text_to_calendar.ts

import { GoogleGenAI } from "npm:@google/genai";
import ical from "npm:ical-generator";

// 1. Load config from config.json
const config = JSON.parse(await Deno.readTextFile("config.json"));

const GEMINI_API_KEY = config.geminiApiKey;
const TARGET_URL = config.targetUrl;
const ENCODING: string = config.encoding || "utf-8";
const DEFAULT_TIME = config.defaultTime || "09:00";
const DURATION_MINUTES = config.eventDurationMinutes || 60;
const CALENDAR_NAME = config.calendarName || "Generated Calendar";
const PROMPT = config.prompt || "";
type IntermediateEvent = {
  date: string;
  time: string | null;
  title: string;
  description: string;
};
type Event = { date: string; time: string; title: string; description: string };

// 2. Fetch URL content
async function fetchContent(
  url: string,
  encoding: string,
): Promise<string> {
  const response = await fetch(url);
  if (!response.ok) {
    throw new Error(`HTTP Failed, status ${response.status}`);
  }
  return new TextDecoder(ENCODING).decode(await response.arrayBuffer());
}

// 3. Define structured schema
const structuredSchema = {
  type: "array",
  items: {
    type: "object",
    properties: {
      date: { type: "string" },
      time: { type: "string", nullable: true },
      title: { type: "string" },
      description: { type: "string" },
    },
    required: ["date", "title", "description"],
  },
};

// 4. Use Gemini with structured output
const ai = new GoogleGenAI({ apiKey: GEMINI_API_KEY });
async function parseWithGemini(content: string) {
  const result = await ai.models.generateContent({
    model: "gemini-2.5-flash",
    contents:
      `Extract events.\n${PROMPT}\ndate should follow this format: YYYY-MM-DD\ntime should follow this format: HH:MM\nContent:\n${content}`,
    config: {
      responseMimeType: "application/json",
      responseSchema: structuredSchema,
    },
  });

  if (!result.text) {
    throw new Error("Gemini did not say anything");
  }

  return (JSON.parse(result.text) as IntermediateEvent[]);
}

// 5. Fill missing times
function fillMissingTimes(
  events: IntermediateEvent[],
): Event[] {
  return events.map((ev) => {
    if (!ev.time) {
      ev.time = DEFAULT_TIME;
    }
    return ev as Event;
  });
}

// 6. Convert to ICS
function generateICS(
  events: Event[],
): string {
  const cal = ical({ name: CALENDAR_NAME });

  for (const ev of events) {
    const start = new Date(`${ev.date}T${ev.time}:00`);
    cal.createEvent({
      start,
      end: new Date(start.getTime() + DURATION_MINUTES * 60 * 1000),
      summary: ev.title,
      description: ev.description,
    });
  }

  return cal.toString();
}

// 7. Main function
const main = async () => {
  try {
    console.log("📥 Fetching content...");
    const rawContent = await fetchContent(TARGET_URL, ENCODING);

    console.log("🤖 Parsing with Gemini...");
    const parsed = await parseWithGemini(rawContent);

    console.log("🕒 Filling missing times...");
    const filled = fillMissingTimes(parsed);

    console.log("📅 Generating ICS...");
    const ics = generateICS(filled);

    await Deno.writeTextFile("calendar.ics", ics);
    console.log("✅ Saved to calendar.ics");
  } catch (error) {
    console.error("❌ Error:", String(error));
  }
};

main();