#! /bin/bash

set -e

PWD=`pwd`
GITHUB_USER=squaremo
DOCKERHUB_USER=squaremo
RELEASE_NAME="Weave"
RELEASE_DESCRIPTION="Weaving Containers into Applications"

setup() {
    ## Get the new version number from the most recent tag
    LATEST_TAG=$(git describe --abbrev=0 --match='v*')
    LATEST_TAG_SHA=$(git rev-parse $LATEST_TAG)
    VERSION=${LATEST_TAG#v}
    # NB does not check that this tag is on master
    RELEASE_DIR=./releases/$LATEST_TAG
}

prepare() {
    setup

    echo "Attempting to build distributables for version $VERSION"
    if [ -d $RELEASE_DIR ]; then
        echo Release directory $RELEASE_DIR already exists, you may want to >&2
        echo     rm -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
    latest_changelog=$(grep -o "Release v.*" -m1 ./CHANGELOG.md)
    if ! [ `echo "$latest_changelog" | grep -o 'v[^ ]*'` == $LATEST_TAG ]; then
        echo Latest changelog entry $latest_changelog does not match >&2
        echo the latest tag $LATEST_TAG >&2
        exit 1
    fi

    echo
    echo == Build and test

    ## Inject the version numbers and build the distributables
    ## (library versions?)

    sed -i "/var version = / c\var version = \"$VERSION\"" weaver/main.go
    make \
        WEAVER_IMAGE=$DOCKERHUB_USER/weave \
        WEAVEDNS_IMAGE=$DOCKERHUB_USER/weavedns

    if make tests; then
        echo '** Tests pass'
    else
        echo Tests failed, probably best not publish this one >&2
        exit 1
    fi

    ## Run tests with the distributables, including version check
    v=$(./weaver/weaver --version)
    if ! [ "$v" == "weaver $VERSION" ]; then
        echo Version of distributable "$v" does not match tag $LATEST_TAG >&2
        exit 1
    fi

    echo '** Build OK'
    echo '** Release artefacts in' $RELEASE_DIR
}

publish() {
    setup
    cd $PWD/$RELEASE_DIR

    echo == Sanity checks

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

    ## Check that the tag exists by looking at github
    if ! curl -sSf https://api.github.com/repos/$GITHUB_USER/weave/git/tags/$LATEST_TAG_SHA >/dev/null 2>&1; then
        echo -e "\u2757 Tag $LATEST_TAG is not on GitHub" >&2
        echo -e "\thttps://github.com/$GITHUB_USER/weave/tags" >&2
        echo "You may need to" >&2
        echo -e "\tgit push --tags"
        exit 1
    fi
    echo -e "\u2713 Tag $LATEST_TAG exists in GitHub repo $GITHUB_USER/weave"

    ## Check that the version doesn't already exist by looking at github
    ## releases
    if github-release info --user $GITHUB_USER --repo weave --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/weave/releases/$LATEST_TAG" >&2
        exit 1
    fi

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

    echo == Tagging $DOCKERHUB_USER/weave and $DOCKERHUB_USER/weavedns as $VERSION
    docker tag $DOCKERHUB_USER/weave $DOCKERHUB_USER/weave:$VERSION
    docker tag $DOCKERHUB_USER/weavedns $DOCKERHUB_USER/weavedns:$VERSION

    docker push $DOCKERHUB_USER/weave:$VERSION
    echo == Pushed $DOCKERHUB_USER/weave:$VERSION to docker hub
    docker push $DOCKERHUB_USER/weavedns:$VERSION
    echo == Pushed $DOCKERHUB_USER/weavedns:$VERSION to docker hub

    echo == Creating GitHub release $RELEASE_NAME $VERSION
    # This cannot be done as a draft because of a bug in
    # github-release: https://github.com/aktau/github-release/issues/7
    github-release release \
        --user $GITHUB_USER \
        --repo weave \
        --tag $LATEST_TAG \
        --name "$RELEASE_NAME $VERSION" \
        --description "$RELEASE_DESCRIPTION"

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

    echo "** Published release $RELEASE_NAME $VERSION"
    echo -e "\thttps://github.com/$GITHUB_USER/weave/releases/$LATEST_TAG"
}

usage() {
    echo Usage:
    echo     ./bin/release prepare
    echo -- Build artefacts for the latest version tag
    echo     ./bin/release publish
    echo -- Publish the artefacts for the latest tag to GitHub and DockerHub
}

case "$1" in
    prepare)
        prepare
        ;;
    publish)
        publish
        ;;
    *)
        echo Unknown command "$1"
        usage
        ;;
esac