/**
 * @file ChatOutline.tsx
 * @description The right-hand panel of a Chat pane, laid out like
 * Claude Desktop's activity panel: the session's Progress (its
 * TaskCreate/TaskUpdate or TodoWrite plan, only when it has one — how many
 * steps are done of how many, a bar, and the step in progress highlighted), the Outputs
 * it wrote or edited (name + EXT tag; a click previews the file), and "Used in
 * this session" — the files attached to its prompts, the files it read and the
 * memory files it used and its skills (a click opens the list with a
 * preview — a skill's SKILL.md), and its MCP servers (a click opens the
 * Claude config page). Every row but MCP drags into the prompt box: a file
 * as an attachment, a group as all of its files, a lone skill as `/name`.
 * Read from
 * `GET /api/sessions/:id/outline` by `useSessionOutline`, which the pane also
 * uses for the collapsed button's count.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import {
  useEffect,
  useState,
  type ComponentType,
  type DragEvent,
  type ReactNode,
  type RefObject,
} from "react";
import { useTranslation } from "react-i18next";
import { Link } from "react-router-dom";
import { useSettingsHref } from "../../lib/settingsLink";
import {
  BookOpen,
  Check,
  ChevronDown,
  FileCode,
  FileImage,
  FileSearch,
  FileSpreadsheet,
  FileText,
  History,
  Paperclip,
  Plug,
  X,
} from "lucide-react";
import { api, type SessionOutline } from "../../lib/api";
import { keepIfSame } from "../../lib/keepIfSame";
import { isShown } from "../../hooks/useOnScreen";
import { displayName, extOf } from "./ChatFilePreview";
import { dragAttachments, dragSkill, type Attachment } from "../../lib/promptAttach";

const POLL_MS = 5000;
const EMPTY: SessionOutline = {
  progress: [],
  outputs: [],
  files: [],
  uploads: [],
  memory: [],
  skills: [],
  mcp: [],
};

/** The session's outline, re-read on a visibility-gated poll — skipped too
 *  while `onScreen` says the pane is hidden (another workspace or tab, kept
 *  mounted). An unchanged answer keeps the old object: no re-render. */
export function useSessionOutline(
  sessionId: string,
  onScreen?: RefObject<boolean>
): SessionOutline {
  const [outline, setOutline] = useState<SessionOutline>(EMPTY);
  useEffect(() => {
    let live = true;
    const load = () =>
      api.sessions
        .outline(sessionId)
        .then((o) => live && setOutline(keepIfSame<SessionOutline>({ ...EMPTY, ...o })))
        .catch(() => {});
    void load();
    const timer = window.setInterval(() => {
      if (onScreen ? isShown(onScreen) : document.visibilityState === "visible") void load();
    }, POLL_MS);
    return () => {
      live = false;
      window.clearInterval(timer);
    };
  }, [sessionId, onScreen]);
  return outline;
}

export type OutlineList = "uploads" | "files" | "memory" | "skills";

/** A listed file as a prompt attachment: an upload by its bare path, as the
 *  composer attaches one; anything else as an `@` mention. */
export function outlineAttachment(path: string, upload = false): Attachment {
  return { path: upload ? path : `@${path}`, name: displayName(path) };
}

const dragFiles =
  (paths: string[], upload = false) =>
  (e: DragEvent) =>
    dragAttachments(
      e,
      paths.map((p) => outlineAttachment(p, upload))
    );

function fileIcon(path: string) {
  const ext = extOf(path).toLowerCase();
  if (["xlsx", "xls", "csv", "tsv"].includes(ext)) return FileSpreadsheet;
  if (["png", "jpg", "jpeg", "gif", "webp", "svg"].includes(ext)) return FileImage;
  if (
    /^(c|cc|cpp|cs|css|go|h|html|java|js|jsx|json|kt|mjs|cjs|php|py|rb|rs|sh|sql|swift|ts|tsx|vue|ya?ml|toml)$/.test(
      ext
    )
  )
    return FileCode;
  return FileText;
}

function Section({
  title,
  count,
  action,
  grow,
  children,
}: {
  title: string;
  /** Beside the title: a count, or a "3/7". */
  count?: number | string;
  action?: ReactNode;
  /** Takes the panel's free height and scrolls inside it. */
  grow?: boolean;
  children: ReactNode;
}) {
  const [open, setOpen] = useState(true);
  return (
    <section className={`flex flex-col px-3 pt-3 ${grow && open ? "min-h-0 flex-1" : ""}`}>
      <div className="flex items-center gap-1.5 px-1 pb-1">
        <button
          type="button"
          onClick={() => setOpen((o) => !o)}
          aria-expanded={open}
          className="flex items-center gap-1.5 text-sm font-medium text-fg-primary"
        >
          {title}
          {count ? <span className="text-xs font-normal text-fg-muted">{count}</span> : null}
          <ChevronDown
            className={`h-3.5 w-3.5 text-fg-muted transition-transform ${open ? "" : "-rotate-90"}`}
          />
        </button>
        <div className="ml-auto flex items-center">{action}</div>
      </div>
      {open && (
        <div
          className={
            grow
              ? "min-h-0 flex-1 overflow-y-auto [mask-image:linear-gradient(to_bottom,transparent,black_8px,black_calc(100%-8px),transparent)]"
              : ""
          }
        >
          {children}
        </div>
      )}
    </section>
  );
}

const rowClass =
  "flex w-full items-center gap-2 rounded-md px-1.5 py-1.5 text-left text-[13px] text-fg-secondary enabled:hover:bg-surface-3";

/** A "Used in this session" row: icon, label, the first names, +N. */
function UsedRow({
  icon: Icon,
  label,
  names,
  onClick,
  onDragStart,
  to,
}: {
  icon: ComponentType<{ className?: string }>;
  label: string;
  names: string[];
  onClick?: () => void;
  /** The row drags into the prompt box. */
  onDragStart?: (e: DragEvent) => void;
  to?: string;
}) {
  const shown = names.slice(0, 2).join(", ");
  const inner = (
    <>
      <Icon className="h-4 w-4 flex-shrink-0 text-fg-muted" />
      <span className="flex-shrink-0 text-fg-primary">{label}</span>
      <span className="min-w-0 flex-1 truncate text-xs text-fg-muted">{shown}</span>
      {names.length > 2 && (
        <span className="flex-shrink-0 text-xs text-fg-muted">+{names.length - 2}</span>
      )}
    </>
  );
  const title = `${label}: ${names.join(", ")}`;
  return to ? (
    <Link to={to} title={title} className={`${rowClass} hover:bg-surface-3`}>
      {inner}
    </Link>
  ) : (
    <button
      type="button"
      title={title}
      onClick={onClick}
      draggable={!!onDragStart}
      onDragStart={onDragStart}
      className={rowClass}
    >
      {inner}
    </button>
  );
}

const stem = (p: string) => displayName(p).replace(/\.[A-Za-z0-9]+$/, "");

export function ChatOutline({
  outline: o,
  onClose,
  onOpenFile,
  onOpenList,
}: {
  outline: SessionOutline;
  onClose: () => void;
  onOpenFile: (path: string) => void;
  onOpenList: (list: OutlineList) => void;
}) {
  const { t } = useTranslation("run");
  const href = useSettingsHref();
  const doneSteps = o.progress.filter((p) => p.status === "completed").length;
  const used = o.uploads.length + o.files.length + o.memory.length + o.skills.length + o.mcp.length;
  const close = (
    <button
      type="button"
      onClick={onClose}
      title={t("chat.outline.hide")}
      aria-label={t("chat.outline.hide")}
      className="flex h-6 w-6 items-center justify-center rounded text-fg-muted hover:bg-surface-3 hover:text-fg-primary"
    >
      <X className="h-4 w-4" />
    </button>
  );

  return (
    <aside
      data-testid="chat-outline"
      aria-label={t("chat.outline.panel")}
      // Over the conversation in a narrow pane (the container is PaneChat's
      // root; `--chat-area` keeps the prompt box below it uncovered),
      // beside it once the pane has room, as wide as PaneChat's splitter says.
      className="absolute right-3 top-3 bottom-[calc(100%-var(--chat-area,100%)+0.75rem)] z-30 flex w-[clamp(15rem,34%,20rem)] max-w-[calc(100%-1.5rem)] flex-shrink-0 flex-col overflow-hidden rounded-xl border border-border bg-surface-1 pb-2 shadow-xl [@container(min-width:40rem)]:static [@container(min-width:40rem)]:m-3 [@container(min-width:40rem)]:ml-0 [@container(min-width:40rem)]:w-[calc(var(--chat-side)-0.75rem)] [@container(min-width:40rem)]:max-w-none [@container(min-width:40rem)]:shadow-none"
    >
      {o.progress.length > 0 && (
        <Section
          title={t("chat.outline.progress")}
          count={`${doneSteps}/${o.progress.length}`}
          action={close}
        >
          <div
            role="progressbar"
            aria-valuemin={0}
            aria-valuemax={o.progress.length}
            aria-valuenow={doneSteps}
            aria-label={t("chat.outline.progress")}
            className="mx-1.5 mb-1.5 h-1 overflow-hidden rounded-full bg-surface-3"
          >
            <div
              className="h-full rounded-full bg-accent-solid transition-[width] duration-500"
              style={{ width: `${(doneSteps / o.progress.length) * 100}%` }}
            />
          </div>
          {o.progress.map((task) => {
            const done = task.status === "completed";
            const now = task.status === "in_progress";
            return (
              <div
                key={task.id}
                className={`${rowClass} ${now ? "bg-accent/10 font-medium" : ""}`}
                title={task.subject}
                aria-current={now ? "step" : undefined}
              >
                {done ? (
                  <span className="flex h-4 w-4 flex-shrink-0 items-center justify-center rounded-full bg-accent-solid text-white">
                    <Check className="h-3 w-3" />
                  </span>
                ) : (
                  <span
                    className={`h-4 w-4 flex-shrink-0 rounded-full border-2 ${task.status === "in_progress" ? "animate-pulse-dot border-accent" : "border-border"}`}
                  />
                )}
                <span
                  className={`min-w-0 flex-1 truncate ${done ? "text-fg-muted line-through" : task.status === "in_progress" ? "text-fg-primary" : ""}`}
                >
                  {task.subject}
                </span>
              </div>
            );
          })}
        </Section>
      )}
      <Section
        title={t("chat.outline.outputs")}
        count={o.outputs.length}
        action={o.progress.length ? undefined : close}
        grow
      >
        {o.outputs.length ? (
          o.outputs.map((p) => {
            const Icon = fileIcon(p);
            return (
              <button
                key={p}
                type="button"
                title={p}
                aria-label={`${extOf(p)}: ${stem(p)}`}
                onClick={() => onOpenFile(p)}
                draggable
                onDragStart={dragFiles([p])}
                className={rowClass}
              >
                <Icon className="h-4 w-4 flex-shrink-0 text-fg-muted" />
                <span className="min-w-0 flex-1 truncate">{stem(p)}</span>
                <span className="flex-shrink-0 text-[11px] text-fg-muted">{extOf(p)}</span>
              </button>
            );
          })
        ) : (
          <p className="px-1.5 py-1 text-xs text-fg-muted">{t("chat.outline.empty")}</p>
        )}
      </Section>
      {used > 0 && (
        <Section title={t("chat.outline.used")}>
          {o.uploads.length > 0 && (
            <UsedRow
              icon={Paperclip}
              label={t("chat.outline.uploads")}
              names={o.uploads.map(displayName)}
              onClick={() => onOpenList("uploads")}
              onDragStart={dragFiles(o.uploads, true)}
            />
          )}
          {o.files.length > 0 && (
            <UsedRow
              icon={FileSearch}
              label={t("chat.outline.files")}
              names={o.files.map(displayName)}
              onClick={() => onOpenList("files")}
              onDragStart={dragFiles(o.files)}
            />
          )}
          {o.memory.length > 0 && (
            <UsedRow
              icon={History}
              label={t("chat.outline.memory")}
              names={o.memory.map(stem)}
              onClick={() => onOpenList("memory")}
              onDragStart={dragFiles(o.memory)}
            />
          )}
          {o.skills.length > 0 && (
            <UsedRow
              icon={BookOpen}
              label={t("chat.skills")}
              names={o.skills}
              onClick={() => onOpenList("skills")}
              // One command per prompt: several are dragged one by one from the list.
              onDragStart={o.skills.length === 1 ? (e) => dragSkill(e, o.skills[0]!) : undefined}
            />
          )}
          {o.mcp.length > 0 && (
            <UsedRow
              icon={Plug}
              label={t("chat.outline.connectors")}
              names={o.mcp}
              to={href("agents/claude-code?tab=mcp")}
            />
          )}
        </Section>
      )}
    </aside>
  );
}