package de.mrbesen.youtubecrawler;

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;

public class Profiler {
	private final List<String> sectionList = Lists.<String>newArrayList();
	private final List<Long> timestampList = Lists.<Long>newArrayList();

	/** Flag profiling enabled */
	public boolean profilingEnabled;

	/** Current profiling section */
	private String profilingSection = "";
	private final Map<String, Long> profilingMap = Maps.<String, Long>newHashMap();
	private long start = -1;

	/**
	 * Clear profiling.
	 */
	public void clearProfiling() {
		this.profilingMap.clear();
		this.profilingSection = "";
		this.sectionList.clear();
		start = -1;
	}

	/**
	 * Start section
	 */
	public void startSection(String name) {
		if (this.profilingEnabled) {
			if(start == -1)
				start = System.nanoTime();
			
			if (this.profilingSection.length() > 0) {
				this.profilingSection = this.profilingSection + ".";
			}

			this.profilingSection = this.profilingSection + name;
			this.sectionList.add(this.profilingSection);
			this.timestampList.add(Long.valueOf(System.nanoTime()));
			//System.out.println("started section: " + name + " currently in: " + profilingSection);
		}
	}

	/**
	 * End section
	 */
	public void endSection() {
		if (this.profilingEnabled) {
			try {
				long start = System.nanoTime();
				long stop = ((Long) this.timestampList.remove(this.timestampList.size() - 1)).longValue();
				this.sectionList.remove(this.sectionList.size() - 1);
				long delta = start - stop;

				if (this.profilingMap.containsKey(this.profilingSection)) {
					this.profilingMap.put(this.profilingSection,
							Long.valueOf(((Long) this.profilingMap.get(this.profilingSection)).longValue() + delta));
				} else {
					this.profilingMap.put(this.profilingSection, Long.valueOf(delta));
				}

				this.profilingSection = this.sectionList.isEmpty() ? "" : (String) this.sectionList.get(this.sectionList.size() - 1);
			} catch (Exception e ) {
				e.printStackTrace();
			}
		}
	}

	private int sectioncount(String profilername) {
		int count = 1;
		for(char c : profilername.toCharArray()) {
			if(c == '.')
				count ++;
		}
		return count;
	}

	public List<Profiler.Result> getProfilingData(String profilerName) {
		if (this.profilingEnabled) {
			List<Profiler.Result> out = Lists.<Profiler.Result>newArrayList();
			long totaltime = System.nanoTime() - start;

			//calculate percentage of each child section
			int count = sectioncount(profilerName);
			for (String prfiler_name : this.profilingMap.keySet()) {
				if (prfiler_name.startsWith(profilerName) && sectioncount(prfiler_name) == count+1) {
					long subsectiontime = ((Long) this.profilingMap.get(prfiler_name)).longValue();
					double totaltimep = (double) subsectiontime * 100.0D / (double) totaltime;
					out.add(new Profiler.Result(prfiler_name, totaltimep, subsectiontime));
				}
			}
			
			for (String key : this.profilingMap.keySet()) {
				this.profilingMap.put(key, Long.valueOf(((Long) this.profilingMap.get(key)).longValue() * 999L / 1000L));
			}

			return out;
		} else {
			return Collections.<Profiler.Result>emptyList();
		}
	}

	public LinkedList<String> getTreeView() {
		return getTreeView("root", "");
	}

	private LinkedList<String> getTreeView(String name, String leading) {
		LinkedList<String> out = new LinkedList<>();
		if(new Exception().getStackTrace().length > 50)//prevent stack overflow debug only
			return out;
		
		for(Result res : getProfilingData(name)) {
			out.add(leading + res.profilerName + " " + (res.time/10000000)/100D + "s " + form(res.totalUsePercentage) + "% ");
			out.addAll(getTreeView(res.profilerName, leading + "\t"));
		}
		return out;
	}

	private String form(double d) {
		return (((long) (d*1000))/1000)+"";
	}

	/**
	 * End current section and start a new section
	 */
	public void endStartSection(String name) {
		this.endSection();
		this.startSection(name);
	}

	public String getNameOfLastSection() {
		return this.sectionList.size() == 0 ? "[UNKNOWN]" : (String) this.sectionList.get(this.sectionList.size() - 1);
	}

	public static final class Result {
		public double totalUsePercentage;
		public String profilerName;
		public long time;

		public Result(String profilerName, double totalUsePercentage, long time) {
			this.profilerName = profilerName;
			this.totalUsePercentage = totalUsePercentage;
			this.time = time;
		}
	}
}