import * as THREE from "three";
import { describeHoverLabel, getSelectionGroup } from "./viewerSelection";
import { ACTIVE_SYSTEM_DETAIL_SCALE } from "./viewerConstants";
import { DISPLAY_UNITS_PER_KILOMETER, DISPLAY_UNITS_PER_LIGHT_YEAR, KILOMETERS_PER_AU, formatAdaptiveDistanceFromKilometers, formatSystemDistance } from "./viewerMath";
import type { Selectable, SelectionGroup, WorldState, ZoomLevel } from "./viewerTypes";

export interface HoverPickResult {
  selection: Selectable;
  object: THREE.Object3D;
}

export function pickSelectableAtClientPosition(
  renderer: THREE.WebGLRenderer,
  raycaster: THREE.Raycaster,
  mouse: THREE.Vector2,
  camera: THREE.Camera,
  selectableTargets: Map<THREE.Object3D, Selectable>,
  clientX: number,
  clientY: number,
) {
  const hit = pickSelectableHitAtClientPosition(renderer, raycaster, mouse, camera, selectableTargets, clientX, clientY);
  return hit?.selection;
}

export function pickSelectableHitAtClientPosition(
  renderer: THREE.WebGLRenderer,
  raycaster: THREE.Raycaster,
  mouse: THREE.Vector2,
  camera: THREE.Camera,
  selectableTargets: Map<THREE.Object3D, Selectable>,
  clientX: number,
  clientY: number,
): HoverPickResult | undefined {
  const bounds = renderer.domElement.getBoundingClientRect();
  mouse.x = ((clientX - bounds.left) / bounds.width) * 2 - 1;
  mouse.y = -(((clientY - bounds.top) / bounds.height) * 2 - 1);
  raycaster.setFromCamera(mouse, camera);
  const hit = raycaster.intersectObjects([...selectableTargets.keys()], false)[0];
  const selection = hit ? selectableTargets.get(hit.object) : undefined;
  return hit && selection
    ? { selection, object: hit.object }
    : undefined;
}

export function updateHoverLabel(params: {
  dragMode?: string;
  hoverLabelEl: HTMLDivElement;
  hoverPick: HoverPickResult | undefined;
  activeSystemId?: string;
  zoomLevel: ZoomLevel;
  world?: WorldState;
  point: THREE.Vector2;
  camera: THREE.Camera;
}) {
  const {
    dragMode,
    hoverLabelEl,
    hoverPick,
    activeSystemId,
    zoomLevel,
    world,
    point,
    camera,
  } = params;

  if (dragMode) {
    hoverLabelEl.hidden = true;
    return;
  }

  if (!hoverPick) {
    hoverLabelEl.hidden = true;
    return;
  }

  const { selection, object } = hoverPick;
  const label = describeHoverLabel(world, selection);
  if (!label) {
    hoverLabelEl.hidden = true;
    return;
  }

  const distance = formatHoverDistance(camera, object, selection, zoomLevel, activeSystemId);

  hoverLabelEl.hidden = false;
  hoverLabelEl.textContent = `${label}\n${distance}`;
  hoverLabelEl.style.left = `${point.x + 14}px`;
  hoverLabelEl.style.top = `${point.y + 14}px`;
}

function formatHoverDistance(
  camera: THREE.Camera,
  object: THREE.Object3D,
  selection: Selectable,
  zoomLevel: ZoomLevel,
  activeSystemId?: string,
) {
  const worldPosition = object.getWorldPosition(new THREE.Vector3());
  const displayDistance = camera.position.distanceTo(worldPosition);

  if (selection.kind === "system") {
    return formatAdaptiveDistanceFromKilometers((displayDistance / DISPLAY_UNITS_PER_LIGHT_YEAR) * 9.4607e12);
  }

  const inActiveSystem = selection.kind === "planet"
    ? selection.systemId === activeSystemId
    : selection.kind === "ship"
      || selection.kind === "station"
      || selection.kind === "node"
      || selection.kind === "spatial-node"
      || selection.kind === "bubble"
      || selection.kind === "claim"
      || selection.kind === "construction-site";

  if (inActiveSystem && activeSystemId) {
    const kilometers = displayDistance / (DISPLAY_UNITS_PER_KILOMETER * ACTIVE_SYSTEM_DETAIL_SCALE);
    return zoomLevel === "system"
      ? formatSystemDistance(kilometers / KILOMETERS_PER_AU)
      : formatAdaptiveDistanceFromKilometers(kilometers);
  }

  return formatAdaptiveDistanceFromKilometers(displayDistance / DISPLAY_UNITS_PER_KILOMETER);
}

export function updateMarqueeBox(
  marqueeEl: HTMLDivElement,
  dragStart: THREE.Vector2,
  dragLast: THREE.Vector2,
) {
  const minX = Math.min(dragStart.x, dragLast.x);
  const minY = Math.min(dragStart.y, dragLast.y);
  const maxX = Math.max(dragStart.x, dragLast.x);
  const maxY = Math.max(dragStart.y, dragLast.y);
  marqueeEl.style.left = `${minX}px`;
  marqueeEl.style.top = `${minY}px`;
  marqueeEl.style.width = `${maxX - minX}px`;
  marqueeEl.style.height = `${maxY - minY}px`;
}

export function hideMarqueeBox(marqueeEl: HTMLDivElement) {
  marqueeEl.style.display = "none";
  marqueeEl.style.width = "0";
  marqueeEl.style.height = "0";
}

export function completeMarqueeSelection(params: {
  renderer: THREE.WebGLRenderer;
  camera: THREE.Camera;
  dragStart: THREE.Vector2;
  dragLast: THREE.Vector2;
  selectableTargets: Map<THREE.Object3D, Selectable>;
}) {
  const {
    renderer,
    camera,
    dragStart,
    dragLast,
    selectableTargets,
  } = params;

  const bounds = renderer.domElement.getBoundingClientRect();
  const minX = Math.min(dragStart.x, dragLast.x);
  const minY = Math.min(dragStart.y, dragLast.y);
  const maxX = Math.max(dragStart.x, dragLast.x);
  const maxY = Math.max(dragStart.y, dragLast.y);
  const grouped = new Map<SelectionGroup, Selectable[]>();

  for (const [object, selectable] of selectableTargets.entries()) {
    if (object instanceof THREE.Sprite && !object.visible) {
      continue;
    }
    if (!object.visible) {
      continue;
    }

    const worldPosition = new THREE.Vector3();
    object.getWorldPosition(worldPosition);
    worldPosition.project(camera);
    const screenX = ((worldPosition.x + 1) * 0.5) * bounds.width;
    const screenY = ((1 - worldPosition.y) * 0.5) * bounds.height;
    if (screenX < minX || screenX > maxX || screenY < minY || screenY > maxY) {
      continue;
    }

    const group = getSelectionGroup(selectable);
    const list = grouped.get(group) ?? [];
    if (!list.some((entry) => JSON.stringify(entry) === JSON.stringify(selectable))) {
      list.push(selectable);
    }
    grouped.set(group, list);
  }

  return [...grouped.entries()]
    .sort((left, right) => right[1].length - left[1].length)[0]?.[1] ?? [];
}