load('smbdefs.js');

// ANSItex specific includes
load('ansitex/load/defs.js');
load('ansitex/load/funcs.js');

/**
 * Work out which key should be used for a page, or validate if a key used is valid
 *
 * @param page
 * @param signed
 * @returns {*}
 */
function getKey(page,signed) {
	log(LOG_DEBUG,'+ CHECKING key:'+signed+' for page: '+page);

	var f = new File(file_cfgname(system.mods_dir,'ansitex/ctrl/videotex.ini'));
	var match = '';

	if (f.open("r")) {
		var BreakException = {};

		// Default Key
		var key = f.iniGetValue('prefix','key');

		try {
			f.iniGetSections("prefix:").forEach(function (prefix) {
				var p = prefix.substr(7);
				var pk = f.iniGetValue(prefix, 'Key', '');
				var re = new RegExp('^' + p, 'g');

				// If it was signed, is the key a value one
				if (signed && signed.length) {
					if (pk === signed) {
						//print('SIGNED key is valid:' + signed);
						key = signed;
						throw BreakException;
					}

				// Which key should sign this page
				} else if (page.toString().match(re) && (p.length > match.length)) {
					match = p;
					key = pk;
				}
			});

		} catch (e) {
			if (e !== BreakException) throw e;
		}
	}

	f.close();

	log(LOG_DEBUG,'- key:'+key);
	return key;
}

/**
 * Export message from message base
 *
 * @param msgbase
 */
function msgBaseExport(msgbase) {
	var ini = new File(msgbase.file+'.ini');
	var i=0;

	if (ini.open("r")) {
		export_ptr=ini.iniGetValue('videotex','export_ptr',0);
		ini.close();

	} else {
		log(LOG_ERROR,'! ERROR: Unable to open INI for ['+msgbase.file+']');
	}

	// If pointer doesnt exist, reset it from the message base.
	if (export_ptr === undefined) {
		var f = new File(file_getcase(msgbase.file+'.sbl'));

		if (f.open('rb')) {
			export_ptr = f.readBin(4);
			f.close();
		}
	}

	highest = export_ptr;
	var total_msgs = msgbase.total_msgs;

	log(LOG_DEBUG,'| msgBaseExport: export_ptr='+export_ptr+'|last_msg='+msgbase.last_msg+'|total_msgs='+total_msgs);

	if (msgbase.last_msg >= export_ptr)
		i = total_msgs-(msgbase.last_msg-export_ptr);

	for (; i<total_msgs; i++) {
		if (js.terminated)
			break;

		var idx = msgbase.get_msg_index(true,i);
		if (! idx) {
			log(LOG_ERROR,'! ERROR: Reading index of msg offset ['+i+'] : ['+msgbase.error+']');
			continue;
		}

		// Skip message until we get to our last one read.
		if (idx.number <= export_ptr)
			continue;

		if (idx.number > highest)
			highest = idx.number;

		// Only check messages from Videotex
		if (idx.from !== crc16_calc('videotex')) {
			log(LOG_DEBUG,'! IGNORING: Message offset ['+i+'] in ['+msgbase.file+']');
			continue;
		}

		// Get the message header
		var hdr = msgbase.get_msg_header(true,i);

		// Ignore deleted messages
		if (hdr.attr&MSG_DELETE) {
			log(LOG_DEBUG,'! IGNORING: Deleted message offset ['+i+'] in ['+msgbase.file+']');
			continue;
		}

		// Ignore locally posted messages
		if (! hdr.from_net_type) {
			log(LOG_DEBUG,'! IGNORING: Local message offset ['+i+'] in ['+msgbase.file+']');
			continue;
		}

		log(LOG_DEBUG,'+ PROCESSING: Message offset ['+i+'] in ['+msgbase.file+'] from ['+hdr.from_net_addr+'] ('+hdr.subject+')');

		var body = msgbase.get_msg_body(
			/* by_offset: */true,
			i,
			/* strip Ctrl-A */true,
			/* rfc822-encoded: */false,
			/* include tails: */false);

		t = new File(system.temp_dir+'videotex.gpg');
		if (! t.open('w+')) {
			log(LOG_ERROR,'! ERROR: Unable to open temp file ['+system.temp_dir+'videotex.gpg'+']');
			exit(1);
		}

		try {
			t.write(base64_decode(body));
			t.close();

		} catch (error) {
			log(LOG_ERROR,error);
			exit(1);
		}

		// Check if the signature is good
		result = system.exec('gpgv --keyring '+system.mods_dir+'ansitex/keys/pubring.kbx '+system.temp_dir+'videotex.gpg');

		if (result !== 0 ) {
			log(LOG_ERROR,'! ERROR: Invalid Signature for message offset ['+i+'] in ['+msgbase.file+']');
			continue;
		}

		if (file_exists(system.temp_dir+'videotex.tex'))
			file_remove(system.temp_dir+'videotex.tex')

		// Check that the signature is allowed to author the frames
		result = system.exec('gpg --homedir '+system.mods_dir+'ansitex/keys --batch --status-fd 2 -o '+system.temp_dir+'videotex.tex '+system.temp_dir+'videotex.gpg 2>'+system.temp_dir+'videotex.log');

		if (result !== 0 ) {
			log(LOG_ERROR,'! ERROR: Failed to extract message offset ['+i+'] in ['+msgbase.file+']');
			continue;
		}

		// Put frame in place.
		f = new File(system.temp_dir+'videotex.tex');
		if (! f.exists || ! f.open('r')) {
			log(LOG_ERROR,'! ERROR: Failed to open frame for message offset ['+i+'] in ['+msgbase.file+']');
			exit(1);
		}

		try {
			frame = JSON.parse(f.read());
			x = new Frame(0);
			frame.render = x.render;

			// @todo Figure out how to delete this duplicate code
			Object.defineProperty(frame,'page', {
				get: function() {return this.frame+this.index}
			});

			x = null;

		} catch (error) {
			log(LOG_ERROR,error);
			continue;
		}

		// Get the key that signed the message
		f = new File(system.temp_dir+'videotex.log');
		if (! f.exists || ! f.open('r')) {
			log(LOG_ERROR,'! ERROR: Failed to open gpg log for message offset ['+i+'] in ['+msgbase.file+']');
			continue;
		}

		var signed = '';
		while (string = f.readln()) {
			var matches = string.match(/\s+GOODSIG\s+.*\<(.*)\>/);

			if (matches) {
				signed = matches[1];
			}
		}
		f.close();

		if (signed !== getKey(frame.frame,signed)) {
			log(LOG_ERROR,'! ERROR: Key ['+signed+' is not authorised for message offset ['+i+'] in ['+msgbase.file+']');
			continue;
		}

		// Save the frame.
		log(LOG_INFO,'Updating page ['+frame.page+'] from ['+hdr.from_net_addr+'] signed with ['+signed+']');
		saveFrame(frame);
	}

	if (ini.open(file_exists(ini.name) ? 'r+':'w+')) {
		ini.iniSetValue('videotex','export_ptr',highest);
		ini.close();

	} else {
		log(LOG_ERROR,'! ERROR: Unable to save to INI for ['+msgbase.file+']');
	}
}

var msgbase = new MsgBase(findMsgBase(null).code);
log(LOG_DEBUG,'+ ANSITEX_EXPORT: Open message base in ['+msgbase.file+']');

if (! msgbase.open()) {
	log(LOG_ERROR,'! ERROR: Unable to open ['+msgbase.file+']');
	exit(-1);
}

msgBaseExport(msgbase);
msgbase.close();