import "server-only";
import { cache } from "react";
import type { PolyModel } from "@/lib/ai/core/types";
import { listRegistryModels } from "@/lib/ai/registry";
import { buildBadgeContext, sortWeightOf, type BadgeContext } from "./badges";
import { compareSlug } from "./slug";
import { log } from "@/lib/log";

export interface PublicModelsData {
  models: PolyModel[];
  ctx: BadgeContext;
  /** False when the registry could not be read (DB down) — pages render an honest empty state. */
  ok: boolean;
}

/** Registry snapshot for the public SEO pages (no auth, no user data). Memoized per request via React `cache`. */
export const getPublicModels = cache(async (): Promise<PublicModelsData> => {
  const now = Date.now();
  try {
    const models = await listRegistryModels();
    return { models, ctx: buildBadgeContext(models, now), ok: true };
  } catch (e) {
    log.warn("public models: registry unavailable", { error: (e as Error).message });
    return { models: [], ctx: buildBadgeContext([], now), ok: false };
  }
});

/** Best active model per native provider (highest sort weight). */
export function flagshipModels(models: PolyModel[], limit = 6): PolyModel[] {
  const seen = new Set<string>();
  const out: PolyModel[] = [];
  for (const m of [...models].filter((m) => m.status === "active" && m.provider !== "openrouter").sort((a, b) => sortWeightOf(b) - sortWeightOf(a))) {
    if (seen.has(m.provider)) continue;
    seen.add(m.provider);
    out.push(m);
    if (out.length >= limit) break;
  }
  return out;
}

/** Pairwise comparison slugs between flagships (for "Popular comparisons"). */
export function popularComparisons(models: PolyModel[], limit = 8): { slug: string; a: PolyModel; b: PolyModel }[] {
  const flags = flagshipModels(models, 5);
  const out: { slug: string; a: PolyModel; b: PolyModel }[] = [];
  for (let i = 0; i < flags.length; i++) for (let j = i + 1; j < flags.length; j++) out.push({ slug: compareSlug([flags[i], flags[j]]), a: flags[i], b: flags[j] });
  return out.slice(0, limit);
}