import { debounce } from "./dom-utils.js";
import { emitEvent, listenTo } from "./events.js";

const tooltips = {};
let tooltipsCounter = 0;
let lastCoordinates = null;
let suppressTooltips = false;
let activeTooltipTarget = null;

export function initializeTooltips() {
  document.querySelectorAll("[data-retain-tooltip-hover]").forEach(elem =>
      elem.addEventListener("mousemove", e => {
        if (lastCoordinates !== null) {
          e.stopPropagation();
          lastCoordinates = { x: e.pageX, y: e.pageY };
          emitEvent("tooltips:show");
        }
      }));
  window.addEventListener("mousemove", () => {
    if (lastCoordinates !== null) {
      emitEvent("tooltips:hide");
    }
    lastCoordinates = null;
  });
  window.addEventListener("mousemove", debounce(e => {
    lastCoordinates = { x: e.pageX, y: e.pageY };
    emitEvent("tooltips:show");
  }, 500));
  window.addEventListener("wheel", () => {
    if (lastCoordinates !== null) {
      setTimeout(() => emitEvent("tooltips:show"), 200);
    }
  });

  listenTo("tooltips:show", showTooltip);
  listenTo("tooltips:hide", hideTooltip);

  document.addEventListener("keydown", e => {
    if (e.key === "T") {
      suppressTooltips = !suppressTooltips;
    }
  });
}

export function createTooltip(data) {
  const id = tooltipsCounter;
  tooltips[id] = data;
  tooltipsCounter++;
  return id;
}

export function getTooltip(id) {
  return tooltips[id];
}

export function deleteTooltip(id) {
  delete tooltips[id];
}

export function positionAsTooltip(mainElement, tooltipElement, { horizontal = "left", vertical = "bottom" } = {}) {
  const targetRect = mainElement.getBoundingClientRect();
  const domRect = tooltipElement.getBoundingClientRect();
  const windowWidth = window.innerWidth, windowHeight = window.innerHeight;
  tooltipElement.style.left = `${Math.min(targetRect[horizontal], windowWidth - domRect.width)}px`;
  tooltipElement.style.top = `${Math.min(targetRect[vertical], windowHeight - domRect.height)}px`;
}

function showTooltip() {
  if (suppressTooltips) return;
  if (!lastCoordinates) return;
  if (activeTooltipTarget) hideTooltip();

  const target = document.elementFromPoint(lastCoordinates.x, lastCoordinates.y);
  if (!target) return;
  if (!target.dataset.tooltip) return;

  const dom = createTooltipDom(target.dataset.tooltip);
  if (!dom) return;

  const targetRect = target.getBoundingClientRect();
  dom.style.left = `${targetRect.left}px`;
  dom.style.top = `${targetRect.bottom}px`;

  target.appendChild(dom);
  positionAsTooltip(target, dom);

  activeTooltipTarget = target;
}
function hideTooltip() {
  if (suppressTooltips) return;
  if (!activeTooltipTarget) return;

  const tooltip = activeTooltipTarget.querySelector(".tooltip");
  if (!tooltip) return;

  activeTooltipTarget.removeChild(tooltip);
  activeTooltipTarget = null;
}

function createTooltipDom(id) {
  const data = tooltips[id];
  if (!Array.isArray(data)) {
    console.warn("tooltip %s is not an array: %o", id, data);
    return null;
  }
  const div = document.createElement("div");
  div.classList.add("tooltip");
  for (const row of data) {
    const rowElem = document.createElement("div");

    if (typeof row === "string") {
      rowElem.innerText = row;
    } else {
      // TODO: support rich tooltips
      throw row;
    }

    div.appendChild(rowElem);
  }
  return div;
}