// ---------------------------------------------------------------------------
// Nextcloud WebDAV client
// Uses native fetch — no npm package needed.
// ---------------------------------------------------------------------------

function getConfig() {
  const url = process.env.NEXTCLOUD_URL
  const user = process.env.NEXTCLOUD_USER
  const password = process.env.NEXTCLOUD_PASSWORD
  const basePath = process.env.NEXTCLOUD_BASE_PATH || 'Models'

  if (!url || !user || !password) {
    throw new Error('Nextcloud non configure (NEXTCLOUD_URL, NEXTCLOUD_USER, NEXTCLOUD_PASSWORD)')
  }

  // WebDAV base: https://cloud.example.com/remote.php/dav/files/{user}/
  const davBase = `${url.replace(/\/+$/, '')}/remote.php/dav/files/${encodeURIComponent(user)}`
  const auth = 'Basic ' + Buffer.from(`${user}:${password}`).toString('base64')

  return { davBase, auth, basePath }
}

function davUrl(davBase: string, path: string): string {
  const clean = path.replace(/^\/+/, '').replace(/\/+$/, '')
  return `${davBase}/${clean}`
}

// ---------------------------------------------------------------------------
// Low-level WebDAV helpers
// ---------------------------------------------------------------------------

async function davRequest(
  method: string,
  path: string,
  body?: Buffer | string | null,
  extraHeaders?: Record<string, string>,
): Promise<Response> {
  const { davBase, auth } = getConfig()
  const url = davUrl(davBase, path)

  const res = await fetch(url, {
    method,
    headers: {
      Authorization: auth,
      ...extraHeaders,
    },
    body: body ?? undefined,
  })

  return res
}

// ---------------------------------------------------------------------------
// Public API
// ---------------------------------------------------------------------------

/** Check if a folder exists on the Nextcloud instance. */
export async function folderExists(path: string): Promise<boolean> {
  try {
    const res = await davRequest('PROPFIND', path + '/', null, { Depth: '0' })
    return res.status >= 200 && res.status < 300
  } catch {
    return false
  }
}

/**
 * Create a folder and all parent segments if they don't exist.
 * Like `mkdir -p`.
 */
export async function mkdirRecursive(path: string): Promise<void> {
  const segments = path.replace(/^\/+/, '').replace(/\/+$/, '').split('/')
  let current = ''

  for (const seg of segments) {
    current += '/' + seg
    const exists = await folderExists(current)
    if (!exists) {
      const res = await davRequest('MKCOL', current + '/')
      if (res.status !== 201 && res.status !== 405) {
        // 405 = already exists (race condition), that's fine
        const text = await res.text().catch(() => '')
        throw new Error(`MKCOL ${current} failed (${res.status}): ${text.slice(0, 200)}`)
      }
    }
  }
}

/** Upload a file (overwrite if exists). */
export async function uploadFile(path: string, content: Buffer): Promise<void> {
  const res = await davRequest('PUT', path, content, {
    'Content-Type': 'application/octet-stream',
    'Content-Length': String(content.length),
  })

  if (res.status < 200 || res.status >= 300) {
    const text = await res.text().catch(() => '')
    throw new Error(`PUT ${path} failed (${res.status}): ${text.slice(0, 200)}`)
  }
}

/** Move (rename) a folder or file. */
export async function moveFolder(from: string, to: string): Promise<void> {
  const { davBase } = getConfig()
  const destination = davUrl(davBase, to) + '/'

  const res = await davRequest('MOVE', from + '/', null, {
    Destination: destination,
    Overwrite: 'F',
  })

  if (res.status < 200 || res.status >= 300) {
    const text = await res.text().catch(() => '')
    throw new Error(`MOVE ${from} -> ${to} failed (${res.status}): ${text.slice(0, 200)}`)
  }
}

// ---------------------------------------------------------------------------
// High-level: find next available version folder
// ---------------------------------------------------------------------------

/**
 * Find the next available Vx folder for archiving.
 * E.g. if V1/coffeetest exists but V2/coffeetest doesn't, returns "V2".
 */
export async function findNextVersion(
  basePath: string,
  folderName: string,
): Promise<string> {
  for (let i = 1; ; i++) {
    const versionPath = `${basePath}/V${i}/${folderName}`
    const exists = await folderExists(versionPath)
    if (!exists) return `V${i}`
  }
}