Add popover functionality

internal/assets/static/js/popover.js

@@ -0,0 +1,155 @@
+const defaultShowDelayMs = 200;
+const defaultHideDelayMs = 500;
+const defaultMaxWidth = "300px";
+const defaultDistanceFromTarget = "0px"
+const htmlContentSelector = "[data-popover-html]";
+
+let activeTarget = null;
+let pendingTarget = null;
+let cleanupOnHidePopover = null;
+let togglePopoverTimeout = null;
+
+const containerElement = document.createElement("div");
+const containerComputedStyle = getComputedStyle(containerElement);
+containerElement.addEventListener("mouseenter", clearTogglePopoverTimeout);
+containerElement.addEventListener("mouseleave", handleMouseLeave);
+containerElement.classList.add("popover-container");
+
+const frameElement = document.createElement("div");
+frameElement.classList.add("popover-frame");
+
+const contentElement = document.createElement("div");
+contentElement.classList.add("popover-content");
+
+frameElement.append(contentElement);
+containerElement.append(frameElement);
+document.body.append(containerElement);
+
+const observer = new ResizeObserver(repositionContainer);
+
+function handleMouseEnter(event) {
+    clearTogglePopoverTimeout();
+    const target = event.target;
+    pendingTarget = target;
+    const showDelay = target.dataset.popoverShowDelay || defaultShowDelayMs;
+
+    if (activeTarget !== null) {
+        if (activeTarget !== target) {
+            hidePopover();
+            setTimeout(showPopover, 5);
+        }
+
+        return;
+    }
+
+    togglePopoverTimeout = setTimeout(showPopover, showDelay);
+}
+
+function handleMouseLeave(event) {
+    clearTogglePopoverTimeout();
+    const target = activeTarget || event.target;
+    togglePopoverTimeout = setTimeout(hidePopover, target.dataset.popoverHideDelay || defaultHideDelayMs);
+}
+
+function clearTogglePopoverTimeout() {
+    clearTimeout(togglePopoverTimeout);
+}
+
+function showPopover() {
+    activeTarget = pendingTarget;
+    pendingTarget = null;
+
+    const popoverType = activeTarget.dataset.popoverType;
+    const contentMaxWidth = activeTarget.dataset.popoverMaxWidth || defaultMaxWidth;
+
+    if (popoverType === "text") {
+        const text = activeTarget.dataset.popoverText;
+        if (text === undefined || text === "") return;
+        contentElement.textContent = text;
+    } else if (popoverType === "html") {
+        const htmlContent = activeTarget.querySelector(htmlContentSelector);
+        if (htmlContent === null) return;
+        /**
+         * The reason for all of the below shenanigans is that I want to preserve
+         * all attached event listeners of the original HTML content. This is so I don't have to
+         * re-setup events for things like lazy images, they'd just work as expected.
+         */
+        const placeholder = document.createComment("");
+        htmlContent.replaceWith(placeholder);
+        contentElement.replaceChildren(htmlContent);
+        htmlContent.removeAttribute("data-popover-html");
+        cleanupOnHidePopover = () => {
+            htmlContent.setAttribute("data-popover-html", "");
+            placeholder.replaceWith(htmlContent);
+            placeholder.remove();
+        };
+    } else {
+        return;
+    }
+
+    contentElement.style.maxWidth = contentMaxWidth;
+    containerElement.style.display = "block";
+    activeTarget.classList.add("popover-active");
+    document.addEventListener("keydown", handleHidePopoverOnEscape);
+    window.addEventListener("resize", repositionContainer);
+    observer.observe(containerElement);
+}
+
+function repositionContainer() {
+    const activeTargetBounds = activeTarget.getBoundingClientRect();
+    const containerBounds = containerElement.getBoundingClientRect();
+    const containerInlinePadding = parseInt(containerComputedStyle.getPropertyValue("padding-inline"));
+    const activeTargetBoundsWidthOffset = activeTargetBounds.width * (activeTarget.dataset.popoverOffset || 0.5);
+    const left = activeTargetBounds.left + activeTargetBoundsWidthOffset - (containerBounds.width / 2);
+
+    if (left < 0) {
+        containerElement.style.left = 0;
+        containerElement.style.removeProperty("right");
+        containerElement.style.setProperty("--triangle-offset", activeTargetBounds.left - containerInlinePadding + activeTargetBoundsWidthOffset + "px");
+    } else if (left + containerBounds.width > window.innerWidth) {
+        containerElement.style.removeProperty("left");
+        containerElement.style.right = 0;
+        containerElement.style.setProperty("--triangle-offset", containerBounds.width - containerInlinePadding - (window.innerWidth - activeTargetBounds.left - activeTargetBoundsWidthOffset) + "px");
+    } else {
+        containerElement.style.removeProperty("right");
+        containerElement.style.left = left + "px";
+        containerElement.style.removeProperty("--triangle-offset");
+    }
+
+    frameElement.style.marginTop = activeTarget.dataset.popoverMargin || defaultDistanceFromTarget;
+    containerElement.style.top = activeTargetBounds.top + window.scrollY + activeTargetBounds.height + "px";
+}
+
+function hidePopover() {
+    if (activeTarget === null) return;
+
+    activeTarget.classList.remove("popover-active");
+    containerElement.style.display = "none";
+    document.removeEventListener("keydown", handleHidePopoverOnEscape);
+    window.removeEventListener("resize", repositionContainer);
+    observer.unobserve(containerElement);
+
+    if (cleanupOnHidePopover !== null) {
+        cleanupOnHidePopover();
+        cleanupOnHidePopover = null;
+    }
+
+    activeTarget = null;
+}
+
+function handleHidePopoverOnEscape(event) {
+    if (event.key === "Escape") {
+        hidePopover();
+    }
+}
+
+export function setupPopovers() {
+    const targets = document.querySelectorAll("[data-popover-type]");
+
+    for (let i = 0; i < targets.length; i++) {
+        const target = targets[i];
+
+        target.addEventListener("mouseenter", handleMouseEnter);
+        target.addEventListener("mouseleave", handleMouseLeave);
+    }
+}