#!/usr/bin/env bash

set -eu +x

ROOT=$(cd $(dirname $0) ; pwd)
TARGET=$1

# For nightly-YYYY-MM-DD, tag should be nightly
# For lts-X.Y, tag should be ltsX
SHORTNAME=$(echo $TARGET | cut -d- -f 1)
if [ $SHORTNAME = "lts" ]
then
    TAG=$(echo $TARGET | sed 's@^lts-\([0-9]*\)\.[0-9]*@lts\1@')
else
    TAG=$SHORTNAME
fi

IMAGE=commercialhaskell/stackage:$TAG

CABAL_DIR=$ROOT/cabal
STACK_DIR=$ROOT/stack
GHC_DIR=$ROOT/ghc
DOT_STACKAGE_DIR=$ROOT/dot-stackage
WORKDIR=$ROOT/$TAG/work
# ssh key is used for committing snapshots (and their constraints) to Github
SSH_DIR=$ROOT/ssh
USERID=$(id -u)

mkdir -p \
	"$CABAL_DIR" \
	"$STACK_DIR" \
	"$GHC_DIR" \
	"$DOT_STACKAGE_DIR" \
	"$WORKDIR" \
	"$SSH_DIR"

GITCONFIG=$ROOT/gitconfig
cat >$GITCONFIG <<EOF
[user]
	email = michael+stackage-build@fpcomplete.com
	name = Stackage Build host
EOF

HACKAGE_CREDS=$ROOT/hackage-creds

function require_400_file {
    if [ ! -f "$1" ]
    then
        echo File not found: "$1"
        exit 1
    fi

    chmod 400 "$1"
}

require_400_file "$SSH_DIR/id_rsa"
require_400_file "$HACKAGE_CREDS"

mkdir -p $ROOT/bin
BINDIR=$(cd $ROOT/bin ; pwd)
(
cd $BINDIR
rm -f stackage-curator stackage-curator-2*.bz2
CURATOR2=stackage-curator-2-7e65b644121812d9a3a8b24d7130bb8865485f8f
wget "https://download.fpcomplete.com/stackage-curator-2/$CURATOR2.bz2"
bunzip2 "$CURATOR2.bz2"
chmod +x $CURATOR2
mv $CURATOR2 stackage-curator
./stackage-curator --version
)


ARGS_COMMON="--rm -v $WORKDIR:$HOME/work -w $HOME/work -v $BINDIR/stackage-curator:/usr/bin/stackage-curator:ro -v /etc/passwd:/etc/passwd:ro -v /etc/group:/etc/group:ro -v $BINDIR/stack:/usr/bin/stack:ro -v $STACK_DIR:$HOME/.stack"
ARGS_PREBUILD="$ARGS_COMMON -u $USERID -e HOME=$HOME -v $CABAL_DIR:$HOME/.cabal -v $GHC_DIR:$HOME/.ghc -v $DOT_STACKAGE_DIR:$HOME/.stackage"
ARGS_BUILD="$ARGS_COMMON -v $CABAL_DIR:$HOME/.cabal:ro -v $GHC_DIR:$HOME/.ghc:ro"
# instance-data is an undocumented feature of S3 used by amazonka,
# see https://github.com/brendanhay/amazonka/issues/271
ARGS_UPLOAD="$ARGS_COMMON -u $USERID -e HOME=$HOME -v $HACKAGE_CREDS:/hackage-creds:ro -v $DOT_STACKAGE_DIR:$HOME/.stackage -v $SSH_DIR:$HOME/.ssh:ro -v $GITCONFIG:$HOME/.gitconfig:ro -v $CABAL_DIR:$HOME/.cabal:ro --add-host instance-data:169.254.169.254"

# Make sure we actually need this snapshot. We only check this for LTS releases
# since, for nightlies, we'd like to run builds even if they are unnecessary to
# get early warning information of upcoming failures. (See the duplicate check
# below for why this is safe.)
if [ $SHORTNAME = "lts" ]
then
  docker run $ARGS_UPLOAD $IMAGE /bin/bash -c "exec stackage-curator check-target-available --target $TARGET"
fi

# Get latest stack
(
cd $BINDIR
rm -f stack stack-*.bz2
STACK=stack-7e65b644121812d9a3a8b24d7130bb8865485f8f
wget "https://download.fpcomplete.com/stackage-curator-2/$STACK.bz2"
bunzip2 "$STACK.bz2"
chmod +x $STACK
mv $STACK stack
./stack --version
)


# Determine the new build plan unless NOPLAN is set
#
# * Update the package index (unless LTS)
# * Create a new plan
if [ "${NOPLAN:-}x" = "x" ]
then
    if [ $SHORTNAME = "lts" ]
    then
        docker run $ARGS_PREBUILD $IMAGE /bin/bash -c "stackage-curator constraints --target $TARGET && stackage-curator snapshot-incomplete && stackage-curator snapshot"
    else
        docker run $ARGS_PREBUILD $IMAGE /bin/bash -c "stackage-curator update && stackage-curator constraints --target $TARGET && stackage-curator snapshot-incomplete && stackage-curator snapshot"
    fi
fi


# Do the rest of the pre-build actions:
#
# * Check that the snapshot is valid
# * Fetch and unpack all needed tarballs (the build step does not have write access to the tarball directory)
docker run $ARGS_PREBUILD $IMAGE /bin/bash -c 'GHCVER=$(sed -n "s/^ghc-version: \(.*\)/\1/p" constraints.yaml) && stack setup ghc-$GHCVER --verbosity=error && stack exec --resolver=ghc-$GHCVER stackage-curator check-snapshot && stackage-curator unpack'

case $SHORTNAME in
    lts) JOBS=1 ;;
    nightly) JOBS=2 ;;
esac

# Now do the actual build. We need to first set the owner of the home directory
# correctly, so we run the command as root, change owner, and then use sudo to
# switch back to the current user
docker run $ARGS_BUILD $IMAGE nice -n 15 /bin/bash -c "chown $USER $HOME && exec sudo -E -u $USER env \"HOME=$HOME\" \"PATH=\$PATH\" stackage-curator build --jobs $JOBS"

# Make sure we actually need this snapshot. We used to perform this check
# exclusively before building. Now we perform it after as well for the case of
# nightly, where we don't perform this check beforehand. This is also slightly
# safer, in case someone else already uploaded a specific snapshot while we
# were building.
docker run $ARGS_UPLOAD $IMAGE /bin/bash -c "exec stackage-curator check-target-available --target $TARGET"

# Successful build, so we need to:
#
# * Upload the docs to S3
# * Upload the new snapshot .yaml file to the appropriate Github repo, also upload its constraints
# * Register as a new Hackage distro (currently disabled)
docker run $ARGS_UPLOAD $IMAGE /bin/bash -c "stackage-curator upload-docs --target $TARGET && exec stackage-curator upload-github --target $TARGET"
# FIXME - add back "stackage-curator hackage-distro --target $TARGET" when we will be ready to publish
# information about the new snapshots on Hackage

echo -n "Completed at "
date