#!/bin/bash

# Variables
REPO_PATH=${1}
PULL_REMOTE=${2}
PUSH_REMOTE=${3}
BRANCH=${4}
PREFIX=${5}
REGEX=${6}

show_help() {
    echo "${0} <repo path> <pull remote> <push remote> <branch> <push tag prefix> v<track regex>" >&2
    echo "Example: ${0} ~/repos/kernel stable origin 3.12 sabayon- 3\.12\.[0-9999]" >&2
}

if [ ! -d "${REPO_PATH}" ]; then
    show_help
    exit 1
fi

if [ -z "${PULL_REMOTE}" ]; then
    show_help
    exit 1
fi

if [ -z "${PUSH_REMOTE}" ]; then
    show_help
    exit 1
fi

if [ -z "${BRANCH}" ]; then
    show_help
    exit 1
fi

if [ -z "${PREFIX}" ]; then
    show_help
    exit 1
fi

if [ -z "${REGEX}" ]; then
    show_help
    exit 1
fi

rollback() {
    cd "${REPO_PATH}" || return 1
    git rebase --abort || true
    git reset --hard "${PUSH_REMOTE}/${BRANCH}" || return 1
}

start() {
    cd "${REPO_PATH}" || return 1

    echo "Fetching ${PULL_REMOTE}"
    git fetch --quiet "${PULL_REMOTE}" || {
        rollback
        return 1;
    }

    echo "Fetching ${PUSH_REMOTE}"
    git fetch --quiet "${PUSH_REMOTE}" || {
        rollback
        return 1;
    }

    local tags=$(git tag | grep -e "v${REGEX}")
    echo "Tracking tags:"
    echo -e "${tags}"
    if [ -z "${tags}" ]; then
        echo "No tags to track for: ${REGEX} in ${REPO_PATH}"
        return 0
    fi

    local bumps=()
    local tag= tracked_tag=
    for tag in ${tags}; do
        tracked_tag="${PREFIX}${tag/v}"
        echo "Checking tag: ${tag}, ${tracked_tag}"
        if ! git tag | grep -q -e "^${tracked_tag}$"; then
            echo "Not tracked: ${tag}, ${tracked_tag}"
            bumps+=( "${tag}" )
        fi
    done

    if [ -z "${bumps[*]}" ]; then
        echo "Nothing to do."
        return 0
    fi

    if ! git show-branch "${BRANCH}" > /dev/null; then
        echo "Creating branch: ${BRANCH}"
        git checkout -q "${PUSH_REMOTE}/${BRANCH}" -b "${BRANCH}" || {
            rollback
            return 1;
        }
    else
        echo "Checking out branch: ${BRANCH}"
        git checkout -q "${BRANCH}" || {
            rollback
            return 1;
        }
    fi

    echo "Updating branch"
    git rebase --quiet "${PUSH_REMOTE}/${BRANCH}" || {
        rollback
        return 1;
    }

    for tag in "${bumps[@]}"; do
        echo "Working on tag: ${tag}"
        git merge --quiet "${tag}" -m "Automatic merge of tag ${PULL_REMOTE}/${tag}" || {
            rollback
            return 1;
        }
        bash sabayon/bump-configs.sh || {
            rollback
            return 1;
        }

        local changed=$(git ls-files -m -d -o --exclude-standard sabayon/config)
        if [ -n "${changed}" ]; then
            git commit --quiet sabayon/config -m "sabayon: bump configs" || {
                rollback
                return 1;
            }
        fi

        git push --quiet || {
            rollback
            return 1;
        }
        git push --quiet --tags || {
            rollback
            return 1;
        }

        tracked_tag="${PREFIX}${tag/v}"
        bash sabayon/tag-version.sh "${tracked_tag}" || {
            rollback
            return 1;
        }

        echo "Released ${tracked_tag}"
    done
}


start