add pagination component

Signed-off-by: Tobias Erbshäußer <tobias@tesoft.dev>

frontend/src/components/pagination.njk

@@ -0,0 +1,40 @@
+<template id="tesoft-pagination-template">
+    <style>
+        @import "/src/styles/default.css";
+
+        :host {
+            display: block;
+        }
+
+        :host > div {
+            align-items: center;
+            display: grid;
+            grid-template-columns: auto auto auto;
+            grid-template-rows: auto;
+        }
+
+        .cur-page {
+            font-size: 1.8rem;
+            padding: 0 1rem;
+        }
+    </style>
+
+    <div>
+        <tesoft-button class="prev" disabled>
+            <svg xmlns="http://www.w3.org/2000/svg" height="2.4rem" viewBox="0 -960 960 960" width="2.4rem" fill="#000000">
+                <path d="M560-240 320-480l240-240 56 56-184 184 184 184-56 56Z"/>
+            </svg>
+        </tesoft-button>
+        <div class="cur-page">
+            1
+        </div>
+        <tesoft-button class="next" disabled>
+            <svg xmlns="http://www.w3.org/2000/svg" height="2.4rem" viewBox="0 -960 960 960" width="2.4rem" fill="#000000">
+                <path d="M504-480 320-664l56-56 240 240-240 240-56-56 184-184Z"/>
+            </svg>
+        </tesoft-button>
+    </div>
+</template>
+
+<script src="/src/components/pagination.ts" type="module"></script>
+{% includeOnce 'components/button.njk' %}

frontend/src/components/pagination.ts

@@ -0,0 +1,83 @@
+import {TesoftComponent} from "../scripts/main.ts";
+import {TesoftButton} from "./button.ts";
+
+export class TesoftPagination extends TesoftComponent {
+    static observedAttributes = ["cur-page", "last-page"];
+
+    private readonly curPageDiv: HTMLDivElement;
+    private readonly prevButton: TesoftButton;
+    private readonly nextButton: TesoftButton;
+
+    constructor() {
+        super();
+
+        const template = document.getElementById("tesoft-pagination-template") as HTMLTemplateElement;
+        const templateContent = template.content;
+
+        const shadowRoot = this.attachShadow({mode: "open"});
+        shadowRoot.appendChild(templateContent.cloneNode(true));
+
+        this.curPageDiv = shadowRoot.querySelector<HTMLDivElement>(".cur-page")!;
+        this.prevButton = shadowRoot.querySelector<TesoftButton>(".prev")!;
+        this.nextButton = shadowRoot.querySelector<TesoftButton>(".next")!;
+    }
+
+    // noinspection JSUnusedGlobalSymbols
+    attributeChangedCallback(name: string, _oldValue: string | null, newValue: string | null) {
+        if (name === "cur-page") {
+            this.update(this.parsePage(newValue), this.parsePage(this.getAttribute("last-page")));
+        } else if (name === "last-page") {
+            this.update(this.parsePage(this.getAttribute("cur-page")), this.parsePage(newValue));
+        }
+    }
+
+    set curPage(value: number) {
+        this.setAttribute("cur-page", value.toString());
+    }
+
+    set lastPage(value: number) {
+        this.setAttribute("last-page", value.toString());
+    }
+
+    private update(curPage: number, lastPage: number) {
+        this.curPageDiv.innerText = curPage.toString();
+
+        if (curPage <= 1) {
+            this.prevButton.setAttribute("disabled", "");
+        } else {
+            this.prevButton.removeAttribute("disabled");
+        }
+        this.prevButton.onclick = () => {
+            this.dispatchEvent(new CustomEvent("update-page", {
+                bubbles: true,
+                cancelable: true,
+                composed: true,
+                detail: {
+                    page: curPage - 1,
+                },
+            }));
+        };
+
+        if (curPage >= lastPage) {
+            this.nextButton.setAttribute("disabled", "");
+        } else {
+            this.nextButton.removeAttribute("disabled");
+        }
+        this.nextButton.onclick = () => {
+            this.dispatchEvent(new CustomEvent("updatePage", {
+                bubbles: true,
+                cancelable: true,
+                composed: true,
+                detail: {
+                    page: curPage + 1,
+                },
+            }));
+        };
+    }
+
+    private parsePage(str: string | null): number {
+        return str ? parseInt(str) : 1;
+    }
+}
+
+customElements.define("tesoft-pagination", TesoftPagination);