"use client";

import { useState } from "react";
import { useRouter } from "next/navigation";
import { useTranslations } from "next-intl";
import { ArrowLeftRight, LoaderCircle } from "lucide-react";
import type { SyncOpResult } from "@/lib/sync/envelope";
import { isSuccess, newClientId, submitOp } from "@/lib/field/client-ops";
import { currentPosition } from "@/lib/field/image";
import { otherSessionOf, type OtherSession } from "@/lib/field/time-rules";
import { btnPrimary, btnSecondary } from "./ui";

type StartKind = "travel" | "work" | "resume";

async function startPayload(workOrderId: string, mode: "travel" | "work", switchFromOther: boolean) {
  const pos = await currentPosition(3000);
  return {
    workOrderId,
    mode,
    clientId: newClientId(),
    at: new Date().toISOString(),
    offline: typeof navigator !== "undefined" ? !navigator.onLine : false,
    deviceInfo: typeof navigator !== "undefined" ? navigator.userAgent.slice(0, 200) : undefined,
    ...(switchFromOther ? { switchFromOther: true } : {}),
    ...(pos ?? {}),
  };
}

/** Sends session.start / session.resume (optionally with the auto switch flag). */
export async function submitStart(workOrderId: string, kind: StartKind, switchFromOther = false): Promise<SyncOpResult> {
  if (kind === "resume") {
    return submitOp({ opType: "session.resume", payload: { workOrderId, at: new Date().toISOString(), ...(switchFromOther ? { switchFromOther: true } : {}) } });
  }
  return submitOp({ opType: "session.start", payload: await startPayload(workOrderId, kind, switchFromOther) });
}

/**
 * L12 auto switch: start/resume work; when another order is still on the clock the server answers
 * `other_session_running` and the bottom sheet asks „A-00041 läuft noch. Pausieren und A-00042 starten?".
 */
export function useSessionStart(workOrderId: string, number: string, onDone?: (result: SyncOpResult) => void) {
  const router = useRouter();
  const [busy, setBusy] = useState<StartKind | null>(null);
  const [pending, setPending] = useState<{ kind: StartKind; other: OtherSession } | null>(null);
  const [result, setResult] = useState<SyncOpResult | null>(null);

  async function start(kind: StartKind, switchFromOther = false) {
    setBusy(kind);
    const r = await submitStart(workOrderId, kind, switchFromOther);
    setBusy(null);
    const other = otherSessionOf(r);
    if (other && !switchFromOther) {
      setPending({ kind, other });
      return r;
    }
    setPending(null);
    setResult(r);
    onDone?.(r);
    if (isSuccess(r)) router.refresh();
    return r;
  }

  const sheet = pending ? (
    <SwitchSessionSheet
      from={pending.other.number}
      to={number}
      busy={busy !== null}
      onConfirm={() => start(pending.kind, true)}
      onCancel={() => setPending(null)}
    />
  ) : null;

  return { start, busy, result, sheet };
}

export function SwitchSessionSheet({ from, to, busy, onConfirm, onCancel }: { from: string; to: string; busy: boolean; onConfirm: () => void; onCancel: () => void }) {
  const t = useTranslations("field.switch");
  return (
    <div className="fixed inset-0 z-50 flex items-end justify-center bg-black/40" onClick={onCancel}>
      <div
        role="dialog"
        aria-modal="true"
        aria-labelledby="switch-session-title"
        className="w-full max-w-xl space-y-4 rounded-t-2xl bg-card p-5 pb-[calc(1.25rem+env(safe-area-inset-bottom))] shadow-card"
        onClick={(e) => e.stopPropagation()}
      >
        <div className="flex items-start gap-3">
          <ArrowLeftRight className="mt-1 size-6 shrink-0 text-primary" aria-hidden />
          <div>
            <h2 id="switch-session-title" className="text-[19px]">
              {t("title")}
            </h2>
            <p className="mt-1 text-[16px]">{from ? t("text", { from, to }) : t("textUnknown", { to })}</p>
          </div>
        </div>
        <button type="button" className={btnPrimary} disabled={busy} onClick={onConfirm} autoFocus>
          {busy ? <LoaderCircle className="size-5 animate-spin" aria-hidden /> : <ArrowLeftRight className="size-5" aria-hidden />}
          {t("confirm")}
        </button>
        <button type="button" className={btnSecondary} disabled={busy} onClick={onCancel}>
          {t("cancel")}
        </button>
      </div>
    </div>
  );
}