package com.sk89q.worldedit.command.util.annotation;

import com.fastasyncworldedit.core.configuration.Caption;
import com.fastasyncworldedit.core.util.task.InterruptableCondition;
import com.sk89q.worldedit.IncompleteRegionException;
import com.sk89q.worldedit.WorldEdit;
import com.sk89q.worldedit.command.argument.Arguments;
import com.sk89q.worldedit.event.Event;
import com.sk89q.worldedit.event.platform.CommandEvent;
import com.sk89q.worldedit.extension.platform.Actor;
import com.sk89q.worldedit.internal.annotation.Selection;
import com.sk89q.worldedit.internal.command.CommandArgParser;
import com.sk89q.worldedit.internal.util.Substring;
import com.sk89q.worldedit.math.BlockVector3;
import com.sk89q.worldedit.regions.Region;
import com.sk89q.worldedit.util.formatting.text.TextComponent;
import org.enginehub.piston.exception.StopExecutionException;
import org.enginehub.piston.inject.InjectAnnotation;
import org.enginehub.piston.inject.InjectedValueAccess;
import org.enginehub.piston.inject.Key;
import org.enginehub.piston.inject.MemoizingValueAccess;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Field;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
import java.util.stream.Stream;

/**
 * Indicates how the affected blocks should be hinted at in the log.
 */
@Retention(RetentionPolicy.RUNTIME)
@Target({
        ElementType.PARAMETER,
        ElementType.METHOD
})
@InjectAnnotation
public @interface Confirm {

    Processor value() default Processor.ALWAYS;

    enum Processor {
        REGION {
            @Override
            public boolean passes(Actor actor, InjectedValueAccess context, double value) {
                if (checkExisting(context)) {
                    return true;
                }
                Region region = context
                        .injectedValue(Key.of(Region.class, Selection.class))
                        .orElseThrow(IncompleteRegionException::new);
                BlockVector3 pos1 = region.getMinimumPoint();
                BlockVector3 pos2 = region.getMaximumPoint();
                long area = (pos2.getX() - pos1.getX()) * (pos2.getZ() - pos1.getZ() + 1)
                        * (long) value;
                long max = 2 << 18;
                if (max != -1 && area > max) {
                    actor.print(Caption.of("fawe.cancel.reason.confirm.region",
                            pos1, pos2, getArgs(context), region.getHeight() * area
                    ));
                    return confirm(actor, context);
                }
                return true;
            }
        },
        RADIUS {
            @Override
            public boolean passes(Actor actor, InjectedValueAccess context, double value) {
                if (checkExisting(context)) {
                    return true;
                }
                int max = WorldEdit.getInstance().getConfiguration().maxRadius;
                if (max != -1 && value > max) {
                    actor.print(Caption.of("fawe.cancel.reason.confirm.radius",
                            value, max, getArgs(context)
                    ));
                    return confirm(actor, context);
                }
                return true;
            }
        },
        LIMIT {
            @Override
            public boolean passes(Actor actor, InjectedValueAccess context, double value) {
                if (checkExisting(context)) {
                    return true;
                }
                int max = 50; //TODO configurable, get Key.of(Method.class) @Limit
                if (max != -1 && value > max) {
                    actor.print(Caption.of("fawe.cancel.reason.confirm.limit",
                            value, max, getArgs(context)
                    ));
                    return confirm(actor, context);
                }
                return true;
            }
        },
        ALWAYS {
            @Override
            public boolean passes(Actor actor, InjectedValueAccess context, double value) {
                if (checkExisting(context)) {
                    return true;
                }
                actor.print(Caption.of("fawe.cancel.reason.confirm", Processor.getArgs(context)));
                return confirm(actor, context);
            }
        };

        public boolean passes(Actor actor, InjectedValueAccess context, double value) {
            return true;
        }

        public <T extends Number> T check(Actor actor, InjectedValueAccess context, T value) {
            boolean isSuggestion = context.injectedValue(Key.of(boolean.class)).orElse(false);
            if (isSuggestion) {
                return value;
            }
            if (checkExisting(context)) {
                return value;
            }
            if (!passes(actor, context, value.doubleValue())) {
                throw new StopExecutionException(TextComponent.empty());
            }
            return value;
        }

        private static String getArgs(InjectedValueAccess context) {
            return context.injectedValue(Key.of(Arguments.class)).map(Arguments::get).get();
        }

        private static String getArg(InjectedValueAccess context, String def) {
            Stream<Substring> split = CommandArgParser.forArgString(getArgs(context)).parseArgs();
            Substring first = split.findFirst().orElse(null);
            if (first == null && def == null) {
                throw new StopExecutionException(TextComponent.of("No arguments"));
            }
            return first != null ? first.getSubstring() : def;
        }

        private static int getInt(InjectedValueAccess context, String def) {
            return Integer.parseInt(getArg(context, def));
        }

        private static boolean confirm(Actor actor, InjectedValueAccess context) {
            Event event = context.injectedValue(Key.of(Event.class)).orElse(null);
            if (!(event instanceof CommandEvent)) {
                return true;
            }
            ReentrantLock lock = new ReentrantLock();
            Condition condition = lock.newCondition();
            InterruptableCondition wait = new InterruptableCondition(lock, condition, Thread.currentThread());
            try {
                lock.lock();
                actor.setMeta("cmdConfirm", wait);
                try {
                    // This is really dumb but also stops the double //confirm requirement...
                    final MemoizingValueAccess memoizingValueAccess;
                    if (!(context instanceof MemoizingValueAccess)) {
                        if (!context.getClass().getSimpleName().contains("AutoValue_CommandParametersImpl")) {
                            return true;
                        }
                        memoizingValueAccess = (MemoizingValueAccess) Reflect.injectedValues.get(context);
                    } else {
                        memoizingValueAccess = (MemoizingValueAccess) context;
                    }
                    Map<Key<?>, Optional<?>> memory = (Map<Key<?>, Optional<?>>) Reflect.memory.get(memoizingValueAccess);
                    memory.put(Key.of(InterruptableCondition.class), Optional.of(wait));
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
                // Waits till 15 seconds then returns false unless awakened
                if (condition.await(15, TimeUnit.SECONDS)) {
                    return true;
                }
            } catch (InterruptedException ignored) {
            } finally {
                if (actor.getMeta("cmdConfirm") == wait) {
                    actor.deleteMeta("cmdConfirm");
                }
            }
            return false;
        }

        boolean checkExisting(InjectedValueAccess context) {
            Optional<InterruptableCondition> lock = context.injectedValue(Key.of(InterruptableCondition.class));
            // lock if locked will be held by current thread unless something has gone REALLY wrong
            //  in which case this is the least of our worries...
            return lock.isPresent();
        }
    }

    class Reflect {

        static final Field memory;
        static final Field injectedValues;

        static {
            Field memoryField;
            try {
                memoryField = MemoizingValueAccess.class.getDeclaredField("memory");
                memoryField.setAccessible(true);
            } catch (NoSuchFieldException e) {
                e.printStackTrace();
                memoryField = null;
            }
            memory = memoryField;

            Field injectedValuesField;
            try {
                Class<?> c = Class.forName("org.enginehub.piston.impl.AutoValue_CommandParametersImpl");
                injectedValuesField = c.getDeclaredField("injectedValues");
                injectedValuesField.setAccessible(true);
            } catch (NoSuchFieldException | ClassNotFoundException e) {
                e.printStackTrace();
                injectedValuesField = null;
            }
            injectedValues = injectedValuesField;
        }
    }

}