import { Router } from "express";
import { standardsLessons } from "../data/training/standards";
import { formFactorLessons } from "../data/training/form-factors";
import { switchesLessons } from "../data/training/switches";
import { infrastructureLessons } from "../data/training/infrastructure";
import { testingBuyingLessons } from "../data/training/testing-buying";
import type { TrainingLesson } from "../data/training/types";

export const trainingRouter = Router();

// ── Aggregate all lessons ────────────────────────────────────────────────────

const ALL_LESSONS: TrainingLesson[] = [
  ...standardsLessons,
  ...formFactorLessons,
  ...switchesLessons,
  ...infrastructureLessons,
  ...testingBuyingLessons,
];

// ── Category metadata ────────────────────────────────────────────────────────

const CATEGORIES = [
  {
    id: "standards",
    title: "Standards",
    title_de: "Standards",
    icon: "📋",
    description: "IEEE 802.3, MSA, DOM/DDMI — the foundation of optical networking",
    description_de: "IEEE 802.3, MSA, DOM/DDMI — das Fundament optischer Netzwerke",
  },
  {
    id: "form-factors",
    title: "Form Factors",
    title_de: "Formfaktoren",
    icon: "🔌",
    description: "SFP, QSFP-DD, OSFP, connectors — physical housings and interfaces",
    description_de: "SFP, QSFP-DD, OSFP, Stecker — physikalische Gehäuse und Interfaces",
  },
  {
    id: "switches",
    title: "Switches & Compatibility",
    title_de: "Switches & Kompatibilität",
    icon: "🖥️",
    description: "Vendor lock, FEC configuration, Cisco / Juniper / Arista CLI",
    description_de: "Vendor-Lock, FEC-Konfiguration, Cisco / Juniper / Arista CLI",
  },
  {
    id: "infrastructure",
    title: "Fiber & Infrastructure",
    title_de: "Glasfaser & Infrastruktur",
    icon: "🔧",
    description: "MMF/SMF grades, link budget math, MPO, WDM wavelength planning",
    description_de: "MMF/SMF-Typen, Link-Budget-Berechnung, MPO, WDM-Wellenlägenplanung",
  },
  {
    id: "testing-buying",
    title: "Testing & Buying",
    title_de: "Testen & Einkaufen",
    icon: "🔬",
    description: "Test equipment, OEM vs. compatible, datasheet interpretation, TCO",
    description_de: "Messgeräte, OEM vs. kompatibel, Datenblatt-Interpretation, TCO",
  },
];

// ── GET /api/training/categories ─────────────────────────────────────────────

trainingRouter.get("/categories", (_req, res) => {
  const result = CATEGORIES.map((cat) => ({
    ...cat,
    lesson_count: ALL_LESSONS.filter((l) => l.category === cat.id).length,
    total_duration_min: ALL_LESSONS
      .filter((l) => l.category === cat.id)
      .reduce((sum, l) => sum + l.duration_min, 0),
    quiz_count: ALL_LESSONS
      .filter((l) => l.category === cat.id)
      .reduce((sum, l) => sum + l.quiz.length, 0),
  }));
  res.json(result);
});

// ── GET /api/training/lessons?category= ──────────────────────────────────────

trainingRouter.get("/lessons", (req, res) => {
  const { category } = req.query;
  let lessons = ALL_LESSONS;
  if (category && typeof category === "string") {
    lessons = lessons.filter((l) => l.category === category);
  }
  // Return metadata only — omit heavy sections + quiz content
  res.json(
    lessons.map(({ id, category, title, title_de, level, duration_min, summary, summary_de, tags }) => ({
      id,
      category,
      title,
      title_de,
      level,
      duration_min,
      summary,
      summary_de,
      tags,
    }))
  );
});

// ── GET /api/training/lessons/:id ────────────────────────────────────────────

trainingRouter.get("/lessons/:id", (req, res) => {
  const lesson = ALL_LESSONS.find((l) => l.id === req.params.id);
  if (!lesson) {
    return res.status(404).json({ error: "Lesson not found" });
  }
  return res.json(lesson);
});

// ── GET /api/training/quiz?lesson=&category= ─────────────────────────────────

trainingRouter.get("/quiz", (req, res) => {
  const { lesson, category } = req.query;
  let questions = ALL_LESSONS.flatMap((l) => l.quiz);

  if (lesson && typeof lesson === "string") {
    questions = questions.filter((q) => q.lesson === lesson);
  } else if (category && typeof category === "string") {
    const catLessonIds = ALL_LESSONS.filter((l) => l.category === category).map((l) => l.id);
    questions = questions.filter((q) => catLessonIds.includes(q.lesson));
  }

  res.json(questions);
});

// ── GET /api/training/stats ───────────────────────────────────────────────────

trainingRouter.get("/stats", (_req, res) => {
  res.json({
    total_lessons: ALL_LESSONS.length,
    total_quiz_questions: ALL_LESSONS.reduce((s, l) => s + l.quiz.length, 0),
    total_duration_min: ALL_LESSONS.reduce((s, l) => s + l.duration_min, 0),
    categories: CATEGORIES.length,
    levels: {
      beginner: ALL_LESSONS.filter((l) => l.level === "beginner").length,
      intermediate: ALL_LESSONS.filter((l) => l.level === "intermediate").length,
      advanced: ALL_LESSONS.filter((l) => l.level === "advanced").length,
    },
  });
});