// Carte des concepts : nœuds (avec maîtrise) + liens typés + compteurs de ressources.
import { NextResponse } from "next/server";
import { apiError, requireEnrollment } from "@/lib/api.ts";
import { requireUser } from "@/lib/auth/session.ts";
import { all } from "@/lib/db/index.ts";
import { masteryForCourse } from "@/lib/learning/mastery.ts";
import { normalizeCourse } from "@/lib/learning/helpers.ts";

export async function GET(_req: Request, ctx: { params: Promise<{ course: string }> }) {
  try {
    const user = await requireUser();
    const course = normalizeCourse((await ctx.params).course);
    requireEnrollment(user.id, course);

    const mastery = new Map(masteryForCourse(user.id, course).map((m) => [m.conceptId, m]));
    const concepts = all<{ id: number; slug: string; name: string; description: string; week: number | null; importance: number; axis: string }>(
      "SELECT id, slug, name, description, week, importance, axis FROM concepts WHERE course_code = ? ORDER BY week, id",
      course
    );
    const counts = new Map<number, { cards: number; questions: number }>();
    for (const r of all<{ concept_id: number; n: number }>(
      "SELECT concept_id, COUNT(*) as n FROM flashcards WHERE course_code = ? AND concept_id IS NOT NULL GROUP BY concept_id", course
    )) counts.set(r.concept_id, { cards: r.n, questions: 0 });
    for (const r of all<{ concept_id: number; n: number }>(
      "SELECT concept_id, COUNT(*) as n FROM quiz_questions WHERE course_code = ? AND concept_id IS NOT NULL GROUP BY concept_id", course
    )) {
      const e = counts.get(r.concept_id) ?? { cards: 0, questions: 0 };
      e.questions = r.n;
      counts.set(r.concept_id, e);
    }

    const ids = concepts.map((c) => c.id);
    const links = ids.length
      ? all<{ from_id: number; to_id: number; type: string }>(
          `SELECT from_id, to_id, type FROM concept_links WHERE from_id IN (${ids.map(() => "?").join(",")}) OR to_id IN (${ids.map(() => "?").join(",")})`,
          ...ids, ...ids
        )
      : [];

    return NextResponse.json({
      nodes: concepts.map((c) => ({
        ...c,
        mastery: mastery.get(c.id)?.score ?? 0,
        level: mastery.get(c.id)?.level ?? "a-decouvrir",
        observations: mastery.get(c.id)?.observations ?? 0,
        cards: counts.get(c.id)?.cards ?? 0,
        questions: counts.get(c.id)?.questions ?? 0,
      })),
      links,
    });
  } catch (e) {
    return apiError(e);
  }
}