"use strict";

const fs = require('fs');
const needle = fs.readFileSync('A_WALK_L_02.BIN');

const blocks = {
	ids : [0,8],
	do_push : 0,
	b01 : {
		ofs : 0x0c,
		start : 0x0c,
		dat : [],
		len : []
	},
	b02 : {
		ofs : needle.readUInt16LE(0x04),
		start : needle.readUInt16LE(0x04),
		dat : [],
		len : []
	},
	b03 : {
		ofs : needle.readUInt16LE(0x06),
		start : needle.readUInt16LE(0x06),
		dat : [],
		len : []
	},
	b04 : {
		ofs : needle.readUInt16LE(0x08),
		start : needle.readUInt16LE(0x08),
		dat : [],
		len : []
	},
	b05 : {
		ofs : needle.readUInt16LE(0x0a),
		start : needle.readUInt16LE(0x0a),
		dat : [],
		len : []
	}
}

// Step 1 : Read

for(blocks.b01.ofs; blocks.b01.ofs < blocks.b02.start; blocks.b01.ofs += 2) {

	const instruction = needle.readUInt16LE(blocks.b01.ofs);
	const node_id = instruction >> 9;

	if(instruction === 0) {
		break;
	}

	blocks.do_push = (blocks.ids.indexOf(node_id) === -1) ? 0 : 1;
	if(blocks.do_push) {
		console.log("DOING PUSH!!!");
		blocks.b01.dat.push(instruction);
		blocks.b01.len.push(2);
	}

	if(instruction & 0x1c0) {

		if(instruction & 0x100) {
			readBlock2();
		}

		if(instruction & 0x80) {
			readBlock2();
		}

		if(instruction & 0x40) {
			readBlock2();
		}

	}

	if(instruction & 0x38) {

		if(instruction & 0x20) {
			readBlock2();
		}

		if(instruction & 0x10) {
			readBlock2();
		}

		if(instruction & 0x08) {
			readBlock2();
		}

	}

}

function readBlock2() {

	// Block 2

	let keyFrameCount = needle.readUInt8(blocks.b02.ofs);
	blocks.b02.ofs++;

	if(blocks.do_push) {
		blocks.b02.dat.push(keyFrameCount);
		blocks.b02.len.push(1);
	}

	// Block 3

	for(let i = 0; i < keyFrameCount; i++) {

		let keyFrame = needle.readUInt8(blocks.b03.ofs);
		blocks.b03.ofs++;

		if(blocks.do_push) {
			blocks.b03.dat.push(keyFrame);
			blocks.b03.len.push(1);
		}

	}

	keyFrameCount += 2;

	// Block 4

	const bits = [
		{ m : 0xc0, a : 0x80, b : 0x40 },
		{ m : 0x30, a : 0x20, b : 0x10 },
		{ m : 0x0c, a : 0x08, b : 0x04 },
		{ m : 0x03, a : 0x02, b : 0x01 }
	];

	let index = 0;

	do {

		let byte = needle.readUInt8(blocks.b04.ofs);
		blocks.b04.ofs++

		if(blocks.do_push) {
			blocks.b04.dat.push(byte);
			blocks.b04.len.push(1);
		}

		if(byte === 0) {
			return;
		}

		bits.forEach( set => {

			if((byte & set.m) === 0) {
				return;
			}

			if(byte & set.a) {
				let a = needle.readUInt16LE(blocks.b05.ofs);
				blocks.b05.ofs += 2;
				let b = needle.readUInt16LE(blocks.b05.ofs);
				blocks.b05.ofs += 2;

				if(blocks.do_push) {
					blocks.b05.dat.push(a,b);
					blocks.b05.len.push(2,2);
				}

			};

			if(byte & set.b) {
				let a = needle.readUInt16LE(blocks.b05.ofs);
				blocks.b05.ofs += 2;

				if(blocks.do_push) {
					blocks.b05.dat.push(a);
					blocks.b05.len.push(2);
				}
			}

			index++;

		});

	} while(index < keyFrameCount);


}

delete blocks.ids;
delete blocks.do_push;

blocks.b01.dat.push(0);
blocks.b01.len.push(2);

for(let key in blocks) {

	const b = blocks[key];
	let ofs = b.start;

	for(let i = 0; i < b.dat.length; i++) {

		switch(b.len[i]) {
		case 1:
			needle.writeUInt8(b.dat[i], ofs);
			break;
		case 2:
			needle.writeUInt16LE(b.dat[i], ofs);
			break;
		}
		ofs += b.len[i];

	}

}

fs.writeFileSync("walk_dat.bin", needle);