#!/usr/bin/env bash

# fail hard
set -o pipefail
# fail harder
set -eu
# for ${DOCUMENT_ROOT%%*(/)} pattern further down
shopt -s extglob
# for detecting when -l 'logs/*.log' matches nothing
shopt -s nullglob

verbose=

php_passthrough() {
    local dir=$(dirname "$1")
    local file=$(basename "$1")
    local out=$(basename "$file" .php)
    if [[ "$out" != "$file" ]]; then
        [[ $verbose ]] && echo "Interpreting ${1#$HEROKU_APP_DIR/} to $out" >&2
        out="$dir/$out"
        hhvm "$1" > "$out"
        echo "$out"
    else
        echo "$1"
    fi
}

check_exists() {
    if [[ ! -f "$HEROKU_APP_DIR/$1" ]]; then
        echo "Cannot read -$2 '$1' (relative to '$HEROKU_APP_DIR')" >&2
        exit 1
    else
        echo "$HEROKU_APP_DIR/$1"
    fi
}

touch_log() {
    mkdir -p $(dirname "$1") && touch "$1"
}

print_help() {
echo "\
${1:-Boots HHVM together with Nginx on Heroku and for local development.}

Usage:
  heroku-hhvm-nginx [options] [<DOCUMENT_ROOT>]

Options:
  -C <nginx.inc.conf>     The path to the configuration file to include inside
                          the Nginx server config (see option -c below). Will
                          be included inside the 'server { ... }' block just
                          after the 'listen', 'root' etc directives.
                          Recommended approach when customizing Nginx's config
                          in most cases, unless you need to set http or
                          fundamental server level options.
                          [default: \$COMPOSER_VENDOR_DIR/heroku/heroku-buildpack-php/conf/nginx/default_include.conf.php]
  -c <nginx.conf>         The path to the full configuration file that is
                          included after Heroku's (or your local) Nginx config
                          is loaded. It must contain an 'http { ... }' block
                          with a 'server { ... }' inside that contains 'listen'
                          and 'root' (see option -C above), but no global,
                          directives (globals are read from the system's default
                          Nginx configuration files).
                          [default: \$COMPOSER_VENDOR_DIR/heroku/heroku-buildpack-php/conf/nginx/heroku.conf.php]
  -h, --help              Display this help screen and exit.
  -I <php.extra.ini>      The path to an extra php.ini to use in addition to the
                          default HHVM php.ini (see option -i below).
  -i <php.ini>            The path to the php.ini file to use. It is highly
                          recommended to use the -I option (see above) instead.
                          [default: \$COMPOSER_VENDOR_DIR/heroku/heroku-buildpack-php/conf/hhvm/php.ini.php]
  -l <tailme.log>         Path to additional log file to tail to STDERR so its
                          contents appear in 'heroku logs'. If the file does not
                          exist, it will be created. Wildcards are allowed, but
                          must be quoted and must match already existing files.
                          Note: this option can be repeated multiple times.
  -p <PORT>               Port to listen on for HTTP traffic. If this argument
                          is not given, then the port number to use is read from
                          the \$PORT environment variable, or a random port is
                          chosen if that variable does not exist.
  -v, --verbose           Be more verbose during startup.

All file paths must be relative to '$HEROKU_APP_DIR'.

Any file name that ends in '.php' will be run through the PHP interpreter first.
You may use this for templating; this is, for instance, necessary for Nginx,
where environment variables cannot be referenced in configuration files.

If you would like to use the -C and -c options together, make sure you retain
the appropriate include mechanisms (see default configs for details).
" >&2
}

# we need this in configs
export HEROKU_APP_DIR=$(pwd)
export DOCUMENT_ROOT="$HEROKU_APP_DIR"
# set a default port if none is given
export PORT=${PORT:-$(( $RANDOM+1024 ))}

# init logs array here as empty before parsing options; -l could append to it, but the default list gets added later since we use $PORT in there and that can be set using -p
declare -a logs

optstring=":-:C:c:I:i:l:p:vh"

# process flags first
while getopts "$optstring" opt; do
    case $opt in
        -)
            case "$OPTARG" in
                verbose)
                    verbose=1
                    ;;
                help)
                    print_help 2>&1
                    exit
                    ;;
                *)
                    echo "Invalid option: --$OPTARG" >&2
                    exit 2
                    ;;
            esac
            ;;
        v)
            verbose=1
            ;;
        h)
            print_help 2>&1
            exit
            ;;
    esac
done

OPTIND=1 # start over with options parsing
while getopts "$optstring" opt; do
    case $opt in
        C)
            nginx_config_include=$(check_exists "$OPTARG" "C")
            ;;
        c)
            nginx_config=$(check_exists "$OPTARG" "c")
            ;;
        I)
            hhvm_config_extra=$(check_exists "$OPTARG" "I")
            ;;
        i)
            php_config=$(check_exists "$OPTARG" "i")
            ;;
        l)
            logarg=( $OPTARG ) # must not quote this or wildcards won't get expanded into individual values
            if [[ ${#logarg[@]} -eq 0 ]]; then # we set nullglob to detect if a pattern matched nothing (then the array is empty)
                echo "Pattern '$OPTARG' passed to option -l matched no files" >&2
                exit 1
            fi
            for logfile in "${logarg[@]}"; do
                if [[ -d "$logfile" ]]; then
                    echo "-l '$logfile': is a directory" >&2
                    exit 1
                fi
                touch_log "$logfile" || { echo "Could not touch '$logfile'; permissions problem?" >&2; exit 1; }
                [[ $verbose ]] && echo "Tailing '$logfile' to stderr" >&2
                logs+=("$logfile") # must quote here in case a wildcard matched a file with a space in the name
            done
            ;;
        p)
            PORT="$OPTARG"
            ;;
        \?)
            echo "Invalid option: -$OPTARG" >&2
            exit 2
            ;;
        :)
            echo "Option -$OPTARG requires an argument" >&2
            exit 2
            ;;
    esac
done
# clear processed arguments
shift $((OPTIND-1))

if [[ "$#" -gt "1" ]]; then
    print_help "$0: too many arguments. If you're using options,
make sure to list them before any document root argument you're providing."
    exit 2
fi

# our standard logs
logs+=( "/tmp/heroku.nginx_access.$PORT.log" )

hhvm --php -r 'exit((int)version_compare(HHVM_VERSION, "3.0.1", "<"));' || { echo "This program requires HHVM 3.0.1 or newer" >&2; exit 1; }

# make sure we run a local composer.phar if present, or global composer if not
composer() {
    local composer_bin=$(which ./composer.phar composer | head -n1)
    # check if we the composer binary is executable by HHVM
    if file --brief --dereference $composer_bin | grep -e "shell" -e "bash" > /dev/null ; then # newer versions of file return "data" for .phar
        # run it directly; it's probably a bash script or similar (homebrew-php does this)
        $composer_bin "$@"
    else
        hhvm $composer_bin "$@"
    fi
}
COMPOSER_VENDOR_DIR=$(composer config vendor-dir 2> /dev/null | tail -n 1) && export COMPOSER_VENDOR_DIR || { echo "Unable to determine Composer vendor-dir setting; is 'composer' executable on path or 'composer.phar' in current working directory?" >&2; exit 1; } # tail, as composer echos outdated version warnings to STDOUT; export after the assignment or exit status will that be of 'export
COMPOSER_BIN_DIR=$(composer config bin-dir 2> /dev/null | tail -n 1) && export COMPOSER_BIN_DIR || { echo "Unable to determine Composer bin-dir setting; is 'composer' executable on path or 'composer.phar' in current working directory?" >&2; exit 1; } # tail, as composer echos outdated version warnings to STDOUT; export after the assignment or exit status will that be of 'export

if [[ "$#" == "1" ]]; then
    DOCUMENT_ROOT="$HEROKU_APP_DIR/$1"
    if [[ ! -d "$DOCUMENT_ROOT" ]]; then
        echo "DOCUMENT_ROOT '$1' does not exist" >&2
        exit 1
    else
        # strip trailing slashes if present
        DOCUMENT_ROOT=${DOCUMENT_ROOT%%*(/)} # powered by extglob
        if [[ $verbose ]]; then
            echo "DOCUMENT_ROOT changed to '$DOCUMENT_ROOT'" >&2
        else
            echo "DOCUMENT_ROOT changed to '${1%%*(/)}/'" >&2
        fi
    fi
fi

function prepare_hhvm_ini() { # we have to do this twice, as the WEB_CONCURRENCY setting is evaluated using PHP code, not ${...} syntax which HHVM does not support; if a value for $1 is passed then it won't echo messages upon second invocation
if [[ ( -n ${php_config:-} && ! ${1:-} ) || ( ${php_config:="$HEROKU_APP_DIR/$COMPOSER_VENDOR_DIR/heroku/heroku-buildpack-php/conf/hhvm/php.ini.php"} && $verbose && ! ${1:-} ) ]]; then
    echo "Using HHVM configuration (php.ini) file '${php_config#$HEROKU_APP_DIR/}'" >&2
fi
php_configs=( "-c" "$(php_passthrough "$php_config")" )

if [[ -n ${hhvm_config_extra:-} ]]; then
    [[ ${1:-} ]] || echo "Using additional HHVM configuration (php.ini) file '${hhvm_config_extra#$HEROKU_APP_DIR/}'" >&2
    php_configs+=( "-c" "$(php_passthrough "$hhvm_config_extra")" )
fi
}
prepare_hhvm_ini

if [[ -n ${nginx_config_include:-} || ( ${nginx_config_include:="$HEROKU_APP_DIR/$COMPOSER_VENDOR_DIR/heroku/heroku-buildpack-php/conf/nginx/default_include.conf.php"} && $verbose ) ]]; then
    echo "Using Nginx server-level configuration include '${nginx_config_include#$HEROKU_APP_DIR/}'" >&2
fi
nginx_config_include=$(php_passthrough "$nginx_config_include")
export HEROKU_PHP_NGINX_CONFIG_INCLUDE="$nginx_config_include"

if [[ -n ${nginx_config:-} || ( ${nginx_config:="$HEROKU_APP_DIR/$COMPOSER_VENDOR_DIR/heroku/heroku-buildpack-php/conf/nginx/heroku.conf.php"} && $verbose) ]]; then
    echo "Using Nginx configuration file '${nginx_config#$HEROKU_APP_DIR/}'" >&2
fi
nginx_config=$(php_passthrough "$nginx_config")

# if WEB_CONCURRENCY starts with a 0, then that's a default value which comes from another buildpack (e.g. Node), so we ignore it
if [[ -z ${WEB_CONCURRENCY:-} || "${WEB_CONCURRENCY}" == 0* ]]; then
    maxprocs=$(ulimit -u)
    ram="512M"
    if [[ -n ${DYNO:-} && "$maxprocs" == "32768" ]]; then
        echo "Optimizing defaults for PX dyno...." >&2
        ram="6G"
    elif [[ -n ${DYNO:-} && "$maxprocs" == "16384" ]]; then
        echo "Optimizing defaults for IX dyno...." >&2
        ram="2560M"
    elif [[ -n ${DYNO:-} && "$maxprocs" == "512" ]]; then
        echo "Optimizing defaults for 2X dyno..." >&2
        ram="1G"
    elif [[ -n ${DYNO:-} && "$maxprocs" == "256" ]]; then
        echo "Optimizing defaults for 1X dyno..." >&2
    elif [[ -n ${DYNO:-} || $verbose ]]; then
        echo "No dyno detected; using defaults for 1X..." >&2
    fi

    # determine number of HHVM threads to run
    read WEB_CONCURRENCY php_memory_limit <<<$(hhvm "${php_configs[@]}" $(composer config vendor-dir 2> /dev/null | tail -n 1)/heroku/heroku-buildpack-php/bin/util/autotune.php "$ram") # tail, as composer echos outdated version warnings to STDOUT
    [[ $WEB_CONCURRENCY -lt 1 ]] && WEB_CONCURRENCY=1
    export WEB_CONCURRENCY
    
    echo "${WEB_CONCURRENCY} threads at ${php_memory_limit}B memory limit." >&2
else
    echo "Using WEB_CONCURRENCY=${WEB_CONCURRENCY} threads." >&2
fi

# we changed WEB_CONCURRENCY; now we need to re-evaluate the configs as HHVM doesn't support ${...} syntax, so the configs contain PHP getenv() calls and are templated; we pass an argument to it to avoid it echoing "using HHVM config ..." messages again because that already happened
prepare_hhvm_ini no_messages

# make a shared pipe; we'll write the name of the process that exits to it once that happens, and wait for that event below
# this particular call works on Linux and Mac OS (will create a literal ".XXXXXX" on Mac, but that doesn't matter).
wait_pipe=$(mktemp -t "heroku.waitpipe-$PORT.XXXXXX" -u)
rm -f $wait_pipe
mkfifo $wait_pipe
exec 3<> $wait_pipe

pids=()

# trap SIGQUIT (ctrl+\ on the console), SIGTERM (when we get killed) and EXIT (upon failure of any command due to set -e, or because of the exit 1 at the very end), we then
# 1) restore the trap for the signal in question so it doesn't fire again due to the kill at the end of the trap, as well as for EXIT, because that would fire too
# 2) call cleanup() to
# 2a) remove our FIFO from above
# 2b) kill all the subshells we've spawned - they in turn have their own traps to kill their respective subprocesses, and because we use SIGUSR1, they know it's the parent's cleanup and can handle it differently from an external SIGKILL
# 2c) send STDERR to /dev/null so we don't see "no such process" errors - after all, one of the subshells may be gone
# 2d) || true so that set -e doesn't cause a mess if the kill returns 1 on "no such process" cases (which is likely on Heroku where all processes get killed and not just this top level one)
# 2e) do that in the background and 'wait' on those processes, sending wait's output to /dev/null - this prevents the logs getting cluttered with "vendor/bin/heroku-...: line 309:    96 Terminated" messages (we can't use 'disown' after launching programs for that purpose because that removes the jobs from the shell's jobs table and the we can no longer 'wait' on the program)
# 3) kill ourselves with the correct signal in case we're handling SIGQUIT or SIGTERM (http://www.cons.org/cracauer/sigint.html and http://mywiki.wooledge.org/SignalTrap#Special_Note_On_SIGINT1)
cleanup() { echo "Going down, terminating child processes..." >&2; rm -f ${wait_pipe} || true; kill -USR1 "${pids[@]}" 2> /dev/null || true; }
trap 'trap - QUIT EXIT; cleanup; kill -QUIT $$' QUIT
trap 'trap - TERM EXIT; cleanup; kill -TERM $$' TERM
trap 'trap - EXIT; cleanup' EXIT
# if FD 1 is a TTY (that's the -t 1 check), trap SIGINT/Ctrl+C, then same procedure as for QUIT and TERM above
if [[ -t 1 ]]; then
    trap 'trap - INT EXIT; cleanup; kill -INT $$' INT;
# if FD 1 is not a TTY (e.g. when we're run through 'foreman start'), do nothing on SIGINT; the assumption is that the parent will send us a SIGTERM or something when this happens. With the trap above, Ctrl+C-ing out of a 'foreman start' run would trigger the INT trap both in Foreman and here (because Ctrl+C sends SIGINT to the entire process group, but there is no way to tell the two cases apart), and while the trap is still doing its shutdown work triggered by the SIGTERM from the Ctrl+C, Foreman would then send a SIGTERM because that's what it does when it receives a SIGINT itself.
else
    trap '' INT;
fi

# we are now launching a subshell for each of the tasks (log tail, app server, web server)
# 1) each subshell has a trap on EXIT that echos the command name to FD 3 (see the FIFO set up above)
# 1a) a 'read' at the end of the script will block on reading from that FD and then trigger the exit trap further above, which does the cleanup
# 2) each subshell also has a trap on TERM that
# 2a) kills $! (the last process executed)
# 2b) ... which in turn will hit the EXIT trap and that unblocks the 'wait' in 5) which will cause the parent to clean up when the exit at the end of the script is hit
# 2c) the 'kill' is done in the background and we immediately 'wait' on $!, sending wait's output to /dev/null - this prevents the logs getting cluttered with "vendor/bin/heroku-...: line 309:    96 Terminated" messages (we can't use 'disown' after launching programs for that purpose because that removes the jobs from the shell's jobs table and the we can no longer 'wait' on the program)
# 2d) finally, if $BASHPID exists, the subshell kills itself using the right signal for maximum compliance ($$ doesn't work in subshells, and $BASHPID is not available in Bash 3, but unlike with the parent, it's not that critical to have this)
# 3) each subshell has another trap on USR1 which gets sent when the parent is cleaning up; it works like 2a) but doesn't trigger the EXIT trap to avoid multiple cleanup runs by the parent
# 4) execute the command in the background
# 5) 'wait' on the command (wait is interrupted by an incoming TERM to the subshell, whereas running 4) in the foreground would wait for that process to finish before triggering the trap)
# 6) add the PID of the subshell to the array that the EXIT trap further above uses to clean everything up

[[ $verbose ]] && echo "Starting log redirection..." >&2
(
    trap '' INT;
    trap 'echo "tail" >&3;' EXIT
    trap 'trap - TERM; kill -TERM $pid 2> /dev/null || true & wait $pid 2> /dev/null || true; [[ ${BASHPID:-} ]] && kill -TERM $BASHPID' TERM
    trap 'trap - USR1 EXIT; kill -TERM $pid 2> /dev/null || true & wait $pid 2> /dev/null || true; [[ ${BASHPID:-} ]] && kill -USR1 $BASHPID' USR1
    
    touch "${logs[@]}"
    
    tail -qF -n 0 "${logs[@]}" 1>&2 & pid=$!
    
    wait
) & pids+=($!)
disown $!

echo "Starting hhvm..." >&2
(
    trap '' INT;
    trap 'echo "hhvm" >&3;' EXIT
    trap 'trap - TERM; kill -TERM $pid 2> /dev/null || true & wait $pid 2> /dev/null || true; [[ ${BASHPID:-} ]] && kill -TERM $BASHPID' TERM
    trap 'trap - USR1 EXIT; kill -TERM $pid 2> /dev/null || true & wait $pid 2> /dev/null || true; [[ ${BASHPID:-} ]] && kill -USR1 $BASHPID' USR1
    
    hhvm --mode server "${php_configs[@]}" & pid=$!
    
    wait
) & pids+=($!)
disown $!

# wait a few seconds for HHVM to finish initializing; otherwise an early request might break Apache with the FastCGI pipe not being ready
sleep 2

echo "Starting nginx..." >&2
(
    trap '' INT;
    trap 'echo "nginx" >&3;' EXIT
    trap 'trap - TERM; kill -TERM $pid 2> /dev/null || true & wait $pid 2> /dev/null || true; [[ ${BASHPID:-} ]] && kill -TERM $BASHPID' TERM
    trap 'trap - USR1 EXIT; kill -TERM $pid 2> /dev/null || true & wait $pid 2> /dev/null || true; [[ ${BASHPID:-} ]] && kill -USR1 $BASHPID' USR1
    
    nginx -g "daemon off; include $nginx_config;" & pid=$!
    
    wait
) & pids+=($!)
disown $!

# on Heroku, there is a "state changed from starting to up", but for local execution, we want a "ready" message
[[ -z ${DYNO:-} || $verbose ]] && echo "Application ready for connections on port $PORT." >&2

# wait for something to come from the FIFO attached to FD 3, which means that the given process was killed or has failed
# this will be interrupted by a SIGTERM or SIGINT in the traps further up
# if the pipe unblocks and this executes, then we won't read it again, so if the traps further up kill the remaining subshells above, their writing to FD 3 will have no effect
read exitproc <&3
# we'll only reach this if one of the processes above has terminated
echo "Process exited unexpectedly: $exitproc" >&2

# this will trigger the EXIT trap further up and kill all remaining children
exit 1