import type { ConsultationDomain } from "./consultation-domain-registry.ts";
import { consultationDomainDefinition } from "./consultation-domain-registry.ts";
import type { ConsultationEntrypoint } from "./consultation-entrypoint.ts";
import {
  isGeneralDailyFortuneQuestion,
  isRectificationHandoffQuestion,
} from "./consultation-entrypoint.ts";

export type ReplyTheme = ConsultationDomain;

import type { ConsultationReplyMetadata } from "./consultation-reply-metadata.ts";

const GENERIC_SESSION_TITLES = new Set([
  "新对话",
  "深入看今日",
  "从今日问起",
  "查看今日运势",
  "生时校正",
  "再次校正",
  "一般占星咨询",
  "深入看今日主题咨询",
]);

function readTitle(value: string): string | undefined {
  const title = value.replace(/\s+/g, " ").trim();
  if (!title || /[\d\p{P}\p{S}]/u.test(title)) return undefined;
  if (/\p{Script=Han}/u.test(title)) {
    const length = Array.from(title.replace(/\s/g, "")).length;
    return length >= 6 && length <= 14 ? title : undefined;
  }
  const words = title.split(" ").filter(Boolean);
  return words.length >= 3 && words.length <= 7 && title.length <= 64 ? title : undefined;
}

// AYANAM_SUGGESTIONS blocks are no longer produced anywhere, but stored answers from
// before the follow-up chips were removed still carry them, so they stay strippable
// rather than leaking a raw HTML comment into a replayed transcript.
function stripAgentReplyMetadata(value: string) {
  let title: string | undefined;
  const text = value
    .replace(/<!--AYANAM_SUGGESTIONS:\[[\s\S]*?\]-->/g, "")
    .replace(/<!--AYANAM_TITLE:([\s\S]*?)-->/g, (_, rawTitle: string) => {
      title = readTitle(rawTitle);
      return "";
    })
    .replace(/<!--AYANAM_[\s\S]*$/, "")
    .trim();

  return { text, title };
}

export function parseAgentReply(value: string, metadata?: ConsultationReplyMetadata) {
  const parsed = stripAgentReplyMetadata(value);
  return { text: parsed.text, title: metadata?.title ?? parsed.title };
}

export type SessionTitleOptions = {
  readonly entrypoint?: ConsultationEntrypoint | null;
  readonly theme?: ConsultationDomain;
  readonly at?: Date;
  readonly existingTitles?: readonly string[];
};

export function isGenericSessionTitle(title: string): boolean {
  const text = title.replace(/\s+/g, " ").trim();
  if (!text) return true;
  if (GENERIC_SESSION_TITLES.has(text)) return true;
  return /^(?:深入看今日|从今日问起|查看今日运势|生时校正|再次校正)/.test(text);
}

function clipTitle(value: string, maxChars = 14): string {
  const characters = Array.from(value);
  return characters.length > maxChars ? `${characters.slice(0, maxChars).join("")}…` : value;
}

function datedSessionTitle(at: Date, suffix: string): string {
  return `${at.getMonth() + 1}月${at.getDate()}日 · ${suffix}`;
}

function uniquifySessionTitle(title: string, existingTitles: readonly string[], at: Date): string {
  if (!existingTitles.includes(title)) return title;
  const hours = String(at.getHours()).padStart(2, "0");
  const minutes = String(at.getMinutes()).padStart(2, "0");
  return `${title} ${hours}:${minutes}`;
}

export function resolveSessionTitle(
  question: string,
  modelTitle?: string,
  options: SessionTitleOptions = {},
): string {
  const at = options.at ?? new Date();
  const existingTitles = options.existingTitles ?? [];
  if (modelTitle && !isGenericSessionTitle(modelTitle)) {
    return uniquifySessionTitle(clipTitle(modelTitle), existingTitles, at);
  }
  if (options.entrypoint === "daily_starlanguage" || isGeneralDailyFortuneQuestion(question)) {
    return uniquifySessionTitle(datedSessionTitle(at, "今日节奏"), existingTitles, at);
  }
  if (options.entrypoint === "birth_time_rectification" || isRectificationHandoffQuestion(question)) {
    return uniquifySessionTitle(datedSessionTitle(at, "生时校正"), existingTitles, at);
  }
  const normalized = question.replace(/\s+/g, " ").trim().replace(/[？?！!。．，,；;：:]+$/u, "");
  if (!normalized) return "新对话";
  if (options.theme && options.theme !== "general") {
    const label = consultationDomainDefinition(options.theme).label;
    return uniquifySessionTitle(`${label} · ${clipTitle(normalized, 10)}`, existingTitles, at);
  }
  return uniquifySessionTitle(clipTitle(normalized), existingTitles, at);
}