From 7b2bf96c5d8bdb152b325b68b239de46415833f0 Mon Sep 17 00:00:00 2001
From: Hiroshi Ogawa <hi.ogawa.zz@gmail.com>
Date: Thu, 7 Sep 2023 15:16:36 +0900
Subject: [PATCH] feat: replace headlessui Transition

---
 packages/app/src/components/transition.tsx | 242 +++++++++++++++++++++
 1 file changed, 242 insertions(+)
 create mode 100644 packages/app/src/components/transition.tsx

diff --git a/packages/app/src/components/transition.tsx b/packages/app/src/components/transition.tsx
new file mode 100644
index 00000000..89a52415
--- /dev/null
+++ b/packages/app/src/components/transition.tsx
@@ -0,0 +1,242 @@
+// the use case of @headlessui/react is limited to simple usage of Transition
+// so implement minimal version on own own
+
+import { typedBoolean } from "@hiogawa/utils";
+import React from "react";
+
+// TODO: rename "enter" => "entering"?
+type TransitionState = "enter" | "leaving" | "left";
+
+interface TransitionClassProps {
+  className?: string;
+  enterFrom?: string;
+  enterTo?: string;
+  // TODO
+  // enter?: string;
+  // entered?: string;
+  // leave?: string;
+  leaveFrom?: string;
+  leaveTo?: string;
+}
+
+interface TransitionEventProps {
+  // TODO
+  // beforeEnter?: () => void;
+  // afterEnter?: () => void;
+  // beforeLeave?: () => void;
+  // afterLeave?: () => void;
+}
+
+export function Transition2(
+  props: React.PropsWithChildren<
+    { show?: boolean } & TransitionClassProps & TransitionEventProps
+  >
+) {
+  const [state, setState] = React.useState<TransitionState>("left");
+
+  React.useEffect(() => {
+    if (props.show && state !== "enter") {
+      setState("enter");
+    }
+    if (!props.show && state === "enter") {
+      setState("leaving");
+    }
+  }, [props.show, state]);
+
+  return (
+    <>
+      {state !== "left" && (
+        <TransitionInner state={state} setState={setState} {...props} />
+      )}
+    </>
+  );
+}
+
+function TransitionInner(
+  props: React.PropsWithChildren<
+    {
+      state: TransitionState;
+      setState: (v: TransitionState) => void;
+    } & TransitionClassProps &
+      TransitionEventProps
+  >
+) {
+  const [manager] = React.useState(
+    () =>
+      new TransitionManager({
+        classes: {
+          className: splitClass(props.className ?? ""),
+          enterFrom: splitClass(props.enterFrom ?? ""),
+          enterTo: splitClass(props.enterTo ?? ""),
+          leaveFrom: splitClass(props.leaveFrom ?? ""),
+          leaveTo: splitClass(props.leaveTo ?? ""),
+        },
+        onChange(state) {
+          props.setState(state);
+        },
+      })
+  );
+
+  React.useSyncExternalStore(
+    React.useCallback((onStorechange) => manager.subscribe(onStorechange), []),
+    () => manager.state
+  );
+
+  // attach to document
+  React.useEffect(() => {
+    manager.startEnter();
+  }, []);
+
+  // leave
+  React.useEffect(() => {
+    if (props.state === "leaving") {
+      manager.startLeave();
+    }
+  }, [props.state]);
+
+  return (
+    <div
+      ref={React.useCallback((el: HTMLElement | null) => {
+        el ? manager.onCreate(el) : manager.onDestroy();
+      }, [])}
+    >
+      {props.children}
+    </div>
+  );
+}
+
+class TransitionManager {
+  private listeners = new Set<() => void>();
+  private disposables = new Set<() => void>();
+  state: TransitionState = "left";
+  el?: HTMLElement;
+
+  constructor(
+    private options: {
+      classes: {
+        className: string[];
+        enterFrom: string[];
+        enterTo: string[];
+        leaveFrom: string[];
+        leaveTo: string[];
+      };
+      onChange: (state: TransitionState) => void;
+    }
+  ) {}
+
+  onCreate(el: HTMLElement) {
+    this.el = el;
+    const classes = this.options.classes;
+
+    // enterFrom
+    el.classList.remove(...Object.values(classes).flat());
+    el.classList.add(...classes.className, ...classes.enterFrom);
+  }
+
+  onDestroy() {
+    this.dispose();
+    this.el = undefined;
+  }
+
+  startEnter() {
+    if (!this.el) return;
+    this.dispose();
+    const el = this.el;
+    const classes = this.options.classes;
+
+    // enterFrom
+    el.classList.remove(...Object.values(classes).flat());
+    el.classList.add(...classes.className, ...classes.enterFrom);
+    forceStyle(el);
+
+    // enterFrom => enterTo
+    el.classList.remove(...classes.enterFrom);
+    el.classList.add(...classes.enterTo);
+
+    // notify after transition
+    // this.disposables.add(onTransitionEnd(el, () => {}));
+  }
+
+  startLeave() {
+    if (!this.el) return;
+    this.dispose();
+    const el = this.el;
+    const classes = this.options.classes;
+
+    // leaveFrom
+    el.classList.remove(...Object.values(classes).flat());
+    el.classList.add(...classes.className, ...classes.leaveFrom);
+    forceStyle(el);
+
+    // leaveFrom => leaveTo
+    el.classList.remove(...classes.leaveFrom);
+    el.classList.add(...classes.leaveTo);
+
+    // notify after transition
+    this.disposables.add(onTransitionEnd(el, () => this.notify("left")));
+  }
+
+  private dispose() {
+    this.disposables.forEach((f) => f());
+    this.disposables.clear();
+  }
+
+  // api for React.useSyncExternalStore
+  subscribe(listener: () => void) {
+    this.listeners.add(listener);
+    return () => this.listeners.delete(listener);
+  }
+
+  private notify(state: TransitionState) {
+    if (this.listeners.size === 0) return;
+    this.options.onChange(state);
+    this.listeners.forEach((f) => f());
+  }
+}
+
+//
+// utils
+//
+
+function onTransitionEnd(el: HTMLElement, callback: () => void) {
+  // watch `transitionend`
+  const handler = (e: HTMLElementEventMap["transitionend"]) => {
+    if (e.target === e.currentTarget) {
+      dispose();
+      callback();
+    }
+  };
+  el.addEventListener("transitionend", handler);
+
+  // also setup `transitionDuration` timeout as a fallback
+  const duration = getComputedStyle(el).transitionDuration;
+  const subscription = window.setTimeout(() => {
+    dispose();
+    callback();
+  }, parseDuration(duration));
+
+  function dispose() {
+    el.removeEventListener("transitionend", handler);
+    window.clearTimeout(subscription);
+  }
+
+  return dispose;
+}
+
+function parseDuration(s: string): number {
+  if (s.endsWith("ms")) {
+    return Number(s.slice(0, -2));
+  }
+  if (s.endsWith("s")) {
+    return Number(s.slice(0, -1)) * 1000;
+  }
+  return 0;
+}
+
+function splitClass(c: string): string[] {
+  return c.split(" ").filter(typedBoolean);
+}
+
+function forceStyle(el: Element) {
+  window.getComputedStyle(el).transition ?? console.log("unreachable");
+}