#!/usr/bin/env bash
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.

set -euo pipefail


function redraw_progress_bar { # int barsize, int base, int current, int top
    # Source: https://stackoverflow.com/a/20311674
    local barsize=$1
    local base=$2
    local current=$3
    local top=$4
    local j=0
    local progress=$(( (barsize * (current - base)) / (top - base ) ))
    echo -n "["
    for ((j=0; j < progress; j++)) ; do echo -n '='; done
    echo -n '=>'
    for ((j=progress; j < barsize ; j++)) ; do echo -n ' '; done
    echo -n "] $current / $top " $'\r'
}

if ! command -v lynx; then
    echo "This script requires lynx to work properly."
    echo
    echo "For more information, look at: http://lynx.browser.org/"
    exit 1
fi

MY_DIR="$(cd "$(dirname "$0")" && pwd)"
pushd "${MY_DIR}" &>/dev/null || exit 1

echo "Working directory: ${MY_DIR}"

DIST_DIR=${1:-"./dist"}
echo "Dist directory: ${DIST_DIR}"

echo ""

if [[ ! -f "${DIST_DIR}/index.html" ]]; then
   echo "You should build website first."
   exit 1
fi

mkdir -pv "${DIST_DIR}"

readarray -d '' pages < <(find "${DIST_DIR}" -name '*.html' -print0)
echo "Found ${#pages[@]} HTML files."

echo "Searching links."
mapfile -t links < <(printf '%s\n' "${pages[@]}" | xargs -n 1 lynx -listonly -nonumbers -dump -display_charset=iso-8859-1 | grep -v " ")
mapfile -t external_links < <(printf '%s\n' "${links[@]}" | grep "^https\?://" | grep -v "http://localhost" | grep -v "http://link/" | grep -v "http://docker.local" | grep -v "https://github.com/apache/beam/edit/master/website/www/site/content/" | sort | uniq)
echo "Found ${#links[@]} links including ${#external_links[@]} unique external links."

echo "Checking links."
invalid_links=()
i=1
for external_link in "${external_links[@]}"
do
    redraw_progress_bar 50 1 $i ${#external_links[@]}

    if ! curl -sSfL --max-time 60 --connect-timeout 30 --retry 3 -4 "${external_link}" > /dev/null ; then
        invalid_links+=("${external_link}")
        echo "${external_link}"
    fi
    i=$((i+1))
done
# Clear line - hide progress bar
echo -n -e "\033[2K"


if [[ ${#invalid_links[@]} -ne 0 ]]; then
    echo "Found ${#invalid_links[@]} invalid links: "
    printf '%s\n' "${invalid_links[@]}"
else
    echo "All links work"
fi

popd &>/dev/null || exit 1