Constellations/js/Share/Decoder/Protocol.js

import size from Config;
import * as CellSet from Geometry.CellSet;
import * as Decoder from Share.Decoder.Class;
import {diagonal, plus, zero} from Geometry.Vector;
import * as Vector from Geometry.Vector;
import * as Protocol from Share.Protocol;

return {
	grid: decodeGrid
};

function decodeGrid(input) {
	if(input != undefined) {
		return decoderLoop(
			Decoder.make(input),
			square(size),
			CellSet.rectangle(zero(), diagonal(size))
		);
	}
}

function decoderLoop(decoder, grid, missing) {
	var queue = [];
	var nextBit = decoder.pop();
	var cell = zero();
	var danglingCells = [];
	while(nextBit != null) {
		if(nextBit == 1) {
			fillBlock(grid, decodeBlock(decoder), missing);
		} else {
			handleCell(grid, cell, decodeDirection(decoder), danglingCells);
		}
		moveToNext(cell, grid, missing);
		nextBit = decoder.pop();
	}
	resolve(grid, danglingCells);
	return grid;
}

function moveToNext(cell, grid, missing) {
	cell.column++;
	while(!missing.contains(cell)) {
		if(cell.column >= grid[cell.row].length) {
			cell.row++;
			cell.column = 0;
		} else {
			cell.column++;
		}
	}
}

function fillBlock(grid, block, missing, cell) {
	var offset = Vector[block.direction](1);
	var newCell = Vector.make(cell.row, cell.column);
	for(var delta = 0; delta < block.size; delta++) {
		set(grid, newCell, block.color);
		missing.remove(newCell);
		newCell = plus(newCell, offset);
	}
}

function decodeBlock(decoder) {
	return {
		direction: decoder.pop() == 1 ? 'vertical' : 'horizontal',
		size: decoder.variableLength6() + Protocol.MIN_BLOCK_SIZE,
		color: decoder.int(3)
	};
}

function handleCell(grid, cell, direction, danglingCells) {

}

function resolve(grid, danglingCells) {

}

function decodeDirection(decoder) {
	return Protocol.directions[decoder.int(2)];
}