const PAGE_LENGTH = 4;				// The size of our page tag as stored in the msgbase for echomail/netmail
const PAGE_LAST_KEY = 'last_page';	// Last page which has the latest message
const MAX_PAGE_NUM = 9999;			// Maximum page number. @todo Can this be changed to '9'.repeat(PAGE_LENGTH)?

// 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);
			}
		}
	}

	Object.defineProperty(this,'list',{
		get: function() {
			writeln('Areas that we are NOT managing mail:'+this.areas_excluded.length);
			writeln('Areas that we ARE managing mail:'+this.areas.length);

			for(var x in this.areas_excluded) {
				writeln(x+':'+((this.areas_excluded[x].area_name === undefined)
					? this.areas_excluded[x]
					: JSON.stringify(this.areas_excluded[x])));
			}
		}
	});
}

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;

	/**
	 * Build a MsgArea once we are given the code
	 */
	Object.defineProperty(this,'code',{
		set: function(code) {
			this.msgbase = new MsgBase(code);

			try {
				if (this.msgbase.open()) {
					headers = this.msgbase.get_all_msg_headers(false,false) || [];

					// Just take the last MAX_MESSAGES
					this.headers = Object.keys(headers).slice(-(MAX_PAGE_NUM+1)).map(function(key) { return headers[key]; });
					headers = undefined;

					this.msgbase.close();

				} else {
					log(LOG_ERROR,code+' cannot be opened:'+this.msgbase.error);
					this.headers = [];
				}

			} catch (e) {
				log(LOG_ERROR,code+' cannot be opened:'+e.message);
				this.headers = [];
			}
		}
	});

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

	// 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('prefix:'+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('prefix:'+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;
		},
	});
}

/**
 * Unread messages [1..]
 * Array key 0 returns the last read message
 *
 * @returns {*[]}
 */
MsgArea.prototype.newMsgs = function() {
	var msgs = [];
	var stats = this.getUserStats();
	//log(LOG_DEBUG,'Users last_read pointer: '+JSON.stringify(stats.last_read));

	for(var x in this.list_tagged) {
		// Advance past our last scan_ptr
		if (this.list_tagged[x].number <= stats.last_read)
			continue;

		msgs.push(this.list_tagged[x]);

		write();		// @todo This is needed for this to work?
	}

	return msgs;
}

/**
 * New Messages for the logged in user
 */
MsgArea.prototype.newMsgsToMe = function() {
	var msgs = [];
	var stats = this.getUserStats();
	var last = null;
	//log(LOG_DEBUG,'Users scan_ptr pointer: '+JSON.stringify(stats.scan_ptr));

	for(var x in this.list_tagged) {
		// Advance past our last scan_ptr
		if (this.list_tagged[x].number <= stats.scan_ptr) {
			if ((this.list_tagged[x].to === user.name) || (this.list_tagged[x].to === user.alias))
				last = x;

			continue;
		}

		// Add our previous to me message
		if (msgs.length === 0)
			msgs.push(last !== null ? this.list_tagged[last] : []);

		if ((this.list_tagged[x].to === user.name) || (this.list_tagged[x].to === user.alias))
			msgs.push(this.list_tagged[x]);

		write();		// @todo This is needed for this to work?
	}

	return msgs;
}

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

	for(var x in this.list_tagged) {
		if (this.list_tagged[x].tags === page) {
			msg = this.list_tagged[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;
}

/**
 * Get a message page by pointer
 *
 * @param number
 * @returns {string}
 */
MsgArea.prototype.getMessagePage = function(number) {
	log(LOG_DEBUG,'Get Message Page with number ['+number+']');

	var r;

	for (var x in this.list_tagged) {
		if (this.list_tagged[x].number === number) {
			r = this.list_tagged[x];

			break;
		}
	}

	if (! r || r.tags === undefined)
		return null;

	return '1'+this.zone_id+this.area_id+r.tags;
}

MsgArea.prototype.getUserStats = function() {
	return this.msgbase.cfg ? msg_area.grp_list[this.msgbase.cfg.grp_number].sub_list[msg_area.sub[this.msgbase.cfg.code].index] : [];
}

MsgArea.prototype.MessageNext = function(page) {
	var x = null;

	if (! page)
		return undefined;

	var msgid = page.substr(7,4);

	for(x in this.list_tagged) {
		if (this.list_tagged[x].tags === msgid) {
			break;
		}

		write();	// @todo This is needed for this to work?
	}

	//log(LOG_DEBUG,'- Next Message is:'+JSON.stringify(this.list_tagged[(parseInt(x)+1)])+', msgid:'+msgid+', page:'+page+', x:'+x);

	/*
		= Our next message is either
		+ x+1 if x < this.list_tagged.length
		+ x=0 if x == this.list_tagged.length (-1)
		+ null if this.list_tagged.length == null; (thus no messages)
	 */

	return x === null ? null : this.list_tagged[(parseInt(x) === this.list_tagged.length-1) ? 0 : (parseInt(x)+1)];
}

MsgArea.prototype.MessagePrev = function(page) {
	var prev = null;
	var x = null;

	if (! page)
		return undefined;

	var msgid = page.substr(7,4);

	for(x in this.list_tagged) {
		if (this.list_tagged[x].tags === msgid) {
			break;

		} else {
			prev = x;
		}

		write();	// @todo This is needed for this to work?
	}

	/*
		= Our previous message is either
		+ prev if a tag was found, unless
		+ prev is null, in which case it is this.list_tagged.length -1
		+ null if x is still null (thus no messages)
	 */

	// If prev is still null, then our last message must be the last one, unless x is null then there are no messages
	return x === null ? null : this.list_tagged[(prev === null) ? this.list_tagged.length-1 : parseInt(prev)];
}

/**
 * Tag messages with a frame number
 * @note: May need to run jsexec with -m 32MB to overcome memory issues
 *
 * @returns {boolean}
 */
MsgArea.prototype.tag_msgs = function() {
	var msgs = this.list_untagged;

	writeln("We have "+msgs.length+" messages to tag.");

	// See if we need to tag 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;
}

MsgArea.prototype.page = function(msgid) {
	return '1'+this.page_prefix+msgid;
}

MsgAreas.prototype.getArea = function(area) {
	log(LOG_DEBUG,'- AREA:'+JSON.stringify(area));
	if (area === undefined)
		return undefined;

	var zone = (''+area).substr(1,4);
	var echo = (''+area).substr(5,2);
	log(LOG_DEBUG,'  - zone:'+zone);
	log(LOG_DEBUG,'  - echo:'+echo);

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

MsgAreas.prototype.getMessage = function(page) {
	var area = this.getArea(page);
	log(LOG_DEBUG,'  - msg:'+JSON.stringify(page.substr(7,4)));

	return area ? area.getMessage(page.substr(7,4)) : undefined;
}

MsgAreas.prototype.getUserStats = function(page) {
	var area = this.getArea(page);

	return area ? msg_area.grp_list[area.msgbase.cfg.grp_number].sub_list[msg_area.sub[area.msgbase.cfg.code].index] : undefined;
}