package dev.lumareth.improvedAerodynamics.client.pipper;

import net.minecraft.client.multiplayer.ClientLevel;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.core.registries.Registries;
import net.minecraft.resources.ResourceLocation;
import net.minecraft.tags.TagKey;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.block.entity.BlockEntity;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.block.state.properties.DirectionProperty;
import net.minecraft.world.level.block.state.properties.Property;
import net.minecraft.world.level.chunk.ChunkAccess;
import net.minecraft.world.level.chunk.ChunkStatus;
import net.minecraft.world.level.chunk.LevelChunkSection;
import net.minecraftforge.fml.ModList;
import net.minecraftforge.registries.ForgeRegistries;
import org.joml.primitives.AABBic;

import java.util.ArrayList;
import java.util.List;

/**
 * Finds the light autocannon of a ship and works out what it will shoot, the same way Warium's LACFireScript does:
 * barrel count, muzzle, aim direction and muzzle speed.
 */
final class GunFinder {
    private static final ResourceLocation LIGHT_AUTOCANNON = new ResourceLocation("crusty_chunks", "light_autocannon");
    private static final TagKey<Block> BARREL = TagKey.create(Registries.BLOCK, new ResourceLocation("crusty_chunks", "acbarrel"));
    private static final TagKey<Block> PASSTHROUGH = TagKey.create(Registries.BLOCK, new ResourceLocation("crusty_chunks", "barrelpassthrough"));
    private static final int RESCAN_TICKS = 100;
    private static final int MAX_GUNS = 16;

    /** Muzzle and direction in ship space and the speed of the shell in blocks per tick. */
    record Shot(double mx, double my, double mz, double dx, double dy, double dz, double speed) {
    }

    private long shipId = Long.MIN_VALUE;
    private long lastScan = Long.MIN_VALUE;
    private final List<BlockPos> guns = new ArrayList<>();

    /** The gun closest to the seat, or null if the ship has none loaded. */
    Shot find(ClientLevel level, long shipId, AABBic aabb, BlockPos seat) {
        if (shipId != this.shipId || level.getGameTime() - lastScan >= RESCAN_TICKS || level.getGameTime() < lastScan) {
            this.shipId = shipId;
            lastScan = level.getGameTime();
            scan(level, aabb);
        }
        BlockPos best = null;
        double bestDistance = Double.MAX_VALUE;
        for (BlockPos pos : guns) {
            double distance = pos.distSqr(seat);
            if (distance < bestDistance) {
                bestDistance = distance;
                best = pos;
            }
        }
        return best == null ? null : shotOf(level, best);
    }

    private void scan(ClientLevel level, AABBic aabb) {
        guns.clear();
        Block gun = ForgeRegistries.BLOCKS.getValue(LIGHT_AUTOCANNON);
        if (gun == null || aabb == null) {
            return;
        }
        BlockPos.MutableBlockPos pos = new BlockPos.MutableBlockPos();
        for (int cx = aabb.minX() >> 4; cx <= aabb.maxX() >> 4; cx++) {
            for (int cz = aabb.minZ() >> 4; cz <= aabb.maxZ() >> 4; cz++) {
                ChunkAccess chunk = level.getChunk(cx, cz, ChunkStatus.FULL, false);
                if (chunk == null) {
                    continue;
                }
                LevelChunkSection[] sections = chunk.getSections();
                for (int i = 0; i < sections.length; i++) {
                    LevelChunkSection section = sections[i];
                    if (section.hasOnlyAir() || !section.maybeHas(state -> state.is(gun))) {
                        continue;
                    }
                    int baseY = level.getSectionYFromSectionIndex(i) << 4;
                    for (int x = 0; x < 16; x++) {
                        for (int y = 0; y < 16; y++) {
                            for (int z = 0; z < 16; z++) {
                                if (section.getBlockState(x, y, z).is(gun) && guns.size() < MAX_GUNS) {
                                    guns.add(pos.set((cx << 4) + x, baseY + y, (cz << 4) + z).immutable());
                                }
                            }
                        }
                    }
                }
            }
        }
    }

    private static Shot shotOf(ClientLevel level, BlockPos gun) {
        BlockState state = level.getBlockState(gun);
        Property<?> property = state.getBlock().getStateDefinition().getProperty("facing");
        if (!(property instanceof DirectionProperty facingProperty)) {
            return null;
        }
        Direction facing = state.getValue(facingProperty);
        int fx = facing.getStepX();
        int fy = facing.getStepY();
        int fz = facing.getStepZ();

        // Barrels, counted like Warium does: up to five more behind the first one
        double barrels = 1.0;
        for (int i = 0; i < 5 && level.getBlockState(gun.offset(fx * (int) (1 + barrels), fy * (int) (1 + barrels), fz * (int) (1 + barrels))).is(BARREL); i++) {
            barrels++;
        }
        // Muzzle: past the barrels, skipping through blocks the shell passes
        double position = barrels;
        for (int i = 0; i < 10; i++) {
            BlockState at = level.getBlockState(gun.offset(fx * (int) (1 + position), fy * (int) (1 + position), fz * (int) (1 + position)));
            if ((!at.isAir() && !at.canOcclude()) || at.is(PASSTHROUGH)) {
                position++;
            } else {
                break;
            }
        }
        double mx = gun.getX() + fx * (1.5 + position) + 0.5;
        double my = gun.getY() + fy * (1.5 + position) + 0.5;
        double mz = gun.getZ() + fz * (1.5 + position) + 0.5;

        // Aim, from the tags of the gun itself
        double aimX = 0.0;
        double aimY = 0.0;
        double aimZ = 0.0;
        BlockEntity entity = level.getBlockEntity(gun);
        double gx = entity == null ? 0.0 : entity.getPersistentData().getDouble("X");
        double gz = entity == null ? 0.0 : entity.getPersistentData().getDouble("Z");
        double gpitch = entity == null ? 0.0 : entity.getPersistentData().getDouble("Pitch");
        if (1.0 > Math.abs(fx - gx) || 1.0 > Math.abs(fz - gz)) {
            aimY = gpitch;
            aimX = gx + fx;
            aimZ = gz + fz;
        }
        if (aimX * aimZ == 0.0) {
            aimX = fx;
            aimZ = fz;
        }
        double length = Math.sqrt(aimX * aimX + aimY * aimY + aimZ * aimZ);
        if (length < 1.0E-6) {
            return null;
        }

        double speed = PipperConfig.MUZZLE_SPEED_OVERRIDE.get();
        if (speed <= 0.0) {
            double multiplier = ModList.get().isLoaded("ritchiesprojectilelib") ? 2.0 : 1.0;
            speed = (5.0 + barrels / 1.5) * multiplier;
        }
        return new Shot(mx, my, mz, aimX / length, aimY / length, aimZ / length, speed);
    }
}