/* ============================================================
   SELECT PAGE — Universal full-screen option picker
   Design: iOS Settings style selection list
   Usage: Navigate to /select with state object
   
   State params:
     title    - Page title shown in header
     options  - Array of option strings
     selected - Currently selected index (number)
     back     - Route to navigate back to after selection
     key      - Identifier for which setting this controls
   ============================================================ */
import { useLocation } from "wouter";
import { ChevronLeft, Check } from "lucide-react";
import { useDevice } from "@/contexts/DeviceContext";
import { cn } from "@/lib/utils";
import { useEffect, useMemo, useState } from "react";
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
} from "@/components/ui/alert-dialog";
import localeZh from "@/locales/data-zh.json";
import localeEn from "@/locales/data-en.json";
import { resolveLocalePack } from "@/locales/resolveLocale";
import { usePageTitleWithConnection } from "@/hooks/usePageTitleWithConnection";

type DacVolumeDirectConfirmLocale = NonNullable<
  NonNullable<(typeof localeZh)["dac"]>["dacVolumeDirectConfirm"]
>;

const iisModeImageUrl = (index: number) =>
  `${import.meta.env.BASE_URL}images/IIS/iis_app${index + 1}.png`;

/* ── Key → API field mapping ── */
const KEY_TO_SETTING: Record<string, string> = {
  effect_value: "effect_value",
  crossfeed_value: "crossfeed_value",
  hearing_select: "hearing_select",
  language: "language",
  analogGain: "analogGain",
  soundStep: "soundStep",
  bootSound: "bootSound",
  filterCharacteristic: "pcm",
  mutePolar: "hdmimutepolar",
  IISMode: "hdmiType",
  xlr: "xlr",
  dacGain: "dacGain",
  dacImpedance: "dacImpedance",
  dacVolumeDirect: "dacVolumeDirect",
  uacVer: "uac_ver",
  vu: "vu",
  input: "input",
  output: "output",
  screenLight: "screenLight",
  screenOff: "screenOff",
  buttonLight: "buttonLight",
  autoHome: "autoHome",
  sleep: "sleep",
  headphone: "peqSelect",
};

// Global state for select page (to avoid URL params)
export let selectPageState: {
  title: string;
  options: string[];
  selected: number;
  back: string;
  key: string;
} | null = null;

// Last select result for pages that need local state update
export let selectPageResult: { key: string; selected: number } | null = null;

export function consumeSelectPageResult() {
  const result = selectPageResult;
  selectPageResult = null;
  return result;
}

// Scroll position of the calling page, captured before navigating to /select.
// The select page is short, so the browser clamps window scroll to 0 while on
// it; without restoring, the calling page (e.g. Effects) reopens at the top.
let selectReturnScroll: number | null = null;

/** Consume the stored scroll position (once). Returns null when absent. */
export function consumeSelectReturnScroll(): number | null {
  const y = selectReturnScroll;
  selectReturnScroll = null;
  return y;
}

// Helper function to set select page state
export function navigateToSelect(title: string, options: string[], selected: number, back: string, key: string) {
  selectReturnScroll = window.scrollY;
  selectPageState = { title, options, selected, back, key };
}

export default function SelectPage() {
  const [location, setLocation] = useLocation();
  const { updateSetting, deviceState } = useDevice();
  const [state, setState] = useState<{
    title: string;
    options: string[];
    selected: number;
    back: string;
    key: string;
  } | null>(() => selectPageState);
  const [saving, setSaving] = useState(false);
  const [volumeDirectConfirmIdx, setVolumeDirectConfirmIdx] = useState<1 | 2 | null>(null);

  const pageTitle = usePageTitleWithConnection(state?.title ?? "");

  const volumeDirectConfirmText = useMemo((): DacVolumeDirectConfirmLocale => {
    const pack = resolveLocalePack(deviceState?.language);
    return (pack.dac?.dacVolumeDirectConfirm ?? localeEn.dac!.dacVolumeDirectConfirm) as DacVolumeDirectConfirmLocale;
  }, [deviceState?.language]);

  // Re-read global state whenever we enter /select (avoids stale key/options after remount)
  useEffect(() => {
    if (location === "/select" && selectPageState) {
      setState({ ...selectPageState });
    }
  }, [location]);

  if (!state) {
    return null;
  }

  const { title, options, selected: selectedIdx, back, key } = state;

  const commitSelect = async (idx: number) => {
    if (saving) return;
    selectPageResult = { key, selected: idx };

    const apiField = KEY_TO_SETTING[key];
    if (apiField) {
      setSaving(true);
      try {
        await updateSetting({ [apiField]: idx });
      } finally {
        setSaving(false);
      }
    }
    selectPageState = null;
    setLocation(back);
  };

  const handleSelect = async (idx: number) => {
    if (
      key === "dacVolumeDirect" &&
      idx !== selectedIdx &&
      (idx === 1 || idx === 2)
    ) {
      setVolumeDirectConfirmIdx(idx);
      return;
    }
    await commitSelect(idx);
  };

  const volumeDirectDialogCopy =
    volumeDirectConfirmIdx === 1
      ? {
          title: volumeDirectConfirmText.title0db ?? "开启 0dB 直通模式？",
          desc:
            volumeDirectConfirmText.desc0db ??
            "直通模式会将音量调到最大，并且不可调节。",
        }
      : volumeDirectConfirmIdx === 2
        ? {
            title: volumeDirectConfirmText.title12db ?? "开启 -12dB 直通模式？",
            desc:
              volumeDirectConfirmText.desc12db ??
              "直通模式会将音量调到 -12dB，并且不可调节。",
          }
        : null;

  return (
    <div className="min-h-screen bg-black">
      {/* ── Header ── */}
      <div className="page-header">
        <button
          onClick={() => setLocation(back)}
          className="mr-4 text-white/60 active:text-white transition-colors">
          <ChevronLeft size={24} />
        </button>
        <h1 className="flex-1 text-center text-[17px] font-semibold text-white">{pageTitle}</h1>
        <div className="w-8" />
      </div>

      <div className="px-4 pt-4 pb-24">
        {key === "IISMode" ? (
          <div className="grid w-full grid-cols-2 gap-3">
            {options.map((opt, idx) => {
              const isSelected = idx === selectedIdx;
              return (
                <button
                  key={idx}
                  type="button"
                  disabled={saving}
                  className={cn(
                    "flex flex-col items-center gap-2 rounded-xl border-2 p-1.5 transition-all active:scale-[0.98] disabled:opacity-60",
                    isSelected
                      ? "border-[#00FFF6] shadow-[0_0_14px_rgba(0,255,246,0.35)]"
                      : "border-white/10",
                  )}
                  onClick={() => void handleSelect(idx)}
                  aria-pressed={isSelected}
                  aria-label={opt}
                >
                  <img
                    src={iisModeImageUrl(idx)}
                    alt={opt}
                    className="block w-full h-auto rounded-lg bg-black/40"
                    loading="lazy"
                  />
                  <span
                    className={cn(
                      "w-6 h-6 rounded-full flex items-center justify-center shrink-0",
                      isSelected
                        ? "bg-[#00FFF6] text-black shadow-[0_0_10px_rgba(0,255,246,0.45)]"
                        : "border-2 border-white/20",
                    )}
                  >
                    {isSelected && <Check size={12} strokeWidth={3} />}
                  </span>
                </button>
              );
            })}
          </div>
        ) : (
          <div className="ios-list-group">
            {options.map((opt, idx) => {
              const isSelected = idx === selectedIdx;
              return (
                <button
                  key={idx}
                  className="ios-list-row w-full text-left active:bg-white/5 transition-colors"
                  onClick={() => void handleSelect(idx)}
                  disabled={saving}
                >
                  <span className={`flex-1 text-[16px] ${isSelected ? "text-white font-medium" : "text-white/75"}`}>
                    {opt}
                  </span>
                  {isSelected && (
                    <Check size={18} style={{ color: "#00FFF6" }} />
                  )}
                </button>
              );
            })}
          </div>
        )}
      </div>

      <AlertDialog
        open={volumeDirectConfirmIdx !== null}
        onOpenChange={(open) => {
          if (!open) setVolumeDirectConfirmIdx(null);
        }}
      >
        <AlertDialogContent className="top-[42%] border-white/10 bg-zinc-900 text-white sm:max-w-md">
          <AlertDialogHeader>
            <AlertDialogTitle className="text-white">{volumeDirectDialogCopy?.title}</AlertDialogTitle>
            <AlertDialogDescription className="text-white/60">
              {volumeDirectDialogCopy?.desc}
            </AlertDialogDescription>
          </AlertDialogHeader>
          <AlertDialogFooter>
            <AlertDialogCancel className="border-white/20 bg-transparent text-white hover:bg-white/10">
              {volumeDirectConfirmText.cancel ?? "取消"}
            </AlertDialogCancel>
            <AlertDialogAction
              className="bg-[#00FFF6] text-black hover:bg-[#00FFF6]/90 focus-visible:ring-[#00FFF6]"
              onClick={() => {
                const idx = volumeDirectConfirmIdx;
                setVolumeDirectConfirmIdx(null);
                if (idx !== null) void commitSelect(idx);
              }}
            >
              {volumeDirectConfirmText.confirm ?? "确认"}
            </AlertDialogAction>
          </AlertDialogFooter>
        </AlertDialogContent>
      </AlertDialog>
    </div>
  );
}