<?php

namespace App\Models;

use Carbon\Carbon;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Database\Eloquent\Collection;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\HasMany;
use Illuminate\Database\Eloquent\SoftDeletes;
use Illuminate\Database\QueryException;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;

use App\Classes\FTN\{Message,Packet};
use App\Exceptions\InvalidFTNException;
use App\Traits\{QueryCacheableConfig,ScopeActive};

/**
 * This represents an FTN AKA.
 *
 * If an address is active, it belongs to the system. There can only be 1 active FTN (z:h/n.p@d)
 * If an address is not active, it belonged to the system at a point in time in the past.
 *
 * If an address is validated, we know that the system is using the address (we've confirmed that during a session).
 * validated is update/removed is during a mailer session, confirming if the node has the address
 *
 * We'll only trigger a poll to a system that we have mail for if active && validated, unless "forced".
 *
 * Any mail for that address will be delivered, if active && validated.
 *
 * @see \App\Http\Requests\AddressAdd::class for rules about AKA and role
 */

// Need to add
// Calculated Region for an FTN, ie: find the parent and use their region id
// - if creating an RC, then the region is part of the creation, ZC region is 0
// Then use this in createFTN

class Address extends Model
{
	use QueryCacheableConfig,ScopeActive,SoftDeletes;

	private const LOGKEY = 'MA-';

	// http://ftsc.org/docs/frl-1028.002
	public const ftn_regex = '(\d+):(\d+)/(\d+)(?:\.(\d+))?(?:@([a-zA-Z0-9\-_~]{0,8}))?';

	public const NODE_ZC		= 1<<0;		// Zone
	public const NODE_RC		= 1<<1;		// Region
	public const NODE_NC		= 1<<2;		// Host
	public const NODE_HC		= 1<<3;		// Hub
	public const NODE_NN		= 1<<4;		// Node
	public const NODE_PVT		= 1<<5;		// Pvt (we dont have address information) @todo
	public const NODE_HOLD		= 1<<6;		// Hold (user has requested hold, we havent heard from the node for 7 days @todo
	public const NODE_DOWN		= 1<<7;		// Down we havent heard from the node for 30 days @todo
	public const NODE_POINT		= 1<<8;		// Point
	public const NODE_UNKNOWN	= 1<<15;	// Unknown
	public const NODE_ALL		= 0x811f;	// Mask to catch all nodes, excluding their status

	// http://ftsc.org/docs/frl-1002.001
	public const ADDRESS_FIELD_MAX = 0x7fff;	// Maximum value for a field in the address

	protected $visible = ['zone_id','region_id','host_id','hub_id','node_id','point_id','security'];

	/* STATIC */

	public static function boot()
	{
		parent::boot();

		// For indexes when deleting, we need to change active to FALSE
		static::softDeleted(function($model) {
			Log::debug(sprintf('%s:Deleting [%d], updating active to FALSE',self::LOGKEY,$model->id));

			$model->active = FALSE;
			$model->save();
		});
	}

	/**
	 * Create an FTN address associated with a system
	 *
	 * @param string $address
	 * @param System $so
	 * @return Address|null
	 * @throws \Exception
	 */
	public static function createFTN(string $address,System $so): ?self
	{
		$ftn = self::parseFTN($address);

		if (! $ftn['d']) {
			// See if we have a default domain for this domain
			if ($ftn['z']) {
				$zo = Zone::where('zone_id',$ftn['z'])->where('default',TRUE)->single();

				if ($zo)
					$ftn['d'] = $zo->domain->name;

				else {
					Log::alert(sprintf('%s:! Refusing to create address [%s] no domain available',self::LOGKEY,$address));

					return NULL;
				}
			}
		}

		Log::debug(sprintf('%s:- Creating AKA [%s] for [%s]',self::LOGKEY,$address,$so->name));

		// Check Domain exists
		Domain::unguard();
		$do = Domain::singleOrNew(['name'=>$ftn['d']]);
		Domain::reguard();

		if (! $do->exists) {
			$do->public = TRUE;
			$do->active = TRUE;
			$do->notes = 'Auto created';

			$do->save();
		}

		// If the zone is zero, see if this is a flatten domain, and if so, find an NC
		if (($ftn['z'] === 0) && $do->flatten) {
			$nc = self::findZone($do,$ftn['n'],0,0);

			if ($nc) {
				Log::info(sprintf('%s:- Setting zone to [%d]',self::LOGKEY,$nc->zone->zone_id));
				$ftn['z'] = $nc->zone->zone_id;
			}
		}

		// Create zone
		Zone::unguard();
		$zo = Zone::singleOrNew(['domain_id'=>$do->id,'zone_id'=>$ftn['z']]);
		Zone::reguard();

		if (! $zo->exists) {
			$zo->active = TRUE;
			$zo->notes = 'Auto created';
			$zo->system_id = System::createUnknownSystem()->id;

			$do->zones()->save($zo);
		}

		if (! $zo->active || ! $do->active) {
			Log::alert(sprintf('%s:! Refusing to create address [%s] in disabled zone or domain',self::LOGKEY,$address));

			return NULL;
		}

		// Create Address, assigned to $so
		$o = new self;
		$o->active = TRUE;
		$o->zone_id = $zo->id;
		$o->region_id = $ftn['r'];
		$o->host_id = $ftn['n'];
		$o->node_id = $ftn['f'];
		$o->point_id = $ftn['p'];

		try {
			$so->addresses()->save($o);

		} catch (QueryException $e) {
			Log::error(sprintf('%s:! ERROR creating address [%s] (%s)',self::LOGKEY,$o->ftn,get_class($e)));
			return NULL;
		}

		return $o;
	}

	/**
	 * Find a record in the DB for a node string, eg: 10:1/1.0
	 *
	 * @param string $address
	 * @param bool $trashed
	 * @return Address|null
	 * @throws \Exception
	 */
	public static function findFTN(string $address,bool $trashed=FALSE): ?self
	{
		$ftn = self::parseFTN($address);
		$o = NULL;

		$query = (new self)
			->select('addresses.*')
			->join('zones',['zones.id'=>'addresses.zone_id'])
			->join('domains',['domains.id'=>'zones.domain_id'])
			->when($trashed,function($query) {
				$query->withTrashed();
			},function($query) {
				$query->active();
			})
			->where('zones.zone_id',$ftn['z'])
			->where('node_id',$ftn['f'])
			->where('point_id',$ftn['p'])
			->when($ftn['d'],function($query,$domain) {
				$query->where('domains.name',$domain);
			},function($query) {
				$query->where('zones.default',TRUE);
			})
			->orderBy('created_at','DESC');

		$q = $query->clone();

		// Are we looking for a region address
		if (($ftn['f'] === 0) && ($ftn['p'] === 0))
			$o = $query
				->where('region_id',$ftn['n'])
				->where('host_id',$ftn['n'])
				->first();

		// Look for a normal address
		if (! $o)
			$o = $q
				->where(function($q) use ($ftn) {
					return $q
						->where(function($q) use ($ftn) {
							return $q
								->where('region_id',$ftn['n'])
								->where('host_id',$ftn['n']);
						})
						->orWhere('host_id',$ftn['n']);
				})
				->first();

		// Check and see if we are a flattened domain, our address might be available with a different zone.
		// This occurs when we are parsing 2D addresses from SEEN-BY, but we have the zone
		if (! $o && ($ftn['p'] === 0)) {
			if ($ftn['d'])
				$do = Domain::where(['name'=>$ftn['d']])->single();
			else {
				$zo = Zone::where('zone_id',$ftn['z'])->where('default',TRUE)->single();
				$do = $zo?->domain;
			}

			if ($do && $do->flatten && (($ftn['z'] === 0) || $do->zones->pluck('zone_id')->contains($ftn['z'])))
				$o = self::findZone($do,$ftn['n'],$ftn['f'],$ftn['p'],$trashed);
		}

		return ($o && $o->system->active) ? $o : NULL;
	}

	public static function newFTN(string $address): self
	{
		$ftn = self::parseFTN($address);
		$do = $ftn['d'] ? Domain::where('name',$ftn['d'])->single() : NULL;

		$zo = Zone::where('zone_id',$ftn['z'])
			->when($do,fn($query)=>$query->where('domain_id',$do->id))
			->single();

		$o = new self;
		$o->zone_id = $zo?->id;
		$o->region_id = $ftn['r'];
		$o->host_id = $ftn['n'];
		$o->node_id = $ftn['f'];
		$o->point_id = $ftn['p'];

		return $o;
	}

	/**
	 * This is to find an address for a domain (like fidonet), which is technically 2D even though it uses multiple zones.
	 *
	 * This was implemented to identify seenby and path kludges
	 *
	 * @param Domain $do
	 * @param int $host
	 * @param int $node
	 * @param int $point
	 * @param bool $trashed
	 * @return self|null
	 * @throws \Exception
	 */
	public static function findZone(Domain $do,int $host,int $node,int $point,bool $trashed=FALSE): ?self
	{
		if (! $do->flatten)
			throw new \Exception(sprintf('Domain is not set with flatten: %d',$do->id));

		$zones = $do->zones->pluck('zone_id');

		$o = (new self)
			->select('addresses.*')
			->join('zones',['zones.id'=>'addresses.zone_id'])
			->when($trashed,function($query) {
				$query->withTrashed();
			},function($query) {
				$query->active();
			})
			->whereIN('zones.zone_id',$zones)
			->where(function($q) use ($host) {
				return $q
					->where(function($q) use ($host) {
						return $q->where('region_id',$host)
							->where('host_id',$host);
					})
					->orWhere('host_id',$host);
			})
			->where('node_id',$node)
			->where('point_id',$point)
			->where('zones.domain_id',$do->id)
			->single();

		return $o;
	}

	/**
	 * Parse a string and split it out as an FTN array
	 *
	 * @param string $ftn
	 * @return array
	 * @throws \Exception
	 */
	public static function parseFTN(string $ftn): array
	{
		if (! preg_match(sprintf('#^%s$#',self::ftn_regex),strtolower($ftn),$matches))
			throw new InvalidFTNException(sprintf('Invalid FTN: [%s] - regex failed',serialize($ftn)));

		// Check our numbers are correct.
		foreach ([1,2,3] as $i)
			if ((! is_numeric($matches[$i])) || ($matches[$i] > self::ADDRESS_FIELD_MAX))
				throw new InvalidFTNException(sprintf('Invalid FTN: [%s] - zone, host, or node address invalid [%d]',$ftn,$matches[$i]));

		if ((! empty($matches[4])) AND ((! is_numeric($matches[$i])) || ($matches[4] > self::ADDRESS_FIELD_MAX)))
			throw new InvalidFTNException(sprintf('Invalid FTN: [%s] - point address invalid [%d]',$ftn,$matches[4]));

		// Work out region
		$region_id = 0;
		$zone_id = NULL;

		// We can only work out region if we have a domain
		if ($matches[5] ?? NULL) {
			$o = new self;
			$o->host_id = $matches[2];
			$o->node_id = $matches[3];
			$o->point_id = empty($matches[4]) ? 0 : (int)$matches[4];

			$zo = Zone::select('zones.*')->where('zone_id',$matches[1])->join('domains',['domains.id'=>'zones.domain_id'])->where('domains.name',$matches[5])->single();
			$o->zone_id = $zo?->id;
			$parent = $o->parent();
			$zone_id = $parent?->zone->zone_id;

			// For flattened domains
			if ($zo?->domain->flatten && is_null($zone_id))
				foreach ($zo->domain->zones as $zoo) {
					$o->zone_id = $zoo->id;
					$parent = $o->parent();

					if ($parent)
						break;
				}

			$region_id = $parent?->region_id;
			$zone_id = $parent?->zone->zone_id;
		}

		return [
			'z' => (int)$zone_id ?: $matches[1],
			'r' => (int)$region_id,
			'n' => (int)$matches[2],
			'f' => (int)$matches[3],
			'p' => empty($matches[4]) ? 0 : (int)$matches[4],
			'd' => $matches[5] ?? NULL
		];
	}

	/* SCOPES */

	/**
	 * An FTN is active only if the address, zone, domain is also active
	 *
	 * @param $query
	 * @return mixed
	 */
	public function scopeActiveFTN($query)
	{
		return $query->select($this->getTable().'.*')
			->join('zones',['zones.id'=>'addresses.zone_id'])
			->join('domains',['domains.id'=>'zones.domain_id'])
			->where('zones.active',TRUE)
			->where('domains.active',TRUE)
			->active()
			->FTNorder();
	}

	/**
	 * Select to support returning FTN address
	 *
	 * @param $query
	 * @return void
	 */
	public function scopeFTN($query)
	{
		return $query->select(['addresses.zone_id','host_id','node_id','point_id'])
			->with('zone.domain');
	}

	public function scopeFTNOrder($query)
	{
		return $query
			->orderBy('region_id')
			->orderBy('host_id')
			->orderBy('node_id')
			->orderBy('point_id');
	}

	public function scopeFTN2DOrder($query)
	{
		return $query
			->orderBy('host_id')
			->orderBy('node_id')
			->orderBy('point_id');
	}

	/**
	 * Return a list of addresses and the amount of uncollected echomail
	 *
	 * @param $query
	 * @return mixed
	 */
	public function scopeUncollectedEchomail($query)
	{
		return $query
			->join('echomail_seenby',['echomail_seenby.address_id'=>'addresses.id'])
			->join('echomails',['echomails.id'=>'echomail_seenby.echomail_id'])
			->whereNotNull('export_at')
			->whereNull('sent_at')
			->whereNull('echomails.deleted_at')
			->groupBy('addresses.id')
			->dontCache();
	}

	public function scopeUncollectedEchomailTotal($query)
	{
		return $query
			->select([
				'addresses.id',
				'zone_id',
				'host_id',
				'node_id',
				'point_id',
				'system_id',
				DB::raw('count(*) as uncollected_echomail'),
				DB::raw('0 as uncollected_netmail'),
				DB::raw('0 as uncollected_files'),
			])
			->UncollectedEchomail();
	}

	/**
	 * Return a list of addresses and the amount of uncollected files
	 *
	 * @param $query
	 * @return mixed
	 */
	public function scopeUncollectedFiles($query)
	{
		return $query
			->join('file_seenby',['file_seenby.address_id'=>'addresses.id'])
			->join('files',['files.id'=>'file_seenby.file_id'])
			->whereNotNull('export_at')
			->whereNull('sent_at')
			->whereNull('files.deleted_at')
			->groupBy('addresses.id')
			->dontCache();
	}

	public function scopeUncollectedFilesTotal($query)
	{
		return $query
			->select([
				'addresses.id',
				'zone_id',
				'host_id',
				'node_id',
				'point_id',
				'system_id',
				DB::raw('0 as uncollected_echomail'),
				DB::raw('0 as uncollected_netmail'),
				DB::raw('count(*) as uncollected_files')
			])
			->UncollectedFiles();
	}

	public function scopeUncollectedNetmail($query)
	{
		return $query
			->join('netmails',['netmails.tftn_id'=>'addresses.id'])
			->where(function($query) {
				return $query->whereRaw(sprintf('(flags & %d) > 0',Message::FLAG_INTRANSIT))
					->orWhereRaw(sprintf('(flags & %d) > 0',Message::FLAG_LOCAL));
			})
			->whereRaw(sprintf('(flags & %d) = 0',Message::FLAG_SENT))
			->whereNull('sent_pkt')
			->whereNull('sent_at')
			->whereNull('netmails.deleted_at')
			->groupBy('addresses.id')
			->dontCache();
	}

	/**
	 * Return a list of addresses and the amount of uncollected netmail
	 *
	 * @param $query
	 * @return mixed
	 */
	public function scopeUncollectedNetmailTotal($query)
	{
		return $query
			->select([
				'addresses.id',
				'zone_id',
				'host_id',
				'node_id',
				'point_id',
				'system_id',
				DB::raw('0 as uncollected_echomail'),
				DB::raw('count(*) as uncollected_netmail'),
				DB::raw('0 as uncollected_files')
			])
			->UncollectedNetmail();
	}

	/* RELATIONS */

	public function domain()
	{
		return $this->hasOneThrough(Domain::class,Zone::class,'id','id','zone_id','domain_id');
	}

	public function dynamics()
	{
		return $this->hasMany(Dynamic::class);
	}

	/**
	 * Echoareas this address is subscribed to
	 *
	 * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
	 */
	public function echoareas()
	{
		return $this->belongsToMany(Echoarea::class)
			->orderBy('name')
			->withPivot(['subscribed']);
	}

	public function echomail_from()
	{
		return $this->hasMany(Echomail::class,'fftn_id','id')
			->orderBy('datetime','DESC')
			->limit(10);
	}

	/**
	 * Echomails that this address has seen
	 *
	 * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
	 * @todo Rework echomail_seenby to not have a specific seenby recorded for the fftn_id, but automatically include it when generating seenbys.
	 */
	public function echomail_seen()
	{
		return $this->belongsToMany(Echomail::class,'echomail_seenby')
			->withPivot(['export_at','sent_at','sent_pkt']);
	}

	/**
	 * Files that this address has seen
	 *
	 * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
	 */
	public function file_seen(): \Illuminate\Database\Eloquent\Relations\BelongsToMany
	{
		return $this->belongsToMany(File::class,'file_seenby')
			->withPivot(['sent_at','export_at']);
	}

	/**
	 * Fileareas this address is subscribed to
	 *
	 * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
	 */
	public function fileareas(): \Illuminate\Database\Eloquent\Relations\BelongsToMany
	{
		return $this->belongsToMany(Filearea::class)
			->orderBy('name')
			->withPivot(['subscribed']);
	}

	/**
	 * If we are a hub, if role === NODE_HC and child entries have us as their hub_id
	 *
	 * @return HasMany
	 */
	public function nodes_hub(): HasMany
	{
		return $this->hasMany(Address::class,'hub_id','id')
			->active()
			->FTNorder()
			->with(['zone.domain']);
	}

	/**
	 * Return the nodes that belong to this NC/RC/ZC
	 *
	 * @return HasMany
	 */
	public function nodes_net(): HasMany
	{
		return HasMany::noConstraints(
			fn()=>$this->newHasMany(
				(new self)->newQuery()
					->where('zone_id',$this->zone_id)
					->where('host_id',$this->host_id)
					->where('point_id',0)
					->whereNot('id',$this->id)
					->active()
					->FTNorder()
					->with(['zone.domain']),
				$this,
				NULL,
				($this->role_id === self::NODE_NC) ? 'id' : NULL)
		);
	}

	/**
	 * If we are a boss node, return our children.
	 *
	 * @return HasMany
	 */
	public function nodes_point(): HasMany
	{
		return HasMany::noConstraints(
			fn()=>$this->newHasMany(
				(new self)->newQuery()
					->where('zone_id',$this->zone_id)
					->where('host_id',$this->host_id)
					->where('node_id',$this->node_id)
					->where('point_id','>',0)
					->whereNot('id',$this->id)
					->active()
					->FTNorder()
					->with(['zone.domain']),
				$this,
				NULL,
				($this->role_id !== self::NODE_POINT) ? 'id' : NULL)
		);
	}

	public function nodes_region(): HasMany
	{
		return HasMany::noConstraints(
			fn()=>$this->newHasMany(
				(new self)->newQuery()
					->where('zone_id',$this->zone_id)
					->where('region_id',$this->region_id)
					->whereNot('id',$this->id)
					->active()
					->FTNorder()
					->with(['zone.domain']),
				$this,
				NULL,
				($this->role_id === self::NODE_RC) ? 'id' : NULL)
		);
	}

	public function nodes_zone(): HasMany
	{
		return HasMany::noConstraints(
			fn()=>$this->newHasMany(
				(new self)->newQuery()
					->where('zone_id',$this->zone_id)
					->whereNot('id',$this->id)
					->active()
					->FTNorder()
					->with(['zone.domain']),
				$this,
				NULL,
				($this->role_id === self::NODE_ZC) ? 'id' : NULL)
		);
	}

	public function system()
	{
		return $this->belongsTo(System::class);
	}

	public function uplink_hub()
	{
		return $this->belongsTo(Address::class,'hub_id','id');
	}

	public function zone()
	{
		return $this->belongsTo(Zone::class);
	}

	/* ATTRIBUTES */

	/**
	 * Return if this address is active
	 *
	 * @param bool $value
	 * @return bool
	 */
	public function getActiveAttribute(bool $value): bool
	{
		return $value && $this->getActiveDomainAttribute();
	}

	public function getActiveDomainAttribute(): bool
	{
		return $this->zone->active && $this->zone->domain->active;
	}

	/**
	 * Render the node name in full 5D
	 *
	 * @return string
	 */
	public function getFTNAttribute(): string
	{
		return sprintf('%s@%s',$this->getFTN4DAttribute(),$this->zone->domain->name);
	}

	public function getFTN2DAttribute(): string
	{
		return sprintf('%d/%d',$this->host_id ?: $this->region_id,$this->node_id);
	}

	public function getFTN3DAttribute(): string
	{
		return sprintf('%d:%s',$this->zone->zone_id,$this->getFTN2DAttribute());
	}

	public function getFTN4DAttribute(): string
	{
		return sprintf('%s.%d',$this->getFTN3DAttribute(),$this->point_id);
	}

	public function getIsDefaultRouteAttribute(): bool
	{
		return ! is_null($this->session('default'));
	}

	public function getIsDownAttribute(): bool
	{
		return $this->role & self::NODE_DOWN;
	}

	public function getIsHostedAttribute(): bool
	{
		return ! is_null($this->getPassSessionAttribute());
	}

	public function getIsHoldAttribute(): bool
	{
		return $this->role & self::NODE_HOLD;
	}

	public function getIsOwnedAttribute(): bool
	{
		return $this->system->is_owned;
	}

	public function getIsPrivateAttribute(): bool
	{
		return (! $this->system->address);
	}

	/**
	 * Determine this address' role (without status)
	 *
	 * @return int
	 * @see \App\Http\Requests\AddressAdd::class
	 */
	public function getRoleIdAttribute(): int
	{
		static $warn = FALSE;

		$val = ($this->role & self::NODE_ALL);
		$role = $this->ftn_role();

		if ($this->isRoleOverride($role)) {
			if (! $warn) {
				$warn = TRUE;
				Log::alert(sprintf('%s:! Address ROLE [%d] is not consistent with what is expected [%d] for [%s]',self::LOGKEY,$val,$role,$this->ftn));
			}

			return $val;

		} else
			return $role;
	}

	/**
	 * Return a name for the role (without status)
	 *
	 * @return string
	 */
	public function getRoleNameAttribute(): string
	{
		if ($this->getIsDownAttribute())
			return 'DOWN';
		if ($this->getIsHoldAttribute())
			return 'HOLD';
		if ($this->getIsPrivateAttribute())
			return 'PVT';

		switch ($this->role_id) {
			case self::NODE_ZC:
				return 'ZC';
			case self::NODE_RC:
				return 'RC';
			case self::NODE_NC:
				return 'NC';
			case self::NODE_HC:
				return 'HUB';
			case self::NODE_NN:
				return 'NODE';
			case self::NODE_POINT:
				return 'POINT';
			default:
				return $this->role_id;
		}
	}

	public function getPassFixAttribute(): ?string
	{
		return strtoupper($this->session('fixpass'));
	}

	public function getPassPacketAttribute(): ?string
	{
		return strtoupper($this->session('pktpass'));
	}

	public function getPassSessionAttribute(): ?string
	{
		return $this->session('sespass');
	}

	public function getPassTicAttribute(): ?string
	{
		return strtoupper($this->session('ticpass'));
	}

	/* METHODS */

	/**
	 * Check the user's activation code for this address is correct
	 *
	 * @param User $uo
	 * @param string $code
	 * @return bool
	 */
	public function activation_check(User $uo,string $code): bool
	{
		try {
			Log::info(sprintf('%s:Checking Activation code [%s] is valid for user [%d]',self::LOGKEY,$code,$uo->id));

			return ($code === $this->activation_set($uo));

		} catch (\Exception $e) {
			Log::error(sprintf('%s:! Activation code [%s] invalid for user [%d]',self::LOGKEY,$code,$uo->id));

			return FALSE;
		}
	}

	/**
	 * Create an activation code for this address
	 *
	 * @param User $uo
	 * @return string
	 */
	public function activation_set(User $uo): string
	{
		return sprintf('%x:%s',
			$this->id,
			substr(md5(sprintf('%d:%x',$uo->id,timew($this->updated_at))),0,10)
		);
	}

	/**
	 * Find the immediate children dependent on this record
	 *
	 * @return Collection
	 */
	public function children(): Collection
	{
		// If we are a point, our parent is the boss
		switch ($this->role_id) {
			case self::NODE_NN:	// Normal Nodes -> Points
				return $this->nodes_point;

			case self::NODE_HC: // Hubs -> Normal Nodes
				return $this->nodes_hub;

			case self::NODE_NC:	// Nets -> Normal Nodes, excluding Hub's Nodes
				return $this->nodes_net->diff($this
					->nodes_net
					->filter(function($item) { return $item->role_id === Address::NODE_HC; })
					->transform(function($item) { return $item->children(); })
					->flatten());

			case self::NODE_RC:	// Regions, excluding NC's Nodes
				return $this->nodes_region->diff($this
					->nodes_region
					->filter(function($item) { return $item->role_id === Address::NODE_NC; })
					->transform(function($item) { return $item->nodes_net; })
					->flatten());

			case self::NODE_ZC:	// Zones, excluding RC's Nodes
				return $this->nodes_zone->diff($this
					->nodes_zone
					->filter(function($item) { return $item->role_id === Address::NODE_RC; })
					->transform(function($item) { return $item->nodes_region; })
					->flatten());
		}

		return new Collection;
	}

	/**
	 * Find who we should forward mail onto, taking into account session details that we have
	 *
	 * @return Collection
	 * @throws \Exception
	 */
	public function downlinks(): Collection
	{
		// We have no session data for this address, by definition it has no children
		if (! $this->is_hosted && (! our_address()->pluck('id')->contains($this->id)))
			return new Collection;

		// If this system is not marked to default route for this address
		if (! $this->is_default_route) {
			$children = $this->children();

		// We route everything for this domain
		} else {
			$children = self::select('addresses.*')
				->join('zones',['zones.id'=>'addresses.zone_id'])
				->where('addresses.id','<>',$this->id)
				->where('domain_id',$this->zone->domain_id)
				->with(['zone.domain'])
				->active()
				->FTNorder()
				->get();
		}

		// If there are no children
		if (! $children->count())
			return new Collection;

		// Exclude links and their children.
		$exclude = collect();
		foreach (our_nodes($this->zone->domain)->merge(our_address($this->zone->domain)) as $o) {
			// If this address is in our list, remove it and it's children
			if ($children->contains($o)) {
				$exclude = $exclude->merge($o->children());
				$exclude->push($o);
			}
		}

		return $children->filter(function($item) use ($exclude) { return ! $exclude->pluck('id')->contains($item->id);});
	}

	/**
	 * List of all our nodes and their children
	 *
	 * @return \Illuminate\Support\Collection
	 * @throws \Exception
	 */
	public function downstream(): \Illuminate\Support\Collection
	{
		return $this->downlinks()->transform(function($item) {
			return $item->nodes()->push($item);
		})->flatten();
	}

	/**
	 * Files waiting to be sent to this system
	 *
	 * @return Collection
	 */
	public function dynamicWaiting(): Collection
	{
		return $this->dynamics()
			->where('next_at','<=',Carbon::now())
			->where('active',TRUE)
			->get();
	}

	/**
	 * Echomail waiting to be sent to this system
	 *
	 * @param int|null $max
	 * @return Builder
	 */
	public function echomailWaiting(int $max=NULL): Builder
	{
		$echomails = $this
			->UncollectedEchomail()
			->select('echomails.id')
			->where('addresses.id',$this->id)
			->when($max,function($query) use ($max) { return $query->limit($max); })
			->groupBy(['echomails.id'])
			->get();

		return Echomail::whereIn('id',$echomails->pluck('id'));
	}

	/**
	 * Files waiting to be sent to this system
	 *
	 * @return Collection
	 */
	public function filesWaiting(): Collection
	{
		return $this->file_seen()
			->whereNull('sent_at')
			->whereNotNull('export_at')
			->get();
	}

	/**
	 * Work out what role this FTN should have
	 *
	 * @return int|null
	 */
	private function ftn_role(): ?int
	{
		$role = NULL;

		// If we have a point address, we're a point
		if ($this->point_id)
			$role = self::NODE_POINT;

		// If we have a node_id, we're either a Node or a Hub
		elseif ($this->node_id) {
			$role = ($this->nodes_hub->count())
				? self::NODE_HC
				: ((($this->role & Address::NODE_ALL) === self::NODE_HC) ? self::NODE_HC : self::NODE_NN);

		// point_id and node_id are zero
		// If our region_id !== host_id, and are not zero, and node_id/point_id === 0, we are an NC
		} elseif (($this->region_id !== $this->host_id) && $this->host_id) {
			$role = self::NODE_NC;

		// point_id and node_id are zero
		} elseif (($this->region_id === $this->host_id) && $this->host_id) {
			$role = self::NODE_RC;

		// point_id and node_id are zero
		} elseif (($this->region_id === $this->host_id) && (! $this->host_id)) {
			$role = self::NODE_ZC;
		}

		if (is_null($role))
			Log::alert(sprintf('%s:! Address ROLE [%d] could not be determined for [%s]',self::LOGKEY,($this->role & Address::NODE_ALL),$this->ftn));

		return $role;
	}

	/**
	 * Get echomail for this node
	 *
	 * @return Packet|null
	 * @throws \Exception
	 * @todo If we export to uplink hubs without our address in the seenby, they should send the message back to
	 *       us with their seenby's.
	 */
	public function getEchomail(): ?Packet
	{
		if (($num=$this->echomailWaiting())->count()) {
			Log::info(sprintf('%s:= Got [%d] echomails for [%s] for sending',self::LOGKEY,$num->count(),$this->ftn));

			// Limit to max messages
			if ($num->count() > $this->system->pkt_msgs)
				Log::notice(sprintf('%s:= Only sending [%d] echomails for [%s]',self::LOGKEY,$this->system->pkt_msgs,$this->ftn));

			return $this->system->packet($this)->mail($num->take($this->system->pkt_msgs)->get());
		}

		return NULL;
	}

	/**
	 * Get netmail for this node (including it's children)
	 *
	 * @return Packet|null
	 * @throws \Exception
	 */
	public function getNetmail(): ?Packet
	{
		if (($num=$this->netmailAlertWaiting())->count()) {
			Log::debug(sprintf('%s:= Packaging [%d] netmail alerts to [%s]',self::LOGKEY,$num->count(),$this->ftn));

			$msgs = $num->get();

			// Find any message that defines a packet password
			$pass = $msgs
				->map(function($item) {
					$passpos = strpos($item->subject,':');
					return (($passpos > 0) && ($passpos <= 8)) ? substr($item->subject,0,$passpos) : NULL;
				})
				->filter()
				->pop();

			Log::debug(sprintf('%s:= Overwriting system packet password with [%s] for [%s]',self::LOGKEY,$pass,$this->ftn));

			return $this->system->packet($this,$pass)->mail(
				$msgs->filter(fn($item)=>preg_match("/^{$pass}:/",$item->subject))
					->transform(function($item) use ($pass) {
						$item->subject = preg_replace("/^{$pass}:/",'',$item->subject);
						return $item;
					})
			);
		}

		if (($num=$this->netmailWaiting())->count()) {
			Log::debug(sprintf('%s:= Got [%d] netmails for [%s] for sending',self::LOGKEY,$num->count(),$this->ftn));

			// Limit to max messages
			if ($num->count() > $this->system->pkt_msgs)
				Log::alert(sprintf('%s:= Only sending [%d] netmails for [%s]',self::LOGKEY,$this->system->pkt_msgs,$this->ftn));

			return $this->system->packet($this)->mail($num->take($this->system->pkt_msgs)->get());
		}

		return NULL;
	}

	public function isRoleOverride(int $role=NULL): bool
	{
		$val = ($this->role & self::NODE_ALL);
		$role = $role ?: $this->ftn_role();

		return ($val && ($role !== $val)) || (! $role);
	}

	/**
	 * Netmail waiting to be sent to this system
	 *
	 * @return Builder
	 * @throws \Exception
	 */
	public function netmailWaiting(): Builder
	{
		$netmails = $this
			->UncollectedNetmail()
			->select('netmails.id')
			->whereIn('addresses.id',$this->downlinks()->add($this)->pluck('id'))
			->groupBy(['netmails.id'])
			->get();

		return Netmail::whereIn('id',$netmails->pluck('id'));
	}

	/**
	 * Netmail alerts waiting to be sent to this system
	 *
	 * @return Builder
	 * @throws \Exception
	 * @note The packet password to use is on the subject line for these alerts
	 */
	public function netmailAlertWaiting(): Builder
	{
		$netmails = $this
			->UncollectedNetmail()
			->whereRaw(sprintf('(flags & %d) > 0',Message::FLAG_LOCAL))
			->whereRaw(sprintf('(flags & %d) > 0',Message::FLAG_PKTPASSWD))
			->whereRaw(sprintf('(flags & %d) = 0',Message::FLAG_SENT))
			->select('netmails.id')
			->whereIn('addresses.id',$this->downlinks()->add($this)->pluck('id'))
			->groupBy(['netmails.id'])
			->get();

		return Netmail::whereIn('id',$netmails->pluck('id'));
	}

	public function nodes(): Collection
	{
		switch ($this->role_id) {
			case self::NODE_NN:
				return $this->nodes_point;

			case self::NODE_HC:
				return $this->nodes_hub;

			case self::NODE_NC:
				return $this->nodes_net;

			case self::NODE_RC:
				return $this->nodes_region;

			case self::NODE_ZC:
				return $this->nodes_zone;

			default:
				return new Collection;
		}
	}

	/**
	 * Find the immediate parent for this node.
	 *
	 * @return Address|null
	 * @throws \Exception
	 */
	public function parent(): ?Address
	{
		// If we are a point, our parent is the boss
		switch ($this->role_id) {
			case self::NODE_POINT:	// BOSS Node
				return Address::active()
					->where('zone_id',$this->zone_id)
					->where('host_id',$this->host_id)
					->where('node_id',$this->node_id)
					->where('point_id',0)
					->single();

			case self::NODE_NN:	// HUB if it exists, otherwise NC
				if ($this->uplink_hub)
					return $this->uplink_hub;

				// Else fall through

			case self::NODE_HC: // RC
				return Address::active()
					->where('zone_id',$this->zone_id)
					->where('host_id',$this->host_id)
					->where('node_id',0)
					->where('point_id',0)
					->single();

			case self::NODE_NC:	// RC
				return Address::active()
					->where('zone_id',$this->zone_id)
					->where('region_id',$this->region_id)
					->where('host_id',$this->region_id)
					->where('node_id',0)
					->where('point_id',0)
					->single();

			case self::NODE_RC:	// ZC
				return Address::active()
					->where('zone_id',$this->zone_id)
					->where('region_id',0)
					->where('node_id',0)
					->where('point_id',0)
					->single();

			default:
				return NULL;
		}
	}

	/**
	 * Retrieve the address session details/passwords
	 *
	 * @param string $type
	 * @return string|null
	 */
	private function session(string $type): ?string
	{
		return ($this->exists && ($x=$this->system->sessions->where('id',$this->zone_id)->first())) ? ($x->pivot->{$type} ?: '') : NULL;
	}

	/**
	 * Get the appropriate parent for this address, taking into account who we have session information with
	 *
	 * @return Address|$this|null
	 * @throws \Exception
	 */
	public function uplink(): ?Address
	{
		// If it is our address
		if (our_address()->contains($this))
			return NULL;

		// If we have session password, then we are the parent
		if ($this->is_hosted)
			return $this;

		if ($x=$this->parent()?->uplink()) {
			return $x;

		} else {
			$sz = SystemZone::whereIn('zone_id',$this->domain->zones->pluck('id'))
				->where('default',TRUE)
				->single();

			return $sz?->system->addresses->sortBy('security')->last();
		}
	}
}