import { isSystemMessageForExtraction } from "./chat-history.js";

export const DEFAULT_TRIGGER_KEYWORDS = [
  "突然",
  "没想到",
  "原来",
  "其实",
  "发现",
  "背叛",
  "死亡",
  "复活",
  "恢复记忆",
  "失忆",
  "告白",
  "暴露",
  "秘密",
  "计划",
  "规则",
  "契约",
  "位置",
  "地点",
  "离开",
  "来到",
];

export function getSmartTriggerDecision(
  chat,
  lastProcessed,
  settings,
  endFloor = null,
) {
  const safeChat = Array.isArray(chat) ? chat : [];
  const startFloor = Math.max(0, (lastProcessed ?? -1) + 1);
  const normalizedEndFloor =
    endFloor == null || endFloor === ""
      ? null
      : Number.isFinite(Number(endFloor))
        ? Math.max(startFloor - 1, Math.floor(Number(endFloor)))
        : null;
  const pendingMessages = safeChat
    .slice(
      startFloor,
      normalizedEndFloor == null ? undefined : normalizedEndFloor + 1,
    )
    .map((msg, offset) => ({
      msg,
      index: startFloor + offset,
    }))
    .filter(({ msg, index }) =>
      !isSystemMessageForExtraction(msg, { index, chat: safeChat }),
    )
    .map(({ msg }) => ({
      role: msg.is_user ? "user" : "assistant",
      content: msg.mes || "",
    }))
    .filter((msg) => msg.content.trim().length > 0);

  if (pendingMessages.length === 0) {
    return { triggered: false, score: 0, reasons: [] };
  }

  const reasons = [];
  let score = 0;
  const combinedText = pendingMessages.map((message) => message.content).join("\n");

  const keywordHits = DEFAULT_TRIGGER_KEYWORDS.filter((keyword) =>
    combinedText.includes(keyword),
  );
  if (keywordHits.length > 0) {
    score += Math.min(2, keywordHits.length);
    reasons.push(`关键词: ${keywordHits.slice(0, 3).join(", ")}`);
  }

  const customPatterns = String(settings?.triggerPatterns || "")
    .split(/\r?\n|,/)
    .map((item) => item.trim())
    .filter(Boolean);
  for (const pattern of customPatterns) {
    try {
      const regex = new RegExp(pattern, "i");
      if (regex.test(combinedText)) {
        score += 2;
        reasons.push(`自定义触发: ${pattern}`);
        break;
      }
    } catch {
      // 忽略无效正则，避免影响主流程
    }
  }

  const roleSwitchCount = pendingMessages.reduce((count, message, index) => {
    if (index === 0) return count;
    return count + (message.role !== pendingMessages[index - 1].role ? 1 : 0);
  }, 0);
  if (roleSwitchCount >= 2) {
    score += 1;
    reasons.push("多轮往返互动");
  }

  const punctuationHits = (combinedText.match(/[!?！？]/g) || []).length;
  if (punctuationHits >= 2) {
    score += 1;
    reasons.push("情绪/冲突波动");
  }

  const entityLikeHits =
    combinedText.match(
      /[A-Z][a-z]{2,}|[\u4e00-\u9fff]{2,6}(先生|小姐|王国|城|镇|村|学院|组织|公司|小队|军团)/g,
    ) || [];
  if (entityLikeHits.length > 0) {
    score += 1;
    reasons.push("疑似新实体/新地点");
  }

  const threshold = Math.max(1, settings?.smartTriggerThreshold || 2);
  return {
    triggered: score >= threshold,
    score,
    reasons,
  };
}