#!/usr/bin/env bash
#
# This script/function will build and flash/upgrade OpenWRT based on user-defined custom profiles
# For Fedora/Debian/Ubuntu only
#
# MIT License
# Copyright (c) 2020 Bryan Roessler
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

setDefaults() {

    debug "${FUNCNAME[0]}"

    export _target _factory_suffix _sysupgrade_suffix _profile _builddir _debug _filesroot
    declare -ag _packages

    [[ -z $_debug ]] && _debug="false" # Set to true to enable debugging by default
    [[ -z $_builddir ]] && _builddir="$PWD"
    [[ -z $_filesroot ]] && _filesroot="$_builddir/files/"

    # Additional packages for all profiles
    _packages+=("luci" "nano" "htop" "tcpdump" "diffutils")

    # If no profile is specified, use the TP-Link Archer C7 v2 dumb AP
    [[ -z $_profile ]] && _profile="tplink_archer-c7-v2"

    # Custom profiles
    # TP-Link Archer C7 v2 dumb AP
    if [[ "$_profile" == "tplink_archer-c7-v2" ]]; then
        [[ -z $_version ]] && _version="19.07.3"
        _target="ath79/generic"
        _factory_suffix="squashfs-factory.bin"
        _sysupgrade_suffix="squashfs-sysupgrade.bin"
        _packages+=("-dnsmasq" "-odhcpd" "-iptables")
    # Raspberry Pi 4B router with USB->Ethernet dongle
    elif [[ "$_profile" == "rpi-4" ]]; then
        [[ -z $_version ]] && _version="snapshot"
        _target="bcm27xx/bcm2711"
        _factory_suffix="ext4-factory.img"
        _sysupgrade_suffix="ext4-sysupgrade.img"
        _packages+=("kmod-usb-net-asix-ax88179" "luci-app-upnp" "luci-app-wireguard" \
        "luci-app-vpn-policy-routing" "-dnsmasq" "dnsmasq-full" "luci-app-ddns" "luci-app-sqm")
    fi
}


printHelpAndExit() {

    debug "${FUNCNAME[0]}"

    cat <<-'EOF'
USAGE:
openwrtBuild [[OPTION] [VALUE]]...

If PROFILE is set and TARGET is not, buildOpenwrt can use a custom profile specified in DEFAULTS

OPTIONS
    --profile, -p PROFILE
    --version, -v OPENWRT_VERSION
    --builddir, -b PATH
    --ssh-upgrade SSH_PATH
        Example: root@192.168.1.1
    --flash, -f DEVICE
        Example: /dev/sdX
    --debug, -d
    --help, -h
EOF
    # Exit using passed exit code
    [[ -z $1 ]] && exit 0 || exit "$1"
}


parseInput() {

    debug "${FUNCNAME[0]}"

    if _input=$(getopt -o +v:p:b:f:dh -l version:,profile:,builddir:,ssh-upgrade:,flash:,debug,help -- "$@"); then
        eval set -- "$_input"
        while true; do
            case "$1" in
                --version|-v)
                    shift && _version="$1"
                    ;;
                --profile|-p)
                    shift && _profile="$1"
                    ;;
                --builddir|-b)
                    shift && _builddir="$1"
                    ;;
                --ssh-upgrade)
                    shift && _ssh_upgrade_path="$1"
                    ;;
                --flash|-f)
                    shift && _flash_dev="$1"
                    ;;
                --debug|-d)
                    echo "Debugging on"
                    _debug="true"
                    ;;
                --help|-h)
                    _printHelpAndExit 0
                    ;;
                --)
                    shift
                    break
                    ;;
            esac
            shift
        done
    else
        echo "Incorrect options provided"
        printHelpAndExit 1
    fi
}


debug () { [[ "$_debug" == "true" ]] && echo "Running: " "$@" ; }


setVars() {

    debug "${FUNCNAME[0]}"

    getOS () {

        debug "${FUNCNAME[0]}"

        if [[ -f /etc/os-release ]]; then
            # shellcheck disable=SC1091
            source /etc/os-release
            export ID="$ID"
            echo "Detected platform: $ID"
        else
            echo "Cannot detect OS!"
            exit 1
        fi
    }
    getOS

    export _source_archive="$_builddir/sources/$_profile-$_version.tar.xz"
    export _source_dir="${_source_archive%.tar.xz}"
    export _out_bin_dir="$_builddir/bin/$_profile-$_version/"

    if [[ "$_version" == "snapshot" ]]; then
        local _out_prefix="$_out_bin_dir/openwrt-${_target//\//-}-$_profile"
    else
        local _out_prefix="$_out_bin_dir/openwrt-$_version-${_target//\//-}-$_profile"
    fi

    export _factory_bin="$_out_prefix-$_factory_suffix"
    export _factory_bin_fname="${_factory_bin##*/}"
    export _factory_bin_gz="$_factory_bin.gz"
    export _factory_bin_gz_fname="${_factory_bin_gz##*/}"

    export _sysupgrade_bin="$_out_prefix-$_sysupgrade_suffix"
    export _sysupgrade_bin_fname="${_sysupgrade_bin##*/}"
    export _sysupgrade_bin_gz="$_sysupgrade_bin.gz"
    export _sysupgrade_bin_gz_fname="${_sysupgrade_bin_gz##*/}"
}


installPrerequisites() {

    debug "${FUNCNAME[0]}"

    local -a _pkg_list
    local _pkg_cmd

    if [[ "$ID" == "fedora" ]]; then
        _pkg_list=("@c-development" "@development-tools" "@development-libs" "zlib-static" "elfutils-libelf-devel" "gawk" "unzip" "file" "wget" "python3" "python2" "axel")
        _pkg_cmd="dnf"
    elif [[ "$ID" =~ ^(debian|ubuntu)$ ]]; then
        _pkg_list=("build-essential" "libncurses5-dev" "libncursesw5-dev" "zlib1g-dev" "gawk" "git" "gettext" "libssl-dev" "xsltproc" "wget" "unzip" "python" "axel")
        _pkg_cmd="apt-get"
    fi

    echo "Installing dependencies"
    debug "sudo $_pkg_cmd -y install ${_pkg_list[*]}"
    if ! sudo "$_pkg_cmd" -y install "${_pkg_list[@]}" > /dev/null 2>&1; then
        echo "Warning: Problem installing prerequisites"
        return 1
    fi
}


acquireImageBuilder() {

    debug "${FUNCNAME[0]}"

    local _url _filename

    if [[ "$_version" == "snapshot" ]]; then
        # Remove existing ImageBuilders
        [[ -f "$_source_archive" ]] && rm "$_source_archive"
        _filename="openwrt-imagebuilder-${_target//\//-}.Linux-x86_64.tar.xz"
        _url="https://downloads.openwrt.org/snapshots/targets/$_target/$_filename"
    else
        # Reuse existing ImageBuilders
        [[ -f "$_source_archive" ]] && return 0
        _filename="openwrt-imagebuilder-$_version-${_target//\//-}.Linux-x86_64.tar.xz"
        _url="https://downloads.openwrt.org/releases/$_version/targets/$_target/$_filename"
    fi

    # Make sources directory if it does not exist
    [[ ! -d "$_builddir/sources" ]] && mkdir -p "$_builddir/sources"

    echo "Downloading image archive"
    debug "axel -o $_source_archive $_url"
    if ! axel -o "$_source_archive" "$_url" > /dev/null 2>&1; then
        echo "Could not download Image Builder"
        exit 1
    fi
}


extractImageBuilder() {

    debug "${FUNCNAME[0]}"

    [[ ! -d "$_source_dir" ]] && mkdir -p "$_source_dir"

    if [[ ! -f "$_source_archive" ]]; then
        echo "Archive missing"
        exit 1
    fi

    echo "Extracting image archive"
    debug "tar -xf $_source_archive -C $_source_dir --strip-components 1"
    if ! tar -xf "$_source_archive" -C "$_source_dir" --strip-components 1; then
        echo "Extraction failed"
        exit 1
    fi
}


makeImage() {

    debug "${FUNCNAME[0]}"

    # move to extracted source directory
    if ! pushd "$_source_dir" > /dev/null 2>&1; then
        exit 1
    fi

    # Make bin dir
    [[ ! -d "$_out_bin_dir" ]] && mkdir -p "$_out_bin_dir"

    # build image
    echo "Running make -j4 image BIN_DIR=$_out_bin_dir PROFILE=$_profile PACKAGES=${_packages[*]} FILES=$_filesroot"
    debug "make -j4 image BIN_DIR=$_out_bin_dir PROFILE=$_profile PACKAGES=${_packages[*]} FILES=$_filesroot > make.log"
    if ! make -j4 image BIN_DIR="$_out_bin_dir" PROFILE="$_profile" \
    PACKAGES="${_packages[*]}" FILES="$_filesroot" > make.log; then
        echo "Make image failed!"
        exit 1
    fi

    if ! popd > /dev/null 2>&1; then
        exit 1
    fi
}


extractImage() {

    debug "${FUNCNAME[0]}" "$@"

    local _gz

    [[ $# -lt 1 ]] && echo "extractImage() requires at least one argument" && exit 1

    for _gz in "$@"; do
        [[ ! -f "$_gz" ]] && return 1
        debug "gunzip -qfk $_gz"
        if ! gunzip -qfk "$_gz"; then
            echo "$_gz extraction failed!"
        fi
    done
}


flashImage() {

    debug "${FUNCNAME[0]}"

    if [[ -z $_factory_bin && -f "$_factory_bin_gz" ]]; then
        extractImage "$_factory_bin_gz"
    fi

    if [[ ! -d "$_flash_dev" ]]; then
        echo "The device specified by --flash could not be found"
        exit 1
    fi

    echo "Unmounting target device $_flash_dev partitions"
    debug "umount $_flash_dev?*"
    sudo umount "$_flash_dev?*"

    debug "sudo dd if=\"$_factory_bin\" of=\"$_flash_dev\" bs=2M conv=fsync"
    if sudo dd if="$_factory_bin" of="$_flash_dev" bs=2M conv=fsync; then
        sync
        echo "Image flashed sucessfully!"
    else
        echo "dd failed!"
        exit 1
    fi
}


sshUpgrade() {

    debug "${FUNCNAME[0]}"

    if [[ -f "$_sysupgrade_bin_gz" ]]; then
        local _source="$_sysupgrade_bin_gz"
        local _source_fname="$_sysupgrade_bin_gz_fname"
    elif [[ -f "$_sysupgrade_bin" ]]; then
        local _source="$_sysupgrade_bin"
        local _source_fname="$_sysupgrade_bin_fname"
    else
        echo "Could not find upgrade file"
        exit 1
    fi

    echo "Copying \"$_source\" to $_ssh_upgrade_path/tmp/"
    debug "scp \"$_source\" \"$_ssh_upgrade_path\":\"/tmp/$_source_fname\""
    # shellcheck disable=SC2140
    if ! scp "$_source" "$_ssh_upgrade_path":"/tmp/$_source_fname"; then
        echo "Could not access the --ssh-upgrade PATH"
        exit 1
    fi

    echo "Executing remote sysupgrade"
    debug "ssh \"$_ssh_upgrade_path\" \"sysupgrade -F /tmp/$_source_fname\""
    # shellcheck disable=SC2029
    ssh "$_ssh_upgrade_path" "sysupgrade -F /tmp/$_source_fname"
}


__main() {

    parseInput "$@"
    setDefaults
    setVars
    installPrerequisites
    acquireImageBuilder
    extractImageBuilder
    if makeImage; then
        [[ -n $_ssh_upgrade_path ]] && sshUpgrade
        [[ -n $_flash_dev ]] && flashImage
    fi
}

__main "$@"
exit $?