/**
 * @file ChatFilePreview.tsx
 * @description A file a Chat pane's session touched, shown the way Claude
 * Desktop shows one: `FilePreview` (name · EXT, Copy path, Close, then the
 * content) and `FileListModal` (a list on the left, the picked file's preview
 * on the right — Claude's Uploads dialog). Content comes only through routes
 * that already guard it: a file inside the workspace through
 * `GET /api/lanes/:id/git/file` (or `/git/raw` for an image), a file under
 * `~/.claude` (a memory file, a plugin's skill) through `GET /api/cc-config/file`,
 * an attached image or text file through `GET /api/run/drop/:name`, an image
 * the session read anywhere else through `GET /api/sessions/:id/image`. Anything
 * else (or an image that route refuses) shows its path only. A Windows path's `\` counts as `/` throughout.
 * `SkillListModal` is the same dialog over the session's skills, each one's
 * SKILL.md found by name (`plugin:name` from the plugin list, else the user's
 * or the project's); a built-in skill has no file and shows by name only.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import { useEffect, useRef, useState, type DragEvent } from "react";
import { createPortal } from "react-dom";
import { useTranslation } from "react-i18next";
import { Copy, FileText, Loader2, X } from "lucide-react";
import { api, gitTarget } from "../../lib/api";
import { copyText } from "../../lib/clipboard";
import { useDialog } from "../../hooks/useDialog";
import { dragSkill } from "../../lib/promptAttach";
import { MarkdownPreview, isMarkdown } from "../MarkdownPreview";

/** Where a Chat pane's files can be read from. */
export interface PreviewScope {
  laneId: number | null;
  /** The workspace's own folder. */
  laneCwd: string;
  /** The pane's folder — the workspace's, or the session's own worktree. */
  cwd: string;
  sessionId: string;
}

const IMAGE_RE = /\.(png|jpe?g|gif|webp)$/i;
// An attached file the drop route serves as text (`DROP_TEXT_TYPES` in server/routes/run.js).
const DROP_TEXT_RE = /\.(txt|md|markdown|csv|tsv|log|json|xml|ya?ml)$/i;
// The drop dir (`<data dir>/drops/`), or the older `<tmp>/agenthub-drops-<uid>/`.
const DROP_RE =
  /[\\/](?:agenthub-drops-\d+|drops)[\\/]([0-9a-f]{16}(?:-[A-Za-z0-9._-]+)?\.[A-Za-z0-9]+)$/;
/** A dropped text file shown at most this long. */
const DROP_TEXT_MAX = 200_000;

/** `C:\a\b` → `C:/a/b`: a Windows path matched like a POSIX one. */
const slashed = (p: string) => p.replace(/\\/g, "/");
export const baseName = (p: string) => p.split(/[\\/]/).pop() || p;
/** `report.v2.xlsx` → `XLSX`; none → "". */
export const extOf = (p: string) => {
  const m = /\.([A-Za-z0-9]+)$/.exec(baseName(p));
  return m ? m[1]!.toUpperCase() : "";
};
/** An attached file's name without the drop dir's random prefix. */
export const displayName = (p: string) =>
  DROP_RE.test(p) ? baseName(p).replace(/^[0-9a-f]{16}-?/, "") || baseName(p) : baseName(p);

type Content =
  | { kind: "loading" }
  | { kind: "image"; src: string }
  | { kind: "text"; text: string; truncated: boolean }
  | { kind: "none" };

function useContent(path: string, scope: PreviewScope): Content {
  const [content, setContent] = useState<Content>({ kind: "loading" });
  useEffect(() => {
    let live = true;
    const show = (p: Promise<Content>) => {
      setContent({ kind: "loading" });
      p.then((c) => live && setContent(c)).catch(() => live && setContent({ kind: "none" }));
    };
    const drop = DROP_RE.exec(path);
    if (drop) {
      const src = `/api/run/drop/${encodeURIComponent(drop[1]!)}`;
      if (IMAGE_RE.test(path)) setContent({ kind: "image", src });
      else if (DROP_TEXT_RE.test(path))
        show(
          fetch(src).then(async (r) => {
            if (!r.ok) throw new Error(String(r.status));
            const text = await r.text();
            return {
              kind: "text",
              text: text.slice(0, DROP_TEXT_MAX),
              truncated: text.length > DROP_TEXT_MAX,
            };
          })
        );
      else setContent({ kind: "none" });
      return () => {
        live = false;
      };
    }
    const file = slashed(path);
    const base = slashed(scope.cwd).replace(/\/+$/, "");
    if (scope.laneId === null || !base || !file.startsWith(`${base}/`)) {
      // Claude Code's own files (memory, a skill): the config pages' guarded read.
      if (/\/\.claude\//.test(file) && !IMAGE_RE.test(file)) {
        show(
          api.ccConfig
            .file(path)
            .then((f) => ({ kind: "text", text: f.text, truncated: !!f.truncated }))
        );
      } else if (IMAGE_RE.test(file) && scope.sessionId) {
        // An image it read elsewhere (a screenshot under ~/.cache): served
        // only because this session's own Read named it.
        setContent({ kind: "image", src: api.sessions.readImageUrl(scope.sessionId, path) });
      } else setContent({ kind: "none" });
      return () => {
        live = false;
      };
    }
    const rel = file.slice(base.length + 1);
    const target =
      base === slashed(scope.laneCwd).replace(/\/+$/, "")
        ? scope.laneId
        : gitTarget(scope.laneId, scope.sessionId);
    if (IMAGE_RE.test(path)) {
      setContent({ kind: "image", src: api.lanes.gitRawUrl(target, rel) });
      return;
    }
    show(
      api.lanes
        .gitFile(target, rel)
        .then((f) =>
          f.available && !f.binary
            ? { kind: "text", text: f.lines.join("\n"), truncated: f.truncated }
            : { kind: "none" }
        )
    );
    return () => {
      live = false;
    };
  }, [path, scope.cwd, scope.laneCwd, scope.laneId, scope.sessionId]);
  return content;
}

function Body({ path, scope }: { path: string; scope: PreviewScope }) {
  const { t } = useTranslation("run");
  const loaded = useContent(path, scope);
  // An image the route refused (gone, server mode) shows like no preview.
  const [broken, setBroken] = useState<string | null>(null);
  const content: Content =
    loaded.kind === "image" && loaded.src === broken ? { kind: "none" } : loaded;
  if (content.kind === "loading") {
    return (
      <div className="flex flex-1 items-center justify-center">
        <Loader2 className="h-5 w-5 animate-spin text-fg-muted" />
      </div>
    );
  }
  if (content.kind === "image") {
    return (
      <div className="flex flex-1 items-center justify-center overflow-auto p-4">
        <img
          src={content.src}
          alt={baseName(path)}
          onError={() => setBroken(content.src)}
          className="max-h-full max-w-full object-contain"
        />
      </div>
    );
  }
  if (content.kind === "none") {
    return (
      <div className="flex flex-1 flex-col items-center justify-center gap-2 p-6 text-center text-sm text-fg-muted">
        <FileText className="h-8 w-8" />
        <p>{t("chat.outline.noPreview")}</p>
        <p className="break-all font-mono text-xs">{path}</p>
      </div>
    );
  }
  return (
    <div className="min-h-0 flex-1 overflow-auto">
      {isMarkdown(path) ? (
        <MarkdownPreview text={content.text} className="p-4" />
      ) : (
        <pre className="p-4 font-mono text-xs leading-relaxed text-fg-secondary">
          {content.text}
        </pre>
      )}
      {content.truncated && (
        <p className="px-4 pb-4 text-xs text-fg-muted">{t("chat.outline.truncated")}</p>
      )}
    </div>
  );
}

/** One file: header (name · EXT, Copy path, Close) over its content. */
export function FilePreview({
  path,
  scope,
  onClose,
  className = "",
}: {
  path: string;
  scope: PreviewScope;
  onClose: () => void;
  className?: string;
}) {
  const { t } = useTranslation("run");
  return (
    <section
      data-testid="chat-file-preview"
      className={`flex min-h-0 min-w-0 flex-col overflow-hidden bg-surface-1 ${className}`}
    >
      <header className="flex items-center gap-2 border-b border-border px-4 py-2.5">
        <span className="min-w-0 truncate text-sm text-fg-primary" title={path}>
          {displayName(path).replace(/\.[A-Za-z0-9]+$/, "")}
        </span>
        <span className="text-xs text-fg-muted">{extOf(path)}</span>
        <div className="ml-auto flex items-center gap-1">
          <button
            type="button"
            onClick={() => void copyText(path)}
            title={t("chat.outline.copyPath", { path })}
            aria-label={t("chat.outline.copyPath", { path })}
            className="flex h-7 w-7 items-center justify-center rounded text-fg-muted hover:bg-surface-3 hover:text-fg-primary"
          >
            <Copy className="h-3.5 w-3.5" />
          </button>
          <button
            type="button"
            onClick={onClose}
            title={t("chat.outline.close")}
            aria-label={t("chat.outline.close")}
            className="flex h-7 w-7 items-center justify-center rounded text-fg-muted hover:bg-surface-3 hover:text-fg-primary"
          >
            <X className="h-4 w-4" />
          </button>
        </div>
      </header>
      <Body path={path} scope={scope} />
    </section>
  );
}

/** Claude's Uploads dialog: the files on the left, the picked one on the right. */
export function FileListModal({
  title,
  paths,
  label = displayName,
  scope,
  onClose,
  onDragItem,
}: {
  title: string;
  paths: string[];
  /** A row's text; the file name by default. */
  label?: (path: string) => string;
  scope: PreviewScope;
  onClose: () => void;
  /** Rows drag into the prompt box; the dialog then closes, out of the way. */
  onDragItem?: (e: DragEvent, path: string) => void;
}) {
  const [picked, setPicked] = useState(paths[0] ?? "");
  const panelRef = useRef<HTMLDivElement>(null);
  useDialog(true, panelRef, onClose);
  // Into document.body, like ImageLightbox: a pane's own stacking layer
  // would otherwise draw over a `fixed` overlay opened from inside it.
  return createPortal(
    <div
      className="fixed inset-0 z-[200] flex items-center justify-center bg-surface-0/70 p-6"
      onClick={onClose}
    >
      <div
        ref={panelRef}
        role="dialog"
        aria-modal="true"
        aria-label={title}
        data-testid="chat-file-modal"
        onClick={(e) => e.stopPropagation()}
        className="flex h-[80vh] w-full max-w-6xl overflow-hidden rounded-xl border border-border bg-surface-1 shadow-2xl"
      >
        <div className="flex w-80 flex-shrink-0 flex-col border-r border-border">
          <h2 className="px-5 pb-3 pt-5 text-lg text-fg-primary">{title}</h2>
          <ul className="min-h-0 flex-1 space-y-0.5 overflow-y-auto px-2 pb-3">
            {paths.map((p) => (
              <li key={p}>
                <button
                  type="button"
                  onClick={() => setPicked(p)}
                  draggable={!!onDragItem}
                  onDragStart={(e) => {
                    onDragItem?.(e, p);
                    // Not in dragstart itself: removing the source there cancels the drag.
                    if (onDragItem) window.setTimeout(onClose, 0);
                  }}
                  title={p}
                  aria-current={p === picked}
                  className={`flex w-full items-center gap-2 rounded-lg px-3 py-2 text-left text-sm ${p === picked ? "bg-surface-3 text-fg-primary" : "text-fg-secondary hover:bg-surface-2"}`}
                >
                  <FileText className="h-4 w-4 flex-shrink-0 text-fg-muted" />
                  <span className="min-w-0 truncate">{label(p)}</span>
                </button>
              </li>
            ))}
          </ul>
        </div>
        {picked && <FilePreview path={picked} scope={scope} onClose={onClose} className="flex-1" />}
      </div>
    </div>,
    document.body
  );
}

/** The session's skills in the list dialog, each one's SKILL.md previewed. */
export function SkillListModal({
  title,
  names,
  scope,
  onClose,
  draggable = false,
}: {
  title: string;
  names: string[];
  scope: PreviewScope;
  onClose: () => void;
  /** Rows drag into the prompt box as `/name`. */
  draggable?: boolean;
}) {
  const [files, setFiles] = useState<Map<string, string> | null>(null);
  useEffect(() => {
    let live = true;
    void Promise.all([
      api.ccConfig.skills(undefined, scope.cwd).catch(() => ({ items: [] })),
      api.ccConfig.plugins().catch(() => ({ plugins: [] })),
    ]).then(([sk, pl]) => {
      const found = new Map<string, string>();
      const add = (name: string, file: string | undefined) => {
        if (file && !found.has(name)) found.set(name, file);
      };
      for (const p of pl.plugins) {
        const items = p.contributes?.items;
        for (const it of [...(items?.skills ?? []), ...(items?.commands ?? [])])
          add(`${p.name}:${it.name}`, it.file);
      }
      // A personal skill wins over a project one of the same name, as in Claude Code.
      for (const s of sk.items) if (s.scope === "user") add(s.name, s.file);
      for (const s of sk.items) add(s.name, s.file);
      if (live) setFiles(found);
    });
    return () => {
      live = false;
    };
  }, [scope.cwd]);
  if (!files) return null;
  // A built-in skill has no file: its name stands in and previews as nothing.
  const byPath = new Map(names.map((n) => [files.get(n) ?? n, n]));
  return (
    <FileListModal
      title={title}
      paths={[...byPath.keys()]}
      label={(p) => byPath.get(p) ?? displayName(p)}
      scope={scope}
      onClose={onClose}
      onDragItem={draggable ? (e, p) => dragSkill(e, byPath.get(p) ?? p) : undefined}
    />
  );
}