/**
 * Whishper speech-to-text tool. Uploads an audio file through Whishper's
 * multipart `/api/transcriptions` endpoint, polls until a transcript is ready,
 * and returns `result.text`. Services are unauthenticated.
 * @module @deepseek-ai/dsh-tool-lab/whish
 */

import type { Context } from '@deepseek-ai/cordis'
import type { FsTarget } from '@deepseek-ai/dsh-fs'
import { defineTool } from '@deepseek-ai/dsh-tools'
import { HttpError, deadline, sleep } from './helpers.ts'

/** One transcription status poll interval (ms). */
export const WHISH_POLL_INTERVAL_MS = 2_000
/** Default Whishper model size when the caller omits it. */
export const WHISH_DEFAULT_MODEL = 'base'

/** Schema-validated arguments for `lab_transcribe_audio`. */
export interface TranscribeAudioArgs {
  file_path: string
  model_size?: string
  language?: string
}

/**
 * Upload an audio blob and poll Whishper until the transcript text is ready,
 * returning it. A queued item reports `status: -1`; once `status >= 0` AND
 * `result.text` is non-empty the transcript is done.
 *
 * @param baseUrl - the Whishper server base URL, e.g. `http://192.168.31.159:8082`.
 * @param bytes - the audio bytes read through `ctx.fs.readBytes`.
 * @param filename - the file name sent in the multipart upload.
 * @param modelSize - optional model size hint.
 * @param language - optional spoken-language hint.
 * @param signal - the executor's cancellation signal (deadline-fused).
 * @param timeoutMs - cooperative timeout budget for the whole call.
 * @returns the transcribed text.
 */
export async function runWhishTranscribe(
  baseUrl: string,
  bytes: Uint8Array,
  filename: string,
  modelSize: string | undefined,
  language: string | undefined,
  signal: AbortSignal | undefined,
  timeoutMs: number,
): Promise<string> {
  using d = deadline(signal, timeoutMs, 'LAB_TOOL_TIMEOUT')

  const form = new FormData()
  form.append('files', new Blob([bytes as BlobPart]), filename)
  if (modelSize !== undefined) form.append('model_size', modelSize)
  if (language !== undefined) form.append('language', language)

  let response = await fetch(`${baseUrl}/api/transcriptions`, { method: 'POST', body: form, signal: d.signal })
  if (!response.ok) {
    throw new HttpError(`lab_transcribe_audio: Whishper upload failed (HTTP ${response.status})`, response.status, 'LAB_WHISH_HTTP')
  }
  const queued = await response.json() as { id?: string; status?: number }
  const id = queued.id
  if (id === undefined) throw new Error('lab_transcribe_audio: /api/transcriptions returned no id')

  while (true) {
    d.signal.throwIfAborted()
    response = await fetch(`${baseUrl}/api/transcriptions/${encodeURIComponent(String(id))}`, { signal: d.signal })
    if (!response.ok) {
      throw new HttpError(`lab_transcribe_audio: Whishper status failed (HTTP ${response.status})`, response.status, 'LAB_WISH_HTTP')
    }
    const state = await response.json() as { status?: number; result?: { text?: string } }
    const status = state.status ?? 0
    const text = state.result?.text
    if (status >= 0 && text !== undefined && text.trim().length > 0) return text
    await sleep(WHISH_POLL_INTERVAL_MS, d.signal)
  }
}

/**
 * Register the `lab_transcribe_audio` tool. Reads the audio file as bytes via
 * `ctx.fs` (`resolve` then `readBytes`, bounded by `maxBytes`) and uploads it.
 *
 * @param ctx - context whose `tools` registry receives the definition and whose
 *   `fs` provides file reads.
 * @param baseUrl - the Whishper server base URL.
 * @param timeoutMs - cooperative timeout budget attached as the tool's `timeoutMs`.
 * @param maxBytes - inclusive cap on the audio bytes read from disk.
 * @param maxOutputChars - cap on the returned transcript; longer text is truncated.
 */
export function registerLabWhishTool(
  ctx: Context,
  baseUrl: string,
  timeoutMs: number,
  maxBytes: number,
  maxOutputChars: number,
): void {
  ctx.tools.register(defineTool({
    name: 'lab_transcribe_audio',
    description:
      'Transcribe speech to text from an audio file via the shared Whishper server (no auth). '
      + `The file is read from disk up to ${formatBytes(maxBytes)} and uploaded as multipart; the tool polls until the transcript is ready or times out.`,
    parameters: {
      file_path: { type: 'string', required: true, description: 'Path to the audio file to transcribe.' },
      model_size: { type: 'string', description: `Optional model size hint; defaults to "${WHISH_DEFAULT_MODEL}".` },
      language: { type: 'string', description: 'Optional spoken-language hint (e.g. "en" or "ru").' },
    },
    output: {
      schema: { type: 'string' },
      render: (_args, value) => [{ type: 'text', text: String(value) }],
    },
    timeoutMs,
    isConcurrencySafe: () => true,
    async execute(args, exec) {
      const target = await ctx.fs.resolve(args.file_path, { signal: exec.signal })
      return runWhishFromTarget(
        baseUrl,
        ctx,
        target,
        args.file_path,
        args.model_size,
        args.language,
        exec.signal,
        timeoutMs,
        maxBytes,
        maxOutputChars,
      )
    },
  }))
}

/** Read the resolved target bytes and run the Whishper flow. */
async function runWhishFromTarget(
  baseUrl: string,
  ctx: Context,
  target: FsTarget,
  displayPath: string,
  modelSize: string | undefined,
  language: string | undefined,
  signal: AbortSignal | undefined,
  timeoutMs: number,
  maxBytes: number,
  maxOutputChars: number,
): Promise<string> {
  const bytes = await ctx.fs.readBytes(target, signal, maxBytes)
  const filename = displayPath.split(/[\\/]/).pop() ?? 'audio.bin'
  const model = modelSize !== undefined && modelSize.trim().length > 0 ? modelSize.trim() : WHISH_DEFAULT_MODEL
  const text = await runWhishTranscribe(baseUrl, bytes, filename, model, language, signal, timeoutMs)
  if (text.length <= maxOutputChars) return text
  return `${text.slice(0, maxOutputChars)}\n\n(Transcript truncated.)`
}

/** Human-readable byte bound for the tool description. */
function formatBytes(bytes: number): string {
  return bytes >= 1024 * 1024 ? `${Math.floor(bytes / (1024 * 1024))}MB` : `${bytes}B`
}