#include "dag_layout.h"
using namespace dags;
using namespace graph_data;

DAGLayerHelper::DAGLayerHelper(const Node& bind)
	: bind_node(bind) { }

Node DAGLayerHelper::bindPoint() const {
	return this->bind_node;
}

int& dags::DAGLayerHelper::inputCount() {
	return this->input_count;
}

int dags::DAGLayerHelper::layerValue() const {
	return this->layer_v;
}

void dags::DAGLayerHelper::setLayerValue(int v) {
	this->layer_v = v;
}

void DAGLayerHelper::nextAppend(std::shared_ptr<DAGLayerHelper> inst) {
	if (this->next_points.contains(inst))
		return;
	this->next_points.append(inst);
	inst->input_count++;
}

QList<std::shared_ptr<DAGLayerHelper>> DAGLayerHelper::nextNodes() const {
	return this->next_points;
}

DAGOrderHelper::DAGOrderHelper(std::shared_ptr<DAGLayerHelper> bind) : layer_bind(bind) {
	this->layer_number = bind->layerValue();
}

DAGOrderHelper::DAGOrderHelper(std::shared_ptr<DAGLayerHelper> f, std::shared_ptr<DAGLayerHelper> t)
	: relate_bind(f), towards_to(t) { }

bool DAGOrderHelper::isFakeNode() const {
	return !this->layer_bind;
}

std::shared_ptr<DAGLayerHelper> dags::DAGOrderHelper::layerNode() const {
	return this->layer_bind;
}

std::shared_ptr<DAGLayerHelper> dags::DAGOrderHelper::tailsNode() const {
	return this->relate_bind;
}

std::shared_ptr<DAGLayerHelper> dags::DAGOrderHelper::headsNode() const {
	return this->towards_to;
}

int dags::DAGOrderHelper::layerNumber() const {
	return this->layer_number;
}

void dags::DAGOrderHelper::setLayerNumber(int v) {
	this->layer_number = v;
}

QVariant dags::DAGOrderHelper::sortNumber() const {
	return this->sort_number;
}

void dags::DAGOrderHelper::setSortNumber(double v) {
	this->sort_number = v;
}

QList<std::shared_ptr<DAGOrderHelper>> DAGOrderHelper::getUpstreamNodes() const {
	return this->__prev_layer_nodes;
}

void DAGOrderHelper::appendUpstreamNode(std::shared_ptr<DAGOrderHelper> inst) {
	this->__prev_layer_nodes.append(inst);
}

void DAGGraph::rebuildFromEdges(const QList<Arrow>& arrow_list) {
	for (auto& arr : arrow_list) {
		auto start = arr.startPoint();
		std::shared_ptr<DAGLayerHelper> start_helper;
		if (this->graph_inst.contains(start.name())) {
			start_helper = this->graph_inst[start.name()];
		}
		else {
			start_helper = std::make_shared<DAGLayerHelper>(start);
			this->graph_inst[start.name()] = start_helper;
		}

		auto end = arr.endPoint();
		std::shared_ptr< DAGLayerHelper> end_helper;
		if (this->graph_inst.contains(end.name())) {
			end_helper = this->graph_inst[end.name()];
		}
		else {
			end_helper = std::make_shared<DAGLayerHelper>(end);
			this->graph_inst[end.name()] = end_helper;
		}

		start_helper->nextAppend(end_helper);
	}
}

QList<std::shared_ptr<DAGOrderHelper>> dags::DAGGraph::nodeWithLayout() const {
	return this->node_with_layout;
}

int dags::DAGGraph::maxLayerCount() const {
	return this->max_layer_count;
}

std::shared_ptr<DAGLayerHelper> DAGGraph::spawns_peak(QList<std::shared_ptr<DAGLayerHelper>>& ref_set) {
	for (auto inst : ref_set) {
		if (!inst->inputCount()) {
			for (auto it_nxt : inst->nextNodes()) {
				it_nxt->inputCount()--;
				if (!ref_set.contains(it_nxt))
					ref_set << it_nxt;
			}

			ref_set.removeAll(inst);
			this->graph_inst.remove(inst->bindPoint().name());
			return inst;
		}
	}

	for (auto inst : this->graph_inst.values()) {
		if (!inst->inputCount()) {
			if (ref_set.contains(inst))
				ref_set.removeAll(inst);

			for (auto it_nxt : inst->nextNodes()) {
				it_nxt->inputCount()--;
				if (!ref_set.contains(it_nxt))
					ref_set << it_nxt;
			}

			this->graph_inst.remove(inst->bindPoint().name());
			return inst;
		}
	}

	if (this->graph_inst.size()) {
		throw "在有向无环图中发现环形回路。";
	}

	return std::shared_ptr<DAGLayerHelper>();
}

void DAGGraph::graph_recovery(const QList<std::shared_ptr<DAGLayerHelper>>& sort_seqs) {
	for (auto it : sort_seqs) {
		it->inputCount() = 0;
	}

	for (auto it : sort_seqs) {
		for (auto nxt : it->nextNodes()) {
			nxt->inputCount()++;
		}
	}

	this->graph_inst.clear();
	for (auto it : sort_seqs) {
		this->graph_inst[it->bindPoint().name()] = it;
	}
}

int DAGGraph::node_layering(const std::shared_ptr<DAGLayerHelper>& inst, int layer_current) {
	auto max_remains = layer_current;
	if (!layer_current || inst->layerValue() < layer_current) {
		inst->setLayerValue(layer_current);

		for (auto fork : inst->nextNodes()) {
			max_remains = std::max(this->node_layering(fork, inst->layerValue() + 1), max_remains);
		}
	}

	return max_remains + 1;
}

int DAGGraph::node_layering_adj(std::shared_ptr<DAGLayerHelper> inst) {
	if (inst->inputCount() > 1)
		return inst->layerValue() - 1;

	if (!inst->nextNodes().size())
		return inst->layerValue() - 1;

	auto layer_number = INT_MAX;
	for (auto cinst : inst->nextNodes()) {
		layer_number = std::min(layer_number, this->node_layering_adj(cinst));
	}

	inst->setLayerValue(layer_number);
	return inst->layerValue() - 1;
}

QList<std::shared_ptr<DAGOrderHelper>> DAGGraph::tidy_graph_nodes() {
	QHash<QString, std::shared_ptr<DAGOrderHelper>> nodes_temp;
	for (auto node : this->graph_inst.values()) {
		nodes_temp[node->bindPoint().name()] = std::make_shared<DAGOrderHelper>(node);
	}

	QList<std::shared_ptr<DAGOrderHelper>> temp_array(nodes_temp.values());
	for (auto node : this->graph_inst.values()) {
		for (auto next : node->nextNodes()) {
			auto node_links = QList<std::shared_ptr<DAGOrderHelper>>{
				nodes_temp[node->bindPoint().name()]
			};
			for (auto layer_index = node->layerValue() + 1; layer_index < next->layerValue(); ++layer_index) {
				node_links.append(std::make_shared<DAGOrderHelper>(node, next));
				node_links.last()->setLayerNumber(layer_index);
			}
			node_links.append(nodes_temp[next->bindPoint().name()]);
			for (auto idx = 1; idx < node_links.size(); ++idx) {
				auto start_point = node_links[idx - 1];
				auto end_point = node_links[idx];
				end_point->appendUpstreamNode(start_point);
			}
			temp_array.append(node_links.mid(1, node_links.size() - 2));
		}
	}
	return temp_array;
}

#include <QDebug>
void dags::DAGGraph::graph_layout_layers_forward(const QList<std::shared_ptr<DAGOrderHelper>>& nodes) {
	for (auto layer_index = 0; layer_index < maxLayerCount(); ++layer_index) {
		this->nodes_sort_forward_within_layer(layer_index, nodes);
		this->nodes_sort_with_above(layer_index, nodes);
	}
}
void DAGGraph::nodes_sort_forward_within_layer(int layer_index, const QList<std::shared_ptr<DAGOrderHelper>>& nodes) {
	QList<std::shared_ptr<DAGOrderHelper>> nodes_within_current_layer;
	std::copy_if(nodes.begin(), nodes.end(), std::back_inserter(nodes_within_current_layer),
		[=](std::shared_ptr<DAGOrderHelper> ins) { return ins->layerNumber() == layer_index; });

	if (nodes_within_current_layer.size()) {
		// 计算当前层次所有节点排序
		if (!layer_index) {
			for (auto idx = 0; idx < nodes_within_current_layer.size(); ++idx) {
				auto target_node = nodes_within_current_layer[idx];
				if (target_node->sortNumber().isNull())
					target_node->setSortNumber(idx + 1);
			}
		}
		else if (layer_index > 0) {
			double min_sortv = DBL_MAX;
			for (auto target_node : nodes_within_current_layer) {
				auto upstream_list = target_node->getUpstreamNodes();
				if (upstream_list.size()) {
					QList<double> sort_values;
					std::transform(upstream_list.begin(), upstream_list.end(), std::back_inserter(sort_values),
						[](std::shared_ptr<DAGOrderHelper> ins) { return ins->sortNumber().toDouble(); });

					auto vals_sum = std::accumulate(sort_values.begin(), sort_values.end(), 0.0);
					target_node->setSortNumber(vals_sum / sort_values.size());
					min_sortv = std::min(target_node->sortNumber().toDouble(), min_sortv);
				}
			}

			QList<std::shared_ptr<DAGOrderHelper>> nodes_hangout;
			std::copy_if(nodes_within_current_layer.begin(), nodes_within_current_layer.end(),
				std::back_inserter(nodes_hangout), [](std::shared_ptr<DAGOrderHelper> ins) {
				return ins->sortNumber().isNull();
			});
			if (nodes_hangout.size()) {
				auto vspan = 1.0 / (nodes_hangout.size() + 1);
				for (int idx = 0; idx < nodes_hangout.size(); ++idx) {
					nodes_hangout[idx]->setSortNumber(min_sortv - (idx + 1) * vspan);
				}
			}

			std::sort(nodes_within_current_layer.begin(), nodes_within_current_layer.end(),
				[](std::shared_ptr<DAGOrderHelper> a, std::shared_ptr<DAGOrderHelper> b) {
				return a->sortNumber() < b->sortNumber();
			});

			// 提取当前层次节点排序值
			this->current_nodelist_filling_indi(nodes_within_current_layer);
		}
	}
}

bool dags::DAGGraph::current_nodelist_filling_indi(const QList<std::shared_ptr<DAGOrderHelper>>& nodes_within_current_layer) {

	// 提取节点划分档次
	QList<int> ordered_values;
	std::transform(nodes_within_current_layer.begin(), nodes_within_current_layer.end(),
		std::back_inserter(ordered_values), [=](std::shared_ptr<DAGOrderHelper> ins) {
		return ins->sortNumber().toInt();
	});
	ordered_values = ordered_values.toSet().toList();
	std::sort(ordered_values.begin(), ordered_values.end());

	//if (ordered_values.size() == nodes_within_current_layer.size())
	//	return false;

	if (!ordered_values.size())
		return false;

	// 填缝
	ordered_values << ordered_values.last() + 1;
	for (auto idx = 1; idx < ordered_values.size(); ++idx) {
		auto prev_sortv = ordered_values[idx - 1];
		auto curr_sortv = ordered_values[idx];

		QList<std::shared_ptr<DAGOrderHelper>> pick_ups;
		std::copy_if(nodes_within_current_layer.begin(), nodes_within_current_layer.end(), std::back_inserter(pick_ups),
			[=](std::shared_ptr<DAGOrderHelper> ins) { return ins->sortNumber() >= prev_sortv && ins->sortNumber() < curr_sortv; });

		for (int idx = 0; idx < std::min(curr_sortv - prev_sortv, pick_ups.size()); idx++) {
			auto target_node = pick_ups[idx];
			target_node->setSortNumber(prev_sortv + idx);
		}
		if (curr_sortv - prev_sortv < pick_ups.size()) {
			auto npicks = pick_ups.mid(curr_sortv - prev_sortv);
			auto inc_span = 1.0 / (npicks.size() + 4);

			for (auto idx = 0; idx < npicks.size(); ++idx) {
				auto nsortv = curr_sortv - 1 + (idx + 1) * inc_span;
				npicks[idx]->setSortNumber(nsortv);
			}
		}
	}
	return true;
}

void dags::DAGGraph::nodes_sort_with_above(int layer_index, const QList<std::shared_ptr<DAGOrderHelper>>& nodes) {
	// 提取所有已知节点
	QList<std::shared_ptr<DAGOrderHelper>> sorting_nodes;
	std::copy_if(nodes.begin(), nodes.end(), std::back_inserter(sorting_nodes),
		[&](std::shared_ptr<DAGOrderHelper> n) { return n->layerNumber() <= layer_index; });

	// 排序值提取与重排
	QList<double> sort_values;
	std::transform(sorting_nodes.begin(), sorting_nodes.end(), std::back_inserter(sort_values),
		[](std::shared_ptr<DAGOrderHelper> n)->double { return n->sortNumber().toDouble(); });
	sort_values = sort_values.toSet().toList();
	std::sort(sort_values.begin(), sort_values.end());

	// 检索排序中轴
	auto temp_anchor = std::make_pair<double, int>(DBL_MAX, -1);
	for (int nidx = 0; nidx < sort_values.size(); ++nidx) {
		auto value_span = std::abs(sort_values[nidx]);
		if (value_span <= temp_anchor.first)
			temp_anchor = std::make_pair(value_span, nidx);
	}

	// 排序值重整
	for (int sorting_idx = 0; sorting_idx < sorting_nodes.size(); ++sorting_idx) {
		auto node = sorting_nodes[sorting_idx];
		auto node_sortv = node->sortNumber().toDouble();
		auto sort_idx = sort_values.indexOf(node_sortv);
		node->setSortNumber(sort_idx - temp_anchor.second);
	}
}

void dags::DAGGraph::graph_adjust_layers_backward(const QList<std::shared_ptr<DAGOrderHelper>>& total_nodes) {
	auto layer_index = this->maxLayerCount() - 1;
	while (layer_index > -1) {
		auto nlist = this->layer_adjust_via_next_sibling(layer_index, total_nodes);
		if (this->current_nodelist_filling_indi(nlist))
			this->nodes_sort_with_belows(layer_index, total_nodes);
		layer_index--;
	};
}

QList<std::shared_ptr<DAGOrderHelper>> dags::DAGGraph::layer_adjust_via_next_sibling(int curr_layer, const QList<std::shared_ptr<DAGOrderHelper>>& total_nodes) {
	QList<std::shared_ptr<DAGOrderHelper>> curr_layer_nodes;
	std::copy_if(total_nodes.begin(), total_nodes.end(), std::back_inserter(curr_layer_nodes),
		[&](std::shared_ptr<DAGOrderHelper> inst) { return inst->layerNumber() == curr_layer; });

	for (auto node : curr_layer_nodes) {
		this->node_adjust_via_next_sibling(node, total_nodes);
	}

	std::sort(curr_layer_nodes.begin(), curr_layer_nodes.end(),
		[](std::shared_ptr<DAGOrderHelper>a, std::shared_ptr<DAGOrderHelper> b)->bool {
			auto prevs_a = a->getUpstreamNodes();
			auto prevs_b = b->getUpstreamNodes();

			if (!prevs_a.size() && !prevs_b.size())
				return a > b;
			if (!prevs_a.size())
				return true;
			if (!prevs_b.size())
				return false;

		auto upnode_a = std::min_element(prevs_a.begin(), prevs_a.end(),
			[](std::shared_ptr<DAGOrderHelper> a, std::shared_ptr<DAGOrderHelper> b) { return a->sortNumber() < b->sortNumber(); });
		auto upnode_b = std::min_element(prevs_b.begin(), prevs_b.end(),
			[](std::shared_ptr<DAGOrderHelper> a, std::shared_ptr<DAGOrderHelper> b) { return a->sortNumber() < b->sortNumber(); });

			return (*upnode_a)->sortNumber() < (*upnode_b)->sortNumber();
		});

	return curr_layer_nodes;
}

void dags::DAGGraph::node_adjust_via_next_sibling(std::shared_ptr<DAGOrderHelper> curr_node, const QList<std::shared_ptr<DAGOrderHelper>>& total_nodes) {
	// 计算下游调整参考节点
	QList<std::shared_ptr<DAGOrderHelper>> next_layer_nodes;
	std::copy_if(total_nodes.begin(), total_nodes.end(), std::back_inserter(next_layer_nodes),
		[&](std::shared_ptr<DAGOrderHelper> inst) {
		if (inst->layerNumber() == curr_node->layerNumber() + 1) {
			if (curr_node->isFakeNode()) {
				if (inst->isFakeNode()) {
					return curr_node->tailsNode() == inst->tailsNode() && curr_node->headsNode() == inst->headsNode();
				}
				return curr_node->headsNode() == inst->layerNode();
			}
			else {
				if (inst->isFakeNode()) {
					return curr_node->layerNode() == inst->tailsNode();
				}
				else {
					auto next_vnodes = curr_node->layerNode()->nextNodes();
					return next_vnodes.contains(inst->layerNode());
				}
			}
		}
		return false;
	});

	std::sort(next_layer_nodes.begin(), next_layer_nodes.end(),
		[](std::shared_ptr<DAGOrderHelper> a, std::shared_ptr<DAGOrderHelper> b) {
		return a->sortNumber() < b->sortNumber();
	});

	if (next_layer_nodes.size()) {
		curr_node->setSortNumber(next_layer_nodes.first()->sortNumber().toDouble());
	}
}

void dags::DAGGraph::nodes_sort_with_belows(int curr_layer, const QList<std::shared_ptr<DAGOrderHelper>>& total_nodes) {
	// 提取所有已知节点
	QList<std::shared_ptr<DAGOrderHelper>> sorting_nodes;
	std::copy_if(total_nodes.begin(), total_nodes.end(), std::back_inserter(sorting_nodes),
		[=](std::shared_ptr<DAGOrderHelper> ins) { return ins->layerNumber() >= curr_layer; });

	// 排序值提取与重排
	QList<double> sort_values;
	std::transform(sorting_nodes.begin(), sorting_nodes.end(), std::back_inserter(sort_values),
		[](std::shared_ptr<DAGOrderHelper> n)->double { return n->sortNumber().toDouble(); });
	sort_values = sort_values.toSet().toList();
	std::sort(sort_values.begin(), sort_values.end());

	// 检索排序中轴
	auto temp_anchor = std::make_pair<double, int>(DBL_MAX, -1);
	for (int nidx = 0; nidx < sort_values.size(); ++nidx) {
		auto value_span = std::abs(sort_values[nidx]);
		if (value_span <= temp_anchor.first)
			temp_anchor = std::make_pair(value_span, nidx);
	}

	// 排序值重整
	for (int sorting_idx = 0; sorting_idx < sorting_nodes.size(); ++sorting_idx) {
		auto node = sorting_nodes[sorting_idx];
		auto sort_idx = sort_values.indexOf(node->sortNumber().toDouble());
		node->setSortNumber(sort_idx - temp_anchor.second);
	}
}




void dags::DAGGraph::primitiveGraphLayout() {
	QList<std::shared_ptr<DAGLayerHelper>> sort_seqs;
	QList<std::shared_ptr<DAGLayerHelper>> refs;
	while (1) {
		auto peaks = this->spawns_peak(refs);
		if (!peaks)
			break;

		sort_seqs.append(peaks);
	}
	this->graph_recovery(sort_seqs);
	for (auto item : sort_seqs) {
		if (!item->inputCount()) {
			this->max_layer_count = std::max(this->max_layer_count, this->node_layering(item, 0));
		}
	}
	for (auto item : sort_seqs) {
		if (!item->inputCount()) {
			this->node_layering_adj(item);
		}
	}

	auto tidy_nodes = this->tidy_graph_nodes();
	this->graph_layout_layers_forward(tidy_nodes);
	this->node_with_layout = tidy_nodes;
}

void dags::DAGGraph::forwardsLayoutImpls() {
	this->graph_layout_layers_forward(this->node_with_layout);
}

void dags::DAGGraph::backwardsLayoutImpls() {
	this->graph_adjust_layers_backward(this->node_with_layout);
}

void dags::DAGGraph::adjustLayoutImpls() {
	
}