#!/bin/bash
function usage {
    echo "Usage: $(basename "$0") [-c] -f FILE_TO_CHANGE REPLACEMENT_FORMAT [-f FILE_TO_CHANGE REPLACEMENT_FORMAT ...]" 2>&1
    echo 'Synchronize files to latest version in source file'
    echo '   -s              Specifies source file for version (default is CHANGELOG.md)'
    echo '   -f              Specifies a file to change and the format for searching and replacing versions'
    echo '                       FILE_TO_CHANGE is the file to be updated/checked for updates'
    echo '                       REPLACEMENT_FORMAT is one of (semver, release, api-release)'
    echo '                           semver indicates to look for a full semver version and replace with the latest full version'
    echo '                           release indicates to look for a release semver version (x.x.x) and replace with the latest release version'
    echo '                           api-release indicates to look for a release semver version in the context of an api route and replace with the latest release version'
    echo '   -c              Compare versions and output proposed changes without changing anything.'
}

function getopts-extra () {
    declare i=1
    # if the next argument is not an option, then append it to array OPTARG
    while [[ ${OPTIND} -le $# && ${!OPTIND:0:1} != '-' ]]; do
        OPTARG[i]=${!OPTIND}
        i+=1
        OPTIND+=1
    done
}

# Parse input options
declare CHECK=0
declare SOURCE_FILE="CHANGELOG.md"
declare -a FILES_TO_CHECK=()
declare -a REPLACEMENT_FORMATS=()
declare args
declare OPTIND OPTARG opt
while getopts ":hcs:f:" opt; do
    case $opt in
        h)
            usage
            exit 0
            ;;
        c)
            CHECK=1
            ;;
        s)
            SOURCE_FILE="$OPTARG"
            ;;
        f)
            getopts-extra "$@"
            args=( "${OPTARG[@]}" )
            # validate length of args, should be 2
            if [ ${#args[@]} -eq 2 ]; then
                FILES_TO_CHECK+=( "${args[0]}" )
                REPLACEMENT_FORMATS+=( "${args[1]}" )
            else
                echo "Exactly 2 arguments must follow -f option." >&2
                exit 1
            fi
            ;;
        \?)
            echo "Invalid option: -$OPTARG." >&2
            usage
            exit 1
            ;;
    esac
done

# Parse REPLACEMENT_FORMATS
RE_SEMVER_FULL="(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)(-((0|[1-9][0-9]*|[0-9]*[a-zA-Z-][0-9a-zA-Z-]*)(\.(0|[1-9][0-9]*|[0-9]*[a-zA-Z-][0-9a-zA-Z-]*))*))?(\+([0-9a-zA-Z-]+(\.[0-9a-zA-Z-]+)*))?"
RE_RELEASE="(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)"
RE_API_RELEASE="v(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)"
# Pull out semver appearing earliest in SOURCE_FILE.
LAST_VERSION=$(grep -o -m 1 -E "${RE_SEMVER_FULL}" "$SOURCE_FILE")
LAST_RELEASE=$(grep -o -m 1 -E "${RE_RELEASE}($|[^-+])" "$SOURCE_FILE" | grep -o -m 1 -E "${RE_RELEASE}")
LAST_API_RELEASE="v$(grep -o -m 1 -E "${RE_RELEASE}($|[^-+])$" "$SOURCE_FILE" | grep -o -m 1 -E "${RE_RELEASE}")"
declare -a RE_SEMVERS=()
declare -a UPDATED_VERSIONS=()
for i in "${!REPLACEMENT_FORMATS[@]}"; do
    REPLACEMENT_FORMAT=${REPLACEMENT_FORMATS[$i]}
    case $REPLACEMENT_FORMAT in
        semver)
            RE_SEMVERS+=( "$RE_SEMVER_FULL" )
            UPDATED_VERSIONS+=( "$LAST_VERSION" )
            ;;
        release)
            RE_SEMVERS+=( "$RE_RELEASE" )
            UPDATED_VERSIONS+=( "$LAST_RELEASE" )
            ;;
        api-release)
            RE_SEMVERS+=( "$RE_API_RELEASE" )
            UPDATED_VERSIONS+=( "$LAST_API_RELEASE" )
            ;;
        *)
            echo "Invalid replacement format: \"${REPLACEMENT_FORMAT}\". Use semver, release, or api-release" >&2
            exit 1
            ;;
    esac
done

if [ -z "$LAST_VERSION" ];
then
    # No match to semver regex in SOURCE_FILE, so no version to go from.
    printf "Error: Unable to find latest version from %s.\n" "$SOURCE_FILE"
    exit 1
fi

# Search files in FILES_TO_CHECK and change (or get diffs)
declare FAILED_CHECK=0

for i in "${!FILES_TO_CHECK[@]}"; do
    FILE_TO_CHANGE=${FILES_TO_CHECK[$i]}
    RE_SEMVER=${RE_SEMVERS[$i]}
    UPDATED_VERSION=${UPDATED_VERSIONS[$i]}
    FILE_VERSION=$(grep -o -m 1 -E "${RE_SEMVER}" "$FILE_TO_CHANGE")
    if [ -z "$FILE_VERSION" ];
    then
        # No match to semver regex in VERSIONFILE, so nothing to replace
        printf "Error: No semver version found in file %s.\n" "$FILE_TO_CHANGE"
        exit 1
    else
        # Replace semver in VERSIONFILE with semver obtained from SOURCE_FILE
        TMPFILE=$(mktemp /tmp/new_version.XXXXXX)
        # Check sed version, exit if version < 4.3
        if ! sed --version > /dev/null 2>&1; then
            CURRENT_VERSION=1.archaic
        else
            CURRENT_VERSION=$(sed --version | head -n1 | cut -d" " -f4)
        fi
        REQUIRED_VERSION="4.3"
        if [ "$(printf '%s\n' "$REQUIRED_VERSION" "$CURRENT_VERSION" | sort -V | head -n1)" != "$REQUIRED_VERSION" ]; then
            echo "sed version must be >= ${REQUIRED_VERSION}" && exit 1
        fi
        sed -E -r "s/$RE_SEMVER/$UPDATED_VERSION/" "$FILE_TO_CHANGE" > "$TMPFILE"
        if [ $CHECK == 1 ];
        then
            DIFF=$(diff "$FILE_TO_CHANGE"  "$TMPFILE" )
            if [ -z "$DIFF" ];
            then
                printf "version sync would make no changes to %s.\n" "$FILE_TO_CHANGE"
                rm "$TMPFILE"
            else
                FAILED_CHECK=1
                printf "version sync would make the following changes to %s:\n%s\n" "$FILE_TO_CHANGE" "$DIFF"
                rm "$TMPFILE"
            fi
        else
            cp "$TMPFILE" "$FILE_TO_CHANGE" 
            rm "$TMPFILE"
        fi
    fi
done

# Exit with code determined by whether changes were needed in a check.
if [ ${FAILED_CHECK} -ne 0 ]; then
    exit 1
else
    exit 0
fi