1 files changed, 73 insertions, 0 deletions
diff --git a/public/shell.js b/public/shell.js
new file mode 100644
index 0000000..9a70846
--- /dev/null
+++ b/public/shell.js
@@ -0,0 +1,73 @@
+const shell = document.querySelector("[data-shell]");
+
+if (shell) {
+  const area = shell.closest("[data-scroll-area]");
+  const history = shell.querySelector("#shell-history");
+  const input = shell.querySelector("[data-shell-input]");
+  const caret = shell.querySelector("[data-shell-caret]");
+  let busy = false;
+
+  const updateCaret = () => {
+    const pos = input.selectionStart ?? input.value.length;
+    caret.style.left = `calc(${pos}ch - ${input.scrollLeft}px)`;
+    caret.textContent = input.value[pos] ?? "\u00a0";
+    caret.style.animation = "none"; // restart the blink so the caret is solid while typing
+    void caret.offsetWidth;
+    caret.style.animation = "";
+  };
+
+  const snapToBottom = () => {
+    area.scrollTop = area.scrollHeight;
+  };
+
+  const run = async (cmd) => {
+    busy = true;
+    try {
+      const res = await fetch("/shell/run", {
+        method: "POST",
+        headers: { "Content-Type": "application/x-www-form-urlencoded" },
+        body: new URLSearchParams({ cmd }),
+      });
+      const data = await res.json();
+      if (data.clear) history.replaceChildren();
+      if (data.html) history.insertAdjacentHTML("beforeend", data.html);
+      if (data.vars) {
+        for (const [key, value] of Object.entries(data.vars)) {
+          document.documentElement.style.setProperty(`--${key}`, value);
+        }
+      }
+    } catch {
+      const el = document.createElement("p");
+      el.textContent = "request failed";
+      history.append(el);
+    } finally {
+      busy = false;
+      snapToBottom();
+    }
+  };
+
+  input.addEventListener("keydown", (e) => {
+    if (e.key !== "Enter") return;
+    e.preventDefault();
+    const cmd = input.value.trim();
+    if (!cmd || busy) return;
+    input.value = "";
+    updateCaret();
+    run(cmd);
+  });
+
+  for (const event of ["input", "keyup", "click", "focus"]) {
+    input.addEventListener(event, updateCaret);
+  }
+  document.addEventListener("selectionchange", () => {
+    if (document.activeElement === input) updateCaret();
+  });
+
+  area.addEventListener("click", () => {
+    if (!getSelection().toString()) input.focus({ preventScroll: true });
+  });
+
+  input.focus({ preventScroll: true });
+  updateCaret();
+  snapToBottom();
+}