import { parseSSEChunk, type StreamEvent } from './chatStream';
import { canonicalDocIdForTask } from '../lib/controlledDocHydrate';
import type { TaskRunContext } from '../types/workbench';

export type { TaskRunContext };

/**
 * streamTask 消费 POST /api/v1/tasks/run/stream 的 SSE 事件流。
 * 复用 chatStream 的 parseSSEChunk 解析与中止语义。
 */
export async function streamTask(
  body: Record<string, unknown>,
  handlers: {
    onEvent: (ev: StreamEvent) => void;
    onRequestId?: (id: string) => void;
  },
  signal?: AbortSignal,
): Promise<void> {
  const resp = await fetch('/api/v1/tasks/run/stream', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json', Accept: 'text/event-stream' },
    body: JSON.stringify(body),
    signal,
  });
  const rid = resp.headers.get('X-Request-Id') || resp.headers.get('x-request-id');
  if (rid) handlers.onRequestId?.(rid);
  if (!resp.ok || !resp.body) {
    throw Object.assign(new Error(`HTTP ${resp.status}`), {
      httpStatus: resp.status,
      requestId: rid,
    });
  }
  const reader = resp.body.getReader();
  const decoder = new TextDecoder();
  let buf = '';
  while (true) {
    const { done, value } = await reader.read();
    if (done) break;
    buf += decoder.decode(value, { stream: true });
    const parsed = parseSSEChunk(buf);
    buf = parsed.rest;
    for (const ev of parsed.events) handlers.onEvent(ev);
  }
  if (buf) {
    const flushed = parseSSEChunk(buf, { flush: true });
    for (const ev of flushed.events) handlers.onEvent(ev);
  }
}

/** 构造新任务运行请求（五要素 + task_key + 用户/项目标识） */
export function buildTaskRequest(task: TaskRunContext): Record<string, unknown> {
  const body: Record<string, unknown> = {
    task_key: task.taskKey,
    project_name: task.projectName,
    customer_name: task.customerName,
    device_type: task.deviceType,
  };
  if (task.intendedUse) body.intended_use = task.intendedUse;
  if (task.targetMarket) body.target_market = task.targetMarket;
  if (task.sessionId) body.session_id = task.sessionId;
  if (task.userId) body.user_id = task.userId;
  if (task.projectId) body.project_id = task.projectId;
  if (task.clientTurnId) body.client_turn_id = task.clientTurnId;
  if (task.materials && task.materials.length > 0) {
    body.materials = task.materials;
  }
  const canonicalDocId = canonicalDocIdForTask(
    task.projectId,
    task.taskKey,
    undefined,
    task.docId,
  );
  if (canonicalDocId) body.doc_id = canonicalDocId;
  return body;
}

/** 构造 resume 请求：在任务请求基础上追加 work_dir（可选动态步骤），交由后端续跑既有工作区 */
export function buildResumeRequest(
  task: TaskRunContext,
  workDir: string,
  addSteps?: Array<Record<string, unknown>>,
): Record<string, unknown> {
  const body = buildTaskRequest(task);
  body.work_dir = workDir;
  if (addSteps && addSteps.length > 0) {
    body.add_steps = addSteps;
  }
  return body;
}