#!/bin/sh

usage() {
    printf "Usage: %s [-l DEBUG_LEVEL] [-h] [-f /path/to/CHANGELOG.md] [-u https://example.com/CHANGELOG.md]\n" "$0"
}

help() {
    cat << EOH
 SYNOPSIS
    $0 [-l DEBUG_LEVEL] [-h] [-f /path/to/CHANGELOG.md] [-u https://example.com/CHANGELOG.md]

 DESCRIPTION

    $0 generates a markdown content of a changelog file.

 OPTIONS

    -h    Show this help

    -f FILE
          Path to changelog

	-u URL
          URL of the changelog

    -l debug|info|notice|warning|error
          Debug level
EOH
}

on_interrupt() {
    print "Process aborted!\n"

    exit 130
}

main() {
	CHANGELOG_FILE="${CHANGELOG_FILE:-}"
	CHANGELOG_URL="${CHANGELOG_URL:-}"
	LOG_VERBOSE="${CHANGELOG_FILE:-info}"

    while getopts "l:hf:u:" option; do
        case "${option}" in
            h) help; exit 0;;
            f) CHANGELOG_FILE="$OPTARG";;
			u) CHANGELOG_URL="$OPTARG";;
            l) LOG_VERBOSE="$OPTARG";;
            ?) log -l error "$(usage)"; exit 1;;
        esac
    done

	temp_directory="$(mktemp -d)"
    version=
    is_first=1

	if [ -n "$CHANGELOG_FILE" ]; then
		if [ ! -f "$CHANGELOG_FILE" ]; then
			log -l error "No such file: $CHANGELOG_FILE"
		else
			log -l info "File used: $CHANGELOG_FILE"
		fi
	elif [ -n "$CHANGELOG_URL" ]; then
		log -l debug "URL used: $CHANGELOG_URL"

		CHANGELOG_FILE="$temp_directory/_changelog"

		curl -sS -o "$CHANGELOG_FILE" "$CHANGELOG_URL" || exit 0
	else
		log -l error "You must define a file or an url"
		exit 1
	fi

    cat << EOF
---
sidebar_position: 7
---

# Changelog

EOF

    while read -r line; do
        if printf "%s" "$line" | grep -q -E '^## '; then
            version="$(printf "%s" "$line" | sed 's/^## //')"

            if [ "$version" = "[Unreleased]" ]; then
                version=""
            fi
        elif [ -n "$version" ]; then
            printf "%s\n" "$line" >> "$temp_directory/$version"
        fi
    done < "$CHANGELOG_FILE"

    while read -r line; do
        if printf "%s" "$line" | grep -q -E '^## '; then
            version="$(printf "%s" "$line" | sed 's/^## //')"

            if [ "$version" != "[Unreleased]" ]; then
                log -l info "Version detected: $version"

				printf "## %s\n" "$version"

                sed \
                    -e 's/### \(.*\)/\n**\1**\n/g' \
                    "$temp_directory/$version"
            fi
        fi
    done < "$CHANGELOG_FILE"

    exit 0
}

log() {
    LOG_VERBOSE="${LOG_VERBOSE:-info}"
    LEVEL=info
    TIME=

    while getopts "tl:" option; do
        case "${option}" in
            l) LEVEL="$OPTARG"; shift $((OPTIND-1));;
            t) TIME="$(printf "[%s] " "$(date +'%Y-%m-%dT%H:%M:%S.%s')")"; shift $((OPTIND-1));;
            *) exit 1;;
        esac
    done

    if [ -t 2 ] && [ -z "${NO_COLOR-}" ]; then
        case "${LEVEL}" in
            debug) COLOR="$(tput setaf 3)";;
            notice) COLOR="$(tput setaf 4)";;
            warning) COLOR="$(tput setaf 5)";;
            error) COLOR="$(tput setaf 1)";;
            *) COLOR="$(tput sgr0)";;
        esac
    fi

    case "${LEVEL}" in
        debug) LEVEL=100;;
        notice) LEVEL=250;;
        warning) LEVEL=300;;
        error) LEVEL=400;;
        *) LEVEL=200;;
    esac

    case "${LOG_VERBOSE}" in
        debug) LOG_VERBOSE_VALUE=100;;
        notice) LOG_VERBOSE_VALUE=250;;
        warning) LOG_VERBOSE_VALUE=300;;
        error) LOG_VERBOSE_VALUE=400;;
        *) LOG_VERBOSE_VALUE=200;;
    esac

    if [ $LEVEL -ge $LOG_VERBOSE_VALUE ]; then
        printf "%s\n" "$*" | while IFS='' read -r LINE; do
            printf "%s%s%s%s\n" "${COLOR:-}" "${TIME:-}" "$LINE" "$(tput init)" >&2
        done
    fi
}

trap on_interrupt INT

main "$@"