import { useLingui } from "@lingui/react/macro";
import type {
  RakazoDesktopBrowserPreview,
  RakazoDesktopBrowserPreviewState,
} from "@rakazo/contracts";
import { Button, cn, Input } from "@rakazo/ui-web";
import { ArrowLeft, ArrowRight, Code, ExternalLink, RotateCw, X } from "lucide-react";
import { type FormEvent, useCallback, useEffect, useRef, useState } from "react";
import { browserFrameSandbox, normalizeBrowserUrl } from "../../lib/browser-url";
import { desktopBridge } from "../../lib/desktop";

const LAST_URL_KEY = "rk:in-app-browser:url";

function readLastUrl(): string {
  try {
    return window.localStorage.getItem(LAST_URL_KEY) ?? "";
  } catch {
    return "";
  }
}

function rememberUrl(url: string) {
  try {
    window.localStorage.setItem(LAST_URL_KEY, url);
  } catch {
    /* A per-viewer convenience only. */
  }
}

const EMPTY_STATE: RakazoDesktopBrowserPreviewState = {
  url: "",
  title: "",
  loading: false,
  canGoBack: false,
  canGoForward: false,
  error: null,
};

/** DOM layers the native desktop view would otherwise paint over. */
const FLOATING_UI = '[role="dialog"],[role="alertdialog"],[role="menu"],[role="listbox"]';

/**
 * Address bar plus page. On desktop the page is a native Chromium view laid over the reserved
 * area, so dev servers keep hot reload, DevTools and full speed; in a browser it is an iframe.
 */
export function InAppBrowser({ onClose }: { onClose: () => void }) {
  const { t } = useLingui();
  const native = desktopBridge()?.browserPreview;
  const [state, setState] = useState<RakazoDesktopBrowserPreviewState>(() => ({
    ...EMPTY_STATE,
    url: native ? "" : readLastUrl(),
  }));
  const [draft, setDraft] = useState(state.url);
  const [invalid, setInvalid] = useState(false);
  const [frameKey, setFrameKey] = useState(0);
  const editing = useRef(false);
  const inputRef = useRef<HTMLInputElement>(null);

  useEffect(() => {
    if (!native) return;
    let live = true;
    const apply = (next: RakazoDesktopBrowserPreviewState) => {
      if (!live) return;
      setState(next);
      if (!editing.current) setDraft(next.url);
    };
    const unsubscribe = native.onState(apply);
    void native
      .state()
      .then((current) => {
        apply(current);
        const last = readLastUrl();
        if (!current.url && last) void native.navigate(last).catch(() => undefined);
      })
      .catch(() => undefined);
    return () => {
      live = false;
      unsubscribe();
    };
  }, [native]);

  useEffect(() => {
    if (!state.url) inputRef.current?.focus();
  }, [state.url]);

  const go = useCallback(
    (input: string) => {
      const url = normalizeBrowserUrl(input);
      setInvalid(!url);
      if (!url) return;
      editing.current = false;
      setDraft(url);
      rememberUrl(url);
      if (native) {
        void native.navigate(url).catch(() => setInvalid(true));
      } else {
        setState((current) => ({ ...current, url, loading: true, error: null }));
        setFrameKey((key) => key + 1);
      }
    },
    [native],
  );

  const reload = useCallback(() => {
    if (native) {
      void (state.loading ? native.stop() : native.reload()).catch(() => undefined);
      return;
    }
    if (!state.url) return;
    setState((current) => ({ ...current, loading: true }));
    setFrameKey((key) => key + 1);
  }, [native, state.loading, state.url]);

  const onSubmit = (event: FormEvent) => {
    event.preventDefault();
    go(draft);
    inputRef.current?.blur();
  };

  return (
    <div className="flex h-full min-h-0 flex-col" data-testid="in-app-browser">
      <form onSubmit={onSubmit} className="relative flex items-center gap-0.5 border-b px-2 py-1.5">
        {native ? (
          <>
            <Button
              type="button"
              variant="ghost"
              size="icon-sm"
              aria-label={t`Back`}
              disabled={!state.canGoBack}
              onClick={() => void native.back().catch(() => undefined)}
            >
              <ArrowLeft strokeWidth={1.7} className="size-icon-md" />
            </Button>
            <Button
              type="button"
              variant="ghost"
              size="icon-sm"
              aria-label={t`Forward`}
              disabled={!state.canGoForward}
              onClick={() => void native.forward().catch(() => undefined)}
            >
              <ArrowRight strokeWidth={1.7} className="size-icon-md" />
            </Button>
          </>
        ) : null}
        <Button
          type="button"
          variant="ghost"
          size="icon-sm"
          aria-label={state.loading ? t`Stop` : t`Reload`}
          disabled={!state.url}
          onClick={reload}
        >
          {state.loading && native ? (
            <X strokeWidth={1.8} className="size-icon-md" />
          ) : (
            <RotateCw strokeWidth={1.7} className="size-icon-md" />
          )}
        </Button>
        <Input
          ref={inputRef}
          value={draft}
          aria-label={t`Address`}
          aria-invalid={invalid || undefined}
          inputMode="url"
          autoComplete="off"
          autoCapitalize="off"
          spellCheck={false}
          placeholder="localhost:5173"
          onFocus={(event) => {
            editing.current = true;
            event.currentTarget.select();
          }}
          onBlur={() => {
            editing.current = false;
          }}
          onChange={(event) => {
            setDraft(event.target.value);
            setInvalid(false);
          }}
          onKeyDown={(event) => {
            if (event.key !== "Escape") return;
            setDraft(state.url);
            setInvalid(false);
            event.currentTarget.blur();
          }}
          className="mx-1 h-control-sm flex-1 rounded-full bg-muted/60 px-3 text-ui-body-sm"
        />
        {native ? (
          <Button
            type="button"
            variant="ghost"
            size="icon-sm"
            aria-label={t`Developer tools`}
            disabled={!state.url}
            onClick={() => void native.openDevTools().catch(() => undefined)}
          >
            <Code strokeWidth={1.7} className="size-icon-md" />
          </Button>
        ) : null}
        <Button
          type="button"
          variant="ghost"
          size="icon-sm"
          aria-label={t`Open in browser`}
          disabled={!state.url}
          onClick={() => window.open(state.url, "_blank", "noopener,noreferrer")}
        >
          <ExternalLink strokeWidth={1.7} className="size-icon-md" />
        </Button>
        <Button
          type="button"
          variant="ghost"
          size="icon-sm"
          aria-label={t`Close panel`}
          onClick={onClose}
        >
          <X strokeWidth={1.8} className="size-icon-md" />
        </Button>
        <div
          aria-hidden
          className={cn(
            "absolute inset-x-0 -bottom-px h-0.5 overflow-hidden transition-opacity duration-300",
            state.loading ? "opacity-100" : "opacity-0",
          )}
        >
          <div className="rk-browser-progress h-full w-1/3 rounded-full bg-primary/70" />
        </div>
      </form>
      <div className="relative min-h-0 flex-1 bg-background">
        {native ? (
          <NativeViewport browser={native} visible={Boolean(state.url) && !state.error} />
        ) : state.url ? (
          <iframe
            key={frameKey}
            title={state.title || t`Page`}
            src={state.url}
            sandbox={browserFrameSandbox(state.url, window.location.origin)}
            allow="clipboard-read; clipboard-write; fullscreen"
            onLoad={() => setState((current) => ({ ...current, loading: false }))}
            className="h-full w-full border-0 bg-background"
            data-testid="in-app-browser-frame"
          />
        ) : null}
        {state.error ? (
          <div
            role="alert"
            className="absolute inset-0 grid place-items-center px-6 text-center text-ui-body-sm text-muted-foreground"
          >
            {state.error}
          </div>
        ) : null}
      </div>
    </div>
  );
}

/**
 * Reserves the page area and keeps the native view glued to it while the panel resizes,
 * hiding it whenever app UI (dialogs, menus) floats where the view would paint over it.
 */
function NativeViewport({
  browser,
  visible,
}: {
  browser: RakazoDesktopBrowserPreview;
  visible: boolean;
}) {
  const ref = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const element = ref.current;
    if (!element) return;
    let last = "";
    let frame = 0;
    const sync = () => {
      frame = 0;
      const rect = element.getBoundingClientRect();
      const covered = Array.from(document.querySelectorAll(FLOATING_UI)).some(
        (node) => !element.contains(node),
      );
      const show = visible && rect.width >= 1 && rect.height >= 1 && !covered;
      const bounds = {
        x: Math.round(rect.left),
        y: Math.round(rect.top),
        width: Math.round(rect.width),
        height: Math.round(rect.height),
      };
      const key = show ? JSON.stringify(bounds) : "hidden";
      if (key === last) return;
      last = key;
      void (show ? browser.show(bounds) : browser.hide()).catch(() => undefined);
    };
    const schedule = () => {
      if (!frame) frame = requestAnimationFrame(sync);
    };
    const resize = new ResizeObserver(schedule);
    resize.observe(element);
    const floating = new MutationObserver(schedule);
    floating.observe(document.body, { childList: true, subtree: true });
    window.addEventListener("resize", schedule);
    // Sibling layout (sidebars, transitions) can move the area without resizing it.
    const settle = setInterval(schedule, 250);
    schedule();
    return () => {
      cancelAnimationFrame(frame);
      resize.disconnect();
      floating.disconnect();
      window.removeEventListener("resize", schedule);
      clearInterval(settle);
      void browser.hide().catch(() => undefined);
    };
  }, [browser, visible]);

  return <div ref={ref} className="absolute inset-0" data-testid="in-app-browser-viewport" />;
}