#!/bin/bash

fail_exit ()
{
    echo "$*"
    echo 'Exiting...'
    exit 1
}

print_help ()
{
    echo "$*"
    echo "Help:"
    echo "  --username    use username for HTTP auth (optional)"
    echo "  --password    use password for HTTP auth (optional)"
    exit 1
}

clean_up ()
{
    if [ -n "$PART_FILE" ]; then
        rm -f $PART_FILE >&/dev/null
    fi
    umount $CD_SQUASH_ROOT >&/dev/null || true
    umount $CD_ROOT >&/dev/null || true
    umount $INST_ROOT >&/dev/null || true
    umount $READ_ROOT >&/dev/null || true
    umount $WRITE_ROOT >&/dev/null || true
    if [ -d "$TEMP_DIR" ]; then
        rm -rf $TEMP_DIR
    fi
}

sig_handler () {
    echo "ERROR: Signal received. Exiting..."
    clean_up
    echo "Done"
    trap - EXIT
    exit 1
}

exit_handler () {
    clean_up
}

# read in commandline - snipped thankfully copied from:
# https://unix.stackexchange.com/a/580258
VRF="default"
while [ $# -gt 0 ]; do
  case "$1" in
    --url*|-u)
        if [[ "$1" != *=* ]]; then shift; fi # Value is next arg if no `=`
        # the image to be installed. only used if installing from an installed,
        # running system.
        NEW_ISO="${1#*=}"
        ;;
    --vrf*|-v)
        if [[ "$1" != *=* ]]; then shift; fi # Value is next arg if no `=`
        VRF="${1#*=}"
        ;;
    --username*)
        if [[ "$1" != *=* ]]; then shift; fi
        # Username and password are optional
        USERNAME="${1#*=}"
        ;;
    --password*)
        if [[ "$1" != *=* ]]; then shift; fi
        PASSWORD="${1#*=}"
        ;;
    --help|-h)
        print_help
        exit 0
        ;;
    *)
        print_help
        >&2 printf "Error: Invalid argument\n"
        exit 1
        ;;
    esac
    shift
done

# source in the functions
source /opt/vyatta/sbin/install-functions

if [ -f /etc/profile.d/vyos-system-proxy.sh ]; then
    source /etc/profile.d/vyos-system-proxy.sh
fi

# export INSTALL_LOG for the scripts invoked
export INSTALL_LOG=/tmp/install-$$.log
# export PROGRESS_PID for the scripts invoked
export PROGRESS_PID=$$

# file for get-partition output
PART_FILE=''

# Temp directory for downloaded ISO
TEMP_DIR="/var/tmp/install-image.$$"

download_file ()
{
    (REMOTE_USERNAME=$USERNAME \
     REMOTE_PASSWORD=$PASSWORD \
     ip vrf exec $VRF python3 -c "import vyos.remote; vyos.remote.friendly_download('$1', '$2')")
}

# Try to fetch the ISO file using a URL provided by the user.
# If successful, we leave $NEW_ISO pointing to the ISO file that
# was downloaded.
fetch_iso_by_url ()
{
    mkdir $TEMP_DIR
    filename="${TEMP_DIR}/${NEW_ISO##*/}"

    echo "Trying to fetch ISO file from $NEW_ISO..."
    download_file "$filename" "$NEW_ISO"
    if [ $? -ne 0 ]; then
        fail_exit 'Failed to download the ISO file.'
    fi
    echo "Done."

    echo "Checking for digital signature file..."
    download_file "${filename}.minisig" "${NEW_ISO}.minisig"
    if [ $? -ne 0 ]; then
        download_file "${filename}.asc" "${NEW_ISO}.asc"
    fi
    if [ $? -ne 0 ]; then
        echo -n "Do you want to continue without signature check? (yes/no) [yes] "

        # In case signature file was partially downloaded...
        rm -f ${filename}.asc ${filename}.minisig

        response=$(get_response "Yes" "Yes No Y N")
        if [ "$response" == "no" ] || [ "$response" == "n" ]; then
            fail_exit 'OK. Installation will not be performed.'
        fi
    else
        echo "Checking digital signature..."
        if [ -f ${filename}.minisig ]; then
            minisign -V -q -p /usr/share/vyos/keys/vyos-release.minisign.pub -m ${filename} -x ${filename}.minisig
            if [ $? -ne 0 ]; then
                echo "Signature check FAILED, trying BACKUP key..."
                minisign -V -q -p /usr/share/vyos/keys/vyos-backup.minisign.pub -m ${filename} -x ${filename}.minisig
            fi
        fi
        if [ -f ${filename}.asc ]; then
            gpg --keyring /etc/apt/trusted.gpg --verify ${filename}.asc
        fi
        if [ $? -ne 0 ]; then
            echo "Signature check FAILED."
            echo -n "Do you want to continue anyway? (yes/no) [no] "
            response=$(get_response "No" "Yes No Y N")
            if [ "$response" == "no" ] || [ "$response" == "n" ]; then
                fail_exit 'OK. Installation will not be performed.'
            fi
            echo "OK. Proceeding with installation anyway."
        else
            echo "Digital signature is valid."
        fi
    fi

    NEW_ISO=$filename
}

# set up the specified ISO image file or URL for install
set_up_new_iso ()
{
    url_scheme=${NEW_ISO%%:*}

    if [ "$url_scheme" != "$NEW_ISO" ]; then
        if [ "$url_scheme" = "http" -o "$url_scheme" = "https" -o \
             "$url_scheme" = "ftp" -o "$url_scheme" = "tftp" -o \
             "$url_scheme" = "scp" -o "$url_scheme" = "sftp" ]; then
            fetch_iso_by_url
        fi
    fi

    if [ ! -f "$NEW_ISO" ] || ! (grep -q ISO9660 $NEW_ISO); then
        fail_exit "\"$NEW_ISO\" is not a valid ISO image file."
    fi

    # make sure mount points exist
    mkdir -p $INST_ROOT $WRITE_ROOT $READ_ROOT $CD_ROOT $CD_SQUASH_ROOT

    # mount ISO
    margs="-o loop,ro $NEW_ISO $CD_ROOT"
    if ! try_mount "$margs"; then
        fail_exit 'Failed to mount the new image.'
    fi

    # check squash image
    local squash_file=$CD_ROOT/live/filesystem.squashfs
    if [ ! -f "$squash_file" ] \
        || ! (file $squash_file | grep -q Squashfs) \
        || ! grep -q '^ii  vyatta-version ' $CD_ROOT/live/packages.txt; then
        fail_exit "\"$NEW_ISO\" is not a VyOS ISO image file."
    fi

    # Verify checksums of all files in ISO image
    if [ ! -f $CD_ROOT/sha256sum.txt ]; then
        if [ ! -f $CD_ROOT/md5sum.txt ]; then
            fail_exit "Checksum file not found. The image file is either corrupt or not a VyOS image."
        else
            # Falling back to MD5 since SHA256 could not be found.
            # This must be an older image.
            echo -n "Checking MD5 checksums of files on the ISO image... "
            sum='md5sum'
        fi
    else
        echo -n "Checking SHA256 checksums of files on the ISO image... "
        sum='sha256sum'
    fi

    resfile=$(mktemp /tmp/install-image-md5check-XXXXXXXX)
    (cd $CD_ROOT ; $sum -c $sum.txt > $resfile)
    failures=$(grep -cv 'OK$' $resfile)
    rm -f $resfile

    if [ $failures == 0 ]; then
        echo "OK."
    else
        echo "Failed!"
        echo "$failures checksum failures found!"
        echo "ISO image is corrupted and can not be used."
        exit 1
    fi

    # mount squash image
    margs="-o loop,ro $squash_file $CD_SQUASH_ROOT"
    if ! try_mount "$margs"; then
        fail_exit 'Failed to mount the squashfs image.'
    fi
}

# install new image into a newly-formatted partition.
# will exit with error if installation fails.
install_new ()
{
    local root_part=$1
    local inst_drv=$2

    if [ ! -e "/dev/$root_part" ] || [ ! -e "/dev/$inst_drv" ]; then
        fail_exit "Invalid drive/partition ($inst_drv and $root_part)."
    fi

    # install new image
    if ! /opt/vyatta/sbin/install-image-new "$root_part"; then
        exit 1
    fi

    # postinst operations
    if ! /opt/vyatta/sbin/install-postinst-new "$inst_drv" "$root_part" union; then
        exit 1
    fi
}

# install new image into the current boot partition.
# will exit with error if installation fails.
install_existing ()
{
    local ctype=$1
    if ! /opt/vyatta/sbin/install-image-existing "$ctype"; then
        exit 1
    fi
}

if [ -z "$USERNAME" ] && [ -n "$PASSWORD" ]; then
    fail_exit "Password cannot be specified without username."
fi
if [ -n "$USERNAME" ] && [ -z "$PASSWORD" ]; then
    fail_exit "Username cannot be specified without password."
fi
if [ $(id -u) != 0 ]; then
    fail_exit "Image installation requires root privileges!"
fi

trap sig_handler INT KILL
trap exit_handler EXIT

if is_live_cd_boot; then
    cat <<EOF
Welcome to the VyOS install program. This script
will walk you through the process of installing the
VyOS image to a local hard drive.
EOF

    response=''
    while [ -z "$response" ]
    do
        echo -n "Would you like to continue? (Yes/No) [Yes]: "
        response=$(get_response "Yes" "Yes No Y N")
        if [ "$response" == "no" ] || [ "$response" == "n" ]; then
            fail_exit 'Ok then.'
        fi
    done
fi

if is_live_cd_boot; then
    if [ -n "$NEW_ISO" ]; then
        echo 'You are trying to install from a live CD boot. The live CD image'
        fail_exit 'will be used. Do not specify an ISO image file or URL.'
    fi
elif [ -z "$NEW_ISO" ]; then
    echo 'You are trying to install from an already installed system. An ISO'
    fail_exit 'image file to install or URL must be specified.'
else
    # installing on an installed system. set up the new image.
    set_up_new_iso
fi

# get install partition
PART_FILE=$(mktemp /tmp/inst-get-part.XXXXXX) \
  || fail_exit 'Failed to create temporary file'
if ! /opt/vyatta/sbin/install-get-partition $PART_FILE; then
    exit 1
fi

# get the partition params
root_part_type=''
root_part=''
inst_drv=''
eval "read root_part_type root_part inst_drv <$PART_FILE" >&/dev/null
rm -f $PART_FILE >&/dev/null

# handle different types
case "$root_part_type" in
    new)
        install_new "$root_part" "$inst_drv"
        exit 0
        ;;
    union|old)
        install_existing "$root_part_type"
        exit 0
        ;;
    *)
        fail_exit "Unknown partition type \"$root_part_type\"."
        ;;
esac