1 files changed, 98 insertions, 0 deletions
diff --git a/services/nuldoc/nuldoc-src/components/Pagination.ts b/services/nuldoc/nuldoc-src/components/Pagination.ts
new file mode 100644
index 0000000..62e796b
--- /dev/null
+++ b/services/nuldoc/nuldoc-src/components/Pagination.ts
@@ -0,0 +1,98 @@
+import { elem, Element } from "../dom.ts";
+
+type Props = {
+  currentPage: number;
+  totalPages: number;
+  basePath: string;
+};
+
+export default function Pagination(
+  { currentPage, totalPages, basePath }: Props,
+): Element {
+  if (totalPages <= 1) {
+    return elem("div", {});
+  }
+
+  const pages = generatePageNumbers(currentPage, totalPages);
+
+  return elem(
+    "nav",
+    { class: "pagination" },
+    elem(
+      "div",
+      { class: "pagination-prev" },
+      currentPage > 1
+        ? elem("a", { href: pageUrlAt(basePath, currentPage - 1) }, "前へ")
+        : null,
+    ),
+    ...pages.map((page) => {
+      if (page === "...") {
+        return elem("div", { class: "pagination-elipsis" }, "…");
+      } else if (page === currentPage) {
+        return elem(
+          "div",
+          { class: "pagination-page pagination-page-current" },
+          elem("span", {}, String(page)),
+        );
+      } else {
+        return elem(
+          "div",
+          { class: "pagination-page" },
+          elem("a", { href: pageUrlAt(basePath, page) }, String(page)),
+        );
+      }
+    }),
+    elem(
+      "div",
+      { class: "pagination-next" },
+      currentPage < totalPages
+        ? elem("a", { href: pageUrlAt(basePath, currentPage + 1) }, "次へ")
+        : null,
+    ),
+  );
+}
+
+type PageItem = number | "...";
+
+/**
+ * Generates page numbers for pagination display.
+ *
+ * - Always show the first page
+ * - Always show the last page
+ * - Always show the current page
+ * - Always show the page before and after the current page
+ * - If there's only one page gap between displayed pages, fill it
+ * - If there are two or more pages gap between displayed pages, show ellipsis
+ */
+function generatePageNumbers(
+  currentPage: number,
+  totalPages: number,
+): PageItem[] {
+  const pages = new Set<number>();
+  pages.add(1);
+  pages.add(Math.max(1, currentPage - 1));
+  pages.add(currentPage);
+  pages.add(Math.min(totalPages, currentPage + 1));
+  pages.add(totalPages);
+
+  const sorted = Array.from(pages).sort((a, b) => a - b);
+
+  const result: PageItem[] = [];
+  for (let i = 0; i < sorted.length; i++) {
+    if (i > 0) {
+      const gap = sorted[i] - sorted[i - 1];
+      if (gap === 2) {
+        result.push(sorted[i - 1] + 1);
+      } else if (gap > 2) {
+        result.push("...");
+      }
+    }
+    result.push(sorted[i]);
+  }
+
+  return result;
+}
+
+function pageUrlAt(basePath: string, page: number): string {
+  return page === 1 ? basePath : `${basePath}${page}/`;
+}