var _ = require('lodash');
var d3 = require('d3');

var MAX_HISTORY = 1000;

var MAX_PEER_PROPAGATION = 36;
var MIN_PROPAGATION_RANGE = 0;
var MAX_PROPAGATION_RANGE = 20000;

var MAX_UNCLES_PER_BIN = 25;
var MAX_BINS = 40;

var History = function History(data)
{
	this._items = [];

	var item = {
		height: 0,
		block: {
			number: 0,
			hash: '0x?',
			arrived: 0,
			received: 0,
			propagation: 0,
			difficulty: 0,
			gasUsed: 0,
			transactions: [],
			uncles: []
		},
		propagTimes: []
	};
}

History.prototype.add = function(block, id)
{
	if(typeof block !== 'undefined' && typeof block.number !== 'undefined' && typeof block.uncles !== 'undefined' && typeof block.transactions !== 'undefined' && typeof block.difficulty !== 'undefined')
	{
		var historyBlock = this.search(block.number);

		var now = (new Date()).getTime();
		block.arrived = now;
		block.received = now;
		block.propagation = 0;

		if(historyBlock)
		{
			var propIndex = _.findIndex(historyBlock.propagTimes, {node: id});

			if(propIndex === -1)
			{
				block.arrived = historyBlock.block.arrived;
				block.received = now;
				block.propagation = now - historyBlock.block.received;

				historyBlock.propagTimes.push({node: id, received: now, propagation: block.propagation});
			}
			else
			{
				block.arrived = historyBlock.block.arrived;
				block.received = historyBlock.propagTimes[propIndex].received;
				block.propagation = historyBlock.propagTimes[propIndex].propagation;
			}
		}
		else
		{
			var item = {
				height: block.number,
				block: block,
				propagTimes: []
			}

			item.propagTimes.push({node: id, received: now, propagation: block.propagation});
			this._save(item);
		}
		this.getNodePropagation(id);

		return block;
	}

	return false;
}

History.prototype._save = function(block)
{
	this._items.push(block);

	if(this._items.length > MAX_HISTORY){
		this._items.shift();
	}
}

History.prototype.search = function(number)
{
	var index = _.findIndex(this._items, {height: number});

	if(index < 0)
		return false;

	return this._items[index];
}

History.prototype.bestBlock = function(obj)
{
	return _.max(this._items, 'height');
}

History.prototype.getNodePropagation = function(id)
{
	var propagation = new Array(MAX_PEER_PROPAGATION);
	var bestBlock = this.bestBlock().height;


	_.fill(propagation, -1);

	var sorted = _(this._items)
		.sortByOrder('height', false)
		.slice(0, MAX_PEER_PROPAGATION)
		.reverse()
		.forEach(function(n, key)
		{
			var index = MAX_PEER_PROPAGATION - 1 - bestBlock + n.height;

			if(index > 0)
			{
				propagation[index] = _.result(_.find(n.propagTimes, 'node', id), 'propagation', -1);
			}
		})
		.value();

	return propagation;
}

History.prototype.getBlockPropagation = function()
{
	var propagation = [];

	_.forEach(this._items, function(n, key)
	{
		_.forEach(n.propagTimes, function(p, i)
		{
			var prop = _.result(p, 'propagation', -1);

			if(prop >= 0)
				propagation.push(prop);
		});
	});

	var x = d3.scale.linear()
		.domain([MIN_PROPAGATION_RANGE, MAX_PROPAGATION_RANGE])
		.interpolate(d3.interpolateRound);

	var data = d3.layout.histogram()
		.frequency(false)
		.bins(x.ticks(MAX_BINS))
		(propagation);

	var freqCum = 0;
	var histogram = data.map(function(val) {
		freqCum += val.length;
		var cumPercent = (freqCum / Math.max(1, propagation.length));
		return {x: val.x, dx: val.dx, y: val.y, frequency: val.length, cumulative: freqCum, cumpercent: cumPercent};
	});

	return histogram;
}

History.prototype.getUncleCount = function(id)
{
	var uncles = _(this._items)
		.sortByOrder('height', false)
		.map(function(item)
		{
			return item.block.uncles.length;
		})
		.value();

	var uncleBins = _.fill(Array(MAX_BINS), 0);

	var sumMapper = function(array, key) {
		uncleBins[key] = _.sum(array);
		return _.sum(array);
	};

	_.map(_.chunk(uncles, MAX_UNCLES_PER_BIN), sumMapper);

	return uncleBins;
}

History.prototype.getTransactionsCount = function(id)
{
	var txCount = _(this._items)
		.sortByOrder('height', false)
		.slice(0, MAX_BINS - 1)
		.reverse()
		.map(function(item)
		{
			return item.block.transactions.length;
		})
		.value();

	return txCount;
}

History.prototype.getDifficulty = function(id)
{
	var difficultyHistory = _(this._items)
		.sortByOrder('height', false)
		.slice(0, MAX_BINS - 1)
		.reverse()
		.map(function(item)
		{
			return item.block.difficulty;
		})
		.value();

	return difficultyHistory;
}

History.prototype.history = function()
{
	return _.chain(this._items).sortBy('number').reverse().value();
}

module.exports = History;