#!/usr/bin/env perl

# Copyright (C) Yichun Zhang (agentzh)

# TODO: port this script into the nginx core for greater flexibility
# and better performance.

use strict;
use warnings;

use File::Spec ();
use FindBin ();
use Getopt::Std qw( getopts );
use File::Temp qw( tempdir );
use POSIX qw( WNOHANG );

my %opts;
getopts("he:c:", \%opts)
    or usage(1);

if ($opts{h}) {
    usage(0);
}

my $luafile;
if (!defined $opts{e}) {
    $luafile = shift
        or die qq{No Lua input file nor -e "" option specified.\n};
}

if (@ARGV) {
    die "unknown arguments: @ARGV\n";
}

my $conns = $opts{c} || 64;

my $nginx_path = File::Spec->catfile($FindBin::Bin, "..", "nginx", "sbin", "nginx");
#warn $nginx_path;
if (!-f $nginx_path) {
    $nginx_path = "nginx";  # find in PATH
}

my $prefix_dir = tempdir(CLEANUP => 1);
#warn "prefix dir: $prefix_dir\n";

my $logs_dir = File::Spec->catfile($prefix_dir, "logs");
mkdir $logs_dir or die "failed to mkdir $logs_dir: $!";

my $conf_dir = File::Spec->catfile($prefix_dir, "conf");
mkdir $conf_dir or die "failed to mkdir $conf_dir: $!";

my $chunk_name;
if (defined $opts{e}) {
    $luafile = File::Spec->catfile($conf_dir, "a.lua");
    open my $out, ">$luafile"
        or die "Cannot open $luafile for writing: $!\n";
    print $out $opts{e};
    close $out;
    $chunk_name = "=(command line -e)";

} else {
    $chunk_name = "\@$luafile";
}

my $loader = <<_EOC_;
            local gen
            do
                local fname = "$luafile"
                local f = assert(io.open(fname, "r"))
                local chunk = f:read("*a")
                gen = assert(loadstring(chunk, "$chunk_name"))
            end
_EOC_

my $conf_file = File::Spec->catfile($conf_dir, "nginx.conf");
open my $out, ">$conf_file"
    or die "Cannot open $conf_file for writing: $!\n";

print $out <<_EOC_;
daemon off;
master_process off;
worker_processes 1;

env LD_LIBRARY_PATH;
env LD_PRELOAD;
env PATH;
env LUA_PATH;
env LUA_CPATH;

error_log /dev/stderr warn;
#error_log /dev/stderr debug;

events {
    worker_connections $conns;
}

http {
    access_log off;
    lua_socket_log_errors off;

    init_by_lua '
        local stdout = io.stdout
        print = function (...) stdout:write(...) end
        ngx.print = print
        ngx.say = function (...) print(...) print("\\\\n") end
    ';

    init_worker_by_lua '
        local exit = os.exit
        local stderr = io.stderr

        local function handle_err(err)
            if err then
                err = string.gsub(err, "^init_worker_by_lua:%d+: ", "")
                stderr:write(err)
            end
            return exit(1)
        end

        local ok, err = pcall(function ()
$loader
            -- print("calling timer.at...")
            local ok, err = ngx.timer.at(0, function ()
                -- io.stderr:write("timer firing")
                local ok, err = pcall(gen)
                if not ok then
                    return handle_err(err)
                end
                local rc = err
                if rc and type(rc) ~= "number" then
                    return handle_err("bad return value of type " .. type(rc))
                end
                return exit(rc)
            end)
            if not ok then
                return handle_err(err)
            end
            -- print("timer created")
        end)

        if not ok then
            return handle_err(err)
        end
    ';
}
_EOC_

close $out;

my $cmd = "$nginx_path -p $prefix_dir/";

my $child_pid;

sub reaper {
    $SIG{CHLD} = \&reaper;
    if ($child_pid) {
        my ($pid, $status);
        do {
            $pid = waitpid(-1, WNOHANG);
            if ($child_pid == $pid) {
                $status = $?;
                undef $child_pid;
                last;
            }
        } while $pid > 0;
        exit($status || 0);
    }
}

$SIG{CHLD}=\&reaper;

sub sigint {
    $SIG{INT} = \&sigint;
    if ($child_pid) {
        kill INT => $child_pid;
    }
}
$SIG{INT} = \&sigint;

my $pid = fork();

if (!defined $pid) {
    die "fork() failed: $!\n";
}

if ($pid == 0) {  # child process
    #warn "exec $cmd...";
    exec $cmd;

} else {
    $child_pid = $pid;
    waitpid($child_pid, 0);
    exit($? || 0);
}

sub usage {
    my $rc = shift;
    my $msg = <<_EOC_;
$0 [-h] [-c num] [-e prog] [lua-file]

Options:
    -c num      set maximal connection count (default: 64).
    -e prog     run the inlined Lua code in "prog".
    -h          print this help.
_EOC_
    if ($rc == 0) {
        print $msg;
        exit(0);
    }

    warn $msg;
    exit($rc);
}