import { requireOptionalNativeModule } from "expo-modules-core";
import { Platform } from "react-native";

import { formatElapsedHoursMinutes, formatElapsedSeconds, resolveClockDescription } from "@/lib/time-clock";
import type { TimeClockActivityProps } from "@/lib/time-clock-live-activity.types";
type RunningEntry = {
  description: string;
  startedAt: Date | string;
  client?: { name: string } | null;
  invoice?: { invoicePrefix: string | null; invoiceNumber: string } | null;
};

type LiveActivityHandle = {
  update: (props: TimeClockActivityProps) => Promise<void>;
  end: (policy?: "default" | "immediate") => Promise<void>;
};

type LiveActivityFactory = {
  start: (props: TimeClockActivityProps, url?: string) => LiveActivityHandle;
  getInstances: () => LiveActivityHandle[];
};

let factoryCache: LiveActivityFactory | null | undefined;

function isExpoWidgetsAvailable() {
  return Platform.OS === "ios" && requireOptionalNativeModule("ExpoWidgets") != null;
}

function getFactory(): LiveActivityFactory | null {
  if (factoryCache !== undefined) {
    return factoryCache;
  }

  if (!isExpoWidgetsAvailable()) {
    factoryCache = null;
    return null;
  }

  try {
    factoryCache = require("@/widgets/TimeClockActivity").default as LiveActivityFactory;
  } catch {
    factoryCache = null;
  }

  return factoryCache;
}

export function isTimeClockLiveActivitySupported() {
  return getFactory() != null;
}

export function buildTimeClockActivityProps(
  running: RunningEntry,
  elapsedSeconds: number,
): TimeClockActivityProps {
  const invoice = running.invoice;
  return {
    startedAtMs: new Date(running.startedAt).getTime(),
    elapsed: formatElapsedSeconds(elapsedSeconds),
    elapsedShort: formatElapsedHoursMinutes(elapsedSeconds),
    clockTime: new Date().toLocaleTimeString(undefined, {
      hour: "numeric",
      minute: "2-digit",
    }),
    description: resolveClockDescription(running.description),
    clientName: running.client?.name ?? "",
    invoiceLabel: invoice
      ? `${invoice.invoicePrefix ?? "#"}${invoice.invoiceNumber}`
      : "",
  };
}

export async function syncTimeClockLiveActivity(
  running: RunningEntry | null | undefined,
  elapsedSeconds: number,
) {
  const factory = getFactory();
  if (!factory) return;

  if (!running) {
    await endTimeClockLiveActivity();
    return;
  }

  try {
    const props = buildTimeClockActivityProps(running, elapsedSeconds);
    const instances = factory.getInstances();

    if (instances.length > 0) {
      await instances[0]!.update(props);
      return;
    }

    factory.start(props, "beenvoice://timer");
  } catch (error) {
    if (__DEV__) {
      console.warn("[LiveActivity] sync failed:", error);
    }
    factoryCache = undefined;
  }
}

export async function endTimeClockLiveActivity() {
  const factory = getFactory();
  if (!factory) return;

  try {
    const instances = factory.getInstances();
    await Promise.all(instances.map((instance) => instance.end("immediate")));
  } catch {
    factoryCache = undefined;
  }
}