/**
 * @file WorkspaceContext — a workspace's context: Instructions, Memory
 * (read-only), Context files and Folders (`GET/PUT/POST/DELETE
 * /api/lanes/:id/sources…`, see server/lib/lane-sources.js). Shown as the
 * workspace home's right column and, `compact`, folded at the bottom of the
 * session view's Changes panel. Folder suggestions are the repo's untracked
 * worktrees from `GET /api/projects`, filtered by Settings → Worktrees; the
 * same form clones related repos beside the workspace (`CloneSourcesForm`).
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import { useEffect, useRef, useState } from "react";
import { useTranslation } from "react-i18next";
import { FileText, Folder, Pencil, Plus, X } from "lucide-react";
import { copyText } from "../../lib/clipboard";
import { dragProjectPath } from "../../lib/promptAttach";
import { useDialog } from "../../hooks/useDialog";
import { api, type LaneMemoryFile, type LaneSource, type LaneSourcesView } from "../../lib/api";
import type { Lane } from "../../lib/types";
import { useAiTools } from "../../hooks/useAiTools";
import { useProjectTreePrefs } from "../../lib/projectTreePrefs";
import { MarkdownPreview } from "../MarkdownPreview";
import { ContextMenu, MenuItem, MenuSeparator, useContextMenu } from "../ContextMenu";
import { PathPickButton } from "../PathPickButton";
import { CloneSourcesForm } from "./CloneSourcesForm";

function fmtBytes(n: number | null): string {
  if (!n) return "";
  if (n < 1024) return `${n} B`;
  if (n < 1024 * 1024) return `${Math.round(n / 1024)} KB`;
  return `${(n / 1024 / 1024).toFixed(1)} MB`;
}

const message = (err: unknown) => (err instanceof Error ? err.message : String(err));

/** Keyed by workspace: an open edit or folder form belongs to ONE workspace. */
export function WorkspaceContext(props: Parameters<typeof ContextBody>[0]) {
  return <ContextBody key={props.lane.id} {...props} />;
}

function ContextBody({
  lane,
  onSourcesChange,
  sourcesVersion = 0,
  compact = false,
}: {
  lane: Lane;
  /** Called with the sources after a folder or file is added or removed. */
  onSourcesChange?: (view: LaneSourcesView) => void;
  /** Bumped when the folder list changed elsewhere: the lists re-read. */
  sourcesVersion?: number;
  /** The Changes panel's narrow fold: no card, tighter rows. */
  compact?: boolean;
}) {
  const { t } = useTranslation("lanes");
  const aiTools = useAiTools();
  const prefs = useProjectTreePrefs();
  const [error, setError] = useState<string | null>(null);
  const [view, setView] = useState<LaneSourcesView | null>(null);
  const [editing, setEditing] = useState<string | null>(null);
  const [memory, setMemory] = useState<LaneMemoryFile[] | null>(null);
  const [memoryOpen, setMemoryOpen] = useState(false);
  const [memoryTab, setMemoryTab] = useState(0);
  const [folderOpen, setFolderOpen] = useState(false);
  const [folderPath, setFolderPath] = useState("");
  const [suggestions, setSuggestions] = useState<string[]>([]);
  const fileInput = useRef<HTMLInputElement>(null);
  const [ctxDrag, setCtxDrag] = useState(false);
  const memoryPanel = useRef<HTMLDivElement>(null);
  useDialog(memoryOpen && !!memory, memoryPanel, () => setMemoryOpen(false));
  const sourceCtx = useContextMenu<LaneSource>();

  useEffect(() => {
    let live = true;
    api.lanes
      .sources(lane.id)
      .then((v) => live && setView(v))
      .catch((err) => live && setError(message(err)));
    api.lanes
      .memory(lane.id)
      .then((r) => live && setMemory(r.files))
      .catch(() => live && setMemory([]));
    return () => {
      live = false;
    };
  }, [lane.id]);

  // Suggestions are read when the folder form opens, not on every visit.
  useEffect(() => {
    if (!folderOpen) return;
    let live = true;
    api.projects
      .list()
      .then(({ projects }) => {
        if (!live) return;
        const p = projects.find((x) => x.workspaces.includes(lane.id));
        const own = new Set((view?.sources ?? []).map((s) => s.path));
        setSuggestions(
          !p || !prefs.showUntracked
            ? []
            : p.worktrees
                .filter((w) => w.workspace_id === null && !own.has(w.path))
                .filter((w) => !(w.source && prefs.hideSources.includes(w.source)))
                .map((w) => w.path)
        );
      })
      .catch(() => undefined);
    return () => {
      live = false;
    };
  }, [folderOpen, lane.id, prefs.showUntracked, prefs.hideSources, view?.sources]);

  useEffect(() => {
    if (!sourcesVersion) return;
    let live = true;
    api.lanes
      .sources(lane.id)
      .then((v) => live && setView(v))
      .catch(() => undefined);
    return () => {
      live = false;
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps -- on a bump only
  }, [sourcesVersion]);

  const run = async (fn: () => Promise<LaneSourcesView>) => {
    setError(null);
    try {
      const next = await fn();
      setView(next);
      onSourcesChange?.(next);
      return true;
    } catch (err) {
      setError(message(err));
      return false;
    }
  };
  const addFiles = async (picked: File[]) => {
    for (const f of picked) {
      if (!(await run(() => api.lanes.addFile(lane.id, f)))) break;
    }
  };

  const files = (view?.sources ?? []).filter((s) => s.kind === "file");
  const folders = (view?.sources ?? []).filter((s) => s.kind === "folder");
  const card = compact
    ? "border-b border-border/60 px-1 py-2 last:border-b-0"
    : "border-b border-border px-4 py-4 last:border-b-0";
  const heading = compact
    ? "text-xs font-medium text-fg-secondary"
    : "text-sm font-medium text-fg-primary";
  const iconBtn =
    "rounded p-1 text-fg-muted transition-colors hover:bg-surface-4 hover:text-fg-primary disabled:opacity-40";

  return (
    <>
      <aside
        data-testid="workspace-context"
        aria-label={t("home.contextPanel")}
        className={compact ? "" : "card w-80 shrink-0 self-start p-0"}
      >
        {view && !view.supported && (
          <p className="border-b border-border px-4 py-3 text-xs text-status-warning">
            {t("home.unsupported", { tool: aiTools.label(lane.tool) })}
          </p>
        )}
        {error && (
          <p role="alert" className="border-b border-border px-4 py-2 text-xs text-status-danger">
            {error}
          </p>
        )}

        <section className={card}>
          <div className="flex items-center justify-between">
            <h3 className={heading}>{t("home.instructions")}</h3>
            {editing === null && (
              <button
                type="button"
                aria-label={t("home.edit")}
                title={t("home.edit")}
                onClick={() => setEditing(view?.instructions ?? "")}
                disabled={!view}
                className={iconBtn}
              >
                <Pencil className="h-3.5 w-3.5" />
              </button>
            )}
          </div>
          {editing === null ? (
            <p
              className={`mt-1 ${compact ? "line-clamp-2" : "line-clamp-3"} whitespace-pre-wrap text-xs text-fg-muted`}
            >
              {view?.instructions || t("home.instructionsEmpty")}
            </p>
          ) : (
            <div className="mt-2 space-y-2">
              <textarea
                data-testid="workspace-instructions"
                aria-label={t("home.instructions")}
                autoFocus
                value={editing}
                maxLength={view?.maxInstructions}
                onChange={(e) => setEditing(e.target.value)}
                rows={compact ? 4 : 6}
                className="w-full rounded border border-border bg-surface-1 p-2 text-xs text-fg-primary"
              />
              <div className="flex justify-end gap-2">
                <button
                  type="button"
                  onClick={() => setEditing(null)}
                  className="btn-ghost text-xs"
                >
                  {t("home.cancel")}
                </button>
                <button
                  type="button"
                  onClick={async () => {
                    if (await run(() => api.lanes.setInstructions(lane.id, editing)))
                      setEditing(null);
                  }}
                  className="btn-primary text-xs"
                >
                  {t("home.save")}
                </button>
              </div>
            </div>
          )}
        </section>

        <section className={card}>
          <div className="flex items-center justify-between">
            <h3 className={heading}>{t("home.memory")}</h3>
            <button
              type="button"
              onClick={() => {
                setMemoryTab(0);
                setMemoryOpen(true);
              }}
              disabled={!memory?.length}
              className="text-xs text-fg-secondary hover:text-fg-primary disabled:opacity-40"
            >
              {t("home.viewMemory")}
            </button>
          </div>
          <p className="mt-1 text-xs text-fg-muted">
            {memory?.length
              ? t("home.memoryCount", { count: memory.length })
              : t("home.memoryEmpty")}
          </p>
        </section>

        <section
          data-testid="workspace-context-files"
          className={`${card} ${ctxDrag ? "ring-2 ring-accent/50" : ""}`}
          // Files dragged in from the OS are added like the + button's pick.
          onDragOver={(e) => {
            if (!view || !e.dataTransfer.types.includes("Files")) return;
            e.preventDefault();
            e.dataTransfer.dropEffect = "copy";
            setCtxDrag(true);
          }}
          onDragLeave={(e) => {
            if (!e.currentTarget.contains(e.relatedTarget as Node | null)) setCtxDrag(false);
          }}
          onDrop={(e) => {
            setCtxDrag(false);
            if (!view || e.dataTransfer.files.length === 0) return;
            e.preventDefault();
            void addFiles([...e.dataTransfer.files]);
          }}
        >
          <div className="flex items-center justify-between">
            <h3 className={heading}>{t("home.context")}</h3>
            <button
              type="button"
              aria-label={t("home.addFile")}
              title={t("home.addFile")}
              onClick={() => fileInput.current?.click()}
              disabled={!view}
              className={iconBtn}
            >
              <Plus className="h-3.5 w-3.5" />
            </button>
            <input
              ref={fileInput}
              data-testid="workspace-file-input"
              type="file"
              multiple
              hidden
              onChange={(e) => {
                const picked = [...(e.target.files ?? [])];
                e.target.value = "";
                void addFiles(picked);
              }}
            />
          </div>
          {!compact && <p className="mt-1 text-xs text-fg-muted">{t("home.contextSnapshot")}</p>}
          {files.length === 0 ? (
            <button
              type="button"
              onClick={() => fileInput.current?.click()}
              className={`mt-2 w-full rounded-lg border border-dashed border-border px-3 ${compact ? "py-2" : "py-5"} text-center text-xs text-fg-muted hover:border-border-light hover:text-fg-secondary`}
            >
              {t("home.contextEmpty")}
            </button>
          ) : (
            <ul className="mt-2 space-y-1">
              {files.map((f) => (
                <li
                  key={f.id}
                  className="group flex items-center gap-2 text-xs"
                  onContextMenu={(e) => sourceCtx.open(e, f)}
                  // Dragged onto a prompt box, it is attached as `@<path>`.
                  draggable
                  onDragStart={(e) => dragProjectPath(e, f.path)}
                >
                  <FileText className="h-3.5 w-3.5 shrink-0 text-fg-muted" />
                  <span title={f.path} className="min-w-0 flex-1 truncate text-fg-secondary">
                    {f.name}
                  </span>
                  <span className="shrink-0 text-fg-muted">
                    {f.missing ? t("home.missing") : fmtBytes(f.size)}
                  </span>
                  <button
                    type="button"
                    aria-label={`${t("home.remove")} ${f.name}`}
                    onClick={() => void run(() => api.lanes.removeSource(lane.id, f.id))}
                    className={`${iconBtn} opacity-0 group-hover:opacity-100 focus:opacity-100`}
                  >
                    <X className="h-3 w-3" />
                  </button>
                </li>
              ))}
            </ul>
          )}
        </section>

        <section className={card}>
          <div className="flex items-center justify-between">
            <h3 className={heading}>{t("home.folder")}</h3>
            <button
              type="button"
              aria-label={t("home.addFolder")}
              title={t("home.addFolder")}
              onClick={() => setFolderOpen((v) => !v)}
              disabled={!view}
              className={iconBtn}
            >
              <Plus className="h-3.5 w-3.5" />
            </button>
          </div>
          <ul className="mt-2 space-y-1.5">
            <li
              className="flex items-start gap-2 text-xs"
              draggable
              onDragStart={(e) => dragProjectPath(e, `${lane.cwd}/`)}
            >
              <Folder className="mt-0.5 h-3.5 w-3.5 shrink-0 text-fg-muted" />
              <span className="min-w-0">
                <span title={lane.cwd} className="block truncate text-fg-secondary">
                  {lane.cwd.split("/").filter(Boolean).pop() || lane.cwd}
                </span>
                <span className="block text-fg-muted">{t("home.ownFolder")}</span>
              </span>
            </li>
            {folders.map((f) => (
              <li
                key={f.id}
                className="group flex items-center gap-2 text-xs"
                onContextMenu={(e) => sourceCtx.open(e, f)}
                draggable
                onDragStart={(e) => dragProjectPath(e, `${f.path}/`)}
              >
                <Folder className="h-3.5 w-3.5 shrink-0 text-fg-muted" />
                <span title={f.path} className="min-w-0 flex-1 truncate text-fg-secondary">
                  {f.name}
                  {f.missing && (
                    <span className="ml-1 text-status-warning">{t("home.missing")}</span>
                  )}
                </span>
                <button
                  type="button"
                  aria-label={`${t("home.remove")} ${f.name}`}
                  onClick={() => void run(() => api.lanes.removeSource(lane.id, f.id))}
                  className={`${iconBtn} opacity-0 group-hover:opacity-100 focus:opacity-100`}
                >
                  <X className="h-3 w-3" />
                </button>
              </li>
            ))}
          </ul>
          {folderOpen && (
            <form
              className="mt-3 space-y-2"
              onSubmit={async (e) => {
                e.preventDefault();
                if (await run(() => api.lanes.addFolder(lane.id, folderPath.trim()))) {
                  setFolderPath("");
                  setFolderOpen(false);
                }
              }}
            >
              <div className="flex gap-2">
                <input
                  data-testid="workspace-folder-input"
                  aria-label={t("home.folderPath")}
                  placeholder={t("home.folderPath")}
                  autoFocus
                  value={folderPath}
                  onChange={(e) => setFolderPath(e.target.value)}
                  className="min-w-0 flex-1 rounded border border-border bg-surface-1 px-2 py-1 font-mono text-[11px] text-fg-primary"
                />
                <PathPickButton start={folderPath || lane.cwd} onPick={setFolderPath} />
                <button type="submit" disabled={!folderPath.trim()} className="btn-ghost text-xs">
                  {t("home.add")}
                </button>
              </div>
              {suggestions.length > 0 && (
                <div>
                  <p className="text-[10px] uppercase tracking-wide text-fg-muted">
                    {t("home.suggested")}
                  </p>
                  <ul className="mt-1 space-y-0.5">
                    {suggestions.map((p) => (
                      <li key={p}>
                        <button
                          type="button"
                          onClick={() => setFolderPath(p)}
                          title={p}
                          className="w-full truncate rounded px-1 text-left font-mono text-[11px] text-fg-secondary hover:bg-surface-3"
                        >
                          {p}
                        </button>
                      </li>
                    ))}
                  </ul>
                </div>
              )}
            </form>
          )}
          {folderOpen && (
            <CloneSourcesForm
              laneId={lane.id}
              parent={lane.cwd.replace(/\/+$/, "").replace(/\/[^/]*$/, "") || "/"}
              onAdded={(next) => {
                setView(next);
                onSourcesChange?.(next);
              }}
            />
          )}
        </section>
      </aside>

      {memoryOpen && memory && (
        <div
          className="fixed inset-0 z-40 flex items-center justify-center bg-black/60 p-4"
          role="presentation"
          onClick={() => setMemoryOpen(false)}
        >
          <div
            ref={memoryPanel}
            role="dialog"
            aria-modal="true"
            aria-label={t("home.memory")}
            onClick={(e) => e.stopPropagation()}
            className="flex max-h-[85vh] w-full max-w-3xl flex-col rounded-xl border border-border bg-surface-1 p-5 shadow-xl"
          >
            <div className="mb-3 flex shrink-0 items-center justify-between">
              <h2 className="text-sm font-semibold text-fg-primary">{t("home.memory")}</h2>
              <button
                type="button"
                autoFocus
                aria-label={t("home.close")}
                onClick={() => setMemoryOpen(false)}
                className={iconBtn}
              >
                <X className="h-4 w-4" />
              </button>
            </div>
            <div
              role="tablist"
              aria-label={t("home.memory")}
              // Wraps, so every file is reachable without a horizontal wheel (a
              // hidden-scrollbar row cut the rest off); past ~3 rows it scrolls
              // with a visible bar. shrink-0: a long file must not squeeze it.
              className="mb-3 flex max-h-28 shrink-0 flex-wrap gap-1.5 overflow-y-auto border-b border-border/60 pb-2"
            >
              {memory.map((f, i) => (
                <button
                  key={f.path}
                  type="button"
                  role="tab"
                  id={`workspace-memory-tab-${i}`}
                  aria-controls="workspace-memory-panel"
                  tabIndex={i === memoryTab ? 0 : -1}
                  title={f.path}
                  aria-selected={i === memoryTab}
                  onClick={() => setMemoryTab(i)}
                  // APG tabs: arrows move (and select), one tab stop.
                  onKeyDown={(e) => {
                    const n = memory.length;
                    const to =
                      e.key === "ArrowRight"
                        ? (i + 1) % n
                        : e.key === "ArrowLeft"
                          ? (i - 1 + n) % n
                          : e.key === "Home"
                            ? 0
                            : e.key === "End"
                              ? n - 1
                              : null;
                    if (to === null) return;
                    e.preventDefault();
                    setMemoryTab(to);
                    document.getElementById(`workspace-memory-tab-${to}`)?.focus();
                  }}
                  className={`flex-shrink-0 whitespace-nowrap rounded-lg border px-3 py-1.5 font-mono text-xs transition-colors ${
                    i === memoryTab
                      ? "border-accent/30 bg-accent/15 text-accent"
                      : "border-border text-fg-secondary hover:bg-surface-3 hover:text-fg-primary"
                  }`}
                >
                  {f.label}
                </button>
              ))}
            </div>
            {memory[memoryTab] && (
              <div
                role="tabpanel"
                id="workspace-memory-panel"
                aria-labelledby={`workspace-memory-tab-${memoryTab}`}
                className="min-h-0 flex-1 overflow-y-auto"
              >
                <MarkdownPreview text={memory[memoryTab].content} />
              </div>
            )}
          </div>
        </div>
      )}

      {sourceCtx.menu && (
        <ContextMenu
          x={sourceCtx.menu.x}
          y={sourceCtx.menu.y}
          onClose={sourceCtx.close}
          testId={`workspace-source-menu-${sourceCtx.menu.item.id}`}
        >
          <MenuItem
            onSelect={() => {
              void copyText(sourceCtx.menu!.item.path);
              sourceCtx.close();
            }}
          >
            {t("menu.copyPath")}
          </MenuItem>
          <MenuSeparator />
          <MenuItem
            danger
            onSelect={() => {
              const id = sourceCtx.menu!.item.id;
              sourceCtx.close();
              void run(() => api.lanes.removeSource(lane.id, id));
            }}
          >
            {t("home.remove")}
          </MenuItem>
        </ContextMenu>
      )}
    </>
  );
}