/**
 * WebDAV integration for the Meatloaf Manipulator UI.
 *
 * Protocol layer is provided by the vendored `webdav-component`
 * (see src/app/vendor/webdav-component). We deliberately do NOT use
 * its `WebDAVUI` — the React components in this app render their own
 * file browser, search, and directory listings.
 *
 * Public surface (kept stable for our own React components):
 *   getWebDAVClient()  – lazy WebDAVManager (high-level state + actions)
 *   getWebDAVBaseUrl() – the server base URL we're talking to
 *   listDirectory(p)   – returns EntryInfo[] for a collection
 *   fileExists(p)      – boolean
 *   createFolder(p)    – create a new (possibly nested) collection
 *   deletePath(p)      – delete a file or (empty) collection
 *   movePath(from, to) – MOVE
 *   putFileContents(p, data) – upload
 *   getFileContents(p)       – download as Blob
 *   humanFileSize(n)         – "1.4 MB" formatter
 *   normalizePath / splitPath / joinPath / basename – path helpers
 */

import {
  WebDAVManager,
  PROPFIND_LIST_BODY,
  type WebDAVEntry,
} from './vendor/webdav-component/esm/index.js';

export type { WebDAVEntry };

// ----- Connection settings ----------------------------------------------

const DEFAULT_BASE_URL =
  (typeof import.meta !== 'undefined' &&
    (import.meta as any).env?.VITE_WEBDAV_URL) ||
  (typeof window !== 'undefined'
    ? `${window.location.protocol}//${window.location.hostname}`
    : 'http://localhost');

let _manager: WebDAVManager | null = null;

export function getWebDAVBaseUrl(): string {
  return DEFAULT_BASE_URL;
}

export function getWebDAVClient(): WebDAVManager {
  if (!_manager) {
    _manager = new WebDAVManager({
      url: DEFAULT_BASE_URL,
    });
  }
  return _manager;
}

// ----- Path helpers (kept stable for our React UI) --------------------

/** Normalize a path so it always starts with `/` and has no trailing `/`. */
export function normalizePath(p: string): string {
  if (!p) return '/';
  let s = p.trim();
  if (!s.startsWith('/')) s = '/' + s;
  s = s.replace(/\/+/g, '/');
  if (s.length > 1 && s.endsWith('/')) s = s.slice(0, -1);
  return s || '/';
}

/** Split a path into parent + name. */
export function splitPath(p: string): { parent: string; name: string } {
  const n = normalizePath(p);
  if (n === '/') return { parent: '/', name: '' };
  const idx = n.lastIndexOf('/');
  if (idx === 0) return { parent: '/', name: n.slice(1) };
  return { parent: n.slice(0, idx), name: n.slice(idx + 1) };
}

/** Join a parent path and a child name. */
export function joinPath(parent: string, name: string): string {
  if (parent === '/' || parent === '') return '/' + name;
  return (parent.endsWith('/') ? parent : parent + '/') + name;
}

/** Last segment of a path. */
export function basename(p: string): string {
  return splitPath(p).name;
}

// ----- Mapping webdav-component entries to our UI's EntryInfo -----------

export type EntryType = 'folder' | 'file';

export interface EntryInfo {
  name: string;
  /** Absolute path on the WebDAV server (always begins with `/`). */
  path: string;
  type: EntryType;
  /** Bytes, or 0 for collections. */
  size: number;
  lastModified: Date | null;
  contentType: string | null;
}

/**
 * Build an absolute WebDAV path (with leading `/`) for a relative name
 * under a given collection URL. The vendored `WebDAVManager` operates on
 * full URLs, so we keep URL-relative work in `manager.open()` and
 * path-relative work everywhere else.
 */
function pathFromUri(uri: string, baseUrl: string): string {
  let p: string;
  try {
    // Absolute URL → take just the pathname.
    if (/^https?:\/\//i.test(uri)) {
      const u = new URL(uri);
      p = u.pathname;
    } else {
      p = uri;
    }
  } catch {
    p = uri;
  }
  // Strip a host prefix if the server added one (e.g. lighttpd).
  try {
    const host = new URL(baseUrl).hostname;
    if (p.startsWith('/' + host + '/')) p = p.slice(host.length + 1);
  } catch {
    /* ignore */
  }
  // Always URL-decode so the rest of the app sees literal characters
  // (e.g. spaces) instead of %20 in names and paths.
  try {
    p = decodeURIComponent(p);
  } catch {
    /* leave as-is on malformed encoding */
  }
  return normalizePath(p);
}

function toEntryInfo(e: WebDAVEntry, baseUrl: string): EntryInfo {
  // The vendored `webdav-component` computes `entry.path` by stripping
  // `baseUrl.length` from the href — that only works when the server
  // sends absolute hrefs (e.g. `http://localhost/sd/foo`). When the
  // server sends relative hrefs (`/sd/foo`), the strip chops off the
  // start of the path. Use `entry.uri` directly instead, which the
  // parser sets verbatim from the href and is always reliable.
  const rawPath = (e.uri && e.uri.length > 0 ? e.uri : e.path) || '';
  const fullPath = pathFromUri(rawPath, baseUrl);
  // Prefer the server-provided displayname when it looks like a leaf
  // (no slashes). Some servers (notably older webdav3.py) used to
  // return the full path as the displayname; in that case fall back to
  // the leaf of the resolved path.
  const looksLikePath = (s: string) => s.includes('/');
  const name =
    (e.name && !looksLikePath(e.name) ? e.name : '') ||
    basename(fullPath) ||
    e.name;
  return {
    name,
    path: fullPath,
    type: e.isDir ? 'folder' : 'file',
    size: typeof e.size === 'number' ? e.size : 0,
    lastModified: e.modified ?? null,
    contentType: e.mime ?? null,
  };
}

// ----- High-level operations -------------------------------------------

/**
 * List the contents of a collection. Returns a sorted array of entries.
 * Pass `recursive: true` to request `Depth: infinity` from the server and
 * return all descendants flattened — requires the server to support it
 * (webdav3.py does after the depth-infinity fix).
 */
export async function listDirectory(
  path: string,
  recursive = false,
  onProgress?: (bytes: number) => void,
): Promise<EntryInfo[]> {
  const manager = getWebDAVClient();
  const base = manager.client.baseUrl;
  const collectionUrl = pathToUrl(normalizePath(path), base);
  const selfPath = normalizePath(path);

  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  const depth: any = recursive ? 'infinity' : 1;

  let doc: Document;
  if (onProgress) {
    const response = await fetch(collectionUrl, {
      method: 'PROPFIND',
      headers: { 'Depth': String(depth), 'Content-Type': 'text/xml; charset=utf-8' },
      body: PROPFIND_LIST_BODY,
    });
    if (!response.body) throw new Error('No response body');
    const reader = response.body.getReader();
    const chunks: Uint8Array[] = [];
    let received = 0;
    for (;;) {
      const { done, value } = await reader.read();
      if (done) break;
      chunks.push(value);
      received += value.byteLength;
      onProgress(received);
    }
    const combined = new Uint8Array(received);
    let offset = 0;
    for (const chunk of chunks) { combined.set(chunk, offset); offset += chunk.byteLength; }
    doc = new DOMParser().parseFromString(new TextDecoder().decode(combined), 'text/xml');
  } else {
    doc = await manager.client.propfind(collectionUrl, PROPFIND_LIST_BODY, depth);
  }
  const entries: EntryInfo[] = [];

  for (const node of Array.from(doc.querySelectorAll('response'))) {
    const hrefEl = node.querySelector('href');
    if (!hrefEl?.textContent) continue;

    // Find the first 200 propstat.
    let propsNode: Element | null = null;
    for (const propstat of Array.from(node.querySelectorAll('propstat'))) {
      const status = propstat.querySelector('status');
      if (status && /200/.test(status.textContent ?? '')) {
        propsNode = propstat;
        break;
      }
    }
    if (!propsNode) continue;

    const fullPath = pathFromUri(hrefEl.textContent, base);

    // Skip the collection itself.
    if (fullPath === selfPath) continue;

    // Non-recursive: only include direct children.
    if (!recursive && splitPath(fullPath).parent !== selfPath) continue;

    const isDir = !!node.querySelector('resourcetype collection');
    const displaynameEl = propsNode.querySelector('displayname');
    const lengthEl = propsNode.querySelector('getcontentlength');
    const mimeEl = propsNode.querySelector('getcontenttype');
    const modifiedEl = propsNode.querySelector('getlastmodified');

    // Prefer server displayname unless it looks like a full path.
    const nameFromPath = basename(fullPath) || fullPath;
    const dn = displaynameEl?.textContent ?? '';
    const name = dn && !dn.includes('/') ? dn : nameFromPath;

    entries.push({
      name,
      path: fullPath,
      type: isDir ? 'folder' : 'file',
      size: !isDir && lengthEl?.textContent ? parseInt(lengthEl.textContent, 10) : 0,
      lastModified: modifiedEl?.textContent ? new Date(modifiedEl.textContent) : null,
      contentType: !isDir && mimeEl?.textContent ? mimeEl.textContent : null,
    });
  }

  // Folders first, then alpha (case-insensitive).
  entries.sort((a, b) => {
    if (a.type !== b.type) return a.type === 'folder' ? -1 : 1;
    return a.name.localeCompare(b.name, undefined, { sensitivity: 'base' });
  });
  return entries;
}

export async function fileExists(path: string): Promise<boolean> {
  const manager = getWebDAVClient();
  const base = manager.client.baseUrl;
  return manager.client.exists(pathToUrl(normalizePath(path), base));
}

/**
 * Probe a path via a depth-0 PROPFIND to determine whether it is a file
 * or a folder, and return its parsed `WebDAVEntry`. Returns `null` if the
 * path does not exist (or the server returns 404).
 */
export async function stat(path: string): Promise<EntryInfo | null> {
  const manager = getWebDAVClient();
  const base = manager.client.baseUrl;
  const url = pathToUrl(normalizePath(path), base);
  try {
    const doc = await manager.client.propfind(url, PROPFIND_LIST_BODY, 0);
    const resp = doc.querySelector('response');
    if (!resp) return null;
    const isDir = !!doc.querySelector('resourcetype collection');
    // We re-use the same path-resolution logic as `toEntryInfo` to keep
    // naming and path handling consistent.
    const href = doc.querySelector('href')?.textContent ?? url;
    const fakeEntry = {
      uri: href,
      url: href,
      path: href,
      name: doc.querySelector('displayname')?.textContent ?? '',
      isDir,
      size: null,
      mime: null,
      modified: null,
      permissions: null,
    } as unknown as WebDAVEntry;
    return toEntryInfo(fakeEntry, base);
  } catch {
    return null;
  }
}

export async function createFolder(path: string, _recursive = true): Promise<void> {
  const manager = getWebDAVClient();
  const base = manager.client.baseUrl;
  // The vendored client only does flat MKCOL; emulate "recursive" by
  // walking up and creating each missing parent first.
  const target = normalizePath(path);
  const parts = target.split('/').filter(Boolean);
  let built = '';
  for (const part of parts) {
    built += '/' + part;
    if (await fileExists(built)) continue;
    const r = await manager.client.mkcol(pathToUrl(built, base));
    if (!r.ok && r.status !== 405 /* already exists */) {
      throw new Error(`MKCOL ${built} failed: ${r.status} ${r.statusText}`);
    }
  }
}

export async function deletePath(path: string): Promise<void> {
  const manager = getWebDAVClient();
  const base = manager.client.baseUrl;
  const r = await manager.client.delete(pathToUrl(normalizePath(path), base));
  if (!r.ok && r.status !== 204 && r.status !== 200) {
    throw new Error(`DELETE failed: ${r.status} ${r.statusText}`);
  }
}

export async function movePath(from: string, to: string): Promise<void> {
  const manager = getWebDAVClient();
  const base = manager.client.baseUrl;
  await manager.client.copymove(
    'MOVE',
    pathToUrl(normalizePath(from), base),
    pathToUrl(normalizePath(to), base),
    true,
  );
}

export async function copyPath(from: string, to: string): Promise<void> {
  const manager = getWebDAVClient();
  const base = manager.client.baseUrl;
  await manager.client.copymove(
    'COPY',
    pathToUrl(normalizePath(from), base),
    pathToUrl(normalizePath(to), base),
    true,
  );
}

export async function putFileContents(
  path: string,
  data: string | ArrayBuffer | Uint8Array | Blob,
): Promise<void> {
  const manager = getWebDAVClient();
  const base = manager.client.baseUrl;
  const url = pathToUrl(normalizePath(path), base);
  // The vendored client expects a `BodyInit`. Convert our variants to one.
  let body: BodyInit;
  if (typeof data === 'string') body = data;
  else if (data instanceof Blob) body = data;
  else if (data instanceof Uint8Array) {
    body = data.buffer.slice(
      data.byteOffset,
      data.byteOffset + data.byteLength,
    ) as ArrayBuffer;
  } else {
    body = data;
  }
  const r = await manager.client.put(url, body);
  if (!r.ok) {
    throw new Error(`PUT failed: ${r.status} ${r.statusText}`);
  }
}

export async function getFileContents(path: string): Promise<Blob> {
  const manager = getWebDAVClient();
  const base = manager.client.baseUrl;
  const r = await manager.client.get(pathToUrl(normalizePath(path), base));
  if (!r.ok) {
    throw new Error(`GET failed: ${r.status} ${r.statusText}`);
  }
  return r.blob();
}

/**
 * Fetch a byte range of a file using HTTP Range requests.
 * Returns a Blob containing the requested bytes. Falls back to a full
 * fetch if the server responds 200 (no Range support).
 */
export async function getFileRange(path: string, start: number, end: number): Promise<Blob> {
  const base = getWebDAVClient().client.baseUrl;
  const url  = pathToUrl(normalizePath(path), base);
  const r    = await fetch(url, { headers: { Range: `bytes=${start}-${end}` } });
  if (r.status === 206 || r.status === 200) return r.blob();
  throw new Error(`GET range failed: ${r.status} ${r.statusText}`);
}

// ----- Helpers --------------------------------------------------------

/** Convert a server-relative path to an absolute URL on the configured base. */
function pathToUrl(p: string, baseUrl: string): string {
  // Encode each segment so spaces and special characters become valid URL
  // components, while preserving the '/' separators.
  const encoded = p.split('/').map(seg => seg ? encodeURIComponent(seg) : '').join('/');
  const sep = baseUrl.endsWith('/') || encoded.startsWith('/') ? '' : '/';
  return baseUrl + sep + encoded;
}

/** Convert a raw byte count to a short human string (e.g. "1.4 MB"). */
export function humanFileSize(bytes: number): string {
  if (!Number.isFinite(bytes) || bytes < 0) return '—';
  if (bytes < 1024) return `${bytes} B`;
  const units = ['KB', 'MB', 'GB', 'TB'];
  let v = bytes / 1024;
  let i = 0;
  while (v >= 1024 && i < units.length - 1) {
    v /= 1024;
    i++;
  }
  return `${v.toFixed(v >= 10 ? 0 : 1)} ${units[i]}`;
}

export type FetchProgress = { received: number; total: number };

export async function clearDirectory(path: string): Promise<void> {
  try {
    const entries = await listDirectory(path);
    await Promise.all(entries.filter(e => e.type === 'file').map(e => deletePath(e.path)));
  } catch {
    // Directory may not exist yet — ignore
  }
}

export async function streamFetch(
  res: Response,
  onProgress: (p: FetchProgress) => void,
): Promise<ArrayBuffer> {
  if (!res.body) return res.arrayBuffer();
  const total = +(res.headers.get('content-length') ?? 0);
  const reader = res.body.getReader();
  const chunks: Uint8Array[] = [];
  let received = 0;
  for (;;) {
    const { done, value } = await reader.read();
    if (done) break;
    chunks.push(value);
    received += value.byteLength;
    onProgress({ received, total });
  }
  const out = new Uint8Array(received);
  let off = 0;
  for (const c of chunks) { out.set(c, off); off += c.byteLength; }
  return out.buffer;
}