import { useSessionStream } from "../stream/useSessionStream";
import { useSessionStore } from "../store/sessionStore";
import { WidgetHost } from "./WidgetHost";
import { Transcript } from "./Transcript";
import { NavSessions } from "./NavSessions";
import { SessionMenu } from "./SessionMenu";
import { SessionDocumentsPanel } from "./SessionDocumentsPanel";
import { RenameDialog } from "./RenameDialog";
import { DeleteConfirmDialog } from "./DeleteConfirmDialog";
import { SteerInput, ComposerFooter } from "./SteerInput";
import { WorkflowBar } from "./WorkflowBar";
import { Button } from "../components/ui/button";
import { Toaster } from "../components/ui/sonner";
import {
  closeSession, listSessions, resumeSession,
  renameSession, setSessionGroup, archiveSession, unarchiveSession, deleteSession,
} from "../api/sessions";
import type { SessionSummary } from "../api/types";
import { useQuery, useQueryClient } from "@tanstack/react-query";
import { useMemo, useRef, useState } from "react";

/**
 * The page is designed to live INSIDE the Omics Portal chrome (its left sidebar
 * + topbar) once embedded, so this shell intentionally has no left rail and no
 * top header of its own. The session rail sits on the RIGHT, mirroring the
 * portal's left sidebar, and the workflow phases ride a slim strip above the chat.
 */
export function AppShell() {
  const [activeSessionId, setActiveSessionId] = useState<string | null>(null);
  const { data: sessions = [] } = useQuery<SessionSummary[]>({
    queryKey: ["sessions"], queryFn: listSessions, refetchInterval: 10_000,
  });
  const composerRef = useRef<HTMLInputElement>(null);

  const queryClient = useQueryClient();
  const [panelSession, setPanelSession] = useState<SessionSummary | null>(null);
  const [showArchive, setShowArchive] = useState(false);
  const [renameTarget, setRenameTarget] = useState<SessionSummary | null>(null);
  const [deleteTarget, setDeleteTarget] = useState<SessionSummary | null>(null);
  const [collapsedGroups, setCollapsedGroups] = useState<Record<string, boolean>>({});

  const groups = useMemo(
    () => [...new Set(sessions.map((s) => s.group).filter((g): g is string => !!g))].sort(),
    [sessions],
  );
  const activeList = sessions.filter((s) => !s.archived);
  const archivedList = sessions.filter((s) => s.archived);
  const refresh = () => queryClient.invalidateQueries({ queryKey: ["sessions"] });

  function openPanel(id: string) {
    const s = sessions.find((x) => x.id === id);
    if (s) setPanelSession(s);
  }
  async function doResume(id: string) {
    await resumeSession(id);
    setPanelSession(null);
    setActiveSessionId(id);
  }
  async function move(s: SessionSummary, group: string) { await setSessionGroup(s.id, group); refresh(); }
  async function newGroup(s: SessionSummary) {
    const name = window.prompt("New group:");
    if (name && name.trim()) { await setSessionGroup(s.id, name.trim()); refresh(); }
  }
  async function toggleArchive(s: SessionSummary) {
    await (s.archived ? unarchiveSession(s.id) : archiveSession(s.id));
    if (panelSession?.id === s.id) setPanelSession(null);
    refresh();
  }

  function menuFor(s: SessionSummary) {
    return (
      <SessionMenu
        session={s}
        groups={groups}
        onView={() => setPanelSession(s)}
        onRename={() => setRenameTarget(s)}
        onMove={(g) => move(s, g)}
        onNewGroup={() => newGroup(s)}
        onArchiveToggle={() => toggleArchive(s)}
        onDelete={() => setDeleteTarget(s)}
      />
    );
  }

  // The harness "holds the ball" whenever a session is live and no widget is
  // waiting on the human; once a widget appears, input is back in the user's court.
  const pendingWidget = useSessionStore((s) => s.pendingWidget);
  const resetSession = useSessionStore((s) => s.resetSession);
  const working = Boolean(activeSessionId) && !pendingWidget;

  useSessionStream(activeSessionId);

  function startNewSession() {
    resetSession();
    setActiveSessionId(null);
    requestAnimationFrame(() => composerRef.current?.focus());
  }

  async function stopSession() {
    if (!activeSessionId) return;
    try {
      await closeSession(activeSessionId);
    } finally {
      resetSession();
      setActiveSessionId(null);
    }
  }

  return (
    <div className="flex h-screen bg-background text-foreground">
      {panelSession && (
        <SessionDocumentsPanel
          session={panelSession}
          onClose={() => setPanelSession(null)}
          onResume={doResume}
        />
      )}

      {/* Conversation column */}
      <div className="flex min-w-0 flex-1 flex-col">
        {activeSessionId && (
          <div className="shrink-0 border-b border-border/70 bg-background/80 px-6 py-2.5 backdrop-blur">
            <div className="mx-auto max-w-3xl">
              <WorkflowBar />
            </div>
          </div>
        )}

        <main className="flex-1 overflow-y-auto px-6 py-8">
          <div className="mx-auto flex max-w-3xl flex-col gap-6">
            {activeSessionId ? (
              <>
                <Transcript />
                <WidgetHost sessionId={activeSessionId} />
              </>
            ) : (
              <EmptyState />
            )}
          </div>
        </main>

        {/* Sticky composer: the box stays pinned while the conversation scrolls above. */}
        <div className="shrink-0 px-6 pb-6 pt-2">
          <div className="mx-auto max-w-3xl">
            <div className="rounded-2xl border border-input bg-card shadow-sm transition-colors focus-within:border-primary/40 focus-within:ring-3 focus-within:ring-ring/15">
              <div className="px-2.5 py-2">
                <SteerInput
                  sessionId={activeSessionId}
                  onSessionCreated={setActiveSessionId}
                  onStop={stopSession}
                  inputRef={composerRef}
                />
              </div>
              <ComposerFooter />
            </div>
          </div>
        </div>
      </div>

      {/* Right session rail — symmetric to the portal's left sidebar */}
      <aside className="flex w-[280px] shrink-0 flex-col border-l border-border bg-sidebar">
        <div className="relative px-4 pb-3 pt-5 text-center">
          {working && (
            <WorkingSpinner className="absolute left-4 top-[1.35rem]" />
          )}
          <h1 className="font-heading text-xl font-semibold leading-none tracking-tight text-foreground">
            Thoth<span className="text-primary">II</span>
          </h1>
          <p className="mt-1.5 text-[0.7rem] uppercase tracking-[0.14em] text-muted-foreground">
            Datamart Builder with
            <br />
            Human In The Loop
          </p>
        </div>

        <div className="flex flex-col gap-2 px-4 pb-3">
          <Button
            variant="default"
            size="sm"
            className="w-full"
            onClick={startNewSession}
          >
            New session
          </Button>
        </div>

        <div className="px-4 pb-1.5 pt-1">
          <span className="text-[0.7rem] font-bold uppercase tracking-[0.12em] text-primary">
            Sessions
          </span>
        </div>
        <div className="flex-1 overflow-y-auto px-2 pb-4">
          {showArchive ? (
            <NavSessions sessions={archivedList} activeSessionId={activeSessionId} onOpenPanel={openPanel} menuFor={menuFor} />
          ) : (
            <div className="flex flex-col gap-3">
              {groups.map((g) => (
                <div key={g}>
                  <button
                    type="button"
                    onClick={() => setCollapsedGroups((c) => ({ ...c, [g]: !c[g] }))}
                    aria-expanded={!collapsedGroups[g]}
                    className="flex w-full items-center gap-1 px-1 pb-1 text-left text-[0.7rem] font-semibold uppercase tracking-wide text-muted-foreground hover:text-foreground"
                  >
                    <span className="select-none">{collapsedGroups[g] ? "▸" : "▾"}</span>
                    <span className="truncate">{g}</span>
                  </button>
                  {!collapsedGroups[g] && (
                    <NavSessions
                      sessions={activeList.filter((s) => s.group === g)}
                      activeSessionId={activeSessionId}
                      onOpenPanel={openPanel}
                      menuFor={menuFor}
                    />
                  )}
                </div>
              ))}
              <div>
                {groups.length > 0 && (
                  <p className="px-1 pb-1 text-[0.7rem] font-semibold uppercase tracking-wide text-muted-foreground">No group</p>
                )}
                <NavSessions
                  sessions={activeList.filter((s) => !s.group)}
                  activeSessionId={activeSessionId}
                  onOpenPanel={openPanel}
                  menuFor={menuFor}
                />
              </div>
            </div>
          )}
          <button
            onClick={() => setShowArchive((v) => !v)}
            className="mt-3 w-full rounded-md px-2 py-1.5 text-left text-[0.7rem] font-semibold uppercase tracking-wide text-muted-foreground hover:bg-accent"
          >
            {showArchive ? "← Active sessions" : `Archive (${archivedList.length})`}
          </button>
        </div>
      </aside>

      <Toaster />

      {renameTarget && (
        <RenameDialog
          open
          initial={renameTarget.name ?? ""}
          onOpenChange={(o) => { if (!o) setRenameTarget(null); }}
          onSubmit={async (name) => { await renameSession(renameTarget.id, name); setRenameTarget(null); refresh(); }}
        />
      )}
      {deleteTarget && (
        <DeleteConfirmDialog
          open
          label={deleteTarget.name || deleteTarget.question}
          onOpenChange={(o) => { if (!o) setDeleteTarget(null); }}
          onConfirm={async () => {
            await deleteSession(deleteTarget.id);
            if (panelSession?.id === deleteTarget.id) setPanelSession(null);
            if (activeSessionId === deleteTarget.id) { resetSession(); setActiveSessionId(null); }
            setDeleteTarget(null); refresh();
          }}
        />
      )}
    </div>
  );
}

/** Brand-tinted spinner shown while the assistant/harness is working. */
function WorkingSpinner({ className }: { className?: string }) {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      role="status"
      aria-label="Assistant is working"
      className={["size-4 animate-spin text-primary", className].filter(Boolean).join(" ")}
    >
      <circle cx="12" cy="12" r="9" stroke="currentColor" strokeWidth="3" opacity="0.2" />
      <path d="M21 12a9 9 0 0 0-9-9" stroke="currentColor" strokeWidth="3" strokeLinecap="round" />
    </svg>
  );
}

function EmptyState() {
  return (
    <div className="flex min-h-[60vh] flex-col items-center justify-center text-center">
      <span className="font-heading text-5xl font-semibold tracking-tight text-foreground">
        Thoth<span className="text-primary">II</span>
      </span>
      <p className="mt-4 max-w-md text-balance text-[0.95rem] leading-relaxed text-muted-foreground">
        Build datamarts from your data warehouse through a guided,
        human-in-the-loop workflow. Type your question in the box below to begin
        a session.
      </p>
    </div>
  );
}