS $OSVer $Mode"
    if [ $OSVer == 'Other' ]; then
        OSVer=0
        read -p "[Input] Path to IPSW (drag IPSW to terminal window): " IPSW
        IPSW="$(basename "$IPSW" .ipsw)"
        read -p "[Input] Path to SHSH (drag SHSH to terminal window): " SHSH
    fi
    
    iBSS="iBSS.$HWModel.RELEASE"
    IV=$(cat $Firmware/12H321/iv)
    Key=$(cat $Firmware/12H321/key)    
    if [[ $Mode == 'Downgrade' ]]; then
        Downgrade
    elif [[ $Mode == 'SaveOTABlobs' ]]; then
        SaveOTABlobs
    elif [[ $Mode == 'kDFU' ]]; then
        kDFU
    fi
    exit
}

function SaveOTABlobs {
    BuildManifest="resources/manifests/BuildManifest_${ProductType}_${OSVer}.plist"
    Log "Saving $OSVer blobs with tsschecker..."
    env "LD_PRELOAD=libcurl.so.3" resources/tools/tsschecker_$platform -d $ProductType -i $OSVer -o -s -e $UniqueChipID -m $BuildManifest
    SHSH=$(ls *_${ProductType}_${OSVer}-*.shsh2)
    [ ! -e "$SHSH" ] && Error "Saving $OSVer blobs failed. Please run the script again" "It is also possible that $OSVer for $ProductType is no longer signed"
    mkdir -p saved/shsh 2>/dev/null
    cp "$SHSH" saved/shsh
    Log "Successfully saved $OSVer blobs."
}

function kDFU {
    if [ ! -e saved/$ProductType/$iBSS.dfu ]; then
        Log "Downloading iBSS..."
        resources/tools/pzb_$platform -g Firmware/dfu/${iBSS}.dfu -o $iBSS.dfu $(cat $Firmware/12H321/url)
        mkdir -p saved/$ProductType 2>/dev/null
        mv $iBSS.dfu saved/$ProductType
    fi
    Log "Decrypting iBSS..."
    Log "IV = $IV"
    Log "Key = $Key"
    resources/tools/xpwntool_$platform saved/$ProductType/$iBSS.dfu tmp/iBSS.dec -k $Key -iv $IV -decrypt
    dd bs=64 skip=1 if=tmp/iBSS.dec of=tmp/iBSS.dec2
    Log "Patching iBSS..."
    bspatch tmp/iBSS.dec2 tmp/pwnediBSS resources/patches/$iBSS.patch
    
    # Regular kloader only works on iOS 6 to 9, so other versions are provided for iOS 5 and 10
    if [[ $VersionDetect == 1 ]]; then
        kloader='kloader_hgsp'
    elif [[ $VersionDetect == 5 ]]; then
        kloader='kloader5'
    else
        kloader='kloader'
    fi

    if [[ $VersionDetect == 1 ]]; then
        # ifuse+MTerminal is used instead of SSH for devices on iOS 10
        [ ! $(which ifuse) ] && Error "One of the dependencies (ifuse) cannot be found. Please re-install dependencies and try again" "For macOS systems, install osxfuse and ifuse with brew"
        WifiAddr=$(ideviceinfo -s | grep 'WiFiAddress' | cut -c 14-)
        WifiAddrDecr=$(echo $(printf "%x\n" $(expr $(printf "%d\n" 0x$(echo "${WifiAddr}" | tr -d ':')) - 1)) | sed 's/\(..\)/\1:/g;s/:$//')
        echo '#!/bin/bash' > tmp/pwn.sh
        echo "nvram wifiaddr=$WifiAddrDecr
        chmod 755 kloader_hgsp
        ./kloader_hgsp pwnediBSS" >> tmp/pwn.sh
        Log "Mounting device with ifuse..."
        mkdir mount
        ifuse mount
        Log "Copying stuff to device..."
        cp "tmp/pwn.sh" "resources/tools/$kloader" "tmp/pwnediBSS" "mount/"
        Log "Unmounting device... (Enter root password of your PC/Mac when prompted)"
        sudo umount mount
        echo
        Log "Open MTerminal and run these commands:"
        echo
        echo '$ su'
        echo "(Enter root password of your iOS device, default is 'alpine')"
        echo "# cd Media"
        echo "# chmod +x pwn.sh"
        echo "# ./pwn.sh"
    else
        # SSH kloader and pwnediBSS
        echo "Make sure SSH is installed and working on the device!"
        echo "Please enter Wi-Fi IP address of device for SSH connection"
        read -p "[Input] IP Address: " IPAddress
        Log "Connecting to device via SSH... (Enter root password of your iOS device, default is 'alpine')"
        Log "Copying stuff to device..."
        scp resources/tools/$kloader tmp/pwnediBSS root@$IPAddress:/
        [ $? == 1 ] && Error "Cannot connect to device via SSH." "Please check your ~/.ssh/known_hosts file and try again"
        Log "Entering kDFU mode..."
        ssh root@$IPAddress "chmod 755 /$kloader && /$kloader /pwnediBSS" &
    fi
    echo
    echo "Press home/power button once when screen goes black on the device"
    
    Log "Finding device in DFU mode..."
    while [[ $DFUDevice != 1 ]]; do
        DFUDevice=$(lsusb | grep -c "1227")
        sleep 2
    done
    Log "Found device in DFU mode."
}

function Downgrade {    
    if [ $OSVer != 'Other' ]; then
        SaveOTABlobs
        IPSW="${ProductType}_${OSVer}_${BuildVer}_Restore"
        if [ ! -e "$IPSW.ipsw" ]; then
            Log "iOS $OSVer IPSW cannot be found. Downloading IPSW..."
            curl -L $(cat $Firmware/$BuildVer/url) -o tmp/$IPSW.ipsw
            mv tmp/$IPSW.ipsw .
        fi
        Log "Verifying IPSW..."
        IPSWSHA1=$(cat $Firmware/$BuildVer/sha1sum)
        IPSWSHA1L=$(sha1sum "$IPSW.ipsw" | awk '{print $1}')
        [ $IPSWSHA1L != $IPSWSHA1 ] && Error "Verifying IPSW failed. Delete/replace the IPSW and run the script again"
        if [ ! $kDFUManual ]; then
            Log "Extracting iBSS from IPSW..."
            mkdir -p saved/$ProductType 2>/dev/null
            unzip -o -j "$IPSW.ipsw" Firmware/dfu/$iBSS.dfu -d saved/$ProductType
        fi
    fi
    
    [ ! $kDFUManual ] && kDFU
    
    Log "Extracting IPSW..."
    unzip -q "$IPSW.ipsw" -d "$IPSW/"
    
    Log "Preparing for futurerestore... (Enter root password of your PC/Mac when prompted)"
    cd resources
    sudo bash -c "python3 -m http.server 80 &"
    cd ..
    
    if [ $Baseband == 0 ]; then
        Log "Device $ProductType has no baseband"
        Log "Proceeding to futurerestore..."
        sudo env "LD_PRELOAD=libcurl.so.3" resources/tools/futurerestore_$platform -t "$SHSH" --no-baseband --use-pwndfu "$IPSW.ipsw"
    else
        if [ ! -e saved/$ProductType/*.bbfw ]; then
            Log "Downloading baseband..."
            resources/tools/pzb_$platform -g Firmware/$Baseband -o $Baseband $BasebandURL
            resources/tools/pzb_$platform -g BuildManifest.plist -o BuildManifest.plist $BasebandURL
            mkdir -p saved/$ProductType 2>/dev/null
            cp $(ls *.bbfw) BuildManifest.plist saved/$ProductType
        else
            cp saved/$ProductType/*.bbfw saved/$ProductType/BuildManifest.plist .
        fi
        BasebandSHA1L=$(sha1sum $(ls *.bbfw) | awk '{print $1}')
        if [ ! -e *.bbfw ] || [ $BasebandSHA1L != $BasebandSHA1 ]; then
            rm saved/$ProductType/*.bbfw saved/$ProductType/BuildManifest.plist
            echo "[Error] Downloading/verifying baseband failed."
            echo "Your device is still in kDFU mode and you may run the script again"
            echo "You can also continue and futurerestore can attempt to download the baseband again"
            echo "Proceeding to futurerestore in 10 seconds (Press Ctrl+C to cancel)"
            sleep 10
            Log "Proceeding to futurerestore..."
            sudo env "LD_PRELOAD=libcurl.so.3" resources/tools/futurerestore_$platform -t "$SHSH" --latest-baseband --use-pwndfu "$IPSW.ipsw"
        else
            Log "Proceeding to futurerestore..."
            sudo env "LD_PRELOAD=libcurl.so.3" resources/tools/futurerestore_$platform -t "$SHSH" -b $(ls *.bbfw) -p BuildManifest.plist --use-pwndfu "$IPSW.ipsw"
        fi
    fi
        
    echo
    Log "futurerestore done!"    
    Log "Stopping local server... (Enter root password of your PC/Mac when prompted)"
    ps aux | awk '/python3/ {print "sudo kill -9 "$2" 2>/dev/null"}' | bash
    Log "Downgrade script done!"
}

function InstallDependencies {
    echo "Install Dependencies"
    . /etc/os-release 2>/dev/null
    
    if [[ $(which pacman) ]]; then
        # Arch Linux
        Log "Installing dependencies for Arch with pacman..."
        sudo pacman -Sy --noconfirm --needed bsdiff curl libcurl-compat libpng12 libzip openssh openssl-1.0 python unzip usbutils
        sudo pacman -S --noconfirm libimobiledevice usbmuxd
        git clone https://aur.archlinux.org/ifuse.git
        cd ifuse
        makepkg -sic --noconfirm
        cd ..
        rm -rf ifuse
        sudo ln -sf /usr/lib/libzip.so.5 /usr/lib/libzip.so.4
    elif [[ $VERSION_ID == "16.04" ]] || [[ $VERSION_ID == "18.04" ]] || [[ $VERSION_ID == "20.04" ]]; then
        # Ubuntu Xenial, Bionic, Focal
        Log "Running APT update..." 
        sudo apt update
        Log "Installing dependencies for Ubuntu $VERSION_ID with APT..."
        sudo apt -y install bsdiff curl ifuse libimobiledevice-utils python3 usbmuxd
        if [[ $VERSION_ID != "16.04" ]]; then
            sudo apt -y install binutils
            mkdir tmp
            cd tmp
            curl -L http://archive.ubuntu.com/ubuntu/pool/universe/c/curl3/libcurl3_7.58.0-2ubuntu2_amd64.deb -o libcurl3.deb
            ar x libcurl3.deb data.tar.xz
            tar xf data.tar.xz
            sudo cp usr/lib/x86_64-linux-gnu/libcurl.so.4.* /usr/lib/libcurl.so.3
            if [[ $VERSION_ID == "20.04" ]]; then
                URLlibpng12=http://ppa.launchpad.net/linuxuprising/libpng12/ubuntu/pool/main/libp/libpng/libpng12-0_1.2.54-1ubuntu1.1+1~ppa0~focal_amd64.deb
                curl -L http://archive.ubuntu.com/ubuntu/pool/universe/libz/libzip/libzip4_1.1.2-1.1_amd64.deb -o libzip4.deb
                sudo dpkg -i libzip4.deb
                curl -L http://archive.ubuntu.com/ubuntu/pool/main/o/openssl1.0/libssl1.0.0_1.0.2n-1ubuntu5.3_amd64.deb -o libssl1.0.0.deb
                sudo dpkg -i libssl1.0.0.deb
            else
                URLlibpng12=http://mirrors.edge.kernel.org/ubuntu/pool/main/libp/libpng/libpng12-0_1.2.54-1ubuntu1.1_amd64.deb
                sudo apt -y install libzip4
            fi
            curl -L $URLlibpng12 -o libpng12.deb
            sudo dpkg -i libpng12.deb
        else
            sudo apt -y install libzip4
        fi
        
    elif [[ $OSTYPE == "darwin"* ]]; then
        # macOS
        if [[ ! $(which brew) ]]; then
            Log "Homebrew is not detected/installed, installing Homebrew..."
            /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"
        fi
        Log "Installing dependencies for macOS with Homebrew..."
        brew uninstall --ignore-dependencies usbmuxd
        brew uninstall --ignore-dependencies libimobiledevice
        brew install --HEAD usbmuxd
        brew install --HEAD libimobiledevice
        brew install libzip lsusb python3
        brew cask install osxfuse
        brew install ifuse
        
    else
        Error "Distro not detected/supported by the install script." "See the repo README for OS versions/distros tested on"
    fi
    Log "Install script done! Please run the script again to proceed"
}

# --- MAIN SCRIPT STARTS HERE ---

trap 'Clean; exit' INT TERM EXIT
clear
echo "******* 32bit-OTA-Downgrader *******"
echo "    Downgrade script by LukeZGD     "
echo
if [[ $OSTYPE == "linux-gnu" ]]; then
    platform='linux'
elif [[ $OSTYPE == "darwin"* ]]; then
    platform='macos'
else
    Error "OSTYPE unknown/not supported." "Supports Linux and macOS only"
fi
[[ ! $(ping -c1 google.com 2>/dev/null) ]] && Error "Please check your Internet connection before proceeding."
[[ $(uname -m) != 'x86_64' ]] && Error "Only x86_64 distributions are supported. Use a 64-bit distro and try again"

HWModel=$(ideviceinfo -s | grep 'HardwareModel' | cut -c 16- | tr '[:upper:]' '[:lower:]' | sed 's/.\{2\}$//')
ProductType=$(ideviceinfo -s | grep 'ProductType' | cut -c 14-)
[ ! $ProductType ] && ProductType=$(ideviceinfo | grep 'ProductType' | cut -c 14-)
ProductVer=$(ideviceinfo -s | grep 'ProductVer' | cut -c 17-)
VersionDetect=$(echo $ProductVer | cut -c 1)
UniqueChipID=$(ideviceinfo -s | grep 'UniqueChipID' | cut -c 15-)

if [ ! $(which bspatch) ] || [ ! $(which ideviceinfo) ] || [ ! $(which lsusb) ] || [ ! $(which ssh) ] || [ ! $(which python3) ]; then
    InstallDependencies
else
    chmod +x resources/tools/*
    Clean
    mkdir tmp
    rm -rf resources/firmware
    curl -Ls https://github.com/LukeZGD/32bit-OTA-Downgrader/archive/firmware.zip -o tmp/firmware.zip
    unzip -q tmp/firmware.zip -d tmp
    mkdir resources/firmware
    mv tmp/32bit-OTA-Downgrader-firmware/* resources/firmware
    MainMenu
fi