import { z } from "zod";
import { consultationDomainSchema, consultationDomainIds } from "./consultation-domain-registry";
import { generalGuidedJyotishTopics } from "./guided-jyotish-topics";

const detachedStarterQuestionPattern = /印度占星|一般如何|通常(?:会)?(?:看|观察|分析|理解|包含)|哪些(?:因素|证据层)|如何划分/;

const userCenteredStarterQuestionSchema = z.string()
  .trim()
  .min(4)
  .max(80)
  .refine((text) => text.includes("我"), "starter_question_must_be_first_person")
  .refine((text) => !detachedStarterQuestionPattern.test(text), "starter_question_must_not_be_encyclopedic");

// Every domain the home screen renders needs a question, in registry order, so the
// page never has to fall back to a static prompt for part of the grid.
export const onboardingSuggestionThemes = consultationDomainIds;

const onboardingSchema = z.object({
  suggestions: z.array(z.object({
    theme: consultationDomainSchema,
    text: userCenteredStarterQuestionSchema,
  })).refine(
    (items) => items.length === onboardingSuggestionThemes.length
      && items.every((item, index) => item.theme === onboardingSuggestionThemes[index]),
    "suggestions_must_cover_every_domain_in_order",
  ),
});

export type OnboardingPayload = z.infer<typeof onboardingSchema>;

export const fallbackOnboardingPayload: OnboardingPayload = {
  suggestions: generalGuidedJyotishTopics.map((topic) => ({ theme: topic.id, text: topic.prompt })),
};

class OnboardingJsonError extends Error {
  readonly name = "OnboardingJsonError";
}

export function parseOnboardingPayload(value: unknown): OnboardingPayload | null {
  const parsed = onboardingSchema.safeParse(value);
  return parsed.success ? parsed.data : null;
}

export function parseOnboardingText(text: string): OnboardingPayload | null {
  const normalized = text.trim().replace(/^```(?:json)?\s*/i, "").replace(/\s*```$/, "");
  const start = normalized.indexOf("{");
  const end = normalized.lastIndexOf("}");
  if (start < 0 || end <= start) throw new OnboardingJsonError("onboarding_json_missing");
  const parsed: unknown = JSON.parse(normalized.slice(start, end + 1));
  return parseOnboardingPayload(parsed);
}