package PVE::RESTEnvironment;

# NOTE: you can/should provide your own specialice class, and
# use this a bas class (as example see PVE::RPCEnvironment).

# we use this singleton class to pass RPC related environment values

use strict;
use warnings;

use Exporter qw(import);
use Fcntl qw(:flock);
use IO::File;
use IO::Handle;
use IO::Select;
use POSIX qw(:sys_wait_h EINTR);
use AnyEvent;

use PVE::Exception qw(raise raise_perm_exc);
use PVE::INotify;
use PVE::ProcFSTools;
use PVE::SafeSyslog;
use PVE::Tools;

our @EXPORT_OK = qw(log_warn);

my $rest_env;

# save $SIG{CHLD} handler implementation.
# simply set $SIG{CHLD} = $worker_reaper;
# and register forked processes with &$register_worker(pid)
# Note: using $SIG{CHLD} = 'IGNORE' or $SIG{CHLD} = sub { wait (); } or ...
# has serious side effects, because perls built in system() and open()
# functions can't get the correct exit status of a child. So we can't use
# that (also see perlipc)

my $WORKER_PIDS;
my $WORKER_FLAG = 0;

my $log_task_result = sub {
    my ($upid, $user, $status) = @_;

    return if !$rest_env;

    my $msg = 'successful';
    my $pri = 'info';
    if ($status != 0) {
        my $ec = $status >> 8;
        my $ic = $status & 255;
        $msg = $ec ? "failed ($ec)" : "interrupted ($ic)";
        $pri = 'err';
    }

    my $tlist = $rest_env->active_workers($upid);
    eval { $rest_env->broadcast_tasklist($tlist); };
    syslog('err', $@) if $@;

    my $task;
    foreach my $t (@$tlist) {
        if ($t->{upid} eq $upid) {
            $task = $t;
            last;
        }
    }
    if ($task && $task->{status}) {
        $msg = $task->{status};
    }

    $rest_env->log_cluster_msg($pri, $user, "end task $upid $msg");
};

my $worker_reaper = sub {
    local $!;
    local $?;
    foreach my $pid (keys %$WORKER_PIDS) {
        my $waitpid = waitpid($pid, WNOHANG);
        if (defined($waitpid) && ($waitpid == $pid)) {
            my $info = $WORKER_PIDS->{$pid};
            if ($info && $info->{upid} && $info->{user}) {
                &$log_task_result($info->{upid}, $info->{user}, $?);
            }
            delete($WORKER_PIDS->{$pid});
        }
    }
};

my $register_worker = sub {
    my ($pid, $user, $upid) = @_;

    return if !$pid;

    # do not register if already finished
    my $waitpid = waitpid($pid, WNOHANG);
    if (defined($waitpid) && ($waitpid == $pid)) {
        delete($WORKER_PIDS->{$pid});
        return;
    }

    $WORKER_PIDS->{$pid} = {
        user => $user,
        upid => $upid,
    };
};

# initialize environment - must be called once at program startup
sub init {
    my ($class, $type, %params) = @_;

    $class = ref($class) || $class;

    die "already initialized" if $rest_env;

    die "unknown environment type"
        if !$type || $type !~ m/^(cli|pub|priv|ha)$/;

    $SIG{CHLD} = sub {
        # when we're using AnyEvent, we have to postpone the call to worker_reaper, otherwise it
        # might interfere with running api calls
        if (defined($AnyEvent::MODEL)) {
            AnyEvent::postpone { $worker_reaper->() };
        } else {
            $worker_reaper->();
        }
    };

    # environment types
    # cli  ... command started fron command line
    # pub  ... access from public server (pveproxy)
    # priv ... access from private server (pvedaemon)
    # ha   ... access from HA resource manager agent (pve-ha-manager)

    my $self = {
        type => $type,
        warning_count => 0,
    };

    bless $self, $class;

    foreach my $p (keys %params) {
        if ($p eq 'atfork') {
            $self->{$p} = $params{$p};
        } else {
            die "unknown option '$p'";
        }
    }

    $rest_env = $self;

    my ($sysname, $nodename) = POSIX::uname();

    $nodename =~ s/\..*$//; # strip domain part, if any

    $self->{nodename} = $nodename;

    return $self;
}

# convenience function for command line tools
sub setup_default_cli_env {
    my ($class, $username) = @_;

    $class = ref($class) || $class;

    $username //= 'root@pam';

    PVE::INotify::inotify_init();

    my $rpcenv = $class->init('cli');
    $rpcenv->init_request();
    $rpcenv->set_language($ENV{LANG});
    $rpcenv->set_user($username);

    die "please run as root\n"
        if ($username eq 'root@pam') && ($> != 0);
}

# get the singleton
sub get {

    die "REST environment not initialized" if !$rest_env;

    return $rest_env;
}

sub set_client_ip {
    my ($self, $ip) = @_;

    $self->{client_ip} = $ip;
}

sub get_client_ip {
    my ($self) = @_;

    return $self->{client_ip};
}

sub set_result_attrib {
    my ($self, $key, $value) = @_;

    $self->{result_attributes}->{$key} = $value;
}

sub get_result_attrib {
    my ($self, $key) = @_;

    return $self->{result_attributes}->{$key};
}

sub set_language {
    my ($self, $lang) = @_;

    # fixme: initialize I18N

    $self->{language} = $lang;
}

sub get_language {
    my ($self) = @_;

    return $self->{language};
}

sub set_user {
    my ($self, $user) = @_;

    $self->{user} = $user;
}

sub get_user {
    my ($self, $noerr) = @_;

    return $self->{user} if defined($self->{user}) || $noerr;

    die "user name not set\n";
}

sub set_u2f_challenge {
    my ($self, $challenge) = @_;

    $self->{u2f_challenge} = $challenge;
}

sub get_u2f_challenge {
    my ($self, $noerr) = @_;

    return $self->{u2f_challenge} if defined($self->{u2f_challenge}) || $noerr;

    die "no active u2f challenge\n";
}

sub set_request_host {
    my ($self, $host) = @_;

    $self->{request_host} = $host;
}

sub get_request_host {
    my ($self, $noerr) = @_;

    return $self->{request_host} if defined($self->{request_host}) || $noerr;

    die "no hostname available in current environment\n";
}

sub is_worker {
    my ($class) = @_;

    return $WORKER_FLAG;
}

# read/update list of active workers.
#
# we move all finished tasks to the archive index, but keep active, and most recent tasks in the
# active file.
# $nocheck ... consider $new_upid still running (avoid that we try to read the result to early).
sub active_workers {
    my ($self, $new_upid, $nocheck) = @_;

    my $timeout = 10;

    my $res = PVE::Tools::lock_file(
        "/var/log/pve/tasks/.active.lock",
        $timeout,
        sub {
            my $tasklist = PVE::INotify::read_file('active');

            my @ta;
            my $tlist = [];
            my $thash = {}; # only list task once

            my $check_task = sub {
                my ($task, $running) = @_;

                if (
                    $running
                    || PVE::ProcFSTools::check_process_running($task->{pid}, $task->{pstart})
                ) {
                    push @$tlist, $task;
                } else {
                    delete $task->{pid};
                    push @ta, $task;
                }
                delete $task->{pstart};
            };

            foreach my $task (@$tasklist) {
                my $upid = $task->{upid};
                next if $thash->{$upid};
                $thash->{$upid} = $task;
                &$check_task($task);
            }

            if ($new_upid && !$thash->{$new_upid}) {
                my $task = PVE::Tools::upid_decode($new_upid);
                $task->{upid} = $new_upid;
                $thash->{$new_upid} = $task;
                &$check_task($task, $nocheck);
            }

            @ta = sort { $b->{starttime} <=> $a->{starttime} } @ta;

            my $save = defined($new_upid);

            foreach my $task (@ta) {
                next if $task->{endtime};
                $task->{endtime} = time();
                $task->{status} = PVE::Tools::upid_read_status($task->{upid});
                $save = 1;
            }

            my $archive = '';
            my @arlist = ();
            foreach my $task (@ta) {
                if (!$task->{saved}) {
                    $archive .=
                        sprintf("%s %08X %s\n", $task->{upid}, $task->{endtime}, $task->{status});
                    $save = 1;
                    push @arlist, $task;
                    $task->{saved} = 1;
                }
            }

            if ($archive) {
                my $size = 0;
                my $filename = "/var/log/pve/tasks/index";
                eval {
                    my $fh = IO::File->new($filename, '>>', 0644)
                        || die "unable to open file '$filename' - $!\n";
                    PVE::Tools::safe_print($filename, $fh, $archive);
                    $size = -s $fh;
                    close($fh)
                        || die "unable to close file '$filename' - $!\n";
                };
                my $err = $@;
                if ($err) {
                    syslog('err', $err);
                    foreach my $task (@arlist) { # mark as not saved
                        $task->{saved} = 0;
                    }
                }
                my $maxsize = 50000; # about 1000 entries
                if ($size > $maxsize) {
                    rename($filename, "$filename.1");
                }
            }

            # we try to reduce the amount of data list all running tasks and task and a few others
            my $MAX_FINISHED = 25;
            my $max = $MAX_FINISHED - scalar(@$tlist);
            foreach my $task (@ta) {
                last if $max <= 0;
                push @$tlist, $task;
                $max--;
            }

            PVE::INotify::write_file('active', $tlist) if $save;

            return $tlist;
        },
    );
    die $@ if $@;

    return $res;
}

my $kill_process_group = sub {
    my ($pid, $pstart) = @_;

    # send kill to process group (negative pid)
    my $kpid = -$pid;

    # always send signal to all pgrp members
    kill(15, $kpid); # send TERM signal

    # give max 5 seconds to shut down
    for (my $i = 0; $i < 5; $i++) {
        return if !PVE::ProcFSTools::check_process_running($pid, $pstart);
        sleep(1);
    }

    # to be sure
    kill(9, $kpid);
};

sub check_worker {
    my ($self, $upid, $killit) = @_;

    my $task = PVE::Tools::upid_decode($upid);

    my $running = PVE::ProcFSTools::check_process_running($task->{pid}, $task->{pstart});

    return 0 if !$running;

    if ($killit) {
        &$kill_process_group($task->{pid});
        return 0;
    }

    return 1;
}

# acts almost as tee: writes an output both to STDOUT and a task log,
# we differ as we're worker aware and look also at the childs control pipe,
# so we know if the function could be executed successfully or not.
my $tee_worker = sub {
    my ($childfd, $ctrlfd, $taskfh, $cpid) = @_;

    eval {
        my $int_count = 0;
        local $SIG{INT} = local $SIG{QUIT} = local $SIG{TERM} = sub {
            # always send signal to all pgrp members
            my $kpid = -$cpid;
            if ($int_count < 3) {
                kill(15, $kpid); # send TERM signal
            } else {
                kill(9, $kpid); # send KILL signal
            }
            $int_count++;
        };
        local $SIG{PIPE} = sub { die "broken pipe\n"; };

        my $select = IO::Select->new();
        my $fh = IO::Handle->new_from_fd($childfd, 'r');
        $select->add($fh);

        my $readbuf = '';
        my $count;
        while ($select->count) {
            my @handles = $select->can_read(1);
            if (scalar(@handles)) {
                my $count = sysread($handles[0], $readbuf, 4096);
                if (!defined($count)) {
                    my $err = $!;
                    die "sync pipe read error: $err\n";
                }
                last if $count == 0; # eof

                print $readbuf;
                select->flush();

                print $taskfh $readbuf;
                $taskfh->flush();
            } else {
                # some commands daemonize without closing stdout
                last if !PVE::ProcFSTools::check_process_running($cpid);
            }
        }

        POSIX::read($ctrlfd, $readbuf, 4096);
        if ($readbuf =~ m/^TASK OK\n?$/) {
            # skip printing to stdout
            print $taskfh $readbuf;
        } elsif ($readbuf =~ m/^TASK ERROR: (.*)\n?$/) {
            print STDERR "$1\n";
            print $taskfh "\n$readbuf"; # ensure start on new line for webUI
        } elsif ($readbuf =~ m/^TASK WARNINGS: (\d+)\n?$/) {
            print STDERR "Task finished with $1 warning(s)!\n";
            print $taskfh "\n$readbuf"; # ensure start on new line for webUI
        } else {
            die "got unexpected control message: $readbuf\n";
        }
        $taskfh->flush();
    };
    my $err = $@;

    POSIX::close($childfd);
    POSIX::close($ctrlfd);

    if ($err) {
        $err =~ s/\n/ /mg;
        print STDERR "$err\n";
        print $taskfh "TASK ERROR: $err\n";
    }
};

# start long running workers
# STDIN is redirected to /dev/null
# STDOUT,STDERR are redirected to the filename returned by upid_decode
# NOTE: we simulate running in foreground if ($self->{type} eq 'cli')
sub fork_worker {
    my ($self, $dtype, $id, $user, $function, $background) = @_;

    $dtype = 'unknown' if !defined($dtype);
    $id = '' if !defined($id);

    # note: below is only used for the task log entry
    $user = $self->get_user(1) // 'root@pam' if !defined($user);

    my $sync = ($self->{type} eq 'cli' && !$background) ? 1 : 0;

    local $SIG{INT} = local $SIG{QUIT} = local $SIG{PIPE} = local $SIG{TERM} = 'IGNORE';

    my $starttime = time();

    my @psync = POSIX::pipe();
    my @csync = POSIX::pipe();
    my @ctrlfd = $sync ? POSIX::pipe() : ();

    my $node = $self->{nodename};

    my $cpid = fork();
    die "unable to fork worker - $!" if !defined($cpid);

    my $workerpuid = $cpid ? $cpid : $$;

    my $pstart = PVE::ProcFSTools::read_proc_starttime($workerpuid)
        || die "unable to read process start time";

    my $upid = PVE::Tools::upid_encode({
        node => $node,
        pid => $workerpuid,
        pstart => $pstart,
        starttime => $starttime,
        type => $dtype,
        id => $id,
        user => $user,
    });

    my $outfh;

    if (!$cpid) { # child

        $0 = "task $upid";
        $WORKER_FLAG = 1;

        $SIG{INT} = $SIG{QUIT} = $SIG{TERM} = sub { die "received interrupt\n"; };

        $SIG{CHLD} = $SIG{PIPE} = 'DEFAULT';
        $SIG{TTOU} = 'IGNORE';

        my $ppgid;
        # set session/process group allows to kill the process group
        if ($sync && -t STDIN) {
            # some sync'ed workers operate on the tty but setsid sessions lose
            # the tty, so just create a new pgroup and give it the tty
            $ppgid = POSIX::getpgrp() or die "failed to get old pgid: $!\n";
            POSIX::setpgid(0, 0) or die "failed to setpgid: $!\n";
            POSIX::tcsetpgrp(fileno(STDIN), $$) or die "failed to tcsetpgrp: $!\n";
        } else {
            POSIX::setsid();
        }

        POSIX::close($psync[0]);
        POSIX::close($ctrlfd[0]) if $sync;
        POSIX::close($csync[1]);

        $outfh = $sync ? $psync[1] : undef;
        my $resfh = $sync ? $ctrlfd[1] : undef;

        eval {
            PVE::INotify::inotify_close();

            if (my $atfork = $self->{atfork}) {
                &$atfork();
            }

            # same algorithm as used inside SA
            # STDIN = /dev/null
            my $fd = fileno(STDIN);

            if (!$sync) {
                close STDIN;
                POSIX::close(0) if $fd != 0;

                open(STDIN, '<', '/dev/null') or die "unable to redirect STDIN - $!";

                $outfh = PVE::Tools::upid_open($upid);
                $resfh = fileno($outfh);
            }

            # redirect STDOUT
            $fd = fileno(STDOUT);
            close STDOUT;
            POSIX::close(1) if $fd != 1;

            open(STDOUT, ">&", $outfh) or die "unable to redirect STDOUT - $!";

            STDOUT->autoflush(1);

            #  redirect STDERR to STDOUT
            $fd = fileno(STDERR);
            close STDERR;
            POSIX::close(2) if $fd != 2;

            open(STDERR, '>&', '1') or die "unable to redirect STDERR - $!";

            STDERR->autoflush(1);
        };
        if (my $err = $@) {
            my $msg = "ERROR: $err";
            POSIX::write($psync[1], $msg, length($msg));
            POSIX::close($psync[1]);
            POSIX::_exit(1);
            kill(-9, $$);
        }

        # sync with parent (signal that we are ready)
        POSIX::write($psync[1], $upid, length($upid));
        POSIX::close($psync[1]) if !$sync; # don't need output pipe if async

        eval {
            my $readbuf = '';
            # sync with parent (wait until parent is ready)
            POSIX::read($csync[0], $readbuf, 4096);
            die "parent setup error\n" if $readbuf ne 'OK';

            if ($self->{type} eq 'ha') {
                print "task started by HA resource agent\n";
            }
            &$function($upid);
        };
        my ($msg, $exitcode);
        my $err = $@;
        if ($err) {
            chomp $err;
            $err =~ s/\n/ /mg;
            syslog('err', $err);
            $msg = "TASK ERROR: $err\n";
            $exitcode = -1;
        } elsif (my $warnings = $self->{warning_count}) {
            $msg = "TASK WARNINGS: $warnings\n";
            $exitcode = 0;
        } else {
            $msg = "TASK OK\n";
            $exitcode = 0;
        }
        POSIX::write($resfh, $msg, length($msg));

        if ($sync) {
            POSIX::close($resfh);
            if (-t STDIN) {
                POSIX::tcsetpgrp(fileno(STDIN), $ppgid)
                    or die "failed to tcsetpgrp to parent: $!\n";
            }
        }
        POSIX::_exit($exitcode);
        kill(-9, $$); # not really needed, just to be sure
    }

    # parent

    POSIX::close($psync[1]);
    POSIX::close($ctrlfd[1]) if $sync;
    POSIX::close($csync[0]);

    my $readbuf = '';
    # sync with child (wait until child starts)
    POSIX::read($psync[0], $readbuf, 4096);

    if (!$sync) {
        POSIX::close($psync[0]);
        &$register_worker($cpid, $user, $upid);
    } else {
        chomp $readbuf;
    }

    eval {
        die "got no worker upid - start worker failed\n" if !$readbuf;

        if ($readbuf =~ m/^ERROR:\s*(.+)$/m) {
            die "starting worker failed: $1\n";
        }

        if ($readbuf ne $upid) {
            die "got strange worker upid ('$readbuf' != '$upid') - start worker failed\n";
        }

        if ($sync) {
            $outfh = PVE::Tools::upid_open($upid);
        }
    };
    my $err = $@;

    if (!$err) {
        my $msg = 'OK';
        POSIX::write($csync[1], $msg, length($msg));
        POSIX::close($csync[1]);

    } else {
        POSIX::close($csync[1]);
        kill(-9, $cpid); # make sure it gets killed
        die $err;
    }

    $self->log_cluster_msg('info', $user, "starting task $upid");

    my $tlist = $self->active_workers($upid, $sync);
    eval { $self->broadcast_tasklist($tlist); };
    syslog('err', $@) if $@;

    my $res = 0;

    if ($sync) {

        $tee_worker->($psync[0], $ctrlfd[0], $outfh, $cpid);

        &$kill_process_group($cpid, $pstart); # make sure it gets killed

        close($outfh);

        waitpid($cpid, 0);
        $res = $?;
        &$log_task_result($upid, $user, $res);
    }

    return wantarray ? ($upid, $res) : $upid;
}

sub log_warn {
    my ($message) = @_;

    if ($rest_env) {
        $rest_env->warn($message);
    } else {
        chomp($message);
        syslog('warning', "%s", $message);
        print STDERR "WARN: $message\n";
    }
}

sub warn {
    my ($self, $message) = @_;

    chomp($message);

    syslog('warning', "%s", $message);
    print STDERR "WARN: $message\n";

    $self->{warning_count}++;
}

# Abstract function

sub log_cluster_msg {
    my ($self, $pri, $user, $msg) = @_;

    syslog($pri, "%s", $msg);

    # PVE::Cluster::log_msg($pri, $user, $msg);
}

sub broadcast_tasklist {
    my ($self, $tlist) = @_;

    # PVE::Cluster::broadcast_tasklist($tlist);
}

sub check_api2_permissions {
    my ($self, $perm, $username, $param) = @_;

    return 1 if !$username && $perm->{user} eq 'world';

    raise_perm_exc("user != null") if !$username;

    return 1 if $username eq 'root@pam';

    raise_perm_exc('user != root@pam') if !$perm;

    return 1 if $perm->{user} && $perm->{user} eq 'all';

    ##return $self->exec_api2_perm_check($perm->{check}, $username, $param)
    ##if $perm->{check};

    raise_perm_exc();
}

# init_request - should be called before each REST/CLI request
sub init_request {
    my ($self, %params) = @_;

    $self->{result_attributes} = {}

    # if you nedd more, implement in subclass
}

1;