#!/usr/bin/env bash
#
# Derives a valid npm semver version from the Git tag produced by
# `git describe` and writes it into the root package.json.
#
# Examples of the conversion:
#   2.14.0                     ->  2.14.0
#   2.14.0-RC1                 ->  2.14.0-rc.1
#   2.14.0-RC1-140-g9f2ca9965  ->  2.14.0-rc.1.140
#   2.14.0-140-g9f2ca9965      ->  2.14.1-dev.140
#
# The last case (commits after a release tag) bumps the patch level so
# the resulting semver sorts higher than the release.

set -euo pipefail

raw=$(git describe --tags --match "*.*.*")

# Parse: <major>.<minor>.<patch>[-<label><n>][-<commits>-g<hash>]
if [[ "$raw" =~ ^([0-9]+\.[0-9]+\.[0-9]+)(-([A-Za-z]+)([0-9]*))?(-([0-9]+)-g[0-9a-f]+)?$ ]]; then
    base="${BASH_REMATCH[1]}"
    label="${BASH_REMATCH[3]}"        # e.g. RC
    label_num="${BASH_REMATCH[4]}"    # e.g. 1
    commits="${BASH_REMATCH[6]}"      # e.g. 140

    # build dot-separated pre-release identifiers
    pre=""
    if [[ -n "$label" ]]; then
        pre="${label,,}"  # use lower-case label
        [[ -n "$label_num" ]] && pre="${pre}.${label_num}"
    elif [[ -n "$commits" ]]; then
        # commits after a release tag: bump patch, mark as dev
        IFS='.' read -r major minor patch <<< "$base"
        base="${major}.${minor}.$((patch + 1))"
        pre="dev"
    fi
    [[ -n "$commits" && -n "$pre" ]] && pre="${pre}.${commits}"

    if [[ -n "$pre" ]]; then
        version="${base}-${pre}"
    else
        version="$base"
    fi
else
    echo "ERROR: Cannot parse version from git describe output: $raw" >&2
    exit 1
fi

cd "$(dirname "$0")/.."
npm pkg set "version=${version}"
echo "$version"