#!/bin/bash
# Copyright (c)2022 https://bookfere.com
# This is a batch script for fixing Google Translate and making it available
# in the Chinese mainland. If you experience any problem, visit the page below:
# https://bookfere.com/post/1020.html

set -e

IPS=(
    74.125.137.90
    74.125.193.186
    74.125.196.113
    108.177.97.100
    108.177.111.90
    108.177.122.90
    108.177.125.186
    108.177.126.90
    108.177.127.90
    142.250.0.90
    142.250.1.90
    142.250.4.90
    142.250.8.90
    142.250.9.90
    142.250.10.90
    142.250.11.90
    142.250.12.90
    142.250.13.90
    142.250.27.90
    142.250.28.90
    142.250.30.90
    142.250.31.90
    142.250.96.90
    142.250.97.90
    142.250.98.90
    142.250.99.90
    142.250.100.90
    142.250.101.90
    142.250.102.90
    142.250.103.90
    142.250.105.90
    142.250.107.90
    142.250.111.90
    142.250.112.90
    142.250.113.90
    142.250.114.90
    142.250.115.90
    142.250.123.90
    142.250.125.90
    142.250.126.90
    142.250.128.90
    142.250.138.90
    142.250.141.90
    142.250.142.90
    142.250.145.90
    142.250.152.90
    142.250.153.90
    142.250.157.90
    142.250.157.183
    142.250.157.184
    142.250.157.186
    142.250.158.90
    142.250.159.90
    142.251.1.90
    142.251.2.90
    142.251.4.90
    142.251.5.90
    142.251.6.90
    142.251.8.90
    142.251.9.90
    142.251.10.90
    142.251.12.90
    142.251.15.90
    142.251.16.90
    142.251.18.90
    142.251.107.90
    142.251.111.90
    142.251.112.90
    142.251.116.90
    142.251.117.90
    142.251.120.90
    142.251.160.90
    142.251.161.90
    142.251.162.90
    142.251.163.90
    142.251.166.90
    172.217.192.90
    172.217.195.90
    172.217.203.90
    172.217.204.90
    172.217.214.90
    172.217.215.90
    172.253.58.90
    172.253.62.90
    172.253.63.90
    172.253.112.90
    172.253.113.90
    172.253.114.90
    172.253.115.90
    172.253.116.90
    172.253.117.90
    172.253.118.90
    172.253.119.90
    172.253.123.90
    172.253.124.90
    172.253.125.90
    172.253.126.90
    172.253.127.90
    216.58.227.65
    216.58.227.66
    216.58.227.67
)

SED_CMD=/usr/bin/sed
GREP_CMD=/usr/bin/grep
CURL_CMD=/usr/bin/curl

DIVIDER='--------------------------------------'
API='https://translate.googleapis.com/translate_a/single?client=gtx&sl=en&tl=fr&dt=t&dj=1&q=hello'
TARGET_DOMAIN='translate.googleapis.com'
HOSTS_FILE=/etc/hosts

function test_translate_api() {
    $CURL_CMD -sk $API --resolve $TARGET_DOMAIN:443:$1 \
    | $GREP_CMD '"trans":"bonjour"'
}

function generate_new_rule() {
    echo 'Modify hosts file to fix Google translate service.'
    echo $DIVIDER
    echo '[1] Automatically [2] Manually'
    echo $DIVIDER
    echo -n 'Enter a number to choose an IP adding method: '
    read action

    if [ "$action" == '2' ]; then
        echo -n 'Please enter a valid IP address: '
        read IP
        if [ ! -n "$(test_translate_api $IP)" ]; then
            echo 'The IP is not available. Trying to choose one for you ...'
            unset IP
        fi
    fi

    if [ ! -n "$(test_translate_api $IP)" ]; then
        for i in ${IPS[@]}; do
            if [ -n "$(test_translate_api $i)" ]; then IP=$i; break; fi
        done
        if [ ! -n "$IP" ]; then
            echo 'There is no available ip to use. Press any key to exit.';
            read; exit;
        fi
    fi

    NEW_RULE="$IP $TARGET_DOMAIN"
}

OLD_RULE=$(cat $HOSTS_FILE | $GREP_CMD $TARGET_DOMAIN || :)
COMMENT="# Fix Google Translate CN"

if [ -n "$OLD_RULE" ]; then
    echo 'A rule has been added to the hosts file. '
    echo $DIVIDER
    echo '[1] Update [2] Delete'
    echo $DIVIDER
    echo -n 'Enter a number to choose an action: '
    read action
    if [ "$action" == '1' ]; then
        generate_new_rule
        if [ "$OLD_RULE" != "$NEW_RULE" ]; then
            echo "Deleting the rule \"$OLD_RULE\""
            echo "Adding the rule \"$NEW_RULE\""
            $SED_CMD -i '' "s/.*${TARGET_DOMAIN}/${NEW_RULE}/" $HOSTS_FILE
        else
            echo 'The rule already exists, nothing to do.'
        fi
    elif [ "$action" == '2' ]; then
        echo "Deleting the rule \"$OLD_RULE\""
        PATTERN="s/\n*${COMMENT}\n.* ${TARGET_DOMAIN}//"
        $SED_CMD -i '' -e ':a' -e 'N' -e '$!ba' -e "$PATTERN" $HOSTS_FILE
    fi
else
    generate_new_rule
    echo "Adding the rule \"$NEW_RULE\""
    echo -ne "\n${COMMENT}\n${NEW_RULE}" >> $HOSTS_FILE
fi

echo 'Done.'