#!/bin/bash

# Script to create a new local tag in preparation for a release
# This script is idempotent i.e. it always fetches remote tags to create the new tag.
# E.g. If the current remote release tag is v1.0.0,
## 1) running `create-local-tag-for-release -p` will create a new tag v1.0.1
## 2) immediately running `create-local-tag-for-release -m` will create a new tag v2.0.0

set -euo pipefail

REPO_ROOT_PATH="$( cd "$(dirname "$0")"; cd ../; pwd -P )"
MAKEFILE_PATH=$REPO_ROOT_PATH/Makefile
TAG_REGEX="^v[0-9]+\.[0-9]+\.[0-9]+(-[a-zA-Z]*)?$"

HELP=$(cat << 'EOM'
  Create a new local tag in preparation for a release. This script is idempotent i.e. it always fetches remote tags to create the new tag.

  Usage: create-local-tag-for-release [options]

  Options:
    -v      new tag / version number. The script relies on the user to specify a valid and accurately incremented tag.
    -m      increment major version
    -i      increment minor version
    -p      increment patch version
    -h      help

  Examples:
    create-local-tag-for-release -v v1.0.0      Create local tag for new version v1.0.0
    create-local-tag-for-release -i             Create local tag for new version by incrementing minor version only (previous tag=v1.0.0, new tag=v1.1.0)
EOM
)

MAJOR_INC=false
MINOR_INC=false
PATCH_INC=false
NEW_TAG=""
CURR_REMOTE_RELEASE_TAG=""

process_args() {
    while getopts "hmipv:" opt; do
        case ${opt} in
            h )
            echo -e "$HELP" 1>&2
            exit 0
            ;;
            m )
            MAJOR_INC=true
            ;;
            i )
            MINOR_INC=true
            ;;
            p )
            PATCH_INC=true
            ;;
            v )
            NEW_TAG="${OPTARG}"
            ;;
            \? )
            echo "$HELP" 1>&2
            exit 0
            ;;
        esac
    done
}

validate_args() {
    if [[ ! -z $NEW_TAG ]]; then
        if ! [[ $NEW_TAG =~ $TAG_REGEX ]]; then
            echo "❌ Invalid new tag specified $NEW_TAG. Examples: v1.2.3, v1.2.3-dirty"
            exit 1
        fi

        echo "🥑 Using the new tag specified with -v flag. All other flags, if specified, will be ignored."
        echo "   NOTE:The script relies on the user to specify a valid and accurately incremented tag."
        return
    fi

    if ($MAJOR_INC && $MINOR_INC) || ($MAJOR_INC && $PATCH_INC) || ($MINOR_INC && $PATCH_INC); then
        echo "❌ Invalid arguments passed. Specify only one of 3 tag parts to increment for the new tag: -m (major) or -i (minor) or -p (patch)."
        exit 1
    fi

    if $MAJOR_INC || $MINOR_INC || $PATCH_INC; then
        return
    fi

    echo -e "❌ Invalid arguments passed. Specify atleast one argument.\n$HELP"
    exit 1
}

sync_local_tags_from_remote() {
    # setup remote upstream tracking to fetch tags
    git remote add the-real-upstream https://github.com/aws/amazon-ec2-instance-selector.git &> /dev/null || true
    git fetch the-real-upstream

    # delete all local tags
    git tag -l | xargs git tag -d

    # fetch remote tags
    git fetch the-real-upstream --tags

    # record the latest release tag in remote, before creating a new tag
    CURR_REMOTE_RELEASE_TAG=$(get_latest_tag)

    # clean up tracking
    git remote remove the-real-upstream
}

create_tag() {
    git tag $NEW_TAG
    echo -e "\n✅ Created new tag $NEW_TAG (Current latest release tag in remote: v$CURR_REMOTE_RELEASE_TAG)\n"
    exit 0
}

get_latest_tag() {
    make -s -f $MAKEFILE_PATH latest-release-tag | cut -b 2-
}

main() {
    process_args "$@"
    validate_args

    sync_local_tags_from_remote

    # if new tag is specified, create it
    if [[ ! -z $NEW_TAG ]]; then
        create_tag
    fi

    # increment version
    if $MAJOR_INC || $MINOR_INC || $PATCH_INC; then
        curr_major_v=$(echo $CURR_REMOTE_RELEASE_TAG | tr '.' '\n' | head -1)
        curr_minor_v=$(echo $CURR_REMOTE_RELEASE_TAG | tr '.' '\n' | head -2 | tail -1)
        curr_patch_v=$(echo $CURR_REMOTE_RELEASE_TAG | tr '.' '\n' | tail -1)

        if [[ $MAJOR_INC == true ]]; then
            new_major_v=$(echo $(($curr_major_v + 1)))
            NEW_TAG=$(echo v$new_major_v.0.0)
        elif [[ $MINOR_INC == true ]]; then
            new_minor_v=$(echo $(($curr_minor_v + 1)))
            NEW_TAG=$(echo v$curr_major_v.$new_minor_v.0)
        elif [[ $PATCH_INC == true ]]; then
            new_patch_v=$(echo $(($curr_patch_v + 1)))
            NEW_TAG=$(echo v$curr_major_v.$curr_minor_v.$new_patch_v)
        fi
        create_tag
    fi
}

main "$@"