#!/bin/bash

name="Libredbdiff"

baseconfpath="/etc/libredbdiff"
basedbpath="/var/lib/libredbdiff"

conffile="$baseconfpath/pacman.conf.parabola"
conffilearch="$baseconfpath/pacman.conf.archlinux"

dbpath="$basedbpath/pacman.parabola"
dbpatharch="$basedbpath/pacman.archlinux"

mirrorlist="$baseconfpath/mirrorlist.parabola"
mirrorlistarch="$baseconfpath/mirrorlist.archlinux"

mirror='http://repo.parabolagnulinux.org/$repo/os/$arch'
mirrorarch='http://mirrors.kernel.org/archlinux/$repo/os/$arch'


error() { echo -e "Error. $@" > /dev/stderr ; exit 1; }

if [[ $# == 1 ]] ; then
  [[ $1 == -n ]] && UPDATE=0
  [[ $1 == -h ]] && { echo -e "${name}. Show [libre] packages that need to be updated from Arch repositories.\n\nUsage:\nlibredbdiff\t\tInitialize (first run) or update pacman databases\nlibredbdiff -n\t\tPrint results" ; exit 0 ; }
elif [[ $# != 0 ]] ; then
  error "Bad arguments. Nothing done."
else
  UPDATE=1
fi

if (( $UPDATE )) ; then
  [[ $EUID != 0 ]] && { error "To initialize $name or update $name pacman databases, the script must be run as root. Nothing done." ; }
 
  [[ -d "$baseconfpath" && -d "$basedbpath" && -d "$dbpath" && -d "$dbpatharch" && -e "${conffile}" && -e "${conffilearch}" && -e "${mirrorlist}" && -e  "${mirrorlist}" ]] || { echo "${name} files are missing. Initializing." ; init=1 ; }

  createdir() {
    if [[ ! -e $1 ]] ; then
      echo "Creating directory $1"
      mkdir "$1" || error "Failed to create directory $1. Exiting."
    else
      [[ $init ]] && echo "Warning. ${1} already exists. Skipping."
    fi
  }
  createdir "$baseconfpath"
  createdir "$basedbpath"
  createdir "$dbpath"
  createdir "$dbpatharch"

  downloadfile() {
    if [[ ! -e $1 ]] ; then
      echo "$2"
      if wget -q "$3" -O "$1"; then
	return 255
      else
        error "Failed to download ${1}. Exiting."
      fi
    else
      [[ $init ]] && echo "Warning. ${1} already exists. Skipping."
    fi
  }
  downloadfile "${conffile}" "Downloading Parabola pacman.conf" "https://projects.parabolagnulinux.org/abslibre.git/plain/libre/pacman/pacman.conf.x86_64"

  downloadfile "${conffilearch}" "Downloading Arch pacman.conf" "https://projects.archlinux.org/svntogit/packages.git/plain/pacman/trunk/pacman.conf.x86_64"
  if [[ $? == 255 ]] ; then
    echo "Setting Arch mirrorlist file in ${conffilearch}"
    sed -i "s|/etc/pacman\.d/mirrorlist$|$baseconfpath/mirrorlist.archlinux|" "${conffilearch}"
  fi

  setmirror() {
    local distro="$1"
    local mirror="$2"
    local mirrorlist="$3"
    [[ $init ]] && [[ $mirror ]] && {
      mirrorescaped="${mirror//./\\.}" ; mirrorescaped="${mirrorescaped//\$/\\$}"
        echo "Setting ${mirror} as the only enabled ${distro} mirror." && \
          sed -i 's|^#\(Server = '"${mirrorescaped}"'\)$|\1|' "${mirrorlist}"
    }
  }

  downloadfile "${mirrorlist}" "Downloading Parabola mirrorlist" "https://repo.parabolagnulinux.org/mirrorlist.txt"
  if [[ $? == 255 ]] ; then
    sed -i 's|^Server|#Server|' "${mirrorlist}"
    setmirror "Parabola" "$mirror" "$mirrorlist"
  fi

  downloadfile "${mirrorlistarch}" "Downloading Arch mirrorlist" "https://projects.archlinux.org/svntogit/packages.git/plain/pacman-mirrorlist/trunk/mirrorlist"
  if [[ $? == 255 ]] ; then
    setmirror "Arch" "$mirrorarch" "$mirrorlistarch"
  fi

  echo -e "\nSynchronizing $name pacman databases for Parabola"
  pacman --config "${conffile}" -b "${dbpath}" -Sy || error "Failed to synchronize pacman database for Parabola. Exiting."

  echo -e "\nSynchronizing $name pacman databases for Arch"
  pacman --config "${conffilearch}" -b "${dbpatharch}" -Sy || error "Failed to synchronize pacman database for Arch. Exiting."

  echo
  echo "$name pacman databases are updated. $name is ready. Run libredbdiff -n to print results."
  exit 0
else
  filenotfound() {
	  [[ ! -r $1 ]] && { error "Could not read $1. Nothing done.\nIt may be necessary to run libredbdiff without arguments as root to initialize ${name}." ; }
  }
  filenotfound "${dbpath}"
  filenotfound "${dbpatharch}"
  filenotfound "${conffile}"
  filenotfound "${conffilearch}"
  filenotfound "${mirrorlist}"
  filenotfound "${mirrorlistarch}"
fi

unset provides ver verarch
declare -Ax provides ver verarch

comparepkgs() {
  if [[ ${verarch["$pkgname"]} ]] ; then
    cmp=$(vercmp ${ver["$pkgname"]} ${verarch["$pkgname"]})
    [[ $cmp -lt 0 ]] && echo "${pkgname} needs update from the Arch package of the same name. Versions: ${ver["$pkgname"]} - ${verarch["$pkgname"]}"
  elif [[ ${provides["$pkgname"]} ]] ; then
    for provide in ${provides["$pkgname"]} ; do
      [[ ${verarch["$provide"]} ]] && {
        cmp=$(vercmp "${ver["$pkgname"]}" "${verarch["$provide"]}")
        [[ $cmp -lt 0 ]] && echo "${pkgname} may need update from provide candidate ${provide}. Versions: ${ver["$pkgname"]} - ${verarch["$provide"]}"
      }
    done
  else
	  echo "Could not find candidate to compare ${pkgname}"
  fi
}

while read -a line ; do
  verarch["${line[0]}"]="${line[1]}"
done < <(pacman --dbpath "${dbpatharch}" --config "${conffilearch}" -Ss | grep -v '^ ' | awk -F/ '{print $2}')

expac -b "${dbpath}" -c "${conffile}" -Ss '%r/%n %v %S' | awk -F/ '$1 == "libre" {print $2}' | while read -a line ; do
  ver["${line[0]}"]="${line[1]}"
  provides[${line[0]}]="${line[@]:2}"
  pkgname=${line[0]}
  comparepkgs
done