import { useEffect, useRef, useState, type KeyboardEvent as ReactKeyboardEvent } from "react";
import { useTranslation } from "react-i18next";
import { useQuery, useQueryClient } from "@tanstack/react-query";
import { Camera, Flag, Square } from "lucide-react";

import { api, type DebugSession, type DebugSessionLevel } from "../lib/api";
import { canCaptureTab } from "../lib/captureTab";
import {
  closeRecorderStart,
  onSessionChangeElsewhere,
  openComposer,
  openRecorderStart,
  setStepPrompt,
  useComposerSession,
  useRecorderStartOpen,
  useStepCount,
  useStepPrompt,
} from "../lib/debugRecorder";
import { formatDuration } from "../lib/format";
import { useLayer } from "../lib/layerStack";
import { notify } from "../lib/notifications";
import { qk } from "../lib/queryKeys";
import { dockUnderToasts } from "../lib/toastDock";
import { useMe } from "../lib/useMe";
import { Button } from "./ui/Button";
import Modal from "./ui/Modal";
import { LoadingState, StateMessage } from "./ui/QueryState";
import SegmentedToggle from "./ui/SegmentedToggle";
import IssueComposer from "./IssueComposer";
import { useDebugRecording } from "./useDebugRecording";
import { Input } from "./ui/Input";
import { SURFACE } from "./ui/surfaces";

// The debug recorder (E16): Start → reproduce → Stop.
//
// While a session records, its pill sits under the toasts (lib/toastDock), so it rides every toast
// host — the page, each dialog, both players, the fullscreen player — and is reachable wherever the
// bug is being reproduced, above a player's control band rather than on it. Mounted once, in the
// app shell, for a signed-in account other than the demo.

/** The time since `since`, as the app's other clocks show it, re-rendered every second. */
function useElapsed(since: string): string {
  const [, tick] = useState(0);
  useEffect(() => {
    const id = window.setInterval(() => tick((n) => n + 1), 1000);
    return () => window.clearInterval(id);
  }, []);
  // eslint-disable-next-line react-hooks/purity -- the clock is READ at render and the interval above only re-renders — a `now` held in state is the moment the component mounted, which is the defect DiagnosticsSettings records from prod UAT.
  return formatDuration(Math.max(0, Math.floor((Date.now() - Date.parse(since)) / 1000)));
}

export default function DebugRecorder() {
  const { t } = useTranslation();
  const qc = useQueryClient();
  const me = useMe();
  const { session } = useDebugRecording();
  const startOpen = useRecorderStartOpen();
  const composing = useComposerSession();
  const id = session?.id;

  useEffect(() => (id ? dockUnderToasts(RecorderPill) : undefined), [id]);
  // Started or stopped in another tab: this one asks the server what is in force now.
  useEffect(
    () => onSessionChangeElsewhere(() => void qc.invalidateQueries({ queryKey: qk.me() })),
    [qc],
  );

  // The cap: the server ends the session at `until` whether or not anyone stops it. This tab says
  // so, and opens the composer for it — the recording is as useful as one stopped by hand.
  const until = session?.until;
  const minutes = me?.diagnostics?.session_minutes;
  useEffect(() => {
    if (!id || !until) return;
    const wait = Math.min(Date.parse(until) - Date.now(), 2 ** 31 - 1);
    const timer = window.setTimeout(() => {
      notify({ level: "warning", message: t("recorder.pill.expired", { count: minutes ?? 0 }) });
      openComposer(id);
      void qc.invalidateQueries({ queryKey: qk.me() });
    }, wait);
    return () => window.clearTimeout(timer);
  }, [id, until, minutes, qc, t]);

  return (
    <>
      {startOpen && <StartDialog />}
      {composing && <IssueComposer id={composing} />}
    </>
  );
}

function StartDialog() {
  const { t } = useTranslation();
  const me = useMe();
  const { start } = useDebugRecording();
  const [level, setLevel] = useState<DebugSessionLevel>("DEBUG");
  const days = me.diagnostics.retention_days;
  const minutes = me.diagnostics.session_minutes;
  const levels: readonly DebugSessionLevel[] = ["DEBUG", "TRACE"];
  return (
    <Modal title={t("recorder.start.title")} onClose={closeRecorderStart}>
      <div className="flex flex-col gap-4">
        <p className="text-sm text-muted leading-relaxed">{t("recorder.start.intro")}</p>
        <div className="flex flex-col items-start gap-1.5">
          <span className="text-sm text-muted">{t("recorder.start.level")}</span>
          <SegmentedToggle
            size="md"
            ariaLabel={t("recorder.start.level")}
            options={levels.map((l) => ({
              value: l,
              label: t(`settings.diagnostics.levels.${l}`),
            }))}
            value={level}
            onChange={setLevel}
          />
        </div>
        <div className={`${SURFACE.card} px-4 py-3 flex flex-col gap-2 text-sm leading-relaxed`}>
          <div className="font-semibold">{t("recorder.start.whatTitle")}</div>
          <p>{t(`recorder.start.what.${level}`)}</p>
          <p className="text-muted">{t("settings.diagnostics.consent.never")}</p>
          <p className="text-muted">
            {t("recorder.start.kept", { count: days })}{" "}
            {t("recorder.start.cap", { count: minutes })}
          </p>
        </div>
        <div className="flex justify-end gap-2">
          <Button variant="ghost" onClick={closeRecorderStart}>
            {t("common.cancel")}
          </Button>
          <Button
            variant="primary"
            loading={start.isPending}
            icon={<span className="w-2.5 h-2.5 rounded-full bg-danger" aria-hidden />}
            onClick={() => start.mutate(level)}
          >
            {t("recorder.start.confirm")}
          </Button>
        </div>
      </div>
    </Modal>
  );
}

/** The pill: how long it has been recording, and the three things to do while it does. */
function RecorderPill() {
  const { t } = useTranslation();
  const { session, stop, stopping, shooting, markStep, screenshot } = useDebugRecording();
  const [hidden, setHidden] = useState(false);
  const stepOpen = useStepPrompt() !== null;
  const stepButton = useRef<HTMLButtonElement>(null);
  const steps = useStepCount(session?.id ?? "");
  if (!session) return null;
  return (
    <div
      role="group"
      aria-label={t("recorder.pill.label")}
      className={`relative ${SURFACE.floating} h-12 pl-3 sm:pl-4 pr-1.5 flex items-center gap-1.5 sm:gap-2 ${
        hidden ? "invisible" : ""
      }`}
    >
      <span
        aria-hidden
        className="w-2.5 h-2.5 shrink-0 rounded-full bg-danger ring-4 ring-danger/20 motion-safe:animate-pulse"
      />
      <Elapsed since={session.started_at} />
      <span className="chip hidden sm:inline-flex px-2 py-0.5 text-2xs">
        {t(`settings.diagnostics.levels.${session.level}`)}
      </span>
      <span aria-hidden className="hidden sm:block w-px h-6 bg-border" />
      <Button
        ref={stepButton}
        variant="outline-accent"
        size="sm"
        className="rounded-full"
        icon={<Flag className="w-4 h-4" />}
        label={t("recorder.pill.step")}
        aria-expanded={stepOpen}
        onClick={() => setStepPrompt(stepOpen ? null : "")}
      >
        <span className="hidden sm:inline tabular-nums">
          {t("recorder.pill.step")}
          {steps ? ` · ${steps}` : ""}
        </span>
      </Button>
      {canCaptureTab() && (
        <Button
          variant="outline"
          size="sm"
          className="rounded-full"
          icon={<Camera className="w-4 h-4" />}
          label={t("recorder.pill.screenshot")}
          loading={shooting}
          onClick={() => void screenshot(setHidden)}
        >
          <span className="hidden sm:inline tabular-nums">
            {t("recorder.pill.screenshot")}
            {session.screenshots ? ` · ${session.screenshots}` : ""}
          </span>
        </Button>
      )}
      <Button
        variant="danger"
        size="sm"
        className="rounded-full"
        icon={<Square className="w-3.5 h-3.5 fill-current" />}
        label={t("recorder.pill.stop")}
        loading={stopping}
        onClick={() => stop.mutate(session.id)}
      >
        <span className="hidden sm:inline">{t("recorder.pill.stop")}</span>
      </Button>
      {stepOpen && (
        <StepPrompt
          id={session.id}
          onDone={(label) => {
            if (label !== null) markStep(label);
            setStepPrompt(null);
            stepButton.current?.focus();
          }}
        />
      )}
    </div>
  );
}

function Elapsed({ since }: { since: string }) {
  const { t } = useTranslation();
  const time = useElapsed(since);
  return (
    // On a phone only the clock: the pill has to fit the content column beside the rail, and the
    // red dot already says what it is.
    <span className="text-sm font-semibold tabular-nums whitespace-nowrap">
      <span className="hidden sm:inline">{t("recorder.pill.recording", { time })}</span>
      <span className="sm:hidden">{time}</span>
    </span>
  );
}

/** Settings → Diagnosztika: start a recording or stop the one running, and reopen a past one. */
export function RecorderSettings() {
  return (
    <div className="flex flex-col gap-4">
      <RecorderControl />
      <SessionHistory />
    </div>
  );
}

function RecorderControl() {
  const { t } = useTranslation();
  const { session, stop, stopping } = useDebugRecording();
  if (!session)
    return (
      <div className="flex flex-wrap items-center justify-between gap-3">
        <p className="text-sm text-muted max-w-prose">{t("recorder.settings.hint")}</p>
        <Button
          variant="outline"
          icon={<span className="w-2.5 h-2.5 rounded-full bg-danger" aria-hidden />}
          onClick={openRecorderStart}
        >
          {t("recorder.settings.start")}
        </Button>
      </div>
    );
  return (
    <div className="flex flex-wrap items-center justify-between gap-2 rounded-xl border border-danger/40 bg-danger/10 px-3 py-2 text-sm">
      <span className="inline-flex items-center gap-2">
        <span className="h-2 w-2 shrink-0 rounded-full bg-danger" aria-hidden />
        <SettingsElapsed since={session.started_at} />
      </span>
      <Button
        variant="danger-soft"
        size="sm"
        loading={stopping}
        onClick={() => stop.mutate(session.id)}
      >
        {t("recorder.settings.stop")}
      </Button>
    </div>
  );
}

function SettingsElapsed({ since }: { since: string }) {
  const { t } = useTranslation();
  const time = useElapsed(since);
  return <span className="tabular-nums">{t("recorder.settings.recording", { time })}</span>;
}

/** "What did you just do?" — optional; Enter marks the step, Escape leaves it unmarked. */
function StepPrompt({ id, onDone }: { id: string; onDone: (label: string | null) => void }) {
  const { t } = useTranslation();
  const n = useStepCount(id) + 1;
  const label = useStepPrompt() ?? "";
  // A layer of its own, so Escape closes only the prompt — not the dialog or the player the pill may
  // be sitting in: the topmost layer takes Escape (lib/layerStack), and this one opened last. It
  // OWNS the keyboard while it is up (an autofocused field does), so the page's own keys stay quiet.
  // It does NOT take the Tab, though: it is a field inside whatever dialog the pill is docked in,
  // not a dialog of its own, and the trap belongs to that one — it spans the prompt as it spans the
  // rest of the toast host. Claiming it here switched the dialog's off and left every control
  // OUTSIDE this little box untrapped (deep-review round 3).
  useLayer(true, () => onDone(null), { trapsTab: false });
  const onKeyDown = (e: ReactKeyboardEvent<HTMLInputElement>) => {
    if (e.key === "Enter") {
      e.preventDefault();
      onDone(label);
    }
  };
  return (
    <div
      className={`${SURFACE.popover} absolute bottom-full left-0 mb-2 w-80 max-w-[calc(100vw-2rem)] p-3 flex flex-col gap-2`}
    >
      <label htmlFor="debug-step-label" className="text-sm text-muted">
        {t("recorder.pill.stepPrompt", { n })}
      </label>
      <Input
        className="w-full"
        id="debug-step-label"
        autoFocus
        value={label}
        onChange={(e) => setStepPrompt(e.target.value)}
        onKeyDown={onKeyDown}
        maxLength={200}
      />
      <div className="flex items-center justify-between gap-2 text-xs text-muted">
        <span>{t("recorder.pill.stepHint")}</span>
        <Button variant="primary" size="sm" onClick={() => onDone(label)}>
          {t("recorder.pill.mark")}
        </Button>
      </div>
    </div>
  );
}

/** The five words a past session can read as. A union, not `string`, because `chipTone` below
 *  matches on these same keys: untyped, a rename in one of them left the other matching nothing
 *  and every chip untoned, with the gate green (deep-review round 4). */
type HistoryState =
  | "recorder.history.sending"
  | "recorder.history.draft"
  | "recorder.history.unwritten"
  | "recorder.history.partial"
  | "recorder.history.sent";

/** What a past session reads as. An issue that still owes the tracker its attachments, or an edit
 *  that shows its screenshots, is NOT "Sent": this list is where a user goes back to check, and a
 *  green chip there is how a half-delivered report gets forgotten. */
function historyState(s: DebugSession): HistoryState {
  // A send under way outranks every other word here: this is the list a user comes back to in
  // order to check on one, and both "draft" (no issue yet) and "half sent" (the steps it has
  // already committed) would describe a send that STOPPED.
  if (s.sending) return "recorder.history.sending";
  if (!s.issue_url) return s.draft ? "recorder.history.draft" : "recorder.history.unwritten";
  return s.pending_files.length > 0 || s.images_pending
    ? "recorder.history.partial"
    : "recorder.history.sent";
}

/** The colour that reinforces that word. Exhaustive over `HistoryState`, so a key renamed in
 *  `historyState` is a compile error here rather than a chip that quietly loses its tone. */
const chipTone = (s: DebugSession): string => {
  switch (historyState(s)) {
    case "recorder.history.sent":
      return "text-success";
    case "recorder.history.sending":
      return "text-accent";
    case "recorder.history.partial":
      return "text-warn";
    case "recorder.history.draft":
    case "recorder.history.unwritten":
      return "";
  }
};

/** The last sessions, newest first — reopening one opens its composer, with what was written. */
function SessionHistory() {
  const { t, i18n } = useTranslation();
  const q = useQuery({ queryKey: qk.debugSessions(), queryFn: api.debugSessions });
  const items = q.data?.items.filter((s) => s.ended_at) ?? [];
  if (q.isError && !q.data)
    return (
      <StateMessage tone="error" compact onRetry={() => void q.refetch()}>
        {t("recorder.history.failed")}
      </StateMessage>
    );
  if (!q.data) return <LoadingState />;
  return (
    <div className="flex flex-col gap-1.5">
      <div className="text-sm text-muted">{t("recorder.history.title")}</div>
      {items.length === 0 ? (
        <p className="text-sm text-muted">{t("recorder.history.empty")}</p>
      ) : (
        <ul className="flex flex-col divide-y divide-border/60 rounded-xl border border-border">
          {items.map((s) => (
            <li
              key={s.id}
              className="flex flex-wrap items-center gap-x-3 gap-y-1 px-3 py-2 text-sm"
            >
              <span className="tabular-nums">
                {new Date(s.started_at).toLocaleString(i18n.language)}
              </span>
              <span className="min-w-0 flex-1 truncate text-muted">
                {s.draft?.title || t(`settings.diagnostics.levels.${s.level}`)}
              </span>
              <span className={`chip px-2 py-0.5 text-2xs ${chipTone(s)}`}>
                {t(historyState(s))}
              </span>
              <Button variant="outline" size="xs" onClick={() => openComposer(s.id)}>
                {t("recorder.history.open")}
              </Button>
            </li>
          ))}
        </ul>
      )}
    </div>
  );
}