package com.thebrokenrail.energonrelics.block.entity;

import com.thebrokenrail.energonrelics.Config;
import com.thebrokenrail.energonrelics.EnergonRelics;
import com.thebrokenrail.energonrelics.block.DefensiveLaserBlock;
import com.thebrokenrail.energonrelics.energy.core.EnergyReceiverBlockEntity;
import com.thebrokenrail.energonrelics.energy.core.util.Action;
import net.minecraft.block.BlockState;
import net.minecraft.block.entity.BlockEntityType;
import net.minecraft.entity.LivingEntity;
import net.minecraft.nbt.CompoundTag;
import net.minecraft.particle.ParticleTypes;
import net.minecraft.server.world.ServerWorld;
import net.minecraft.util.hit.HitResult;
import net.minecraft.util.math.Box;
import net.minecraft.util.math.Direction;
import net.minecraft.util.math.MathHelper;
import net.minecraft.util.math.Vec3d;
import net.minecraft.world.RayTraceContext;

import java.util.Collections;
import java.util.List;
import java.util.Optional;
import java.util.function.Predicate;

public class DefensiveLaserBlockEntity extends EnergyReceiverBlockEntity {
    private static final float MAX_PITCH = 60;
    private static final float MIN_PITCH = -20;

    private static final float ROTATION_INCREMENT = 2;

    private static final int COUNTDOWN = 6;

    public final Rotation rotation = new Rotation(0, 0, "Rotation");
    private LivingEntity target;
    private int countdown = 0;

    private final Predicate<LivingEntity> predicate = entity -> {
        if (entity.getBlockPos().isWithinDistance(getPos(), Config.DEFENSIVE_LASER_RANGE)) {
            Vec3d start = getPosVec().add(rotation.getRayVector());
            Vec3d end = entity.getPos();
            HitResult result = entity.getEntityWorld().rayTrace(new RayTraceContext(start, end, RayTraceContext.ShapeType.COLLIDER, RayTraceContext.FluidHandling.ANY, entity));
            return result.getType() == HitResult.Type.MISS;
        } else {
            return false;
        }
    };

    private Vec3d getPosVec() {
        return new Vec3d(getPos().getX() + 0.5d, getPos().getY() + 0.5d, getPos().getZ() + 0.5d);
    }

    @Override
    public BlockState getCachedState() {
        if (hasWorld()) {
            return super.getCachedState();
        } else {
            return EnergonRelics.DEFENSIVE_LASER_BLOCK.getDefaultState();
        }
    }

    private interface SwapFunction {
        class SwapData {
            private final float yaw;
            private final float pitch;

            public SwapData(float yaw, float pitch) {
                this.yaw = yaw;
                this.pitch = pitch;
            }
        }

        Vec3d swap(SwapData data);
        SwapData line(Vec3d data);

        static SwapFunction upDown(boolean up) {
            return new SwapFunction() {
                @Override
                public Vec3d swap(SwapData data) {
                    return new Vec3d(-data.yaw, data.pitch, 0);
                }

                private SwapData reverseSwap(Vec3d data) {
                    return new SwapData((float) -data.getX(), (float) data.getY());
                }

                @Override
                public SwapData line(Vec3d data) {
                    SwapData reverse = reverseSwap(data);
                    return new SwapData(-reverse.yaw, reverse.pitch);
                }
            };
        }
        static SwapFunction northSouth(boolean north) {
            return new SwapFunction() {
                @Override
                public Vec3d swap(SwapData data) {
                    if (north) {
                        return new Vec3d(0, data.pitch, data.yaw);
                    } else {
                        return new Vec3d(0, -data.pitch, data.yaw);
                    }
                }

                private SwapData reverseSwap(Vec3d data) {
                    if (north) {
                        return new SwapData((float) data.getZ(), (float) data.getY());
                    } else {
                        return new SwapData((float) data.getZ(), (float) -data.getY());
                    }
                }

                @Override
                public SwapData line(Vec3d data) {
                    SwapData reverse = reverseSwap(data);
                    if (north) {
                        return new SwapData(reverse.pitch + 90, reverse.yaw + 90);
                    } else {
                        return new SwapData(reverse.pitch - 180, reverse.yaw - 90);
                    }
                }
            };
        }
        SwapFunction SWAP_PITCH_ROLL = new SwapFunction() {
            @Override
            public Vec3d swap(SwapData data) {
                return new Vec3d(data.yaw, data.pitch, 0);
            }

            private SwapData reverseSwap(Vec3d data) {
                return new SwapData((float) data.getX(), (float) data.getY());
            }

            @Override
            public SwapData line(Vec3d data) {
                SwapData reverse = reverseSwap(data);
                return new SwapData(-reverse.pitch, reverse.yaw);
            }
        };
    }

    public class Rotation {
        private float yaw = 0;
        private float pitch = 0;
        private final String key;

        private Rotation(float yaw, float pitch, String key) {
            setRaw(yaw, pitch);
            this.key = key;
        }

        private void fromTag(CompoundTag tag) {
            CompoundTag rotation = tag.getCompound(key);
            setRaw(rotation.getInt("Yaw"), rotation.getInt("Pitch"));
        }

        private void toTag(CompoundTag tag) {
            CompoundTag rotation = new CompoundTag();
            rotation.putFloat("Yaw", yaw);
            rotation.putFloat("Pitch", pitch);
            tag.put(key, rotation);
        }

        private void change(float yaw, float pitch) {
            setRaw(this.yaw + yaw, this.pitch + pitch);
            markDirty();
        }

        private void setRaw(float yaw, float pitch) {
            setYaw(yaw);
            setPitch(pitch);
        }

        private void setYaw(float yaw) {
            this.yaw = yaw % 360;
        }

        private void setPitch(float pitch) {
            this.pitch = Math.max(MIN_PITCH, Math.min(MAX_PITCH, pitch % 360));
        }

        public float getYaw(boolean display) {
            return (float) getBaseVector(display).getX();
        }

        public float getPitch(boolean display) {
            return (float) getBaseVector(display).getY();
        }

        public float getRoll(boolean display) {
            return (float) getBaseVector(display).getZ();
        }

        private Vec3d getBaseModifier() {
            Direction facing = getCachedState().get(DefensiveLaserBlock.FACING);
            switch (facing) {
                case DOWN: {
                    return new Vec3d(0, 0, 0);
                }
                case UP: {
                    return new Vec3d(0, 180, 0);
                }
                case NORTH: {
                    return new Vec3d(0, 0, 90);
                }
                case SOUTH: {
                    return new Vec3d(180, 90, 90);
                }
                case EAST: {
                    return new Vec3d(180, 0, 90);
                }
                case WEST: {
                    return new Vec3d(0, 0, -90);
                }
                default: {
                    throw new UnsupportedOperationException();
                }
            }
        }

        public SwapFunction getSwapFunction() {
            Direction facing = getCachedState().get(DefensiveLaserBlock.FACING);
            switch (facing) {
                case DOWN: {
                    return SwapFunction.upDown(false);
                }
                case UP: {
                    return SwapFunction.upDown(true);
                }
                case EAST:
                case WEST: {
                    return SwapFunction.SWAP_PITCH_ROLL;
                }
                case NORTH: {
                    return SwapFunction.northSouth(true);
                }
                case SOUTH: {
                    return SwapFunction.northSouth(false);
                }
                default: {
                    throw new UnsupportedOperationException();
                }
            }
        }

        private Vec3d getBaseVector(boolean display) {
            Vec3d modifier = getBaseModifier();
            return getSwapFunction().swap(new SwapFunction.SwapData(yaw, -(pitch - (display ? 45 : 0)))).add(modifier);
        }

        private Vec3d getRayVector() {
            SwapFunction.SwapData data = getSwapFunction().line(getBaseVector(false));
            float pitch = data.pitch * (float) DEG2RAD;
            float yaw = data.yaw * (float) DEG2RAD;
            float cosYaw = MathHelper.cos(yaw);
            float sinYaw = MathHelper.sin(yaw);
            float cosPitch = MathHelper.cos(pitch);
            float sinPitch = MathHelper.sin(pitch);
            return new Vec3d(sinYaw * cosPitch, -sinPitch, cosYaw * cosPitch);
        }

        private float getAngleChange(float from, float to) {
            float diff = MathHelper.subtractAngles(from, to);
            return MathHelper.clamp(diff, -ROTATION_INCREMENT, ROTATION_INCREMENT);
        }

        private void target(float targetYaw, float targetPitch) {
            SwapFunction function = getSwapFunction();
            SwapFunction.SwapData data = function.line(getBaseVector(false));
            Vec3d vec = new Vec3d(targetYaw, targetPitch, 0);
            float yawChange = getAngleChange(data.yaw, (float) vec.getX());
            float pitchChange = getAngleChange(data.pitch, (float) vec.getY());
            change(yawChange, pitchChange);
        }
    }

    public DefensiveLaserBlockEntity(BlockEntityType<?> type) {
        super(type);
    }

    public static final double DEG2RAD = Math.PI / 180d;
    private static final double RAD2DEG = 180d / Math.PI;

    private float getTargetPitch(double x, double y, double z) {
        Vec3d pos = getPosVec();
        double diffX = x - pos.getX();
        double diffY = y - pos.getY();
        double diffZ = z - pos.getZ();
        double g = MathHelper.sqrt(diffX * diffX + diffZ * diffZ);
        return (float) -(MathHelper.atan2(diffY, g) * RAD2DEG);
    }

    private float getTargetYaw(double x, double z) {
        Vec3d pos = getPosVec();
        double diffX = x - pos.getX();
        double diffZ = z - pos.getZ();
        return (float) (MathHelper.atan2(diffZ, diffX) * RAD2DEG) - 90.0F;
    }

    @Override
    protected void tickEnergy() {
        assert getWorld() != null;
        Vec3d vec = rotation.getRayVector().add(getPosVec());
        ((ServerWorld) getWorld()).spawnParticles(ParticleTypes.END_ROD, vec.getX(), vec.getY(), vec.getZ(), 1, 0, 0, 0, 0);
        addAction(Action.createBlockStatePropertyAction(Config.DEFENSIVE_LASER_IDLE_ENERGY_REQUIRED, DefensiveLaserBlock.POWERED, true, false));
        rotation.target(45, 45);
        if (getCachedState().get(DefensiveLaserBlock.POWERED)) {
            if (countdown > 0) {
                countdown--;
            }
            if (countdown == 1) {
                // Fire!
                target = null;
            } else if (countdown < 1) {
                if (target == null) {
                    List<LivingEntity> entities = getWorld().getEntities(LivingEntity.class, new Box(getPos()).expand(Config.DEFENSIVE_LASER_RANGE), predicate);
                    if (entities.size() > 0) {
                        Collections.shuffle(entities);
                        target = entities.get(0);
                    }
                } else {
                    if (predicate.test(target)) {
                        Optional<Vec3d> optional = target.getBoundingBox().rayTrace(getPosVec(), getPosVec().add(rotation.getRayVector().multiply(Config.DEFENSIVE_LASER_RANGE)));
                        if (optional.isPresent()) {
                            countdown = COUNTDOWN;
                        } else {
                            Vec3d targetPos = target.getPos();
                            float targetYaw = getTargetYaw(targetPos.getX(), targetPos.getZ());
                            float targetPitch = getTargetPitch(targetPos.getX(), targetPos.getY(), targetPos.getZ());
                            rotation.target(targetYaw, targetPitch);
                        }
                    } else {
                        target = null;
                    }
                }
            }
        }
    }

    @Override
    public CompoundTag toTag(CompoundTag tag) {
        super.toTag(tag);
        rotation.toTag(tag);
        tag.putInt("Countdown", countdown);
        return tag;
    }

    @Override
    public void fromTag(BlockState state, CompoundTag tag) {
        super.fromTag(state, tag);
        rotation.fromTag(tag);
        countdown = tag.getInt("Countdown");
    }
}