const PAGE_LENGTH = 4;			// The size of our page tag.
const PAGE_LAST_KEY = 'last_page';
const MAX_PAGE_NUM = 9999;

// Our message bases
function MsgAreas() {
	'use strict';

	this.areas = [];
	this.areas_excluded = [];
	var zone_id;
	var zone_name;
	var ma;

	for(var g in msg_area.grp_list) {
		if (msg_area.grp_list[g].name.indexOf(':') !== -1) {
			zone_id = msg_area.grp_list[g].name.split(':')[0];
			zone_name = msg_area.grp_list[g].name.split(':')[1];

			for (var a in msg_area.grp_list[g].sub_list) {
				if (msg_area.grp_list[g].sub_list[a].name.indexOf(':') !== -1) {
					ma = new MsgArea();
					ma.zone_id = zone_id;
					ma.zone_name = zone_name;
					ma.area_id = msg_area.grp_list[g].sub_list[a].name.split(':')[0];
					ma.area_name = msg_area.grp_list[g].sub_list[a].name.split(':')[1];
					ma.code = msg_area.grp_list[g].sub_list[a].code;

					this.areas.push(ma);
				} else {
					this.areas_excluded.push(zone_name+':'+msg_area.grp_list[g].sub_list[a].name);
				}
			}

		} else {
			zone_name = msg_area.grp_list[g].name;

			for (var a in msg_area.grp_list[g].sub_list) {
				this.areas_excluded.push(zone_name+':'+msg_area.grp_list[g].sub_list[a].name);
			}
		}
	}
}

function MsgArea() {
	this.zone_id = undefined;
	this.zone_name = undefined;
	this.area_id = undefined;
	this.area_name = undefined;
	this.msgbase = undefined;
	this.headers = undefined;
	this.tagged_list = undefined;
	this.untagged_list = undefined;
	this.grp_number = undefined;
	this.subnum = undefined;

	Object.defineProperty(this,'code',{
		set: function(code) {
			this.msgbase = new MsgBase(code);

			if (! this.msgbase.open()) {
				writeln(code+' cannot be opened:'+this.msgbase.error);
				exit(2);
			}

			this.headers = this.msgbase.get_all_msg_headers(false,false);
			this.msgbase.close();
		}
	});

	// Get Area's full name
	Object.defineProperty(this,'full_name',{
		get: function() {
			return this.zone_name+':'+this.area_name;
		}
	});

	// Total Messages
	Object.defineProperty(this,'list',{
		get: function() {
			return this.headers ? Object.keys(this.headers) : [];
		}
	});

	// Total tagged messages
	Object.defineProperty(this,'list_tagged',{
		get: function() {
			if (this.tagged_list === undefined) {
				this.tagged_list = [];

				if (! this.headers)
					return this.tagged_list;

				for(var x in this.headers) {
					if (this.headers[x].tags && (this.headers[x].tags.length === PAGE_LENGTH)) {
						this.tagged_list.push(this.headers[x]);
						write();		// @todo This is needed for this to work?
					}
				}
			}

			return this.tagged_list;
		}
	});

	// List untagged messages
	Object.defineProperty(this,'list_untagged',{
		get: function() {
			if (this.untagged_list === undefined) {
				this.untagged_list = [];

				if (! this.headers)
					return this.untagged_list;

				for(var x in this.headers) {
					if ((! this.headers[x].tags) || (this.headers[x].tags.length !== PAGE_LENGTH)) {
						this.untagged_list.push(this.headers[x]);
						write();		// @todo This is needed for this to work?
					}
				}
			}

			return this.untagged_list;
		}
	});

	// Get Next page number
	Object.defineProperty(this,'page_next',{
		get: function() {
			var f = new File(file_cfgname(system.mods_dir,'ansitex/ctrl/videotex.ini'));
			if (! f.open('r')) {
				writeln('Unable to open ini file');
				exit(2);
			}

			var page = f.iniGetValue('zone:'+this.page_prefix,PAGE_LAST_KEY)
			f.close();

			return page ? page : '0'.repeat(PAGE_LENGTH);
		},

		set: function(page) {
			var f = new File(file_cfgname(system.mods_dir,'ansitex/ctrl/videotex.ini'));
			if (! f.open('r+')) {
				writeln('Unable to open ini file');
				exit(2);
			}

			f.iniSetValue('zone:'+this.page_prefix,PAGE_LAST_KEY,(''+page).padStart(4,'0'));
			f.close();
		}
	});

	// Our page prefix for this msg area
	Object.defineProperty(this,'page_prefix',{
		get: function() {
			return ''+this.zone_id+this.area_id;
		},
	});
}

/**
 * Get a specific message with a tag
 */
MsgArea.prototype.getMessage = function(page) {
	var msg = undefined;

	for(var x in this.headers) {
		if (this.headers[x].tags === page) {
			msg = this.headers[x];
			break;
		}
		write();	// @todo This is needed for this to work?
	}

	if (! msg)
		return undefined;

	if (! this.msgbase.open()) {
		writeln(code+' cannot be opened:'+this.msgbase.error);
		return undefined;
	}

	msg.grp_number = this.msgbase.cfg.grp_number;
	var cfg = this.msgbase.cfg;
	msg.subnum = msg_area.grp_list[cfg.grp_number].sub_list.filter(function(x) { return x.number === cfg.number; }).pop().index;
	msg.content = this.msgbase.get_msg_body(false,msg.number,false,false,true,true);
	this.msgbase.close();

	return msg;
}

/**
 * Tag messages with a frame number
 *
 * @returns {boolean}
 */
MsgArea.prototype.tag_msgs = function() {
	const MAX_PAGE_NUM = 9999;

	var msgs = this.list_untagged;

	// See if we need to something
	if (! msgs.length)
		return;

	if (! this.msgbase.open()) {
		writeln(code+' cannot be opened:'+this.msgbase.error);
		return false;
	}

	var page_next = this.page_next;

	for(var x in msgs) {
		msgs[x].tags = (''+(page_next)).padStart(4,'0');

		if(! this.msgbase.put_msg_header(msgs[x].number,msgs[x])) {
			writeln('ERROR:'+this.msgbase.error);

		} else {
			page_next++;
			if (page_next > MAX_PAGE_NUM)
				page_next = 0;
		}
	}

	this.msgbase.close();
	this.page_next = page_next;

	return true;
}

MsgAreas.prototype.getMessage = function(page) {
	if (page === undefined)
		return undefined;

	var zone = page.substr(0,4);
	var echo = page.substr(4,2);
	var page = page.substr(6);

	area = this.areas.filter(function(x) {
		return x.zone_id === zone && x.area_id === echo;
	})[0]

	return area ? area.getMessage(page) : undefined;
}