import { useCallback } from "react";
import { useIsMutating, useMutation, useQueryClient } from "@tanstack/react-query";
import { useTranslation } from "react-i18next";

import { api, type DebugSession, type DebugSessionLevel } from "../lib/api";
import { notifyActionError } from "../lib/actionErrors";
import { captureTab } from "../lib/captureTab";
import {
  announceSessionChange,
  closeRecorderStart,
  nextStep,
  openComposer,
  setStepPrompt,
} from "../lib/debugRecorder";
import { flushNow, liveSession } from "../lib/diagnostics";
import { log } from "../lib/log";
import { notify } from "../lib/notifications";
import { qk } from "../lib/queryKeys";
import { updateMeCache, useMe } from "../lib/useMe";

/** The debug recording's actions, shared by everything that drives it: the pill, Settings →
 *  Diagnosztika and the command palette. The session itself is `me.debug_session` — the server's
 *  answer, so a reload, another tab or the cap all show the same thing. */
export function useDebugRecording() {
  const { t } = useTranslation();
  const qc = useQueryClient();
  const me = useMe();
  const session = liveSession(me?.debug_session);
  const setSession = (next: DebugSession | null) => {
    updateMeCache(qc, (prev) => ({ ...prev, debug_session: next }));
    void qc.invalidateQueries({ queryKey: qk.debugSessions(), exact: true });
    announceSessionChange();
    setStepPrompt(null); // a prompt left open belongs to the session that ended
  };

  const start = useMutation({
    mutationFn: (level: DebugSessionLevel) => api.startDebugSession(level),
    meta: { failTitle: "recorder.start.failed" },
    onSuccess: (r) => {
      setSession(r.session);
      closeRecorderStart();
    },
  });

  const stop = useMutation({
    mutationKey: STOP_KEY,
    mutationFn: async (id: string) => {
      log.info("debug.stop", "recording stopped by the user");
      // The events of the last seconds before Stop are the ones closest to what went wrong. Sent
      // while the session still tags them: once it is closed the server no longer does.
      await flushNow();
      return api.stopDebugSession(id);
    },
    meta: { failTitle: "recorder.pill.stopFailed" },
    onSuccess: (r) => {
      setSession(null);
      notify({ level: "success", message: t("recorder.pill.stopped") });
      openComposer(r.session.id);
    },
  });

  const shoot = useMutation({
    mutationKey: SHOOT_KEY,
    mutationFn: async ({ id, image }: { id: string; image: Blob }) =>
      api.addDebugScreenshot(id, image),
    meta: { failTitle: "recorder.pill.shotFailed" },
    onSuccess: (r) => {
      updateMeCache(qc, (prev) =>
        prev.debug_session
          ? {
              ...prev,
              debug_session: {
                ...prev.debug_session,
                screenshots: prev.debug_session.screenshots + 1,
              },
            }
          : prev,
      );
      // In the evidence too, where the step list is drafted from: which step it belongs to.
      log.info("debug.screenshot", "screenshot taken", { screenshot: r.screenshot.id });
      notify({ level: "success", message: t("recorder.pill.shotSaved") });
    },
  });

  // In flight anywhere, not only through this hook's own observer: the pill remounts when it moves
  // to another toast host, and a Stop still running must keep its button busy there.
  const stopping = useIsMutating({ mutationKey: STOP_KEY }) > 0;
  const shooting = useIsMutating({ mutationKey: SHOOT_KEY }) > 0;

  /** Mark the next step; `label` is what the user says they just did (may be empty). */
  const sessionId = session?.id;
  const markStep = useCallback(
    (label: string) => {
      if (!sessionId) return;
      const n = nextStep(sessionId);
      const text = label.trim();
      log.info("debug.step", text || `step ${n}`, { n, ...(text ? { label: text } : {}) });
      notify({ level: "info", message: t("recorder.pill.stepMarked", { n }) });
    },
    [sessionId, t],
  );

  /** Capture this tab and attach it. `hide` runs around the capture so the pill is not in the
   *  frame. Nothing happens when the user cancels the browser's picker. */
  const screenshot = async (hide: (hidden: boolean) => void) => {
    if (!session) return;
    hide(true);
    let image: Blob | null = null;
    try {
      // Two frames: the pill's `invisible` must be painted before the capture reads the tab.
      await new Promise((r) => requestAnimationFrame(() => requestAnimationFrame(r)));
      image = await captureTab();
    } catch (err) {
      notifyActionError(err, t("recorder.pill.shotFailed"));
    }
    hide(false);
    if (image) shoot.mutate({ id: session.id, image });
  };

  return { session, start, stop, stopping, shoot, shooting, markStep, screenshot };
}

const STOP_KEY = ["debug-session", "stop"];
const SHOOT_KEY = ["debug-session", "screenshot"];