tw2/examples/agent/a2ui_agent/samples/client/lit/contact/contact.ts

/*
 Copyright 2025 Google LLC

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

      https://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */

import { SignalWatcher } from "@lit-labs/signals";
import { provide } from "@lit/context";
import {
  LitElement,
  html,
  css,
  nothing,
  HTMLTemplateResult,
  unsafeCSS,
} from "lit";
import { customElement, state } from "lit/decorators.js";
import { theme as uiTheme } from "./theme/theme.js";
import { A2UIClient } from "./client.js";
import {
  SnackbarAction,
  SnackbarMessage,
  SnackbarUUID,
  SnackType,
} from "./types/types.js";
import { type Snackbar } from "./ui/snackbar.js";
import { repeat } from "lit/directives/repeat.js";
import { v0_8 } from "@a2ui/lit";
import * as UI from "@a2ui/lit/ui";

// Demo elements.
import "./ui/ui.js";
import { registerContactComponents } from "./ui/custom-components/register-components.js";

// Register custom components for the contact app
registerContactComponents();

@customElement("a2ui-contact")
export class A2UIContactFinder extends SignalWatcher(LitElement) {
  @provide({ context: UI.Context.themeContext })
  accessor theme: v0_8.Types.Theme = uiTheme;

  @state()
  accessor #requesting = false;

  @state()
  accessor #error: string | null = null;

  @state()
  accessor #lastMessages: v0_8.Types.ServerToClientMessage[] = [];

  static styles = [
    unsafeCSS(v0_8.Styles.structuralStyles),
    css`
      :host {
        display: block;
        max-width: 640px;
        margin: 0 auto;
        min-height: 100%;
      }

      #surfaces {
        display: flex;
        flex-direction: column;
        width: 100%;
        padding: var(--bb-grid-size-3) 0;
        animation: fadeIn 1s cubic-bezier(0, 0, 0.3, 1) 0.3s backwards;

        & a2ui-surface {
          align-items: center;
        }
      }

      form {
        display: flex;
        flex-direction: column;
        flex: 1;
        gap: 16px;
        align-items: center;
        padding: 16px 0;
        animation: fadeIn 1s cubic-bezier(0, 0, 0.3, 1) 1s backwards;

        & > div {
          display: flex;
          flex: 1;
          gap: 16px;
          align-items: center;
          width: 100%;

          & > input {
            display: block;
            flex: 1;
            border-radius: 32px;
            padding: 16px 24px;
            border: 1px solid var(--p-60);
            font-size: 16px;
          }

          & > button {
            display: flex;
            align-items: center;
            background: var(--p-40);
            color: var(--n-100);
            border: none;
            padding: 8px 16px;
            border-radius: 32px;
            opacity: 0.5;

            &:not([disabled]) {
              cursor: pointer;
              opacity: 1;
            }
          }
        }
      }

      .rotate {
        animation: rotate 1s linear infinite;
      }

      .pending {
        width: 100%;
        min-height: 200px;
        display: flex;
        align-items: center;
        justify-content: center;
        animation: fadeIn 1s cubic-bezier(0, 0, 0.3, 1) 0.3s backwards;

        & .g-icon {
          margin-right: 8px;
        }
      }

      .error {
        color: var(--e-40);
        background-color: var(--e-95);
        border: 1px solid var(--e-80);
        padding: 16px;
        border-radius: 8px;
      }

      @keyframes fadeIn {
        from {
          opacity: 0;
        }

        to {
          opacity: 1;
        }
      }

      @keyframes rotate {
        from {
          rotate: 0deg;
        }

        to {
          rotate: 360deg;
        }
      }
    `,
  ];

  #processor = v0_8.Data.createSignalA2uiMessageProcessor();
  #a2uiClient = new A2UIClient();
  #snackbar: Snackbar | undefined = undefined;
  #pendingSnackbarMessages: Array<{
    message: SnackbarMessage;
    replaceAll: boolean;
  }> = [];

  render() {
    return [
      this.#maybeRenderForm(),
      this.#maybeRenderData(),
      this.#maybeRenderError(),
    ];
  }

  #maybeRenderError() {
    if (!this.#error) return nothing;

    return html`<div class="error">${this.#error}</div>`;
  }

  #maybeRenderForm() {
    if (this.#requesting) return nothing;
    if (this.#lastMessages.length > 0) return nothing;
    return html`<form
      @submit=${async (evt: Event) => {
        evt.preventDefault();
        if (!(evt.target instanceof HTMLFormElement)) {
          return;
        }
        const data = new FormData(evt.target);
        const body = data.get("body") ?? null;
        if (!body) {
          return;
        }
        const message = body as v0_8.Types.A2UIClientEventMessage;
        await this.#sendAndProcessMessage(message);
      }}
    >
      <h1 class="typography-f-sf typography-v-r typography-w-400 color-c-p30">
        Contact Finder
      </h1>
      <div>
        <input
          required
          value="Casey Smith"
          autocomplete="off"
          id="body"
          name="body"
          type="text"
          ?disabled=${this.#requesting}
        />
        <button type="submit" ?disabled=${this.#requesting}>
          <span class="g-icon filled-heavy">send</span>
        </button>
      </div>
    </form>`;
  }

  #maybeRenderData() {
    if (this.#requesting) {
      return html` <div class="pending">
        <span class="g-icon filled-heavy rotate">progress_activity</span>
        Awaiting an answer...
      </div>`;
    }

    const surfaces = this.#processor.getSurfaces();
    if (surfaces.size === 0) {
      return nothing;
    }

    return html`<section id="surfaces">
      ${repeat(
      this.#processor.getSurfaces(),
      ([surfaceId]) => surfaceId,
      ([surfaceId, surface]) => {
        return html`<a2ui-surface
              @a2uiaction=${async (
          evt: v0_8.Events.StateEvent<"a2ui.action">
        ) => {
            const [target] = evt.composedPath();
            if (!(target instanceof HTMLElement)) {
              return;
            }

            const context: v0_8.Types.A2UIClientEventMessage["userAction"]["context"] =
              {};
            if (evt.detail.action.context) {
              const srcContext = evt.detail.action.context;
              for (const item of srcContext) {
                if (item.value.literalBoolean) {
                  context[item.key] = item.value.literalBoolean;
                } else if (item.value.literalNumber) {
                  context[item.key] = item.value.literalNumber;
                } else if (item.value.literalString) {
                  context[item.key] = item.value.literalString;
                } else if (item.value.path) {
                  const path = this.#processor.resolvePath(
                    item.value.path,
                    evt.detail.dataContextPath
                  );
                  const value = this.#processor.getData(
                    evt.detail.sourceComponent,
                    path,
                    surfaceId
                  );
                  context[item.key] = value;
                }
              }
            }

            const message: v0_8.Types.A2UIClientEventMessage = {
              userAction: {
                surfaceId: surfaceId,
                name: evt.detail.action.name,
                sourceComponentId: target.id,
                timestamp: new Date().toISOString(),
                context,
              },
            };

            await this.#sendAndProcessMessage(message);
          }}
              .surfaceId=${surfaceId}
              .surface=${surface}
              .processor=${this.#processor}
            ></a2-uisurface>`;
      }
    )}
    </section>`;
  }

  async #sendAndProcessMessage(request) {
    const messages = await this.#sendMessage(request);

    this.#lastMessages = messages;
    this.#processor.clearSurfaces();
    this.#processor.processMessages(messages);
  }

  async #sendMessage(
    message: v0_8.Types.A2UIClientEventMessage
  ): Promise<v0_8.Types.ServerToClientMessage[]> {
    try {
      this.#requesting = true;
      const response = this.#a2uiClient.send(message);
      await response;
      this.#requesting = false;

      return response;
    } catch (err) {
      this.snackbar(err as string, SnackType.ERROR);
    } finally {
      this.#requesting = false;
    }

    return [];
  }

  snackbar(
    message: string | HTMLTemplateResult,
    type: SnackType,
    actions: SnackbarAction[] = [],
    persistent = false,
    id = globalThis.crypto.randomUUID(),
    replaceAll = false
  ) {
    if (!this.#snackbar) {
      this.#pendingSnackbarMessages.push({
        message: {
          id,
          message,
          type,
          persistent,
          actions,
        },
        replaceAll,
      });
      return;
    }

    return this.#snackbar.show(
      {
        id,
        message,
        type,
        persistent,
        actions,
      },
      replaceAll
    );
  }

  unsnackbar(id?: SnackbarUUID) {
    if (!this.#snackbar) {
      return;
    }

    this.#snackbar.hide(id);
  }
}