import "server-only";

import { Prisma, PrismaClient } from "@prisma/client";
import { buildStyle8DPromptBlock } from "@/lib/types/style-profile";

const globalForPrisma = globalThis as unknown as {
  prisma?: PrismaClient & { __schemaFingerprint?: string };
};

/** 與 schema 同步；dmmf 不可用時用固定字串讓 dev 快取仍能失效。 */
const SCHEMA_FINGERPRINT_FALLBACK =
  "ProductProfile:accountId,brand,brandId,context,createdAt,id,label,matchTags,topics,updatedAt|Topic:accountId,active,brief,brandProfileId,createdAt,id,label,productContext,productProfileId,query,researchMap,selectedTags,topicGoal";

let schemaFingerprint: string | null = null;

function getSchemaFingerprint(): string {
  if (schemaFingerprint) return schemaFingerprint;
  try {
    const models = Prisma.dmmf?.datamodel?.models;
    if (models) {
      const account = models.find((m) => m.name === "Account");
      const product = models.find((m) => m.name === "ProductProfile");
      const topic = models.find((m) => m.name === "Topic");
      const productFields = product?.fields.map((f) => f.name).sort().join(",") ?? "";
      const topicFields = topic?.fields.map((f) => f.name).sort().join(",") ?? "";
      const accountFields = account?.fields.map((f) => f.name).sort().join(",") ?? "";
      schemaFingerprint = `Account:${accountFields}|ProductProfile:${productFields}|Topic:${topicFields}`;
      return schemaFingerprint;
    }
  } catch {
    // Prisma.dmmf 僅在 server runtime 可用
  }
  schemaFingerprint = SCHEMA_FINGERPRINT_FALLBACK;
  return schemaFingerprint;
}

function createPrismaClient() {
  const fingerprint = getSchemaFingerprint();
  const client = new PrismaClient({
    log: process.env.NODE_ENV === "development" ? ["error", "warn"] : ["error"],
  }) as PrismaClient & { __schemaFingerprint?: string };
  client.__schemaFingerprint = fingerprint;
  return client;
}

function isPrismaClientCurrent(
  client: PrismaClient & { __schemaFingerprint?: string }
): boolean {
  return (
    "backgroundJob" in client &&
    "user" in client &&
    "productProfile" in client &&
    "brandProfile" in client &&
    client.__schemaFingerprint === getSchemaFingerprint()
  );
}

function getPrismaClient() {
  const cached = globalForPrisma.prisma;
  if (cached && isPrismaClientCurrent(cached)) return cached;

  const client = createPrismaClient();
  if (process.env.NODE_ENV !== "production") {
    globalForPrisma.prisma = client;
  }
  return client;
}

export const prisma = getPrismaClient();

export function resolvePersona(
  settings: { persona: string | null },
  account?: {
    persona: string | null;
    styleProfile?: string | null;
    targetAudience?: string | null;
    goals?: string | null;
  } | null
) {
  const blocks = [
    account?.persona?.trim() || settings.persona?.trim(),
    buildStyle8DPromptBlock(account?.styleProfile),
    account?.targetAudience?.trim() ? `目標受眾：${account.targetAudience.trim()}` : null,
    account?.goals?.trim() ? `經營目標：${account.goals.trim()}` : null,
  ].filter(Boolean);

  return blocks.length > 0 ? blocks.join("\n\n") : null;
}