(function(global){

'use strict';

function createBlock(name, value, contents){

var item = elem('div', {'class': 'block', draggable: true, 'data-name': name}, [name]);

if (value !== undefined && value !== null){

item.appendChild(elem('input', {type: 'number', value: value}));

}

if (Array.isArray(contents)){

item.appendChild(elem('div', {'class': 'container'}, contents.map(function(block){

return createBlock.apply(null, block);

})));

}else if (typeof contents === 'string'){ // Add units specifier

item.appendChild(document.createTextNode(' ' + contents));

}

return item;

}

function blockContents(block){

var container = block.querySelector('.container');

return container ? [].slice.call(container.children) : null;

}

function blockValue(block){

var input = block.querySelector('input');

return input ? Number(input.value) : null;

}

function blockUnits(block){

if (block.children.length > 1 && block.lastChild.nodeType === Node.TEXT_NODE && block.lastChild.textContent){

return block.lastChild.textContent.slice(1);

}

}

function blockScript(block){

var script = [block.dataset.name];

var value = blockValue(block);

if (value !== null){

script.push(blockValue(block));

}

var contents = blockContents(block);

var units = blockUnits(block);

if (contents){script.push(contents.map(blockScript));}

if (units){script.push(units);}

return script.filter(function(notNull){ return notNull !== null; });

}

function runBlocks(blocks){

blocks.forEach(function(block){ trigger('run', block); });

}

global.Block = {

create: createBlock,

value: blockValue,

contents: blockContents,

script: blockScript,

run: runBlocks,

trigger: trigger

};

window.addEventListener('unload', file.saveLocal, false);

window.addEventListener('load', file.restoreLocal, false);

})(window);