<?php

namespace App\Classes\File;

use Illuminate\Support\Arr;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Storage;
use Symfony\Component\HttpFoundation\File\Exception\FileException;

use App\Classes\{File,Protocol};
use App\Classes\FTN\{InvalidPacketException,Packet};
use App\Exceptions\FileGrewException;
use App\Jobs\{MessageProcess,TicProcess};
use App\Models\Address;

/**
 * Object representing the files we are receiving
 *
 * @property-read resource $fd
 * @property-read int total_recv
 * @property-read int total_recv_bytes
 */
final class Receive extends Item
{
	private const LOGKEY = 'IR-';

	private const compression = [
		'BZ2',
		'GZ',
	];

	private Address $ao;
	private Collection $list;
	private ?Item $receiving;

	private string $file;			// Local filename for file received
	/** @var ?string The compression used by the incoming file */
	private ?string $comp;
	/** @var string|null The compressed data received */
	private ?string $comp_data;

	public function __construct()
	{
		// Initialise our variables
		$this->list = collect();
		$this->receiving = NULL;
	}

	public function __get($key)
	{
		switch ($key) {
			case 'fd':
				return is_resource($this->f);

			case 'filepos':
				return $this->file_pos;

			case 'mtime':
			case 'name':
			case 'size':
				return $this->receiving?->{'file_'.$key};

			case 'name_size_time':
				return sprintf('%s %lu %lu',$this->name,$this->size,$this->mtime);

			case 'to_get':
				return $this->list
					->filter(function($item) { return ($item->action & self::I_RECV) && $item->received === FALSE; })
					->count();

			case 'total_recv':
				return $this->list
					->filter(function($item) { return ($item->action & self::I_RECV) && $item->received === TRUE; })
					->count();

			case 'total_recv_bytes':
				return $this->list
					->filter(function($item) { return ($item->action & self::I_RECV) && $item->received === TRUE; })
					->sum(function($item) { return $item->size; });

			default:
				throw new \Exception('Unknown key: '.$key);
		}
	}

	/**
	 * Close the file descriptor for our incoming file
	 *
	 * @throws \Exception
	 */
	public function close(): void
	{
		if (! $this->receiving)
			throw new \Exception('No file to close');

		if ($this->f) {
			if ($this->file_pos !== $this->receiving->size) {
				Log::warning(sprintf('%s:- Closing [%s], but missing [%d] bytes',self::LOGKEY,$this->receiving->name,$this->receiving->size-$this->file_pos));
				$this->receiving->incomplete = TRUE;
			}

			$this->receiving->received = TRUE;

			$end = time()-$this->start;
			Log::debug(sprintf('%s:- Closing [%s], received in [%d]',self::LOGKEY,$this->receiving->name,$end));

			if ($this->comp)
				Log::info(sprintf('%s:= Compressed file using [%s] was [%d] bytes (%d). Compression rate [%3.2f%%]',self::LOGKEY,$this->comp,$x=strlen($this->comp_data),$this->receiving->size,$x/$this->receiving->size*100));

			fclose($this->f);
			// Set our mtime
			touch($this->file,$this->mtime);
			$this->file_pos = 0;
			$this->f = NULL;

			// If the packet has been received but not the right size, dont process it any more.

			// If we received a packet, we'll dispatch a job to process it
			if (! $this->receiving->incomplete)
				switch ($this->receiving->type) {
					case self::IS_ARC:
					case self::IS_PKT:
						Log::info(sprintf('%s:- Processing mail %s [%s]',self::LOGKEY,$this->receiving->type === self::IS_PKT ? 'PACKET' : 'ARCHIVE',$this->file));

						try {
							$f = new File($this->file);
							$processed = FALSE;

							foreach ($f as $packet) {
								$po = Packet::process($packet,Arr::get(stream_get_meta_data($packet),'uri'),$f->itemSize(),$this->ao->system);

								// Check the messages are from the uplink
								if ($this->ao->system->addresses->search(function($item) use ($po) { return $item->id === $po->fftn_o->id; }) === FALSE) {
									Log::error(sprintf('%s:! Packet [%s] is not from this link? [%d]',self::LOGKEY,$po->fftn_o->ftn,$this->ao->system_id));

									break;
								}

								// Check the packet password
								if ($this->ao->session('pktpass') != $po->password) {
									Log::error(sprintf('%s:! Packet from [%s] with password [%s] is invalid.',self::LOGKEY,$this->ao->ftn,$po->password));

									// @todo Generate message to system advising invalid password - that message should be sent without a packet password!
									break;
								}

								Log::info(sprintf('%s:- Packet has [%d] messages',self::LOGKEY,$po->count()));

								// Queue messages if there are too many in the packet.
								if ($queue = ($po->count() > config('app.queue_msgs')))
									Log::info(sprintf('%s:- Messages will be sent to the queue for processing',self::LOGKEY));

								$count = 0;
								foreach ($po as $msg) {
									Log::info(sprintf('%s:- Mail from [%s] to [%s]',self::LOGKEY,$msg->fftn,$msg->tftn));

									// @todo Quick check that the packet should be processed by us.
									// @todo validate that the packet's zone is in the domain.

									try {
										// Dispatch job.
										if ($queue)
											MessageProcess::dispatch($msg,$f->pktName());
										else
											MessageProcess::dispatchSync($msg,$f->pktName());

									} catch (\Exception $e) {
										Log::error(sprintf('%s:! Got error dispatching message [%s] (%d:%s-%s).',self::LOGKEY,$msg->msgid,$e->getLine(),$e->getFile(),$e->getMessage()));
									}

									$count++;
								}

								if ($count === $po->count())
									$processed = TRUE;
							}

							if (! $processed) {
								Log::alert(sprintf('%s:- Not deleting packet [%s], it doesnt seem to be processed?',self::LOGKEY,$this->file));

							// If we want to keep the packet, we could do that logic here
							} elseif (! config('app.packet_keep')) {
								Log::debug(sprintf('%s:- Deleting processed packet [%s]',self::LOGKEY,$this->file));
								unlink($this->file);
							}

						} catch (InvalidPacketException $e) {
							Log::error(sprintf('%s:- Not deleting packet [%s], as it generated an InvalidPacketException',self::LOGKEY,$this->file),['e'=>$e->getMessage()]);

						} catch (\Exception $e) {
							Log::error(sprintf('%s:- Not deleting packet [%s], as it generated an uncaught exception',self::LOGKEY,$this->file),['e'=>$e->getMessage()]);
						}

						break;

					case self::IS_TIC:
						Log::info(sprintf('%s:- Processing TIC file [%s]',self::LOGKEY,$this->file));

						// Queue the tic to be processed later, in case the referenced file hasnt been received yet
						TicProcess::dispatch($this->file);

						break;

					default:
						Log::debug(sprintf('%s:- Leaving file [%s] in the inbound dir',self::LOGKEY,$this->file));
				}
		}

		$this->receiving = NULL;
	}

	/**
	 * Open the file descriptor to receive a file
	 *
	 * @param Address $ao
	 * @param bool $check
	 * @param string|null $comp If the incoming file will be compressed
	 * @return int
	 * @throws \Exception
	 * @todo $comp should be parsed, in case it contains other items
	 */
	public function open(Address $ao,bool $check=FALSE,string $comp=NULL): int
	{
		// @todo implement return 4 - SUSPEND(?) file
		// @todo Change to use Storage::class()
		if (! $this->receiving)
			throw new \Exception('No files currently receiving');

		$this->comp_data = '';
		$this->comp = $comp;

		/*
		if ($this->receiving->size <= self::MAX_COMPSIZE) {
			$this->comp = $comp;

		} else {
			Log::alert(sprintf('%s:- Compression [%s] disabled for file [%s], its size is too big [%d]',self::LOGKEY,$comp,$this->receiving->name,$this->receiving->size));
		}
		*/

		if ($this->comp && (! in_array($this->comp,self::compression)))
			throw new \Exception('Unsupported compression:'.$this->comp);
		elseif ($this->comp)
			Log::debug(sprintf('%s:- Receiving file with [%s] compression',self::LOGKEY,$this->comp));

		$this->ao = $ao;
		$this->file_pos = 0;
		$this->start = time();
		$this->file = sprintf('storage/app/%s',$this->local_path($ao));

		if (file_exists($this->file)
			&& (Storage::disk('local')->lastModified($this->local_path($ao)) === $this->mtime)
			&& (Storage::disk('local')->size($this->local_path($ao)) === $this->size))
		{
			Log::alert(sprintf('%s:- File already exists - skipping [%s]', self::LOGKEY, $this->file));
			return Protocol::FOP_GOT;

		} elseif (file_exists($this->file) && (Storage::disk('local')->size($this->local_path($ao)) > 0)) {
			Log::alert(sprintf('%s:- File exists with different details - skipping [%s]',self::LOGKEY,$this->file));
			return Protocol::FOP_SKIP;

		} else {
			// @todo I dont think we are enabling resumable sessions - need to check
			Log::debug(sprintf('%s:- Opening [%s]',self::LOGKEY,$this->file));
		}

		// If we are only checking, we'll return (NR mode)
		if ($check)
			return Protocol::FOP_OK;

		$this->f = fopen($this->file,'wb');
		if (! $this->f) {
			Log::error(sprintf('%s:! Unable to open file [%s] for writing',self::LOGKEY,$this->receiving->name));
			return Protocol::FOP_ERROR;
		}

		Log::info(sprintf('%s:= open - File [%s] opened for writing',self::LOGKEY,$this->receiving->name));
		return Protocol::FOP_OK;
	}

	/**
	 * Add a new file to receive
	 *
	 * @param array $file
	 * @throws \Exception
	 */
	public function new(array $file): void
	{
		Log::debug(sprintf('%s:+ new [%s]',self::LOGKEY,join('|',$file)));

		if ($this->receiving)
			throw new \Exception('Can only have 1 file receiving at a time');

		$o = new Item($file,self::I_RECV);
		$this->list->push($o);

		$this->receiving = $o;
	}

	private function local_path(Address $ao): string
	{
		return sprintf('%s/%04X-%s',config('app.fido'),$ao->id,$this->receiving->recvas);
	}

	/**
	 * Write data to the file we are receiving
	 *
	 * @param string $buf
	 * @return bool
	 * @throws \Exception
	 */
	public function write(string $buf): bool
	{
		if (! $this->f)
			throw new \Exception('No file open for write');

		$data = '';

		// If we are using compression mode, then we need to buffer the right until we have everything
		if ($this->comp) {
			$this->comp_data .= $buf;

			// See if we can uncompress the data yet
			switch ($this->comp) {
				case 'BZ2':
					if (($data=bzdecompress($this->comp_data,TRUE)) === FALSE)
						throw new FileException('BZ2 decompression failed?');
					elseif (is_numeric($data))
						throw new FileException(sprintf('BZ2 decompression failed with (:%d)?',$data));

					break;

				case 'GZ':
					if (($data=gzdeflate($this->comp_data)) === FALSE)
						throw new FileException('BZ2 decompression failed?');

					break;
			}

			// Compressed file grew
			if (! strlen($data)) {
				if (strlen($this->comp_data) > $this->receiving->size) {
					fclose($this->f);
					$this->f = NULL;

					throw new FileGrewException(sprintf('Error compressed file grew, rejecting [%d] -> [%d]', strlen($this->comp_data), $this->receiving->size));
				}

				return TRUE;
			}

		} else {
			$data = $buf;
		}

		if ($this->file_pos+strlen($data) > $this->receiving->size)
			throw new \Exception(sprintf('Too many bytes received [%d] (%d)?',$this->file_pos+strlen($buf),$this->receiving->size));

		$rc = fwrite($this->f,$data);

		if ($rc === FALSE)
			throw new FileException('Error while writing to file');

		$this->file_pos += $rc;
		Log::debug(sprintf('%s:- Write [%d] bytes, file pos now [%d] of [%d] (%d)',self::LOGKEY,$rc,$this->file_pos,$this->receiving->size,strlen($buf)));

		if (strlen($this->comp_data) > $this->receiving->size)
			Log::alert(sprintf('%s:- Compression grew the file during transfer (%d->%d)',self::LOGKEY,$this->receiving->size,strlen($this->comp_data)));

		return TRUE;
	}
}