// ============================================================================
//  Project   : modelmap
//  File      : site/lib/comments.js
//  Purpose   : Visitor comments — persistent JSON store, validation, limits
//  Author    : Simon-Pierre Boucher
//  Contact   : contact@spboucher.ai
//  Website   : https://modelmap.io
//  Created   : 2026-08-12
//  Modified  : 2026-08-12
//  Platform  : macOS / Apple Silicon (arm64) — Node.js (deployed on MacLustr)
//  License   : All rights reserved (research code)
// ============================================================================
"use strict";

const fs = require("fs");
const os = require("os");
const path = require("path");
const crypto = require("crypto");

// Stored OUTSIDE the app directory so rsync --delete redeploys never wipe it.
const STORE = process.env.COMMENTS_FILE ||
  path.join(os.homedir(), ".modelmap-web", "comments.json");

const MAX_NAME = 60;
const MAX_MESSAGE = 2000;
const MIN_MESSAGE = 3;
const MAX_TOTAL = 5000;             // hard cap on stored comments
const RATE_LIMIT = 5;               // posts per IP per window
const RATE_WINDOW_MS = 60 * 60 * 1000;

const recentByIp = new Map();       // ipHash -> [timestamps]

function ensureStore() {
  fs.mkdirSync(path.dirname(STORE), { recursive: true });
  if (!fs.existsSync(STORE)) fs.writeFileSync(STORE, "[]\n");
}

function list() {
  try {
    ensureStore();
    const all = JSON.parse(fs.readFileSync(STORE, "utf8"));
    return Array.isArray(all) ? all.slice().reverse() : [];
  } catch {
    return [];
  }
}

function clean(s, max) {
  return String(s || "")
    .replace(/[\u0000-\u0008\u000B-\u001F\u007F]/g, "")
    .replace(/\s+/g, (m) => (m.includes("\n") ? "\n" : " "))
    .trim()
    .slice(0, max);
}

function ipHash(ip) {
  return crypto.createHash("sha256").update(String(ip || "")).digest("hex").slice(0, 16);
}

function rateLimited(ip) {
  const key = ipHash(ip);
  const now = Date.now();
  const times = (recentByIp.get(key) || []).filter((t) => now - t < RATE_WINDOW_MS);
  if (times.length >= RATE_LIMIT) return true;
  times.push(now);
  recentByIp.set(key, times);
  return false;
}

/**
 * Add a comment. Returns { ok, error? }.
 * honeypot: hidden "website" field — bots fill it, humans don't.
 */
function add({ name, message, honeypot, ip }) {
  if (honeypot) return { ok: true, dropped: true }; // pretend success, drop silently
  const n = clean(name, MAX_NAME) || "Anonymous";
  const m = clean(message, MAX_MESSAGE);
  if (m.length < MIN_MESSAGE) return { ok: false, error: "Message is too short." };
  if (rateLimited(ip)) return { ok: false, error: "Too many comments from this address — try again later." };
  ensureStore();
  let all;
  try {
    all = JSON.parse(fs.readFileSync(STORE, "utf8"));
    if (!Array.isArray(all)) all = [];
  } catch {
    all = [];
  }
  all.push({
    id: crypto.randomUUID(),
    name: n,
    message: m,
    created: new Date().toISOString(),
  });
  if (all.length > MAX_TOTAL) all = all.slice(all.length - MAX_TOTAL);
  fs.writeFileSync(STORE, JSON.stringify(all, null, 2) + "\n");
  return { ok: true };
}

module.exports = { list, add, STORE };