Example: Context history with ApplicationStorage

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/**
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 * Voximplant + Deepgram Voice Agent connector demo
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 * Feature highlighted: CROSS-CALL CONTEXT HISTORY using ApplicationStorage + agent.context.messages
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 */
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require(Modules.Deepgram);
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require(Modules.ApplicationStorage);
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const HISTORY_TTL_SECONDS = 14 * 24 * 3600; // 2 weeks
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const MAX_HISTORY_ITEMS = 10;
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const SYSTEM_PROMPT = `
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You are a helpful English-speaking voice assistant for phone callers.
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Keep your turns short and telephony-friendly (usually 1–2 sentences).
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If conversation history is present, start by briefly summarizing what the caller asked last time in 1 sentence, then ask how you can help.
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`;
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function safeParseJsonArray(value) {
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    if (!value) return [];
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    try {
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        const parsed = JSON.parse(value);
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        return Array.isArray(parsed) ? parsed : [];
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    } catch (error) {
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        void error;
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        return [];
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    }
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}
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VoxEngine.addEventListener(AppEvents.CallAlerting, async ({call}) => {
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    let voiceAIClient;
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    // Caller ID is used as a simple "user identity" for the demo.
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    const callerId = call.callerid() || null;
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    const historyKey = callerId ? `dgva_history:${callerId}` : null;
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    let rollingHistory = [];
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    async function saveHistory() {
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        if (!historyKey) return;
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        await ApplicationStorage.put(historyKey, JSON.stringify(rollingHistory), HISTORY_TTL_SECONDS);
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        Logger.write("===CROSS_CALL_HISTORY_SAVED===");
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        Logger.write(JSON.stringify({callerId, messages: rollingHistory.length}));
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    }
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    async function terminate() {
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        try {
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            await saveHistory();
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            voiceAIClient?.close();
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        } catch (error) {
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            Logger.write(`===CROSS_CALL_HISTORY_SAVE_ERROR===> ${JSON.stringify(error)}`);
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        }
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        VoxEngine.terminate();
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    }
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    try {
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        call.answer();
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        // -------------------- Load cross-call history --------------------
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        if (historyKey) {
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            const stored = await ApplicationStorage.get(historyKey);
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            rollingHistory = safeParseJsonArray(stored?.value);
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            Logger.write("===CROSS_CALL_HISTORY_LOADED===");
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            Logger.write(JSON.stringify({callerId, messages: rollingHistory.length}));
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        } else {
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            Logger.write("===CROSS_CALL_HISTORY_DISABLED=== Missing caller ID");
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        }
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        // -------------------- Deepgram Voice Agent settings --------------------
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        const SETTINGS_OPTIONS = {
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            tags: ["voximplant", "deepgram", "voice_agent_connector", "cross_call_history_demo"],
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            agent: {
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                language: "en",
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                greeting: "Hi! I'm Voxi. How can I help today?",
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                context: {
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                    messages: rollingHistory,
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                },
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                listen: {
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                    provider: {
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                        type: "deepgram",
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                        model: "flux-general-en",
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                    },
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                },
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                think: {
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                    provider: {
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                        type: "open_ai",
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                        model: "gpt-4o-mini",
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                        temperature: 0.6,
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                    },
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                    prompt: SYSTEM_PROMPT,
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                },
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                speak: {
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                    provider: {
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                        type: "deepgram",
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                        model: "aura-2-cordelia-en",
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                    },
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                },
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            },
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        };
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        // Create client and wire media
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        voiceAIClient = await Deepgram.createVoiceAgentClient({
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            apiKey: (await ApplicationStorage.get("DEEPGRAM_API_KEY")).value,
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            settingsOptions: SETTINGS_OPTIONS,
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        });
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        VoxEngine.sendMediaBetween(call, voiceAIClient);
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        call.addEventListener(CallEvents.Disconnected, () => {
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            terminate();
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        });
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        call.addEventListener(CallEvents.Failed, () => {
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            terminate();
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        });
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        // -------------------- Update rolling history --------------------
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        // Deepgram emits history items suitable for agent.context.messages.
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        voiceAIClient.addEventListener(Deepgram.VoiceAgentEvents.History, (event) => {
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            const item = event?.data?.payload;
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            if (!item) return;
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            rollingHistory.push(item);
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            rollingHistory = rollingHistory.slice(-MAX_HISTORY_ITEMS);
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        });
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        // Optional: log transcript
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        voiceAIClient.addEventListener(Deepgram.VoiceAgentEvents.ConversationText, (event) => {
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            const {role, text} = event?.data?.payload || {};
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            if (role && text) Logger.write(`===TRANSCRIPT=== ${role}: ${text}`);
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        });
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    } catch (error) {
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        Logger.write("===UNHANDLED_ERROR===");
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        Logger.write(error);
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        terminate();
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    }
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});