import { Vector3 } from "three";

import type { Vec3 } from "../core/vector";

import type { NavigationController, RuntimeControllerContext } from "./navigation-controller";

const MIN_DISTANCE = 2;
const MAX_DISTANCE = 48;
const MIN_PITCH = 0.15;
const MAX_PITCH = Math.PI * 0.48;

function clampDistance(distance: number): number {
  return Math.max(MIN_DISTANCE, Math.min(MAX_DISTANCE, distance));
}

function clampPitch(pitchRadians: number): number {
  return Math.max(MIN_PITCH, Math.min(MAX_PITCH, pitchRadians));
}

function cloneVec3(vector: Vec3): Vec3 {
  return {
    x: vector.x,
    y: vector.y,
    z: vector.z
  };
}

export class OrbitVisitorNavigationController implements NavigationController {
  readonly id = "orbitVisitor" as const;

  private context: RuntimeControllerContext | null = null;
  private readonly lookAtVector = new Vector3();
  private target: Vec3 = {
    x: 0,
    y: 0,
    z: 0
  };
  private distance = 8;
  private yawRadians = Math.PI * 0.25;
  private pitchRadians = Math.PI * 0.35;
  private dragging = false;
  private lastPointerClientX = 0;
  private lastPointerClientY = 0;
  private initializedFromScene = false;

  activate(ctx: RuntimeControllerContext): void {
    this.context = ctx;

    if (!this.initializedFromScene) {
      const runtimeScene = ctx.getRuntimeScene();
      const focusPoint = runtimeScene.playerStart?.position ?? runtimeScene.sceneBounds?.center ?? this.target;
      const focusDistance = runtimeScene.sceneBounds
        ? Math.max(runtimeScene.sceneBounds.size.x, runtimeScene.sceneBounds.size.y, runtimeScene.sceneBounds.size.z) * 1.1
        : 8;

      this.target = cloneVec3(focusPoint);
      this.distance = clampDistance(focusDistance);
      this.initializedFromScene = true;
    }

    ctx.domElement.addEventListener("pointerdown", this.handlePointerDown);
    ctx.domElement.addEventListener("wheel", this.handleWheel, { passive: false });
    ctx.domElement.addEventListener("contextmenu", this.handleContextMenu);
    window.addEventListener("pointermove", this.handlePointerMove);
    window.addEventListener("pointerup", this.handlePointerUp);

    ctx.setRuntimeMessage("Orbit Visitor active. Drag to orbit around the scene and use the mouse wheel to zoom.");
    ctx.setFirstPersonTelemetry(null);
    this.updateCameraTransform();
  }

  deactivate(ctx: RuntimeControllerContext): void {
    ctx.domElement.removeEventListener("pointerdown", this.handlePointerDown);
    ctx.domElement.removeEventListener("wheel", this.handleWheel);
    ctx.domElement.removeEventListener("contextmenu", this.handleContextMenu);
    window.removeEventListener("pointermove", this.handlePointerMove);
    window.removeEventListener("pointerup", this.handlePointerUp);
    ctx.setRuntimeMessage(null);
    this.dragging = false;
    this.context = null;
  }

  update(_dt: number): void {
    void _dt;
    this.updateCameraTransform();
  }

  setFocusPoint(target: Vec3): void {
    this.target = cloneVec3(target);
    this.updateCameraTransform();
  }

  private updateCameraTransform() {
    if (this.context === null) {
      return;
    }

    const horizontalDistance = Math.cos(this.pitchRadians) * this.distance;
    const cameraPosition = {
      x: this.target.x + Math.sin(this.yawRadians) * horizontalDistance,
      y: this.target.y + Math.sin(this.pitchRadians) * this.distance,
      z: this.target.z + Math.cos(this.yawRadians) * horizontalDistance
    };

    this.context.camera.position.set(cameraPosition.x, cameraPosition.y, cameraPosition.z);
    this.lookAtVector.set(this.target.x, this.target.y, this.target.z);
    this.context.camera.lookAt(this.lookAtVector);
  }

  private handlePointerDown = (event: PointerEvent) => {
    if (event.button !== 0) {
      return;
    }

    this.dragging = true;
    this.lastPointerClientX = event.clientX;
    this.lastPointerClientY = event.clientY;
  };

  private handlePointerMove = (event: PointerEvent) => {
    if (!this.dragging) {
      return;
    }

    const deltaX = event.clientX - this.lastPointerClientX;
    const deltaY = event.clientY - this.lastPointerClientY;
    this.lastPointerClientX = event.clientX;
    this.lastPointerClientY = event.clientY;

    this.yawRadians -= deltaX * 0.008;
    this.pitchRadians = clampPitch(this.pitchRadians + deltaY * 0.008);
  };

  private handlePointerUp = () => {
    this.dragging = false;
  };

  private handleWheel = (event: WheelEvent) => {
    event.preventDefault();
    this.distance = clampDistance(this.distance + event.deltaY * 0.01);
  };

  private handleContextMenu = (event: MouseEvent) => {
    event.preventDefault();
  };
}