import { clientStore, config, datastore, editor, index } from "@silverbulletmd/silverbullet/syscalls";
import { convertIcsCalendar } from "https://esm.sh/ts-ics@2.4.0";
import type { IcsCalendar, IcsEvent, IcsDateObjects } from "https://esm.sh/ts-ics@2.4.0";

const VERSION = "0.3.11";
const CACHE_KEY = "icalendar:lastSync";

const TIMEZONE_OFFSETS: Record<string, number> = {
  "GMT Standard Time": 0,
  "W. Europe Standard Time": 1,
  "Central Europe Standard Time": 1,
  "Romance Standard Time": 1,
  "Central European Standard Time": 1,
  "Eastern Standard Time": -5,
  "Central Standard Time": -6,
  "Mountain Standard Time": -7,
  "Pacific Standard Time": -8,
  "UTC": 0,
  "None": 0
};

export async function syncCalendars() {
  const rawConfig = await config.get("icalendar", { sources: [] });
  let sources: any[] = rawConfig.sources || [];
  let tzShift = rawConfig.tzShift || 0;

  if (sources.length === 0) return;
  await editor.flashNotification("Syncing calendars...", "info");
  
  const allEvents: any[] = [];
  for (const source of sources) {
    const response = await fetch(source.url);
    const text = await response.text();
    const calendar = convertIcsCalendar(undefined, text);
    if (!calendar.events) continue;
    
    for (const icsEvent of calendar.events) {
      const obj = icsEvent.start;
      let wallTimeStr = "";
      if (obj.local && typeof obj.local.date === "string") wallTimeStr = obj.local.date;
      else if (typeof obj.date === "string") wallTimeStr = obj.date;
      
      const baseDate = new Date(wallTimeStr.replace("Z", "") + "Z");
      const tzName = obj.local?.timezone || obj.timezone || "UTC";
      const sourceOffset = TIMEZONE_OFFSETS[tzName] ?? 0;
      const utcMillis = baseDate.getTime() - (sourceOffset * 3600000);
      const finalDate = new Date(utcMillis + (tzShift * 3600000));
      
      const pad = (n: number) => String(n).padStart(2, "0");
      const localIso = finalDate.getFullYear() + "-" + pad(finalDate.getMonth() + 1) + "-" + pad(finalDate.getDate()) + "T" + pad(finalDate.getHours()) + ":" + pad(finalDate.getMinutes()) + ":" + pad(finalDate.getSeconds());

      allEvents.push({
        ...icsEvent,
        start: localIso,
        tag: "ical-event",
        sourceName: source.name
      });
    }
  }
  await index.indexObjects("$icalendar", allEvents);
  await editor.flashNotification(`Synced ${allEvents.length} events`, "info");
}

export async function forceSync() {
  await clientStore.del(CACHE_KEY);
  await syncCalendars();
}

export async function showVersion() {
  await editor.flashNotification(`iCalendar Plug ${VERSION}`, "info");
}