#!/usr/bin/env node

var fs=require("fs"),util=require("util"),kbd=require("kbd");

var flags={"debug":false},TRpreload=undefined;

if(process.argv.length<3){
	console.log("Please supply a treetree source file on the command line.");
	console.log("\t-d  Debug stuff.");
	console.log("\t-s  Preload stack in internal JSON array format in next parameter.");
	process.exit(1);
} else {
	var i,j,skipArg=false;
	for(i=2;i<process.argv.length-1;i++){
		if(skipArg){
			skipArg=false;
			continue;
		}
		if(process.argv[i][0]!="-"){
			console.log("Invalid argument '"+process.argv[i]+"'!");
			process.exit(1);
		}
		for(j=1;j<process.argv[i].length;j++){
			switch(process.argv[i][j]){
			case "d":flags.debug=true;break;
			case "s":TRpreload=JSON.parse(process.argv[i+1]);skipArg=true;break;
			default:
				console.log("Invalid flag '-"+process.argv[i][j]+"'!");
				process.exit(1);
			}
		}
	}
}

function TTerror(msg){
	TTerror.super_.apply(this,arguments);
	this.message=msg.toString();
}
util.inherits(TTerror,Error);

function objcpy(obj){return JSON.parse(JSON.stringify(obj));}

var cmd_list=["INP","OUT","IFI","OFI","IUS","OUS","ICH","OCH","PSH","PLL","SWP","POP","DUP","GRB","REL","INT","FLT","STR","NAN","LEN","SPL","SUM","DIF","PRO","QUO","POW","ROO","LOG","MOD","SIG","PI_","OR_","AND","XOR","INV","NOT","EQU","NEQ","SML","GRT","TAU","E__","RND","JMP","EXJ","IFJ","STP","STK"];

//returns [command term,index after end of command]
function extractCmd(code,startat){
	var i;
	while((code[startat]==" "||code[startat]=="\t"||code[startat]=="\n")&&startat<code.length)startat++;
	if(startat==code.length)return false;
	if(code[startat]=='"'||code[startat]=="'"||code[startat]=="{"){
		var term;
		term="";
		for(i=startat+1;i<code.length;i++){
			if(code[i]==code[startat]||(code[startat]=="{"&&code[i]=="}"))break;
			term+=code[i];
		}
		if(code[startat]=="'"||code[startat]=="{")return extractCmd(code,i+1); //'this is a comment,' {and this too.}
		return [["str",term],i+1];
	} else if(code[startat].match(/[0-9]|-|\./)){
		var neg,dot;
		i=startat;
		neg=code[startat]=="-";
		i+=neg;
		dot=false;
		for(;i<code.length;i++){
			if(code[i]=="."){
				if(!dot)dot=true;
				else break;
			}
			if(!code[i].match(/[0-9]/))break;
		}
		return [[dot?"flt":"int",parseFloat(code.slice(startat,i))],i];
	} else if(code[startat]=="#"){
		var term;
		for(i=startat+1;i<code.length;i++)
			if(code[i]==" "||code[i]=="\t"||code[i]=="\n")break;
		return [["lbl",code.slice(startat+1,i)],i];
	} else if(code[startat]=="@"){
		var term;
		for(i=startat+1;i<code.length;i++)
			if(code[i]==" "||code[i]=="\t"||code[i]=="\n")break;
		return [["ref",code.slice(startat+1,i)],i];
	} else {
		var term;
		if(code.length-startat<3)throw new Error("Invalid command '"+code.slice(startat)+"' at end of code with less than 3 characters!");
		term=code.slice(startat,startat+3).toUpperCase();
		if(cmd_list.indexOf(term)!=-1)return [["cmd",term],startat+3];
		else throw new Error("Unrecognised command '"+term+"'!");
	}
}

var runCmds_state={"in":undefined,"out":undefined,"interm":"\n","outterm":"\n","stdinbuf":""};
//Pass command array and the current tree. The tree is edited in-place.
function runCmds(cmds,TR){
	var cmdidx;
	for(cmdidx=0;cmdidx<cmds.length;cmdidx++){
		if(cmds[cmdidx][0]=="str"||cmds[cmdidx][0]=="int"||cmds[cmdidx][0]=="flt")TR=[cmds[cmdidx][1],TR,false];
		else if(cmds[cmdidx][0]=="ref")TR=[labels[cmds[cmdidx][1]],TR,false]; //yes, a label reference is just the position integer.
		else if(cmds[cmdidx][0]=="cmd"){
			switch(cmds[cmdidx][1]){
			case "INP":
				if(runCmds_state["in"]==undefined){
					var idx,str;
					str=kbd.getLineSync()+"\n";
					idx=str.indexOf(runCmds_state["interm"]);
					while(idx==-1){
						runCmds_state["stdinbuf"]+=str;
						str=kbd.getLineSync()+"\n";
						idx=str.indexOf(runCmds_state["interm"]);
					}
					idx=runCmds_state["stdinbuf"].length+idx;
					runCmds_state["stdinbuf"]+=str;
					TR=[runCmds_state["stdinbuf"].slice(0,idx),TR,false];
					runCmds_state["stdinbuf"]=runCmds_state["stdinbuf"].slice(idx+1,runCmds_state["stdinbuf"].length);
				} else {
					var buf,str,c;
					buf=new Buffer(1);
					str="";
					do{
						fs.readSync(runCmds_state["in"],buf,0,1,null);
						c=String.fromCharCode(buf[0])
						str+=c;
					}while(c!=runCmds_state["interm"]);
					TR=[str.slice(0,-1),TR,false];
				}
				break;
			case "OUT":
				var f,stdout,printPrimaryChildTree;
				if(runCmds_state["out"]==undefined)stdout=true;
				else stdout=false;
				printPrimaryChildTree=function(e){
					while(e!=false){
						if(typeof e[0]!="string")throw new TTerror("Value to be printed, "+e[0].toString()+", is not a string!");
						if(stdout)process.stdout.write(e[0]);
						else fs.writeSync(runCmds_state["out"],new Buffer(e[0]),0,e[0].length,null);
						if(e[2]!==false)printPrimaryChildTree(e[2]);
						e=e[1];
					}
				}
				if(TR===false)throw new TTerror("Tree is empty while processing OUT!");
				if(typeof TR[0]!="string")throw new TTerror("Value to be printed, "+TR[0].toString()+", is not a string!");
				if(stdout)process.stdout.write(TR[0]+runCmds_state["outterm"]);
				else fs.writeSync(runCmds_state["out"],new Buffer(TR[0]+runCmds_state["outterm"]),0,TR[0].length+1,null);
				printPrimaryChildTree(TR[2]);
				TR=TR[1];
				break;
			case "IFI":
				var fname;
				if(typeof TR[0]!="string")throw new TTerror("File name (in IFI) is not a string (namely "+TR[0].toString()+")!");
				if(TR[2]!=false)throw new TTerror("Cannot open multiple files (in IFI), but the root node ('"+TR[0]+"') has secondary children!");
				fname=TR[0];
				TR=[1,TR[1],false]; //"return" 1
				try{
					runCmds_state["in"]=fs.openSync(fname,"r");
				} catch(err){
					TR[0]=0; //"return" 0
				}
				break;
			case "OFI":
				var fname;
				if(typeof TR[0]!="string")throw new TTerror("File name (in OFI) is not a string (namely "+TR[0].toString()+")!");
				if(TR[2]!=false)throw new TTerror("Cannot open multiple files (in OFI), but the root node ('"+TR[0]+"') has secondary children!");
				fname=TR[0];
				TR=[1,TR[1],false]; //"return" 1
				try{
					runCmds_state["out"]=fs.openSync(fname,"w");
				} catch(err){
					TR[0]=0; //"return" 0
				}
				break;
			case "IUS":
				if(runCmds_state["in"]!=undefined){
					fs.closeSync(runCmds_state["in"]);
					runCmds_state["in"]=undefined;
				}
				break;
			case "OUS":
				if(runCmds_state["out"]!=undefined){
					fs.closeSync(runCmds_state["out"]);
					runCmds_state["out"]=undefined;
				}
				break;
			case "ICH":
				if(TR[2]!=false)throw new TTerror("Cannot open multiple files (in ICH), but the root node ('"+TR[0]+"') has secondary children!");
				if(typeof TR[0]!="string")throw new TTerror("String expected (in ICH), got '"+TR[0].toString()+"'!");
				if(TR[0].length!=1)throw new TTerror("String is not one character while processing ICH!");
				runCmds_state["interm"]=TR[0];
				TR=TR[1];
				break;
			case "OCH":
				if(TR[2]!=false)throw new TTerror("Cannot open multiple files (in OCH), but the root node ('"+TR[0]+"') has secondary children!");
				if(typeof TR[0]!="string")throw new TTerror("String expected (in OCH), got '"+TR[0].toString()+"'!");
				if(TR[0].length!=1)throw new TTerror("String is not one character while processing OCH!");
				runCmds_state["outterm"]=TR[0];
				TR=TR[1];
				break;
			case "PSH":case "PLL":
				var n;
				if(TR[2]!=false)throw new TTerror("Cannot operate multiple times (in "+cmds[cmdidx][1]+"), but the root node ('"+TR[0]+"') has secondary children!");
				if(typeof TR[0]!="number"||TR[0]%1!=0)throw new TTerror("Integer expected (in "+cmds[cmdidx][1]+"), got '"+TR[0].toString()+"'!");
				n=TR[0];
				TR=TR[1];
				if(cmds[cmdidx][1]=="PLL")n=-n;
				if(n>0){ //PSH
					var next_part,next_part_parent,moved_node,i;
					next_part_parent=TR;
					for(i=0;i<n;i++){
						next_part_parent=next_part_parent[1];
						if(next_part_parent==false)throw new TTerror("Trying to PSH beyond end of tree (in "+cmds[cmdidx][1]+")!");
					}
					next_part=objcpy(next_part_parent[1]);
					moved_node=[TR[0],next_part,objcpy(TR[2])];
					TR=TR[1];
					next_part_parent[1]=moved_node;
				} else if(n<-1){ //PLL; if n==1 then it pulls the root node onto the root node. Which is useless.
					n=-n;
					var moved_node_parent,i;
					moved_node_parent=TR;
					for(i=0;i<n-1;i++){
						moved_node_parent=moved_node_parent[1];
						if(moved_node_parent==false)throw new TTerror("Trying to PLL beyond end of tree (in "+cmds[cmdidx][1]+")!");
					}
					moved_node=moved_node_parent[1];
					if(moved_node==false)throw new TTerror("Trying to PLL just beyond end of tree (in "+cmds[cmdidx][1]+")!");
					moved_node_parent[1]=objcpy(moved_node[1]);
					moved_node=[moved_node[0],TR,moved_node[2]];
					TR=objcpy(moved_node); //Sorry, garbage colector.
				}
				break;
			case "SWP":
				var temp;
				temp=objcpy(TR[1]);
				TR[1]=objcpy(TR[2]);
				TR[2]=temp;
				break;
			case "POP":
				if(TR==false)throw new TTerror("Cannot POP a non-existant root node!");
				TR=TR[1];
				break;
			case "DUP":
				var newroot;
				newroot=[TR[0],TR,objcpy(TR[2])];
				TR=newroot;
				break;
			case "GRB":
				var inserted_tree,end_tree,rest_tree,i,n;
				if(TR==false)throw new TTerror("Cannot GRB from a non-existant root node!");
				if(TR[2]!=false)throw new TTerror("Cannot operate multiple times (in GRB), but the root node ('"+TR[0]+"') has secondary children!");
				n=TR[0];
				if(typeof n!="number")throw new TTerror("Integer expected (in GRB), got '"+n.toString()+"'!");
				TR=TR[1];
				if(n==0)break;
				inserted_tree=objcpy(TR[1]);
				if(inserted_tree==false)throw new TTerror("No primary child of root node to GRB!");
				end_tree=inserted_tree;
				for(i=0;i<n-1&&end_tree!=false;i++)end_tree=end_tree[1];
				rest_tree=objcpy(end_tree[1]);
				end_tree[1]=false;
				inserted_tree[2]=TR[2];
				TR[2]=inserted_tree;
				TR[1]=rest_tree;
				break;
			case "REL":
				var i,n,inserted_tree,last_inserted,after_inserted,rest_main_tree;
				if(TR==false)throw new TTerror("Cannot REL from a non-existant root node!");
				if(TR[2]!=false)throw new TTerror("Cannot operate multiple times (in REL), but the root node ('"+TR[0]+"') has secondary children!");
				n=TR[0];
				if(typeof n!="number")throw new TTerror("Integer expected (in REL), got '"+n.toString()+"'!");
				if(n==0)break;
				TR=TR[1];
				rest_main_tree=TR[1];
				inserted_tree=TR[2];
				if(inserted_tree==false)throw new TTerror("Not enough secondary children to REL!");
				last_inserted=inserted_tree;
				for(i=0;i<n-1;i++){
					if(last_inserted==false)throw new TTerror("Not enough secondary children to REL!");
					last_inserted=last_inserted[1];
				}
				after_inserted=objcpy(last_inserted[1]);
				last_inserted[1]=rest_main_tree;
				TR[1]=inserted_tree;
				TR[2]=after_inserted;
				break;
			case "INT":
				if(TR==false)throw new TTerror("Cannot INT a non-existant root node!");
				TR[0]=parseInt(TR[0],10);
				break;
			case "FLT":
				if(TR==false)throw new TTerror("Cannot INT a non-existant root node!");
				TR[0]=parseInt(TR[0],10);
				break;
			case "STR":
				if(TR==false)throw new TTerror("Cannot INT a non-existant root node!");
				TR[0]=TR[0].toString();
				break;
			case "NAN":
				TR=[NaN,TR,false];
				break;
			case "LEN":
				if(TR==false)throw new TTerror("Cannot LEN a non-existant root node!");
				if(typeof TR[0]!="string")TR=[NaN,TR,false];
				else TR=[TR[0].length,TR,false];
				break;
			case "SPL":
				throw new TTerror("SPL not implemented!");
				break;
			case "SUM":break;
			case "DIF":break;
			case "PRO":break;
			case "QUO":break;
			case "POW":break;
			case "ROO":break;
			case "LOG":break;
			case "MOD":break;
			case "SIG":break;
			case "PI_":break;
			case "OR_":break;
			case "AND":break;
			case "XOR":break;
			case "INV":break;
			case "NOT":break;
			case "EQU":break;
			case "NEQ":break;
			case "SML":break;
			case "GRT":break;
			case "TAU":break;
			case "E__":break;
			case "RND":
				TR=[~~(Math.pow(2,31)*Math.random()),TR,false];
				break;
			case "JMP":break;
			case "EXJ":break;
			case "IFJ":break;
			case "STP":
				process.exit();
				break;
			case "STK":
				var str;
				str=util.inspect(TR,{"depth":null})+runCmds_state["outterm"];
				if(runCmds_state["out"]==undefined)process.stdout.write(str);
				else fs.writeSync(runCmds_state["out"],new Buffer(str),0,str.length,null);
				break;
			default:
				throw new Error("Internal error: Unrecognised command in internal command array! Please report the command '"+cmds[cmdidx][1]+"'!");
			}
		} else throw new Error("Internal error: Invalid command type! Please report the type '"+cmds[cmdidx][0]+"'!");
		if(flags.debug){
			process.stdout.write("\x1B[36m");
			console.log("%j",TR);
			process.stdout.write("\x1B[0m");
		}
	}
}

//Edits `labels` in-place.
function parseLabels(cmds,labels){
	var i;
	for(i=0;i<cmds.length;i++){
		if(cmds[i][0]=="lbl"){
			labels[cmds[i][1]]=i;
			cmds.splice(i,1);
			i--;
		}
	}
}

/*
`TR` stores the main tree in treetree. `false` indicates non-existance. It
contains a root node with a primary child and a secondary child. Every node is
represented by an array with three items, the first containing the contents of
the node, the second containing the primary child (which is also an array like
this node) and the third containing the second child. An absent child is of
course indicated with the literal value `false`.
For example, the following program:
1 2 3 SWP 4
makes the tree (*'s indicating absence of children, / is a primary child, --
is a secondary child):
    4 *
   /
  3--2 *
 *  /
   1 *
  *
and is represented in `TR` like:
[4,
	[3,
		false,
		[2,
			[1,false,false],
			false
		]
	],
	false
]

Commands, in `cmds`, are each an array with two items, the first being the type
and the second being the value. The types are:
"str", "flt", "int", "lbl", "ref" and "cmd".
"str" contains a literal string, "flt" a literal floating-point and "int" a
literal integer. "lbl" and "ref" contain the names of the labels and "irf"
contains the integer mapping of the label after the first pass. "cmd" indicates
a string with the specific command.

The first pass over the code removes all the "lbl" commands and adds those
labels to `labels`. The second pass interprets the code.
*/

var fname,infile,offset,code,cmds,TR,labels;

fname=process.argv[process.argv.length-1];
try{
	infile=fs.openSync(fname,"r");
	fs.closeSync(infile);
}catch(e){
	console.log("Could not open file '"+fname+"'!");
	process.exit(1);
}
code=fs.readFileSync(fname,{"encoding":"utf8"});
cmds=[]; //command list in array form
offset=0;
while(true){
	offset=extractCmd(code,offset);
	if(offset===false)break;
	cmds.push(offset[0]);
	offset=offset[1];
}

if(TRpreload)TR=TRpreload;
else TR=false; //The Big TRee starts non-existant. Yeah. Well, it is true, sort-of.
labels=[]; //label index
parseLabels(cmds,labels);
if(flags.debug){
	process.stdout.write("\x1B[36m");
	process.stdout.write("Commands: ");
	console.log(cmds);
	process.stdout.write("Labels: ");
	console.log(labels);
	process.stdout.write("\x1B[0m");
}
try{
	runCmds(cmds,TR);
} catch(err) {
	if(err instanceof TTerror){
		console.log("\x1B[31;1mTreetree error:\x1B[0m \x1B[31m"+err.message+"\x1B[0m");
		process.exit(1);
	} else throw err;
}