#! /bin/bash

set -e

SUDO=${SUDO-sudo}
GITHUB_USER=${GITHUB_USER:-weaveworks}
DOCKERHUB_USER=${DOCKERHUB_USER:-weaveworks}
RELEASE_NAME=${RELEASE_NAME:-"Weave Scope"}
RELEASE_DESCRIPTION=${RELEASE_DESCRIPTION:-"Container Visibility"}

PWD=`pwd`

infer_release_type() {
    if echo $1 | grep -qE '^v[0-9]+\.[0-9]+\.0+$' ; then
        echo MAINLINE
    elif echo $1 | grep -qE '^v[0-9]+\.[0-9]+\.[0-9]+$' ; then
        echo BRANCH
    else
        echo PRERELEASE
    fi
}

setup() {
    # Ensure we have exactly one annotated tag pointing at HEAD
    HEAD_TAGS=$(git tag --points-at HEAD)
    case $(echo $HEAD_TAGS | wc -w) in
        1)
            if [ $HEAD_TAGS != "latest_release" ] ; then
                LATEST_TAG=$HEAD_TAGS
            else
                echo "Cannot determine version - latest_release points at HEAD" >&2
                exit 1
            fi
            ;;
        0)
            echo "Cannot determine version - no tags point at HEAD" >&2
            exit 1
            ;;
        *)
            echo "Cannot determine version - multiple tags point at HEAD:" >&2
            for TAG in $HEAD_TAGS ; do
                echo -e "\t$TAG" >&2
            done
            exit 1
            ;;
    esac

    RELEASE_TYPE=$(infer_release_type $LATEST_TAG)
    echo "== Inferred release type $RELEASE_TYPE from tag $LATEST_TAG"

    LATEST_TAG_SHA=$(git rev-parse $LATEST_TAG)
    LATEST_TAG_COMMIT_SHA=$(git rev-list -1 $LATEST_TAG)
    LATEST_RELEASE_SHA=$(git rev-parse latest_release)
    LATEST_RELEASE_COMMIT_SHA=$(git rev-list -1 latest_release)
    if [ "$RELEASE_TYPE" != 'PRERELEASE' ] ; then
        VERSION=${LATEST_TAG#v}
    else
        VERSION=${LATEST_TAG}
    fi
    # NB does not check that this tag is on master
    RELEASE_DIR=./releases/$LATEST_TAG
}

build() {
    setup

    echo "== Clone repo at $LATEST_TAG for version $VERSION"
    if [ -d $RELEASE_DIR ]; then
        echo -e "\u2757 Release directory $RELEASE_DIR already exists, you may want to" >&2
        echo -e "\trm -rf $RELEASE_DIR" >&2
        exit 1
    fi

    ## Clone the repo at the tag and go there
    mkdir -p releases
    git clone -q -b $LATEST_TAG . $RELEASE_DIR 2>/dev/null
    cd $RELEASE_DIR

    ## Check that the top changelog entry is this version
    if ! latest_changelog=$(grep -oP '(?<=^## Release ).*' -m1 ./CHANGELOG.md) || \
       ! [ `echo "$latest_changelog" = "$VERSION"` ]; then
        echo -e "\u2757 Latest changelog entry \"$latest_changelog\" does not match the release version $VERSION" >&2
        exit 1
    fi

    echo
    echo "== Build and test"

    ## Inject the version numbers and build the distributables
    ## (library versions?)
    sed -i "/SCRIPT_VERSION=/ c\SCRIPT_VERSION=\"$VERSION\"" ./scope
    make SUDO=$SUDO SCOPE_VERSION=$VERSION DOCKERHUB_USER=$DOCKERHUB_USER

    if make tests; then
        echo -e '\u2713 Tests pass'
    else
        echo -e "\u2757 Tests failed, probably best not publish this one" >&2
        exit 1
    fi

    ## Run tests with the distributables, including version check
    v=$(./prog/scope version | grep -o '[0-9].*')
    if ! [ "$v" == "$VERSION" ]; then
        echo "Version of distributable "$v" does not match release version $VERSION" >&2
        exit 1
    fi

    echo -e '\u2713 Build OK'
    echo '** Release artefacts in' $RELEASE_DIR
}

draft() {
    setup

    cd $PWD/$RELEASE_DIR

    echo "== Sanity checks"

    ## Check that the tag exists by looking at github
    if ! curl -sSf https://api.github.com/repos/$GITHUB_USER/scope/git/tags/$LATEST_TAG_SHA >/dev/null 2>&1; then
        echo -e "\u2757 Tag $LATEST_TAG is not on GitHub, or is not the same as the local tag" >&2
        echo -e "\thttps://github.com/$GITHUB_USER/scope/tags" >&2
        echo "You may need to" >&2
        echo -e "\tgit push git@github.com:$GITHUB_USER/scope $LATEST_TAG"
        exit 1
    fi

    echo -e "\u2713 Tag $LATEST_TAG exists in GitHub repo $GITHUB_USER/scope"

    ## Check that the version does not already exist by looking at github
    ## releases
    if github-release info --user $GITHUB_USER --repo scope --tag $LATEST_TAG >/dev/null 2>&1; then
        echo -e "\u2757 Release $LATEST_TAG already exists on GitHub" >&2
        echo -e "\thttps://github.com/$GITHUB_USER/scope/releases/$LATEST_TAG" >&2
        exit 1
    fi

    echo '** Sanity checks OK for publishing tag' $LATEST_TAG as $DOCKERHUB_USER/scope:$VERSION

    RELEASE_ARGS="--draft"
    if [ "$RELEASE_TYPE" = 'PRERELEASE' ] ; then
        RELEASE_ARGS="$RELEASE_ARGS --pre-release"
    fi

    echo "== Creating GitHub release $RELEASE_ARGS $RELEASE_NAME $VERSION"
    github-release release $RELEASE_ARGS \
        --user $GITHUB_USER \
        --repo scope \
        --tag $LATEST_TAG \
        --name "$RELEASE_NAME $VERSION" \
        --description "$RELEASE_DESCRIPTION"

    github-release upload \
        --user $GITHUB_USER \
        --repo scope \
        --tag $LATEST_TAG \
        --name "scope" \
        --file "./scope"

    echo "** Draft $TYPE $RELEASE_NAME $VERSION created at"
    echo -e "\thttps://github.com/$GITHUB_USER/scope/releases/$LATEST_TAG"
}

publish() {
    setup
    cd $PWD/$RELEASE_DIR

    UPDATE_LATEST=false
    if [ "$RELEASE_TYPE" = 'MAINLINE' ] ; then
        UPDATE_LATEST=true
    fi

    if [ "$RELEASE_TYPE" = 'PRERELEASE' ] ; then
        echo "== Tagging and pushing images on docker hub as user $DOCKERHUB_USER"
        $SUDO docker tag -f $DOCKERHUB_USER/scope $DOCKERHUB_USER/scope:$VERSION
        $SUDO docker push   $DOCKERHUB_USER/scope:$VERSION
        echo "** Docker images tagged and pushed"

        echo "== Publishing pre-release on GitHub"

        github-release publish \
            --user $GITHUB_USER \
            --repo scope \
            --tag $LATEST_TAG

        echo "** Pre-release $RELEASE_NAME $VERSION published at"
        echo -e "\thttps://github.com/$GITHUB_USER/scope/releases/$LATEST_TAG"
    else
        echo "== Sanity checks"
        if ! [ "$LATEST_TAG_COMMIT_SHA" == "$LATEST_RELEASE_COMMIT_SHA" ] ; then
            echo -e "\u2757 The tag latest_release does not point to the same commit as $LATEST_TAG" >&2
            echo "You may need to" >&2
            echo -e "\tgit tag -af latest_release $LATEST_TAG" >&2
            exit 1
        fi

        ## Check that the 'latest_release' tag exists by looking at github
        if ! curl -sSf https://api.github.com/repos/$GITHUB_USER/scope/git/tags/$LATEST_RELEASE_SHA >/dev/null 2>&1; then
            echo -e "\u2757 Tag latest_release is not on GitHub, or is not the same as the local tag" >&2
            echo -e "\thttps://github.com/$GITHUB_USER/scope/tags" >&2
            echo "You may need to" >&2
            echo -e "\tgit push -f git@github.com:$GITHUB_USER/scope latest_release" >&2
            exit 1
        fi
        echo '** Sanity checks OK for publishing tag' $LATEST_TAG as $DOCKERHUB_USER/scope:$VERSION

        echo "== Tagging and pushing images on docker hub as user $DOCKERHUB_USER"
        $SUDO docker tag -f $DOCKERHUB_USER/scope $DOCKERHUB_USER/scope:$VERSION
        $SUDO docker push   $DOCKERHUB_USER/scope:$VERSION
        echo "** Docker images tagged and pushed"

        echo "== Publishing release on GitHub"

        github-release publish \
            --user $GITHUB_USER \
            --repo scope \
            --tag $LATEST_TAG

        if github-release info --user $GITHUB_USER --repo scope \
            --tag latest_release >/dev/null 2>&1; then
            github-release delete \
                --user $GITHUB_USER \
                --repo scope \
                --tag latest_release
        fi

        github-release release \
            --user $GITHUB_USER \
            --repo scope \
            --tag latest_release \
            --name "$RELEASE_NAME latest ($VERSION)" \
            --description "[Release Notes](https://github.com/$GITHUB_USER/scope/releases/$LATEST_TAG)"

        github-release upload \
            --user $GITHUB_USER \
            --repo scope \
            --tag latest_release \
            --name "scope" \
            --file "./scope"

        echo "** Release $RELEASE_NAME $VERSION published at"
        echo -e "\thttps://github.com/$GITHUB_USER/scope/releases/$LATEST_TAG"
        echo -e "\thttps://github.com/$GITHUB_USER/scope/releases/latest_release"
    fi
}

usage() {
    echo "Usage:"
    echo -e "\t./bin/release build"
    echo "-- Build artefacts for the latest version tag"
    echo -e "\t./bin/release draft"
    echo "-- Create draft release with artefacts in GitHub"
    echo -e "\t./bin/release publish"
    echo "-- Publish the GitHub release and update DockerHub"
    exit 1
}

# Ensure required tooling is installed
if ! which github-release >/dev/null; then
    echo "Please install git-release:" >&2
    echo -e "\tgo get github.com/weaveworks/github-release" >&2
    echo "and create a git token per https://github.com/weaveworks/github-release" >&2
    exit 1
fi

[ $# -eq 0 ] && usage
COMMAND=$1
shift

case "$COMMAND" in
    build)
        build "$@"
        ;;
    draft)
        draft "$@"
        ;;
    publish)
        publish "$@"
        ;;
    *)
        echo "Unknown command \"$COMMAND\""
        usage
        ;;
esac