// History

// See https://resource.dopus.com/t/how-to-navigate-from-a-sub-folder-to-next-or-previous-sub-folder/33930/17
// 20191130 v1.0
// 20191202 v1.1 Fix bug when only 1 item at lowest level in depth > 3 structure

//-- Add some useful string methods
String.prototype.left = function(n){return this.substring(0,n);}
String.prototype.right = function(n){return this.slice(-n);}
String.prototype.before = function(s){return this.replace(new RegExp("(.*)("+s+")(.*)"),"$1");}
String.prototype.after = function(s){return this.replace(new RegExp("(.*)("+s+")(.*)"),"$3");}
String.prototype.from = function(s){return this.replace(new RegExp("(.*)("+s+")(.*)"),"$2$3");}
String.prototype.lTrim = function(s){s=s||"\\s";return this.replace(new RegExp("^("+s+"){1,}"),'');}
String.prototype.rTrim = function(s){s=s||"\\s";return this.replace(new RegExp("("+s+"){1,}$"),'');}
String.prototype.trim = function(s){return this.lTrim(s).rTrim(s);}

//-- Global Variables

var me = {
	name:"KHGo",
	version:"1.1 (December 2nd, 2019)",
	desc:"Custom folder structure navigator for Khalid Hosain",
	copyright:"(c) 2019 Aussie",
	template:"",
	minver:"12",
};
var d, cmd, dbg, dlg, fsu;

function OnInit(initData)
{
	initData.name = me.name;
	initData.version = me.version;
	initData.desc = me.desc;
	initData.copyright = me.copyright;
	initData.default_enable = true;
	
	var cmd = initData.AddCommand();
	cmd.name = me.name;
	cmd.method = "do_main";
	cmd.desc = me.desc;
	cmd.label = me.name;
	cmd.template = me.template;
	
	initData.config_desc = DOpus.create.map();
	initData.config.dbg = false;
	initData.config_desc("dbg") = 'Write trace information to "Other" log.';
}

//-- Main script code

function do_main(ScriptCommandData){
	
	d = ScriptCommandData;
	dlg = d.func.dlg;
	fsu = DOpus.FSUtil;
	cmd = DOpus.Create.Command;
	
	// Debug ?
	dbg = Script.config.dbg;
	
	// Who am I?
	if (dbg) DOpus.output(me.name+" version " + me.version + " starting..");
	
	// Check minimum version requirements
	if (!DOpus.version.AtLeast(me.minver)){
		dlg.request(me.name+" requires DOpus version " + me.minver + " or later","OK","["+me.name+"]");
		return;
	}
	
	// Process args
	me.argstring = d.cmdline.slice(me.name.length).trim();
	if (dbg) DOpus.output("argstring = "+me.argstring);
	
	// Any supplied argument should be a positive or negative integer e.g. 3 or -2
	// if the argument is missing or zero or invalid it defaults to 1. Non integer numbers are rounded down.
	n = parseInt(me.argstring);
	if ((isNaN(n)) || (n==0)) n = parseInt(1);
	if (dbg) DOpus.output("n = " + n);
	
	// Process the current folder object
	var src = d.func.sourcetab;
	var curitem, curitems = DOpus.create.vector(), curdirs = fsu.readdir(src.path.def_value);
	while (!curdirs.complete){
		curitem = curdirs.next;
		if ((curitem.is_dir) && (!curitem.fileattr.hidden)) curitems.push_back(curitem);
	}
	
	// Handle current depth = 0 (e.g. starting point is c:\)
	if (src.path.components==1){
		if (curitems.count>1){			
			var ix = (n<0) ? newix(0,n,curitems.count) : newix(0,n-1,curitems.count);
			if (dbg) DOpus.output("ix = " + ix);
			cmd.runcommand("Go "+maybe_quote(curitems(ix)));
		}
		return;
	}
	
	var parentitem, parentix, parentitems = DOpus.create.vector();
	var parentdirs = fsu.readdir(src.path.pathpart);
	while (!parentdirs.complete){
		parentitem = parentdirs.next;
		if ((parentitem.is_dir) && (!parentitem.fileattr.hidden)){
			if (parentitem==src.path.def_value) parentix = parentitems.count;
			parentitems.push_back(parentitem);
		}
	}
	if (dbg) DOpus.output("parentitems.count = " + parentitems.count);
	if (dbg) DOpus.output("parentix = " + parentix);
	
	var ix = newix(parentix,n,parentitems.count);
	
	// Handle current depth = 1 (e.g. c:\animals) or 2 (e.g. c:\animals\cats)
	if (src.path.components<4){
		if (dbg) DOpus.output("ix = " + ix);
		cmd.runcommand("Go "+maybe_quote(parentitems(ix)));
		return;
	}
	
	// Handle current depth > 3 (e.g. c:\animals\cats\burmese)
	var grandparentitem, grandparentix, grandparentitems = DOpus.create.vector();
	var str = src.path.pathpart;
	if (dbg) DOpus.output("parent = " + str);
	str = str.slice(0,str.lastIndexOf("\\"));
	if (dbg) DOpus.output("grandparent = " + str);
	var grandparentdirs = fsu.readdir(str);
	while (!grandparentdirs.complete){
		grandparentitem = grandparentdirs.next;
		if ((grandparentitem.is_dir) && (!grandparentitem.fileattr.hidden)){
			if (dbg) DOpus.output(grandparentitem);
			if (grandparentitem==src.path.pathpart) grandparentix = grandparentitems.count;
			grandparentitems.push_back(grandparentitem);
		}
	}
	if (grandparentitems.count==1) return;
	if (dbg) DOpus.output("grandparentix = " + grandparentix);
	// Establish new parent index within grandparent structure
	var ix = (n>0) ? newix(grandparentix,1,grandparentitems.count) : newix(grandparentix,-1,grandparentitems.count);
	if (dbg) DOpus.output("ix = " + ix);
	// Process new parent
	var newparentitem, newparentix, newparentitems = DOpus.create.vector();
	var newparentdirs = fsu.readdir(grandparentitems(ix));
	while (!newparentdirs.complete){
		newparentitem = newparentdirs.next;
		if ((newparentitem.is_dir) && (!newparentitem.fileattr.hidden)) newparentitems.push_back(newparentitem);
	}
	if (dbg) DOpus.output("newparentitems.count = " + newparentitems.count);
	newparentix = Math.abs(n) - 1;
	if (dbg) DOpus.output("newparentix = " + newparentix);
	if (newparentitems.count>newparentix) cmd.runcommand("Go "+maybe_quote(newparentitems(newparentix)));
	
	return;
}

//-- Functions called from main script code

function maybe_quote(str){
	// Avoid unnecessary use of quotes and always force to string type
	return (String(str).indexOf(" ")<0) ? String(str) : '"'+String(str)+'"';
}

function newix(cur,inc,n){
	// Establish the next index based on a starting point in a 0-base vector
	// and an integer increment that can be +ve or -ve. n = no of elements in the vector.
	var next = (cur+inc)%n;
	return (next<0) ? n+next : next;
}