package net.minecraft.util.profiling;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.mojang.datafixers.util.Pair;
import com.mojang.logging.LogUtils;
import it.unimi.dsi.fastutil.longs.LongArrayList;
import it.unimi.dsi.fastutil.longs.LongList;
import it.unimi.dsi.fastutil.objects.Object2LongMap;
import it.unimi.dsi.fastutil.objects.Object2LongMaps;
import it.unimi.dsi.fastutil.objects.Object2LongOpenHashMap;
import it.unimi.dsi.fastutil.objects.ObjectArraySet;
import java.time.Duration;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.BooleanSupplier;
import java.util.function.IntSupplier;
import java.util.function.LongSupplier;
import java.util.function.Supplier;
import net.minecraft.util.Util;
import net.minecraft.util.profiling.metrics.MetricCategory;
import org.jspecify.annotations.Nullable;
import org.slf4j.Logger;

public class ActiveProfiler implements ProfileCollector {
	private static final long WARNING_TIME_NANOS = Duration.ofMillis(100L).toNanos();
	private static final Logger LOGGER = LogUtils.getLogger();
	private final List<String> paths = Lists.<String>newArrayList();
	private final LongList startTimes = new LongArrayList();
	private final Map<String, ActiveProfiler.PathEntry> entries = Maps.<String, ActiveProfiler.PathEntry>newHashMap();
	private final IntSupplier getTickTime;
	private final LongSupplier getRealTime;
	private final long startTimeNano;
	private final int startTimeTicks;
	private String path = "";
	private boolean started;
	@Nullable
	private ActiveProfiler.PathEntry currentEntry;
	private final BooleanSupplier suppressWarnings;
	private final Set<Pair<String, MetricCategory>> chartedPaths = new ObjectArraySet<>();

	public ActiveProfiler(final LongSupplier getRealTime, final IntSupplier getTickTime, final BooleanSupplier suppressWarnings) {
		this.startTimeNano = getRealTime.getAsLong();
		this.getRealTime = getRealTime;
		this.startTimeTicks = getTickTime.getAsInt();
		this.getTickTime = getTickTime;
		this.suppressWarnings = suppressWarnings;
	}

	@Override
	public void startTick() {
		if (this.started) {
			LOGGER.error("Profiler tick already started - missing endTick()?");
		} else {
			this.started = true;
			this.path = "";
			this.paths.clear();
			this.push("root");
		}
	}

	@Override
	public void endTick() {
		if (!this.started) {
			LOGGER.error("Profiler tick already ended - missing startTick()?");
		} else {
			this.pop();
			this.started = false;
			if (!this.path.isEmpty()) {
				LOGGER.error(
					"Profiler tick ended before path was fully popped (remainder: '{}'). Mismatched push/pop?", LogUtils.defer(() -> ProfileResults.demanglePath(this.path))
				);
			}
		}
	}

	@Override
	public void push(final String name) {
		if (!this.started) {
			LOGGER.error("Cannot push '{}' to profiler if profiler tick hasn't started - missing startTick()?", name);
		} else {
			if (!this.path.isEmpty()) {
				this.path = this.path + "\u001e";
			}

			this.path = this.path + name;
			this.paths.add(this.path);
			this.startTimes.add(Util.getNanos());
			this.currentEntry = null;
		}
	}

	@Override
	public void push(final Supplier<String> name) {
		this.push((String)name.get());
	}

	@Override
	public void markForCharting(final MetricCategory category) {
		this.chartedPaths.add(Pair.of(this.path, category));
	}

	@Override
	public void pop() {
		if (!this.started) {
			LOGGER.error("Cannot pop from profiler if profiler tick hasn't started - missing startTick()?");
		} else if (this.startTimes.isEmpty()) {
			LOGGER.error("Tried to pop one too many times! Mismatched push() and pop()?");
		} else {
			long endTime = Util.getNanos();
			long startTime = this.startTimes.removeLong(this.startTimes.size() - 1);
			this.paths.removeLast();
			long time = endTime - startTime;
			ActiveProfiler.PathEntry currentEntry = this.getCurrentEntry();
			currentEntry.accumulatedDuration += time;
			currentEntry.count++;
			currentEntry.maxDuration = Math.max(currentEntry.maxDuration, time);
			currentEntry.minDuration = Math.min(currentEntry.minDuration, time);
			if (time > WARNING_TIME_NANOS && !this.suppressWarnings.getAsBoolean()) {
				LOGGER.warn(
					"Something's taking too long! '{}' took aprox {} ms", LogUtils.defer(() -> ProfileResults.demanglePath(this.path)), LogUtils.defer(() -> time / 1000000.0)
				);
			}

			this.path = this.paths.isEmpty() ? "" : (String)this.paths.getLast();
			this.currentEntry = null;
		}
	}

	@Override
	public void popPush(final String name) {
		this.pop();
		this.push(name);
	}

	@Override
	public void popPush(final Supplier<String> name) {
		this.pop();
		this.push(name);
	}

	private ActiveProfiler.PathEntry getCurrentEntry() {
		if (this.currentEntry == null) {
			this.currentEntry = (ActiveProfiler.PathEntry)this.entries.computeIfAbsent(this.path, key -> new ActiveProfiler.PathEntry());
		}

		return this.currentEntry;
	}

	@Override
	public void incrementCounter(final String name, final int amount) {
		this.getCurrentEntry().counters.addTo(name, amount);
	}

	@Override
	public void incrementCounter(final Supplier<String> name, final int amount) {
		this.getCurrentEntry().counters.addTo((String)name.get(), amount);
	}

	@Override
	public ProfileResults getResults() {
		return new FilledProfileResults(this.entries, this.startTimeNano, this.startTimeTicks, this.getRealTime.getAsLong(), this.getTickTime.getAsInt());
	}

	@Nullable
	@Override
	public ActiveProfiler.PathEntry getEntry(final String path) {
		return (ActiveProfiler.PathEntry)this.entries.get(path);
	}

	@Override
	public Set<Pair<String, MetricCategory>> getChartedPaths() {
		return this.chartedPaths;
	}

	public static class PathEntry implements ProfilerPathEntry {
		private long maxDuration = Long.MIN_VALUE;
		private long minDuration = Long.MAX_VALUE;
		private long accumulatedDuration;
		private long count;
		private final Object2LongOpenHashMap<String> counters = new Object2LongOpenHashMap<>();

		@Override
		public long getDuration() {
			return this.accumulatedDuration;
		}

		@Override
		public long getMaxDuration() {
			return this.maxDuration;
		}

		@Override
		public long getCount() {
			return this.count;
		}

		@Override
		public Object2LongMap<String> getCounters() {
			return Object2LongMaps.unmodifiable(this.counters);
		}
	}
}