/**
 * FieldInstallPrompt — install prompt for the worker sub-PWA.
 *
 * Cycle 6 sibling of `InstallPrompt` (mounted from the root layout).
 * This one fires only on /water routes and uses the field-PWA
 * branding (forest green icon, "Water Log — Tuxedo") so the prompt
 * that surfaces matches the manifest that will be installed.
 *
 * Same `BeforeInstallPromptEvent` capture pattern as InstallPrompt;
 * split into a separate component file because the worker surface
 * has its own theming + copy.
 */
"use client";

import { useEffect, useSyncExternalStore, useCallback, useReducer } from "react";

interface BeforeInstallPromptEvent extends Event {
  prompt(): Promise<void>;
  userChoice: Promise<{ outcome: "accepted" | "dismissed" }>;
}

type PromptState = {
  deferred: BeforeInstallPromptEvent | null;
  visible: boolean;
};

type PromptAction =
  | { type: "captured"; event: BeforeInstallPromptEvent }
  | { type: "show" }
  | { type: "hide" }
  | { type: "dismissed" }
  | { type: "reset" };

function promptReducer(state: PromptState, action: PromptAction): PromptState {
  switch (action.type) {
    case "captured":
      return { deferred: action.event, visible: false };
    case "show":
      return state.deferred ? { ...state, visible: true } : state;
    case "hide":
      return { deferred: null, visible: false };
    case "dismissed":
      return { ...state, visible: false };
    case "reset":
      return { deferred: null, visible: false };
  }
}

const INITIAL_PROMPT_STATE: PromptState = { deferred: null, visible: false };

export function FieldInstallPrompt() {
  const [prompt, dispatch] = useReducer(promptReducer, INITIAL_PROMPT_STATE);
  const isInstalled = useSyncExternalStore(
    () => () => {},
    () =>
      typeof window !== "undefined" &&
      (window.matchMedia("(display-mode: standalone)").matches ||
        // iOS Safari uses navigator.standalone for the home-screen PWA
        // launch. Cover both.
        (typeof (navigator as Navigator & { standalone?: boolean }).standalone ===
          "boolean" &&
          (navigator as Navigator & { standalone?: boolean }).standalone === true)),
    () => false,
  );
  const mounted = useSyncExternalStore(
    () => () => {},
    () => true,
    () => false,
  );

  useEffect(() => {
    if (isInstalled) return;
    if (typeof window === "undefined") return;

    const handleBeforeInstall = (e: Event) => {
      e.preventDefault();
      dispatch({ type: "captured", event: e as BeforeInstallPromptEvent });
      // Show the field prompt sooner than the main one — workers
      // know they want this installed on day one.
      window.setTimeout(() => {
        dispatch({ type: "show" });
      }, 4000);
    };

    const handleAppInstalled = () => {
      dispatch({ type: "reset" });
    };

    window.addEventListener("beforeinstallprompt", handleBeforeInstall);
    window.addEventListener("appinstalled", handleAppInstalled);

    return () => {
      window.removeEventListener("beforeinstallprompt", handleBeforeInstall);
      window.removeEventListener("appinstalled", handleAppInstalled);
    };
  }, [isInstalled]);

  const handleInstall = useCallback(async () => {
    const deferred = prompt.deferred;
    if (!deferred) return;

    await deferred.prompt();
    const { outcome } = await deferred.userChoice;
    void outcome;
    dispatch({ type: "reset" });
  }, [prompt.deferred]);

  const handleDismiss = useCallback(() => {
    dispatch({ type: "dismissed" });
    try {
      sessionStorage.setItem("field-pwa-install-dismissed", "true");
    } catch {
      // ignore
    }
  }, []);

  if (!mounted || !prompt.visible || isInstalled || !prompt.deferred) {
    return null;
  }

  return (
    <div className="fixed bottom-4 left-4 right-4 sm:left-auto sm:right-4 sm:w-80 bg-white rounded-2xl shadow-2xl border border-[#1a4d2e]/30 p-4 z-50">
      <div className="flex items-start gap-3">
        <div className="w-12 h-12 bg-[#1a4d2e] rounded-xl flex items-center justify-center shrink-0">
          <svg
            className="w-6 h-6 text-white"
            fill="none"
            viewBox="0 0 24 24"
            stroke="currentColor"
            strokeWidth={2}
          >
            <path
              strokeLinecap="round"
              strokeLinejoin="round"
              d="M12 3v12m0 0l-4-4m4 4l4-4M5 21h14"
            />
          </svg>
        </div>
        <div className="flex-1">
          <h3 className="font-semibold text-[#1a4d2e]">
            Install Water Log
          </h3>
          <p className="text-sm text-[rgba(60,60,67,0.65)] mt-1">
            One tap to a full-screen PIN entry from your home screen.
          </p>
        </div>
      </div>
      <div className="flex gap-2 mt-4">
        <button
          type="button"
          onClick={handleDismiss}
          className="flex-1 px-4 py-2 text-sm font-medium text-[rgba(60,60,67,0.55)] hover:text-[rgba(60,60,67,0.85)] transition-colors"
        >
          Not now
        </button>
        <button
          type="button"
          onClick={handleInstall}
          className="flex-1 px-4 bg-[#1a4d2e] text-white rounded-lg text-sm font-medium hover:bg-[#14432a] py-2 transition-colors"
        >
          Install
        </button>
      </div>
    </div>
  );
}

export default FieldInstallPrompt;