#!/bin/sh

# configuration
web_root_path="/service/html"
cert_root_path="/service/ssl"
temp_path="/service/temp"
nginx_pid="/tmp/nginx.pid"
server_retries=10
log_file="" # leave empty for stdout

# variables
domain_file="$temp_path/domains.txt"
certs_updated="$cert_root_path/.updated"
certs_daemon_pid=-1

#functions
function log()
{
    local time=$(date +%F_%T)
    local prefix="LOG"
    case $1 in
        ERR | ERROR)
            prefix="ERR"
            shift
            ;;
        WAR | WARNING)
            prefix="WAR"
            shift
            ;;
    esac
    local func=$1; shift
    # remove any \n 
    #local text=$(echo "$@"| tr '\n' '#' | sed 's|#|\\n |g')
    case "$log_file" in
        "")
            echo "[$time]:[$prefix]:[$0][$func]: $@" 2>&1
            ;;
        *)
            echo "[$time]:[$prefix]:[$0][$func]: $@" >> $log_file
            ;;
    esac
}

function sleep_wait()
{
    # waiting on sleep to be able to handle SIGTERM
    sleep $1 &
    wait $!
}

function exit_handler()
{
    # TODO: because nginx is started in foreground and replaces
    # the shell via exec, this handler is never called, however as there 
    # is no cleanup for the certs_daemon it doesn't really matter
    if [ $certs_daemon_pid -gt 0 ] ; then
        log exit_handler "stopping certs_daemon"
        kill -SIGTERM $certs_daemon_pid
    fi
    log exit_handler "shutting down nginx"
    nginx -s quit
    log exit_handler "container shutting down"
    exit
}

trap "exit_handler" SIGINT
trap "exit_handler" SIGTERM

function var_to_file()
{
    local var=$1
    local file=$2
    log var_to_file "ENV VAR -> [$file]: $var"
    echo -e "$var" > $file
}

function env_domain_file()
{
    log env_domain_file "ENV DOMAINS: $DOMAINS"
    echo -e "$DOMAINS" > $1
}

function read_file()
{
    local func=$1
    local file=$2
    local result=0

    while read -r line || [[ -n "$line" ]]; do
        # skip empty lines if READ_EMPTY_LINES is not set
        [ -z ${READ_EMPTY_LINES+x} ] && [ "${#line}" -lt 1 ] && continue
        log read_file "LINE: $line"
        log read_file "FUNC START [$func]"
        if $func $line; then
            log read_file "FUNC END [$func]"
        else
            result=1
            log ERROR read_file "FUNC END [$func]"
        fi        
    done < "$file"

    return $result
}

function cert_exists()
{
    local domain=$1
    local cert_path="$cert_root_path/$domain"
    [ -f "$cert_path/fullchain.pem" ]
}

function certs_daemon()
{
    (
        # wait for nginx to start
        while [ ! -f "$nginx_pid" ]; do
            log certs_daemon "Waiting for nginx to start"
            sleep_wait 1
        done
        
        # wait for inital cert update
        while [ ! -f "$certs_updated" ]; do
            log certs_daemon "Waiting for initial cert update"
            sleep_wait 1
        done
        
        # reload nginx
        nginx -s reload

        # cert watcher loop
        while inotifywait -e attrib "$certs_updated"; do
            log certs_daemon "Certs updated, reloading nginx"
            nginx -s reload
        done
    ) &
    certs_daemon_pid=$!
}

function nginx_handler()
{
    local retries=0

    # start the daemon (it forks itself)
    certs_daemon

    # wait for certs to exist before starting nginx
    # just have nginx crash after n retries (default 10)
    while ! read_file cert_exists "$domain_file" && [ "$retries" -lt "$server_retries" ]; do
        log nginx_handler "Waiting for certs to be created"
        retries=$(( retries+1 ))
        sleep_wait 1
    done

    # starting nginx in foreground
    log nginx_handler "Starting nginx in foreground"
    exec nginx -g "daemon off;"
}

function main()
{   
    log main "Starting nginx container"
    # TODO: load domains from nginx.conf
    env_domain_file "$domain_file"
    nginx_handler
}

main $@