package PVE::API2::Cluster::MetricServer;

use warnings;
use strict;

use PVE::Tools qw(extract_param extract_sensitive_params);
use PVE::Exception qw(raise_perm_exc raise_param_exc);
use PVE::JSONSchema qw(get_standard_option);
use PVE::INotify;
use PVE::RPCEnvironment;
use PVE::ExtMetric;
use PVE::PullMetric;
use PVE::SafeSyslog;

use PVE::RESTHandler;

use base qw(PVE::RESTHandler);

__PACKAGE__->register_method ({
    name => 'index',
    path => '',
    method => 'GET',
    description => "Metrics index.",
    permissions => { user => 'all' },
    parameters => {
	additionalProperties => 0,
	properties => {},
    },
    returns => {
	type => 'array',
	items => {
	    type => "object",
	    properties => {},
	},
	links => [ { rel => 'child', href => "{name}" } ],
    },
    code => sub {
	my ($param) = @_;

	my $result = [
	    { name => 'server' },
	];

	return $result;
    }
});

__PACKAGE__->register_method ({
    name => 'server_index',
    path => 'server',
    method => 'GET',
    description => "List configured metric servers.",
    permissions => {
	check => ['perm', '/', ['Sys.Audit']],
    },
    parameters => {
	additionalProperties => 0,
	properties => {},
    },
    returns => {
	type => 'array',
	items => {
	    type => "object",
	    properties => {
		id => {
		    description => "The ID of the entry.",
		    type => 'string'
		},
		disable => {
		    description => "Flag to disable the plugin.",
		    type => 'boolean',
		},
		type => {
		    description => "Plugin type.",
		    type => 'string',
		},
		server => {
		    description => "Server dns name or IP address",
		    type => 'string',
		},
		port => {
		    description => "Server network port",
		    type => 'integer',
		},
	    },
	},
	links => [ { rel => 'child', href => "{id}" } ],
    },
    code => sub {
	my ($param) = @_;

	my $res = [];
	my $status_cfg = PVE::Cluster::cfs_read_file('status.cfg');

	for my $id (sort keys %{$status_cfg->{ids}}) {
	    my $plugin_config = $status_cfg->{ids}->{$id};
	    push @$res, {
		id => $id,
		disable => $plugin_config->{disable} // 0,
		type => $plugin_config->{type},
		server => $plugin_config->{server},
		port => $plugin_config->{port},
	    };
	}

	return $res;
    }});

__PACKAGE__->register_method ({
    name => 'read',
    path => 'server/{id}',
    method => 'GET',
    description => "Read metric server configuration.",
    permissions => {
	check => ['perm', '/', ['Sys.Audit']],
    },
    parameters => {
	additionalProperties => 0,
	properties => {
	    id => {
		type => 'string',
		format => 'pve-configid',
	    },
	},
    },
    returns => { type => 'object' },
    code => sub {
	my ($param) = @_;

	my $status_cfg = PVE::Cluster::cfs_read_file('status.cfg');
	my $id = $param->{id};

	if (!defined($status_cfg->{ids}->{$id})) {
	    die "status server entry '$id' does not exist\n";
	}

	return $status_cfg->{ids}->{$id};
    }});

__PACKAGE__->register_method ({
    name => 'create',
    path => 'server/{id}',
    protected => 1,
    method => 'POST',
    description => "Create a new external metric server config",
    permissions => {
	check => ['perm', '/', ['Sys.Modify']],
    },
    parameters => PVE::Status::Plugin->createSchema(),
    returns => { type => 'null' },
    code => sub {
	my ($param) = @_;

	my $type = extract_param($param, 'type');
	my $plugin = PVE::Status::Plugin->lookup($type);
	my $id = extract_param($param, 'id');

	my $sensitive_params = extract_sensitive_params($param, ['token'], []);

	PVE::Cluster::cfs_lock_file('status.cfg', undef, sub {
	    my $cfg = PVE::Cluster::cfs_read_file('status.cfg');

	    die "Metric server '$id' already exists\n"
		if $cfg->{ids}->{$id};

	    my $opts = $plugin->check_config($id, $param, 1, 1);

	    $cfg->{ids}->{$id} = $opts;

	    $plugin->on_add_hook($id, $opts, $sensitive_params);

	    eval {
		$plugin->test_connection($opts, $id);
	    };

	    if (my $err = $@) {
		eval { $plugin->on_delete_hook($id, $opts) };
		warn "$@\n" if $@;
		die $err;
	    }

	    PVE::Cluster::cfs_write_file('status.cfg', $cfg);
	});
	die $@ if $@;

	return;
    }});


__PACKAGE__->register_method ({
    name => 'update',
    protected => 1,
    path => 'server/{id}',
    method => 'PUT',
    description => "Update metric server configuration.",
    permissions => {
	check => ['perm', '/', ['Sys.Modify']],
    },
    parameters => PVE::Status::Plugin->updateSchema(),
    returns => { type => 'null' },
    code => sub {
	my ($param) = @_;

	my $id = extract_param($param, 'id');
	my $digest = extract_param($param, 'digest');
	my $delete = extract_param($param, 'delete');

	if ($delete) {
	    $delete = [PVE::Tools::split_list($delete)];
	}

	my $sensitive_params = extract_sensitive_params($param, ['token'], $delete);

	PVE::Cluster::cfs_lock_file('status.cfg', undef, sub {
	    my $cfg = PVE::Cluster::cfs_read_file('status.cfg');

	    PVE::SectionConfig::assert_if_modified($cfg, $digest);

	    my $data = $cfg->{ids}->{$id};
	    die "no such server '$id'\n" if !$data;

	    my $plugin = PVE::Status::Plugin->lookup($data->{type});
	    my $opts = $plugin->check_config($id, $param, 0, 1);

	    for my $k (keys %$opts) {
		$data->{$k} = $opts->{$k};
	    }

	    if ($delete) {
		my $options = $plugin->private()->{options}->{$data->{type}};
		for my $k (@$delete) {
		    my $d = $options->{$k} || die "no such option '$k'\n";
		    die "unable to delete required option '$k'\n" if !$d->{optional};
		    die "unable to delete fixed option '$k'\n" if $d->{fixed};
		    die "cannot set and delete property '$k' at the same time!\n"
			if defined($opts->{$k});

		    delete $data->{$k};
		}
	    }

	    $plugin->on_update_hook($id, $data, $sensitive_params);

	    $plugin->test_connection($data, $id);

	    PVE::Cluster::cfs_write_file('status.cfg', $cfg);
	});
	die $@ if $@;

	return;
    }});

__PACKAGE__->register_method ({
    name => 'delete',
    protected => 1,
    path => 'server/{id}',
    method => 'DELETE',
    description => "Remove Metric server.",
    permissions => {
	check => ['perm', '/', ['Sys.Modify']],
    },
    parameters => {
	additionalProperties => 0,
	properties => {
	    id => {
		type => 'string',
		format => 'pve-configid',
	    },
	}
    },
    returns => { type => 'null' },
    code => sub {
	my ($param) = @_;

	PVE::Cluster::cfs_lock_file('status.cfg', undef, sub {
	    my $cfg = PVE::Cluster::cfs_read_file('status.cfg');

	    my $id = $param->{id};

	    my $plugin_cfg = $cfg->{ids}->{$id};

	    my $plugin = PVE::Status::Plugin->lookup($plugin_cfg->{type});

	    $plugin->on_delete_hook($id, $plugin_cfg);

	    delete $cfg->{ids}->{$id};
	    PVE::Cluster::cfs_write_file('status.cfg', $cfg);
	});
	die $@ if $@;

	return;
    }});

__PACKAGE__->register_method ({
    name => 'export',
    path => 'export',
    method => 'GET',
    protected => 1,
    description => "Retrieve metrics of the cluster.",
    permissions => {
	check => ['perm', '/', ['Sys.Audit']],
    },
    parameters => {
	additionalProperties => 0,
	properties => {
	    'local-only' => {
		type => 'boolean',
		description =>
		    'Only return metrics for the current node instead of the whole cluster',
		optional => 1,
		default => 0,
	    },
	    'start-time' => {
		type => 'integer',
		description => 'Only include metrics with a timestamp > start-time.',
		optional => 1,
		default => 0,
	    },
	    'history' => {
		type => 'boolean',
		description => 'Also return historic values.'
		  . ' Returns full available metric history unless `start-time` is also set',
		optional => 1,
		default => 0,
	    },
	},
    },
    returns => {
	type => 'object',
	additionalProperties => 0,
	properties => {
	    data => {
		type => 'array',
		description => 'Array of system metrics. Metrics are sorted by their timestamp.',
		items => {
		    type => 'object',
		    additionalProperties => 0,
		    properties => {
			timestamp => {
			    type => 'integer',
			    description => 'Time at which this metric was observed',
			},
			id => {
			    type => 'string',
			    description => "Unique identifier for this metric object,"
				. " for instance 'node/<nodename>' or"
				. " 'qemu/<vmid>'."
			},
			metric => {
			    type => 'string',
			    description => "Name of the metric.",
			},
			value => {
			    type => 'number',
			    description => 'Metric value.',
			},
			type => {
			    type => 'string',
			    description => 'Type of the metric.',
			    enum => [qw(gauge counter derive)],
			}
		    }
		},

	    },

	}
    },
    code => sub {
	my ($param) = @_;
	my $local_only = $param->{'local-only'} // 0;
	my $start = $param->{'start-time'};
	my $history = $param->{'history'} // 0;

	my $now = time();

	my $generations;
	if ($history) {
	    # Assuming update loop time of pvestatd of 10 seconds.
	    if (defined($start)) {
		my $delta = $now - $start;
		$generations = int($delta / 10);
	    } else {
		$generations = PVE::PullMetric::max_generations();
	    }

	} else {
	    $generations = 0;
	};

	my @metrics = @{PVE::PullMetric::get_local_metrics($generations)};

	if (defined($start)) {
	    @metrics = grep {
		$_->{timestamp} > ($start)
	    } @metrics;
	}

	my $nodename = PVE::INotify::nodename();

	# Fan out to cluster members
	# Do NOT remove this check
	if (!$local_only) {
	    my $members = PVE::Cluster::get_members();

	    my $rpcenv = PVE::RPCEnvironment::get();
	    my $authuser = $rpcenv->get_user();

	    my ($user, undef) = PVE::AccessControl::split_tokenid($authuser, 1);

	    my $ticket;
	    if ($user) {
		# Theoretically, we might now bypass token privilege separation, since
		# we use the regular user instead of the token, but
		# since we already passed the permission check for this handler,
		# this should be fine.
		$ticket = PVE::AccessControl::assemble_ticket($user);
	    } else {
		$ticket = PVE::AccessControl::assemble_ticket($authuser);
	    }

	    for my $name (keys %$members) {
		if ($name eq $nodename) {
		    # Skip own node, for that one we already have the metrics
		    next;
		}

		if (!$members->{$name}->{online}) {
		    next;
		}

		my $status = eval {
		    my $fingerprint = PVE::Cluster::get_node_fingerprint($name);
		    my $ip = scalar(PVE::Cluster::remote_node_ip($name));

		    my $conn_args = {
			protocol => 'https',
			host => $ip,
			port => 8006,
			ticket => $ticket,
			timeout => 5,
		    };

		    $conn_args->{cached_fingerprints} = { $fingerprint => 1 };

		    my $api_client = PVE::APIClient::LWP->new(%$conn_args);

		    my $params = {
			# Do NOT remove 'local-only' - potential for request recursion!
			'local-only' => 1,
			history => $history,
		    };
		    $params->{'start-time'} = $start if defined($start);

		    $api_client->get('/cluster/metrics/export', $params);
		};

		if ($@) {
		    syslog('warning', "could not fetch metrics from $name: $@");
		} else {
		    push @metrics, $status->{data}->@*;
		}
	    }
	}

	my @sorted = sort {$a->{timestamp} <=> $b->{timestamp}} @metrics;

	return {
	    data => \@sorted,
	};
    },
});

1;