#! /usr/bin/env bash

######### Repo list

# this is a reference template
# function _repo_template_function() {
#     REPO_FQDN=''    # host FQDN, this will also be the name of the apt list/source file
#     GPG_KEY_URL=''  # [optional] URL to the GPG Key, if not supplied it will be https://$REPO_FQDN/gpg
#     GPG_KEY_PATH='' # [optional] Location on disk for the public GPG key
#     REPO_ARCH=''    # [optional] System architecture specific package, '-' is shorthand for current architecture
#     REPO_URL=''     # [optional] REPO Url if not https://$REPO_FQDN, which is the default.
#     REPO_SUITE=''   # [optional] Suite / Release codename
#     REPO_CMP=''     # [optional] Package Channel - default is 'main', this is vendor specific.
# }

function _repo_docker() {
# for: docker-ce docker-ce-cli containerd.io docker-compose-plugin
# Also don't forget:
#   remove: docker docker-engine docker.io containerd runc 
#   possibly remove docker-compose and install: https://github.com/docker/compose-switch

    REPO_FQDN='download.docker.com'
    REPO_URL="https://download.docker.com/linux/$_OS"
    GPG_KEY_URL="$REPO_URL/gpg"
    REPO_CMP='stable'
}
function _repo_anydesk() {
# for: anydesk
    REPO_FQDN='deb.anydesk.com'
    REPO_URL="http://$REPO_FQDN/" # NOTE, this is http, not https
    GPG_KEY_URL='https://keys.anydesk.com/repos/DEB-GPG-KEY'
    REPO_ARCH='-'
    REPO_CMP='main'
    REPO_SUITE='all'
}
function _repo_gcloud() {
# for: google-cloud-cli
    REPO_FQDN='packages.cloud.google.com'
    REPO_URL="https://$REPO_FQDN/apt"
    GPG_KEY_URL="$REPO_URL/doc/apt-key.gpg"
    REPO_ARCH='-'
    REPO_SUITE='cloud-sdk'
}
function _repo_mspackages() {
# for: code (optionally: powershell dotnet-*)
    REPO_FQDN='packages.microsoft.com'
    GPG_KEY_URL="https://$REPO_FQDN/keys/microsoft.asc"
    REPO_URL="https://$REPO_FQDN/$_OS/$_REL/prod"
}
function _repo_msedge() {
# for: microsoft-edge-stable
    REPO_FQDN='edge.microsoft.com'
    GPG_KEY_URL="https://packages.microsoft.com/keys/microsoft.asc"
    REPO_URL="http://packages.microsoft.com/repos/edge"
    REPO_SUITE='stable'
}
function _repo_hashicorp() {
# for: terraform
    REPO_FQDN='apt.releases.hashicorp.com'
  # GPG_KEY_URL='' # default value is enough here
  # REPO_URL=''    # default value is enough here
}
function _repo_custom_xscreensavers() {
    # I really LOVE xscreensavers, but it's been stuck in limbo on the
    # `stable` repos, so I install it from the `unstable`, aka `sid`, suite.
    # To do that safely, I make sure the repo is pinned to a lower priority.
    # I do this BEFORE I add the repo.

    # # Debian sid (unstable) as low-priority option
    (echo 'Package: *'; echo 'Pin: release a=unstable'; echo 'Pin-Priority: 200') | sudo tee /etc/apt/preferences.d/unstable > /dev/null
    # # pin xscreensaver to unstable
    (echo 'Package: xscreenaver*'; echo 'Pin: release a=unstable'; echo 'Pin-Priority: 2000') | sudo tee /etc/apt/preferences.d/xscreensaver > /dev/null

    # for: xscreensaver xscreensaver-data xscreensaver-data-extra
    #      xscreensaver-screensaver-bsod xscreensaver-screensaver-webcollage
    # Add the unstable/sid repo - THIS IS DANGEROUS without the pinning via
    # /etc/apt/preferences.d files created by the code above.
    sudo apt-add-repository $_YES --no-update "deb [arch=amd64] http://deb.debian.org/debian sid main non-free contrib"
}

############ Script Logic starts here
set -e

ANSI_Print() { printf "\E[${ANSI_Code}m%s\E[0m" "$@"; }
ANSI_Red()     { ANSI_Code=31 ANSI_Print "$@"; }
ANSI_Green()   { ANSI_Code=32 ANSI_Print "$@"; }
ANSI_Yellow()  { ANSI_Code=33 ANSI_Print "$@"; }
ANSI_Blue()    { ANSI_Code=34 ANSI_Print "$@"; }
ANSI_Indiego() { ANSI_Code=35 ANSI_Print "$@"; }
ANSI_Cyan()    { ANSI_Code=36 ANSI_Print "$@"; }

error() {
  (>&2 ANSI_Red 'ERROR: ' && printf '%s\n' "$@" )
}

require_root() {
  if [[ $EUID -ne 0 ]]; then
    error "This script should only be run using sudo or as the root user"
    exit 1
  fi
}

# The function that does the _Heavy Lifting_.
# see the code that follows for the parameter signature
function add_repo() {
    unset REPO_FQDN GPG_KEY_URL GPG_KEY_PATH REPO_ARCH REPO_URL REPO_SUITE REPO_CMP

    # In case custom handling is required, call it and return.
    if [[ "$(type -t _repo_custom_$1)" == 'function' ]]; then
        eval "_repo_custom_$1" && return 0
        return $?
    # If no repo defintion exist, exit with an error
    elif [[ "$(type -t _repo_$1)" != 'function' ]]; then
        error "Can't configure $1, could not find _repo_$1 definition!"
        return 1
    fi
    # Grab the repo's defintion
    eval "_repo_$1"

    # Prepare all necessary vraiables
    [[ -z "$REPO_FQDN" ]] && error "REPO_FQDN not defined for '$1'" && return 1
    GPG_KEY_URL=${GPG_KEY_URL:-https:\/\/$REPO_FQDN\/gpg}
    GPG_KEY_PATH=${GPG_KEY_PATH:-/usr/share/keyrings/$REPO_FQDN.gpg}
    REPO_ARCH=${REPO_ARCH:-${_ARC}}
    [[ $REPO_ARCH == '-' ]] && REPO_ARCH='' || REPO_ARCH="arch=$REPO_ARCH"
    REPO_URL=${REPO_URL:-https:\/\/$REPO_FQDN}
    REPO_SUITE=${REPO_SUITE:-$_CNM}
    REPO_CMP=${REPO_CMP:-main}
    
    # Grab the GPG key and save it.
    curl -fsSL $GPG_KEY_URL | sudo gpg --dearmor -o $GPG_KEY_PATH $_YES
    echo "Key created: $GPG_KEY_PATH"
    # Define the package source
    echo "deb [$(echo "$REPO_ARCH signed-by=$GPG_KEY_PATH" | xargs )] $REPO_URL $REPO_SUITE $REPO_CMP" | \
                sudo tee /etc/apt/sources.list.d/$REPO_FQDN.list > /dev/null
    echo "APT source list added: /etc/apt/sources.list.d/$REPO_FQDN.list"
}

function usage() {
    printf "  %s\n" \
        "Usage:" \
        "  $0 [-v[v]] " \
        "         [--no-init] [--no-overwrite] " \
        "         all|<repo name>[ <repo name 2>...] " \
        "" \
        "Repos: $( \
          printf "\n      %s" $( \
            typeset -f \
              | grep '^_repo_' \
              | sed 's/_repo\(_custom\)\?_\(.*\) ()/\2/' \
              | sort \
        ))" \
        "" \
        "Options:" \
        "  --no-init      - skip package initialization." \
        "  --no-overwrite - don't overwrite gpg keys automatially, ask." \
        "                   new keys will still be written without asking." \
        "  -v[v]          - script verbosity, equivalent to set -x and set -xv" \
        ""
}

function main() {
    [[ ${#REPO_LIST[@]} -eq 0 ]] && usage && return 1

    require_root

    _OS=$(lsb_release -is | awk '{ print tolower($0) }')
    [[ $_OS == 'pop' ]] && _OS='ubuntu'
    _REL=$(lsb_release -rs) # Release
    _CNM=$(lsb_release -cs) # CodeName
    _ARC=$(dpkg --print-architecture) # Architecture

    ANSI_Cyan "Initializing: Installing basic packages..."; echo
    if [[ -n "$SHOULD_INIT" ]]; then
        # Make sure the /usr/share/keyrings dir exists
        mkdir -p /usr/share/keyrings 2>&1 > /dev/null

        # Make sure all of the basic required tools are installed for the code
        # below to work
        apt-get install --yes --no-install-recommends \
            curl gnupg software-properties-common apt-transport-https
    fi
    ANSI_Green "Done."; echo

    while read r; do
        ANSI_Cyan "Installing $r repository..."; echo
        add_repo $r && UPDATE_REQUIRED=1 || return 2
        ANSI_Green "Installation of $r repository completed."; echo
    done < <(printf "%s\n" "${REPO_LIST[@]}")

    # Finally, run `apt update` to check that everything completed successfully
    if [[ $UPDATE_REQUIRED == 1 ]]; then
        ANSI_Cyan "Finalizing: running 'apt update'..."; echo

        MISSING_SIGNATURES=($( \
            sudo apt update 2>&1 1>/dev/null \
                | sed -ne 's/.*NO_PUBKEY //p' \
            ))
        $MISSING_SIGNATURES| while read key; do if ! [[ ${keys[*]} =~ "$key" ]]; then sudo apt-key adv --keyserver hkp://pool.sks-keyservers.net:80 --recv-keys "$key"; keys+=("$key"); fi; done
        sudo apt update
        ANSI_Green "'apt update' completed."; echo
    fi
}

# Iterate through stdin or parameters
if [[ $# == 0 ]]; then
    usage
else
    REPO_LIST=()
    _YES='--yes'
    _SHOULD_INIT=1
    UPDATE_REQUIRED=0

    READCMD='printf "%s\n" "${@}"'
    [[ $# == 1 && $1 == '-' ]] && READCMD='cat - '
    while read a; do
        # Switch on _YES
        [[ "$a" == "-v" ]] && set -x && continue
        [[ "$a" == "-vv" ]] && set -xv && continue
        [[ "$a" == "--no-overwrite" ]] && unset _YES && continue
        [[ "$a" == "--no-init" ]] && unset _SHOULD_INIT && continue

        # Add repo
        [[ -n "$a" ]] && REPO_LIST+=("$a")
    done < <( eval $READCMD )

    main
fi