import { NextRequest, NextResponse } from "next/server";
import { z } from "zod";
import { generateObject } from "ai";
import { requireSessionOrApiKey } from "@/lib/api-auth";
import { applyRateLimit } from "@/lib/rate-limit";
import { withAiQuota, resolveAiConfigOrError } from "@/lib/ai/ai-error";
import { getModelConfigForUseCase } from "@/lib/ai/resolve-user-key";
import { resolveModel } from "@/lib/ai/factory";
import { getUserPrivateBio, buildUserBioContext } from "@/lib/ai/user-bio";

const InputSchema = z.object({
  prompt: z.string().max(300).optional(),
});

const LANG: Record<string, string> = { en: "English", fr: "French" };

const IdeasSchema = z.object({
  ideas: z.array(z.object({
    title: z.string(),
    description: z.string(),
    tags: z.array(z.string()).max(4),
    difficulty: z.enum(["easy", "medium", "hard"]),
    totalMins: z.number().int().optional(),
  })).length(6),
});

export async function POST(req: NextRequest) {
  const { session, response } = await requireSessionOrApiKey(req);
  if (response) return response;

  const body = await req.json() as unknown;
  const parsed = InputSchema.safeParse(body);
  if (!parsed.success) {
    return NextResponse.json({ error: "Validation error" }, { status: 400 });
  }

  const limited = await applyRateLimit(`rl:ai:${session!.user.id}`, 10, 60);
  if (limited) return limited;

  const [configResult, privateBio] = await Promise.all([
    resolveAiConfigOrError(() => getModelConfigForUseCase(session!.user.id, "text")),
    getUserPrivateBio(session!.user.id),
  ]);
  if (!configResult.ok) return configResult.response;
  const aiConfig = configResult.data;
  const model = resolveModel(aiConfig);
  const bioContext = buildUserBioContext(privateBio);

  const userContext = bioContext
    ? `Consider the following user preferences when suggesting ideas:${bioContext}\n\n`
    : "";

  const locale = (session!.user as { locale?: string }).locale ?? "en";
  const lang = LANG[locale] ?? "English";

  const prompt = parsed.data.prompt?.trim()
    ? `${userContext}Generate 6 diverse recipe ideas based on: "${parsed.data.prompt}". Include a mix of difficulty levels.`
    : `${userContext}Generate 6 diverse, creative recipe ideas. Include different cuisines, difficulty levels, and meal types.`;

  const result = await withAiQuota(session!.user.id, session!.user.tier as "free" | "pro" | "family", () =>
    generateObject({
      model,
      schema: IdeasSchema,
      system: `Respond in ${lang}.`,
      prompt,
    }), { skipQuota: aiConfig.isByok }
  );
  if (!result.ok) return result.response;

  return NextResponse.json(result.data.object.ideas);
}
