#!/bin/bash

# This is a very basic script for developper usage. It has a few known
# limitations (feel free to send patches for these):
# - It is targetted at GIMP usage primarily, hence able to check only
#   Flathub (stable and beta remotes) and GNOME-nightly. Yet some
#   generity is built-in so you can set your own application ID on
#   command line and it should work.
# - It assumes the remotes are named 'flathub', 'flathub-beta' and
#   'gnome-nightly' (for stable, beta and nightly branches respectively)
#   as these are the default names proposed by generated .flatpakref
#   files (SuggestRemoteName field) when first installing software from
#   this repository. So most people will have these remotes registered
#   with these names. Yet it could technically be any name locally and
#   this script is not verifying this.
# - It also assumes the flathub remotes are installed at all (it can't
#   search without them being installed and won't install these for
#   you).
# - It uses bash because I lazily didn't bother making it portable as
#   it's really just a tool for core dev testing. Yet we of course
#   welcome patches if some syntax needs to be rewritten for
#   portability.

install=-1
appid=org.gimp.GIMP
remote='flathub'
branch='stable'
prefix='--user'
for var in "$@"
do
  if [[ $var =~ ^-([0-9]+)$ ]]; then
    install=${BASH_REMATCH[1]}
  elif [[ $var = '--beta' ]]; then
    remote='flathub-beta'
    branch='beta'
  elif [[ $var = '--nightly' ]]; then
    remote='gnome-nightly'
    branch='master'
  elif [[ $var = '--system' ]]; then
    prefix='--system'
  elif [[ $var =~ ^- ]]; then
    echo "Usage: ./flathub-releases [--beta] [--system] [-X] [org.example.app]"
    echo
    echo "List all flatpak builds stored on Flathub or GNOME repository."
    echo "The builds for org.gimp.GIMP are looked up by default unless"
    echo "you provide explicitely another AppStream ID."
    echo
    echo "Adding a -X number as option install the numbered release"
    echo "instead of listing them."
    echo
    echo "Options:"
    echo
    echo "-0: install the last build."
    echo "-1: install the previous build."
    echo "-2: install the before-previous build (and so on)."
    echo
    echo "--beta: list or install a beta release"
    echo "--nightly: list or install a nightly release"
    echo "--system: install as system flatpak (default to user install)"
    exit 1
  else
    appid=$var
  fi
done

package_info_cmd="flatpak remote-info $remote $appid"
package_info=`$package_info_cmd 2>&1`
got_info="$?"
if [ "$got_info" -ne 0 ]; then
  # By default flatpak will just use either the user or system install
  # depending on what it finds. Funnily the command may fail if the
  # remote is found not 0 or 1 but 2 times (both on user and system).
  # Normally it would interactively ask to choose, but in this specific
  # non-interactive case, it would just silently fail instead. So let's
  # make a second try on user-installed remote (totally arbitrary
  # choice).
  package_info_cmd="flatpak remote-info --user $remote $appid"
  package_info=`$package_info_cmd 2>&1`
  got_info="$?"
fi
if [ "$got_info" -ne 0 ]; then
  echo "Flathub query failed with the following error: $package_info"
  exit 2
fi

release_number=0
install_commit=
while [ "$got_info" -eq 0 ]
do
  release_date=`echo "$package_info" | grep Date: |sed 's/^ *Date: //'`
  release_commit=`echo "$package_info" | grep Commit: |sed 's/^ *Commit: //'`
  release_subject=`echo "$package_info" | grep Subject: |sed 's/^ *Subject: //'`
  if [ "$install" -eq -1 ]; then
    # In non-install mode, just list the whole release.
    printf "%2d: %s [%s]\n" $release_number "$release_subject" "$release_date"
  elif [ "$install" -eq "$release_number" ]; then
    install_commit=$release_commit
    break
  fi

  parent_commit=`echo "$package_info" | grep Parent: |sed 's/^ *Parent: //'`
  release_number=$(( $release_number + 1 ))

  package_info=`$package_info_cmd --commit $parent_commit 2>&1`
  got_info="$?"
done

if [ "$install" -ne -1 ]; then
  if [ -n "$install_commit" ]; then
    # Flatpak doesn't have a way to install directly a commit, but we
    # can install then update. This will work whether the flatpak is
    # already installed or not.

    echo "[1/2] Installing $appid"
    flatpak install -y $prefix $remote $appid//$branch

    echo "[2/2] Updating to commit '$install_commit' ($release_number's previous build)"
    flatpak update -y $prefix --commit=$install_commit $appid//$branch

    if [ "$?" -eq 0 ]; then
      echo "Build $release_number released on $release_date was installed."
      echo "Build subject: $release_subject"
      echo "Build commit on $remote: $release_commit"
    else
      echo "Failure to install build $release_number released on $release_date."
      exit 2
    fi
  else
    echo "There was no $release_number's build to install. Aborting."
    exit 1
  fi
fi

exit 0
