// ═══════════════════════════════════════
// 铸渊开发Agent · 任务补全引擎
// 高层面规划 → LLM补全 → 详细可执行步骤
// ═══════════════════════════════════════

const fs = require("fs");
const path = require("path");

/**
 * 补全单条高级任务为详细步骤
 * @param {object} task - { id, action, description, context }
 * @param {function} modelCaller - LLM 调用函数 (prompt) => string
 * @returns {object} 补全后的任务
 */
async function expandTask(task, modelCaller) {
  const prompt = [
    "你是一个开发Agent的任务补全引擎。将高级描述补全为可执行的详细步骤。",
    "",
    "原任务:",
    "  ID: " + task.id,
    "  动作: " + task.action,
    "  描述: " + (task.description || "无"),
    "  上下文: " + (task.context || "无"),
    "",
    "请严格基于以上原任务拆解。不要改变原任务的action/target/content。只补充detail、depends_on等元信息。如果原任务已经足够具体，直接返回：",
    "[{\"step\":1,\"action\":\"write_file|run_cmd|call_api|check\",\"target\":\"文件路径或命令\",\"detail\":\"具体做什么\",\"depends_on\":null}]"
  ].join("\n");

  try {
    const raw = await modelCaller(prompt);
    const jsonMatch = raw.match(/\[[\s\S]*\]/);
    if (jsonMatch) {
      const substeps = JSON.parse(jsonMatch[0]);
      return { ...task, substeps, expanded: true, expanded_at: new Date().toISOString() };
    }
  } catch (e) {
    console.warn("[Expander] LLM补全失败，退化为单步模式: " + e.message);
  }

  // 退化：LLM不可用时，原任务本身就是一个步骤
  return {
    ...task,
    substeps: [{ step: 1, action: task.action, target: task.target || "", detail: task.description || "" }],
    expanded: false,
    expanded_at: new Date().toISOString()
  };
}

/**
 * 完整规划补全
 * @param {object} plan - 完整规划 { plan_id, tasks[], ... }
 * @param {function} modelCaller - LLM 调用函数
 * @param {string} plansDir - 规划文件存储目录
 */
async function expandPlan(plan, modelCaller, plansDir) {
  console.log("[Expander] 开始补全规划: " + plan.plan_id + " · " + plan.tasks.length + "个任务");

  const expandedTasks = [];
  for (let i = 0; i < plan.tasks.length; i++) {
    const task = plan.tasks[i];
    console.log("[Expander] 补全 " + (i + 1) + "/" + plan.tasks.length + ": " + task.id);
    const expanded = await expandTask(task, modelCaller);
    expandedTasks.push(expanded);
  }

  plan.tasks = expandedTasks;
  plan._status = "expanded";
  plan._expanded_at = new Date().toISOString();

  // 写回规划文件
  const planFile = path.join(plansDir, plan.plan_id + ".json");
  fs.writeFileSync(planFile, JSON.stringify(plan, null, 2), "utf-8");

  console.log("[Expander] 补全完成 · 共 " + expandedTasks.reduce((s, t) => s + (t.substeps?.length || 0), 0) + " 个子步骤");
  return plan;
}

module.exports = { expandPlan, expandTask };