import { useCallback, useEffect, useMemo, useRef } from "react";
import { RigidBody, TrimeshCollider } from "@react-three/rapier";
import {
  AdditiveBlending,
  DoubleSide,
  Mesh,
  NormalBlending,
  type InstancedMesh,
  type Material,
  type Object3D,
} from "three";
import type { ResolvedDungeonAssets } from "../game/dungeonAssets";
import type { DungeonDefinition, DungeonMaterialRoles } from "../game/dungeonTypes";
import { useGameStore } from "../game/store";
import { collisionTrimeshes, prepareCollision } from "./productionDungeonCollision";
import { disposeObject3DResources } from "./threeResourceDisposal";
import { useGameGLTF } from "./useGameGLTF";

function matchesRole(name: string, patterns: readonly string[], names: readonly string[]): boolean {
  const lower = name.toLowerCase();
  return names.some((candidate) => candidate.toLowerCase() === lower)
    || patterns.some((pattern) => new RegExp(pattern, "i").test(name));
}

function prepareMaterial(source: Material, roles: DungeonMaterialRoles): Material {
  const material = source.clone();
  const name = material.name;
  material.side = DoubleSide;

  if (matchesRole(name, roles.cutoutPatterns, roles.cutoutNames)) {
    material.transparent = false;
    material.opacity = 1;
    material.alphaTest = 0.5;
    material.depthWrite = true;
    material.blending = NormalBlending;
  } else if (matchesRole(name, roles.additivePatterns, roles.additiveNames)) {
    material.transparent = true;
    material.depthWrite = false;
    material.blending = AdditiveBlending;
  } else if (matchesRole(name, roles.blendPatterns, roles.blendNames)) {
    material.transparent = true;
    material.depthWrite = false;
    material.blending = NormalBlending;
  } else {
    material.transparent = false;
    material.opacity = 1;
    material.alphaTest = 0;
    material.depthWrite = true;
    material.blending = NormalBlending;
  }

  material.needsUpdate = true;
  return material;
}

function prepareVisual(root: Object3D, roles: DungeonMaterialRoles): Object3D {
  const clone = root.clone(true);
  const clonedMaterials = new Map<string, Material>();
  clone.traverse((node) => {
    const mesh = node as Mesh;
    if (!mesh.isMesh) return;
    const sources = Array.isArray(mesh.material) ? mesh.material : [mesh.material];
    const prepared = sources.map((source) => {
      const cached = clonedMaterials.get(source.uuid);
      if (cached) return cached;
      const next = prepareMaterial(source, roles);
      clonedMaterials.set(source.uuid, next);
      return next;
    });
    mesh.material = Array.isArray(mesh.material) ? prepared : prepared[0];
    mesh.castShadow = false;
    mesh.receiveShadow = true;
    const instanced = mesh as InstancedMesh;
    if (instanced.isInstancedMesh) {
      instanced.computeBoundingBox();
      instanced.computeBoundingSphere();
    }
  });
  return clone;
}

function VisualChunk({ url, definition }: { readonly url: string; readonly definition: DungeonDefinition }) {
  const gltf = useGameGLTF(url);
  const visual = useMemo(
    () => prepareVisual(gltf.scene, definition.presentation.materials),
    [definition.presentation.materials, gltf.scene],
  );
  useEffect(() => () => { disposeObject3DResources(visual); }, [visual]);
  const { position, rotation, scale } = definition.transform;
  return <primitive object={visual} position={position} rotation={rotation} scale={scale} />;
}

function CollisionChunk({
  url,
  definition,
  registerPrepared,
}: {
  readonly url: string;
  readonly definition: DungeonDefinition;
  readonly registerPrepared: (url: string, ready: boolean) => void;
}) {
  const gltf = useGameGLTF(url);
  const collision = useMemo(() => prepareCollision(gltf.scene), [gltf.scene]);
  const trimeshes = useMemo(() => collisionTrimeshes(collision), [collision]);
  useEffect(() => () => {
    disposeObject3DResources(collision, {
      materials: false,
      textures: false,
      skeletons: false,
    });
  }, [collision]);
  useEffect(() => {
    registerPrepared(url, trimeshes.length > 0);
    return () => registerPrepared(url, false);
  }, [registerPrepared, trimeshes.length, url]);
  const { position, rotation, scale } = definition.transform;
  return (
    <RigidBody
      type="fixed"
      colliders={false}
      name={`${definition.id}-collision`}
      position={position}
      rotation={rotation}
      scale={scale}
    >
      {trimeshes.map((trimesh) => (
        <TrimeshCollider
          key={trimesh.id}
          args={[trimesh.vertices, trimesh.indices]}
        />
      ))}
      <primitive object={collision} />
    </RigidBody>
  );
}

export function ProductionDungeon({
  definition,
  assets,
  onReady,
}: {
  readonly definition: DungeonDefinition;
  readonly assets: ResolvedDungeonAssets;
  readonly onReady?: () => void;
}) {
  if (!assets.visual.length || !assets.collision.length) {
    throw new Error(`${definition.title} mounted without its required visual and collision GLBs.`);
  }
  const preparedCollisions = useRef(new Set<string>());
  const signalledFirstFrame = useRef(false);
  const registerPrepared = useCallback((url: string, ready: boolean) => {
    if (!ready) {
      preparedCollisions.current.delete(url);
      return;
    }
    preparedCollisions.current.add(url);
    if (signalledFirstFrame.current) return;
    if (preparedCollisions.current.size < assets.collision.length) return;
    signalledFirstFrame.current = true;
    useGameStore.getState().setAssetStatus("ready");
    onReady?.();
  }, [assets.collision.length, onReady]);

  return (
    <group name={`${definition.id}-production`}>
      {assets.visual.map((url) => <VisualChunk key={url} url={url} definition={definition} />)}
      {assets.collision.map((url) => (
        <CollisionChunk
          key={url}
          url={url}
          definition={definition}
          registerPrepared={registerPrepared}
        />
      ))}
    </group>
  );
}