// MessageIDDetector（veridrop detectors/message_id.py）：被动，看 id 前缀约定（msg_、toolu_、srvtoolu_）。
// 官方只保证前缀，长度与字符集「以后可能变」，所以不查那些。每种违规扣 25（同一种只扣一次）。

import type { Body } from "../client.js";
import type { DetectorResult } from "../models.js";
import { cpSlice, pyRepr } from "../py.js";
import { PassiveDetector } from "./base.js";

const BASE_CHECK_WEIGHT = 25;
const NESTED_VIOLATION_PENALTY = 25;
const BASE_LABELS = new Set(["id_prefix_invalid", "type_not_message", "role_not_assistant", "model_not_claude"]);

export class MessageIDDetector extends PassiveDetector {
  readonly name = "message_id";
  readonly displayName = "消息标识规范";
  readonly weight = 5;
  private readonly violations = new Set<string>();
  private readonly samples = new Map<string, string>();
  private observations = 0;

  override observe(_request: Body, response: Record<string, unknown>): void {
    this.observations++;
    const rid = response["id"];
    if (!(typeof rid === "string" && rid.startsWith("msg_") && Array.from(rid).length >= 8)) {
      this.record("id_prefix_invalid", cpSlice(pyRepr(rid), 80));
    }
    if (response["type"] !== "message") this.record("type_not_message", cpSlice(pyRepr(response["type"]), 80));
    if (response["role"] !== "assistant") this.record("role_not_assistant", cpSlice(pyRepr(response["role"]), 80));
    const model = response["model"];
    if (typeof model !== "string" || !model.toLowerCase().includes("claude")) {
      this.record("model_not_claude", cpSlice(pyRepr(model), 80));
    }
    const content = Array.isArray(response["content"]) ? (response["content"] as unknown[]) : [];
    for (const block of content) {
      if (!block || typeof block !== "object" || Array.isArray(block)) continue;
      const b = block as Record<string, unknown>;
      const bid = b["id"];
      if (b["type"] === "tool_use" && typeof bid === "string") {
        if (!bid.startsWith("toolu_")) this.record("tool_use_id_prefix_invalid", cpSlice(pyRepr(bid), 80));
      } else if (b["type"] === "server_tool_use" && typeof bid === "string") {
        if (!bid.startsWith("srvtoolu_")) this.record("server_tool_use_id_prefix_invalid", cpSlice(pyRepr(bid), 80));
      }
    }
  }

  private record(label: string, example: string): void {
    this.violations.add(label);
    if (!this.samples.has(label)) this.samples.set(label, example);
  }

  finalize(): DetectorResult {
    if (this.observations === 0) return this.skip("no observations");
    let score = 100;
    for (const label of this.violations) {
      score -= BASE_LABELS.has(label) ? BASE_CHECK_WEIGHT : NESTED_VIOLATION_PENALTY;
    }
    score = Math.max(0, score);
    return this.result(score >= 70 ? "pass" : "fail", score, {
      observation_count: this.observations,
      violations: [...this.violations].sort(),
      samples: Object.fromEntries(this.samples),
    });
  }
}