import React, { useMemo } from 'react';
import { UserRound } from 'lucide-react';
import { Alert, AlertDescription, AlertTitle } from '../../../components/ui/alert';
import { FloatingWindow } from '../../../components/ui/floating-window/FloatingWindow';
import { sideAnchoredRect } from '../../../components/ui/floating-window/floatingGeometry';
import { useActiveEncounterContext } from './ActiveEncounterContext';
import { EncounterDocumentation } from './EncounterDocumentation';
import { useActiveEncounterPatient } from './useActiveEncounterPatient';

/**
 * sub-task 3 - the encounter clinical note, popped out into a window that follows the
 * practitioner anywhere in the app.
 *
 * EXACTLY ONE note editor exists at a time. While this is open, EncounterWorkspace shows a
 * placeholder instead of its editor. Two live editors for one note is the shape deletes.
 *
 * The window id is the STATIC string 'encounter-notes'. The primitive persists geometry under
 * `akashic_floating_window_<id>`, so keying it by patient or encounter would write an identifier into a
 * localStorage key that survives logout on a shared clinic workstation.
 *
 * Reuses `EncounterDocumentation` WHOLE, public/private toggle included - a note-only reimplementation
 * is how the "private - org only, not shown to the patient" distinction gets quietly lost.
 *
 * - WHY THIS PANE DOES **NOT** FOLLOW THE SELECTED PATIENT
 * The card was raised as *"the pane stays bound to the PREVIOUS patient"* after a measured run: with
 * Jacob Miller's notes popped out, selecting Related Two left this pane reading "Notes - Jacob Miller"
 * over Related Two's chart. **The measurement is real; the diagnosis was not.** Selecting a queue item
 * is a PREVIEW - it moves `selectedKey`, never the active slot - so the pane was showing the encounter
 * the practitioner is actually in, which is Spencer's 2026-08-05 ruling verbatim (see
 * `ActiveEncounterContext`). Retargeting to the selected patient would break that ruling AND is
 * incoherent: a previewed patient usually has no open encounter to write to.
 *
 * THE DEFECT THAT **IS** REAL is an asymmetry with the docked editor. Docked, the note is unreachable
 * while you preview someone else - `showWorkspace` requires `selectedKey === openEncounter.item.key`, so
 * the whole workspace unmounts. Floating, the note stays live over another patient's chart **and the only
 * thing tying it to its subject was the window title - which is `truncate`d in a small bar and can be
 * clipped to nothing.** So the pane now states its subject in the BODY, where it cannot be truncated
 * away, and says why it is not following the screen.
 * Do not "fix" this by clearing the pane on selection: that destroys an in-progress note, which is the
 * card's own negative control.
 */
export const FloatingEncounterNotes: React.FC = () => {
  const { active, notesLocation, setNotesLocation } = useActiveEncounterContext();
  // `patient` is already identity-gated at RENDER time inside the hook - see its comment for why an
  // effect cannot fix the lag between `patientId` (synchronous) and the fetched `patient` (async).
  const { patient: current, name } = useActiveEncounterPatient(notesLocation === 'floating');

  // IT USED TO OPEN CENTRED, AND THE CENTRE IS WHERE THE QUEUE RAIL IS. The window centres on the
  // VIEWPORT while the page content centres inside a max-w-[1600px] frame - two different centres on a
  // wide monitor, and the gap between them is exactly where the left column sits. Measured on a 3440px
  // display the centred window spanned x=860 to 2580 while the collapsed rail sat at roughly x=920 to
  // 984, inside it. A clinician with notes open could not click Expand queue to reach their own
  // patient list without minimising the notes first, every time.
  //
  // Computed ONCE, and that is a requirement rather than an optimisation: useFloatingGeometry reads
  // this only in its state initializer and treats it as mount-stable. A fresh object per render would be
  // silently ignored - a worse failure than an obvious one, because it looks configured and is not.
  // It is only a DEFAULT. A rect the clinician has dragged and stored still wins, as it should.
  const defaultRect = useMemo(
    () => sideAnchoredRect({ width: window.innerWidth, height: window.innerHeight }),
    [],
  );

  if (!active || notesLocation !== 'floating') return null;

  return (
    <FloatingWindow
      id="encounter-notes"
      defaultRect={defaultRect}
      title={`Notes — ${name || 'this patient'}`}
      onClose={() => setNotesLocation('docked')}
    >
      <div className="p-3">
        {/* 🚨 THE SUBJECT, IN THE BODY. ⛔ Never add `truncate` here — being clipped is precisely the
            failure mode this exists to cover for the title bar. The second line is not decoration: it
            answers the question the practitioner actually has ("why is this not the patient I'm looking
            at?"), which a name alone leaves them to guess at. */}
        <Alert variant="info" data-testid="floating-notes-subject" className="mb-3">
          {/* Unsized on purpose — the primitive sizes its own icon (`[&>svg]:size-4`). */}
          <UserRound aria-hidden="true" />
          {/* ⛔ `line-clamp-none` is LOAD-BEARING. AlertTitle clamps to a single line by default, which
              is the same clipping the window title already does — and covering for that clipping is the
              entire reason this strip exists. A long name in a narrow window would vanish twice over. */}
          <AlertTitle className="line-clamp-none">
            Note for <span className="font-semibold">{name}</span>
          </AlertTitle>
          <AlertDescription>
            Your open visit — it stays with this patient while you look at other charts.
          </AlertDescription>
        </Alert>
        <EncounterDocumentation patient={current} encounter={active.encounter} />
      </div>
    </FloatingWindow>
  );
};