import fs from "fs";
import path from "path";
import yaml from "js-yaml";

const ROOT = "src/content/glossaire";
const DEFAULTS_FILE = "src/lib/glossary-navigation-defaults.ts";
const HUB_LIMIT = 5;
const EFFECTIVE_TOP_LIMIT = 10;
const PATH_KEYS = ["understand", "deepen", "compare", "apply"];

const defaultsRaw = fs.readFileSync(DEFAULTS_FILE, "utf-8");

const defaultFamilies = new Set(
  [...defaultsRaw.matchAll(/^\s{4}"?([a-z0-9-]+)"?\s*:/gm)].map((m) => m[1]),
);

const defaultPathKeysByFamily = new Map();
const defaultTargetsByFamily = new Map();

for (const match of defaultsRaw.matchAll(
  /^\s{4}"?([a-z0-9-]+)"?\s*:\s*\{([\s\S]*?)^\s{4}\},/gm,
)) {
  const family = match[1];
  const body = match[2];
  const keys = new Set();
  const targetsByKey = new Map();

  for (const key of PATH_KEYS) {
    const pathMatch = body.match(new RegExp(`\\b${key}\\s*:\\s*\\[([^\\]]*)\\]`));
    const targets = pathMatch
      ? pathMatch[1]
          .split(",")
          .map((x) => x.trim().replace(/^["']|["']$/g, ""))
          .filter(Boolean)
      : [];

    if (targets.length > 0) keys.add(key);
    targetsByKey.set(key, targets);
  }

  defaultPathKeysByFamily.set(family, keys);
  defaultTargetsByFamily.set(family, targetsByKey);
}

const files = fs.readdirSync(ROOT).filter((f) => f.endsWith(".md"));
const slugs = new Set(files.map((f) => f.replace(".md", "")));

const entries = [];

for (const file of files) {
  const full = path.join(ROOT, file);
  const raw = fs.readFileSync(full, "utf-8");
  const slug = file.replace(".md", "");

  if (!raw.startsWith("---")) {
    entries.push({ slug, data: {}, noFrontmatter: true });
    continue;
  }

  const frontmatter = raw.split("---", 3)[1];
  const data = yaml.load(frontmatter) || {};
  entries.push({ slug, data, noFrontmatter: false });
}

const missingNavigation = [];
const missingReason = [];
const weakPaths = [];
const selfLoops = [];
const deadPrimaryNext = [];
const directCycles = [];
const edges = {};
const incoming = {};
const families = new Set();

const effectiveOutgoing = new Map();
const effectiveIncoming = new Map();

function addEffectiveEdge(from, to) {
  if (!from || !to || from === to || !slugs.has(to)) return;

  if (!effectiveOutgoing.has(from)) effectiveOutgoing.set(from, new Set());
  if (!effectiveIncoming.has(to)) effectiveIncoming.set(to, new Set());

  effectiveOutgoing.get(from).add(to);
  effectiveIncoming.get(to).add(from);
}

for (const { slug, data, noFrontmatter } of entries) {
  if (noFrontmatter) continue;

  if (data.family) families.add(data.family);

  const nav = data.navigation;

  if (!nav) {
    missingNavigation.push(slug);
    continue;
  }

  const next = nav.primaryNext;

  if (next) {
    edges[slug] = next;
    incoming[next] = (incoming[next] || 0) + 1;
    addEffectiveEdge(slug, next);

    if (next === slug) selfLoops.push(slug);
    if (!slugs.has(next)) deadPrimaryNext.push(`${slug} → ${next}`);

    if (!nav.primaryReason) missingReason.push(slug);
  }

  const explicitPaths = nav.paths || {};
  const familyDefaults = defaultPathKeysByFamily.get(data.family) || new Set();
  const familyDefaultTargets = defaultTargetsByFamily.get(data.family) || new Map();

  const pathCount = PATH_KEYS.filter((key) => {
    const explicit = Array.isArray(explicitPaths[key]) && explicitPaths[key].length > 0;
    const fromDefault = familyDefaults.has(key);
    return explicit || fromDefault;
  }).length;

  if (pathCount < 2) weakPaths.push(slug);

  for (const key of PATH_KEYS) {
    const explicitTargets = Array.isArray(explicitPaths[key]) ? explicitPaths[key] : [];
    const defaultTargets = familyDefaultTargets.get(key) || [];

    for (const target of [...explicitTargets, ...defaultTargets]) {
      addEffectiveEdge(slug, target);
    }
  }
}

const seenPairs = new Set();

for (const [a, b] of Object.entries(edges)) {
  if (edges[b] === a) {
    const pair = [a, b].sort().join(" <-> ");
    if (!seenPairs.has(pair)) {
      seenPairs.add(pair);
      directCycles.push(`${a} <-> ${b}`);
    }
  }
}

const missingDefaults = [...families].filter((f) => !defaultFamilies.has(f));

const bigHubs = Object.entries(incoming)
  .filter(([, count]) => count > HUB_LIMIT)
  .sort((a, b) => b[1] - a[1]);

console.log("\n🔍 Glossary navigation audit");

if (missingNavigation.length > 0) {
  console.log("\n❌ Missing navigation:");
  missingNavigation.forEach((s) => console.log(" -", s));
}

console.log("\n🔍 Direct cycles:");
if (directCycles.length) directCycles.forEach((c) => console.log(" -", c));
else console.log(" (none)");

console.log("\n📊 Top hubs:");
Object.entries(incoming)
  .sort((a, b) => b[1] - a[1])
  .slice(0, 10)
  .forEach(([slug, n]) => {
    if (n > HUB_LIMIT) console.log(`⚠️ ${slug}: ${n}`);
    else console.log(`  ${slug}: ${n}`);
  });

console.log("\n🔗 Checking dead primaryNext:");
if (deadPrimaryNext.length) deadPrimaryNext.forEach((x) => console.log("❌", x));
else console.log(" (none)");

if (missingDefaults.length) {
  console.log("\n❌ Families without defaults:");
  missingDefaults.forEach((f) => console.log(" -", f));
}

if (bigHubs.length) {
  console.log(`\n⚠️ Hubs above limit (${HUB_LIMIT}):`);
  bigHubs.forEach(([slug, n]) => console.log(` - ${slug}: ${n}`));
}

if (missingReason.length) {
  console.log("\n⚠️ Missing primaryReason:");
  missingReason.forEach((s) => console.log(" -", s));
}

if (weakPaths.length) {
  console.log("\n⚠️ Weak path coverage (<2):");
  weakPaths.forEach((s) => console.log(" -", s));
}

if (selfLoops.length) {
  console.log("\n❌ Self-referencing primaryNext:");
  selfLoops.forEach((s) => console.log(" -", s));
}

console.log(`\n📊 Effective convergence top ${EFFECTIVE_TOP_LIMIT}:`);
[...effectiveIncoming.entries()]
  .map(([slug, sources]) => [slug, sources.size])
  .sort((a, b) => b[1] - a[1])
  .slice(0, EFFECTIVE_TOP_LIMIT)
  .forEach(([slug, n]) => {
    console.log(`  ${n} ${slug}`);
  });

console.log(`\n📊 Effective branching top ${EFFECTIVE_TOP_LIMIT}:`);
[...effectiveOutgoing.entries()]
  .map(([slug, targets]) => [slug, targets.size])
  .sort((a, b) => b[1] - a[1])
  .slice(0, EFFECTIVE_TOP_LIMIT)
  .forEach(([slug, n]) => {
    console.log(`  ${n} ${slug}`);
  });

const hardFailures =
  missingNavigation.length +
  directCycles.length +
  deadPrimaryNext.length +
  missingDefaults.length +
  selfLoops.length;

if (hardFailures > 0) {
  console.log(`\n❌ Audit failed: ${hardFailures} hard issue(s)`);
  process.exitCode = 1;
} else {
  console.log("\n✅ Audit done");
}