/**
 * @file promptAttach.ts
 * @description What a prompt box can attach besides a fresh upload: a project
 * file or folder dragged from the Files panel (`ATTACH_MIME`, read back by
 * `PromptEditor`'s drop) or from a Chat pane's activity panel
 * (`dragAttachments`, `dragSkill`: a skill becomes the prompt's `/command`) and the files uploaded through a prompt box in the
 * last day (`recentUploads`, kept in this browser), and `claudeMention`, the
 * `@` form a file is handed to `claude` in, and what a browser on the
 * dashboard's own machine attaches by path instead of uploading
 * (`localCandidates`, checked by the server in `sameFilesHere` —
 * `POST /api/run/local-paths` —, `localAttachment`). An attachment is a path
 * sent with the prompt; that check is the one call here to the server.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import type { DragEvent } from "react";
import { api } from "./api";

/** One attachment, shaped like `PromptImage`: what is sent, and its label. */
export interface Attachment {
  path: string;
  name: string;
  url?: string;
}

export const ATTACH_MIME = "application/x-agenthub-attach";

/** A project path (relative to the box's folder) as Claude Code's `@` mention. */
export function projectAttachment(rel: string): Attachment {
  const name = rel.replace(/\/$/, "").split("/").pop() || rel;
  return { path: `@${rel}`, name: rel.endsWith("/") ? `${name}/` : name };
}

/** Start a drag carrying `rel` (a Files panel row) to a prompt box; plain
 *  text too, so a drop elsewhere (a terminal, an editor) gets the path. A row
 *  under a `data-drag-root` (an extra folder's section) lies outside the
 *  pane's folder, so it carries its absolute path instead. */
export function dragProjectPath(e: DragEvent, rel: string) {
  const root = (e.currentTarget as HTMLElement | null)?.closest?.<HTMLElement>("[data-drag-root]")
    ?.dataset.dragRoot;
  const path = root ? `${root.replace(/[\\/]+$/, "")}/${rel}` : rel;
  e.dataTransfer.setData(ATTACH_MIME, JSON.stringify(projectAttachment(path)));
  e.dataTransfer.setData("text/plain", path);
  e.dataTransfer.effectAllowed = "copy";
}

/** Start a drag carrying attachments as they are (an activity panel's files,
 *  already absolute); plain text too, like `dragProjectPath`. */
export function dragAttachments(e: DragEvent, items: Attachment[]) {
  e.dataTransfer.setData(ATTACH_MIME, JSON.stringify(items));
  e.dataTransfer.setData("text/plain", items.map((a) => a.path.replace(/^@/, "")).join(" "));
  e.dataTransfer.effectAllowed = "copy";
}

/** The attachments a drop carries, if they are ours: one, or a list. */
export function droppedAttachments(dt: DataTransfer | null | undefined): Attachment[] {
  try {
    const v: unknown = JSON.parse(dt?.getData(ATTACH_MIME) || "null");
    return (Array.isArray(v) ? v : [v])
      .filter(
        (a): a is Attachment =>
          !!a &&
          typeof (a as Attachment).path === "string" &&
          typeof (a as Attachment).name === "string"
      )
      .map((a) => ({ path: a.path, name: a.name }));
  } catch {
    return [];
  }
}

/** Whether this browser reaches the dashboard by a loopback address — a
 *  hint only: an SSH tunnel's browser does too, from another machine, so a
 *  dropped path is used only once `sameFilesHere` has checked it. */
export function isLocalBrowser(): boolean {
  return /^(localhost|127(\.\d{1,3}){3}|\[::1\])$/.test(window.location.hostname);
}

/** The `file://` paths a drop or paste carries beside its `files`, when this
 *  may be a browser on the dashboard's machine — read now: a DataTransfer is
 *  empty once its event is over. Null when there is nothing to check. */
export function localCandidates(
  dt: DataTransfer | null | undefined,
  files: File[]
): string[] | null {
  if (!isLocalBrowser()) return null;
  const paths = droppedFilePaths(dt);
  return paths && paths.length === files.length ? paths : null;
}

/** Whether `paths` are the dropped `files` as the dashboard's machine sees
 *  them: every one a regular file there, and the sizes the same. Anything
 *  else (an SSH tunnel's laptop paths, server mode, an error) is false, and
 *  the caller uploads the bytes as before. */
export async function sameFilesHere(paths: string[], files: File[]): Promise<boolean> {
  try {
    const { sizes } = await api.run.localPaths(paths);
    const want = files.map((f) => f.size).sort((a, b) => a - b);
    const have = sizes.slice().sort((a, b) => (a ?? -1) - (b ?? -1));
    return have.length === want.length && have.every((s, i) => s === want[i]);
  } catch {
    return false;
  }
}

/** The local files a drop or a paste names as `file://` URIs (a file
 *  manager's, an editor's), as absolute paths — or null when it names none,
 *  or anything that is not one. `file:///C:/x` is `C:/x`. */
export function droppedFilePaths(dt: DataTransfer | null | undefined): string[] | null {
  try {
    const paths = (dt?.getData("text/uri-list") ?? "")
      .split(/\r?\n/)
      .filter((l) => l && !l.startsWith("#"))
      .map((l) => {
        try {
          const u = new URL(l.trim());
          if (u.protocol !== "file:" || (u.host && u.host !== "localhost")) return null;
          return decodeURIComponent(u.pathname).replace(/^\/([A-Za-z]:\/)/, "$1");
        } catch {
          return null;
        }
      });
    return paths.length && paths.every(Boolean) ? (paths as string[]) : null;
  } catch {
    return null;
  }
}

/** A file on this machine, by its absolute path, as an attachment. */
export function localAttachment(path: string): Attachment {
  return {
    // A space would end the mention: Claude Code reads `@"…"` whole.
    path: /\s/.test(path) ? `@"${path}"` : `@${path}`,
    name:
      path
        .replace(/[\\/]$/, "")
        .split(/[\\/]/)
        .pop() || path,
  };
}

/** A drop that carries no file and none of ours, only text — a file manager
 *  or an editor (VS Code) that hands over `file://` URIs, a selection, a
 *  link: the local `file://` URIs as `@path` attachments, else the text to
 *  insert, as a terminal pastes it. */
export function droppedText(
  dt: DataTransfer | null | undefined
): { attachments: Attachment[] } | { text: string } | null {
  try {
    const paths = droppedFilePaths(dt);
    if (paths) return { attachments: paths.map(localAttachment) };
    const text = dt?.getData("text/plain") ?? "";
    return text.trim() ? { text } : null;
  } catch {
    return null;
  }
}

/** An attached file as Claude Code's `@` mention, which `claude` reads at
 *  submit — an image as an image — whether it came on the command line or in
 *  a paste. A bare pasted PATH becomes `[Image #n]` only when the TUI catches
 *  the paste on its own and finishes before Enter: on Windows (psmux) it
 *  stayed a plain `C:\…\drops\…png` in the prompt, and on the command line
 *  a path is never an image at all. A Windows path's backslashes become `/`
 *  (Windows takes either); a path with a space is quoted. */
export function claudeMention(path: string): string {
  if (path.startsWith("@")) return path;
  const p = /^[A-Za-z]:\\/.test(path) ? path.replace(/\\/g, "/") : path;
  return /\s/.test(p) ? `@"${p}"` : `@${p}`;
}

const IMAGE_PATH = /\.(png|jpe?g|gif|webp)$/i;

/** What a terminal pastes for files dropped or pasted on a `claude` pane, one
 *  paste per entry, as a local terminal hands them over: the images as their
 *  bare paths, each a paste of its own — the shape Claude Code turns into
 *  `[Image #n]`, as it does a native drop — and every other file as an `@`
 *  mention, together in one. A Windows path, or
 *  one with a space, stays a mention — the bare path stayed plain text there
 *  (see `claudeMention`). */
export function claudePastes(paths: string[]): string[] {
  const bare = (p: string) => IMAGE_PATH.test(p) && p.startsWith("/") && !/\s/.test(p);
  const images = paths.filter(bare);
  const others = paths.filter((p) => !bare(p)).map(claudeMention);
  return [...images, others.join(" ")].filter(Boolean);
}

export const SKILL_MIME = "application/x-agenthub-skill";
// A skill's name as Claude Code types it: `name` or `plugin:name`.
const SKILL_RE = /^[\w.-]+(?::[\w.-]+)?$/;

/** Start a drag carrying a skill; dropped on a prompt box it becomes `/name`. */
export function dragSkill(e: DragEvent, name: string) {
  e.dataTransfer.setData(SKILL_MIME, name);
  e.dataTransfer.setData("text/plain", `/${name}`);
  e.dataTransfer.effectAllowed = "copy";
}

/** The skill a drop carries, if it is one of ours. */
export function droppedSkill(dt: DataTransfer | null | undefined): string | null {
  try {
    const name = dt?.getData(SKILL_MIME) ?? "";
    return SKILL_RE.test(name) ? name : null;
  } catch {
    return null;
  }
}

/** `prev` plus whichever of `items` it does not hold yet. */
export function addAttachments<T extends Attachment>(prev: T[], items: T[]): T[] {
  const fresh = items.filter(
    (a, i) =>
      !prev.some((p) => p.path === a.path) && items.findIndex((b) => b.path === a.path) === i
  );
  return fresh.length ? [...prev, ...fresh] : prev;
}

const RECENT_KEY = "agenthub.prompt.recentUploads";
const RECENT_MAX = 20;
// The server prunes an upload a day after it was written (`saveDrop`).
// ponytail: a client-side guess of that TTL, a few minutes short; a listing
// route instead if uploads must outlive it or follow the user to another browser.
const RECENT_TTL_MS = 23.9 * 60 * 60_000;

interface Recent extends Attachment {
  at: number;
}

function readRecent(): Recent[] {
  try {
    const v: unknown = JSON.parse(localStorage.getItem(RECENT_KEY) || "[]");
    const cutoff = Date.now() - RECENT_TTL_MS;
    return (Array.isArray(v) ? (v as Recent[]) : []).filter(
      (r) => typeof r?.path === "string" && typeof r.name === "string" && r.at > cutoff
    );
  } catch {
    return [];
  }
}

export function recentUploads(): Attachment[] {
  return readRecent().map(({ path, name, url }) => ({ path, name, ...(url ? { url } : {}) }));
}

/** Remember uploads just saved, newest first; an image keeps a thumbnail
 *  through `GET /api/run/drop/:name` (its local blob URL dies with the page). */
export function rememberUploads(items: { path: string; name: string; image: boolean }[]) {
  const at = Date.now();
  const added: Recent[] = items.map(({ path, name, image }) => ({
    path,
    name,
    at,
    ...(image ? { url: `/api/run/drop/${encodeURIComponent(path.split("/").pop() || "")}` } : {}),
  }));
  const kept = readRecent().filter((r) => !added.some((a) => a.path === r.path));
  try {
    localStorage.setItem(RECENT_KEY, JSON.stringify([...added, ...kept].slice(0, RECENT_MAX)));
  } catch {
    /* storage full or blocked: the list is a convenience */
  }
}