// Circle Suite usage metering. Per-position, per-tool, per-calendar-month
// counters with level-based quotas. Storage matches the house pattern: one
// JSON file in the data volume, read/written on demand (low volume, human
// scale — a member generating copy is not a hot path).
//
// Quotas rise with level because cost should scale with commitment, and the
// meter is ALWAYS visible to the member: no silent throttling, no surprise
// cutoffs. Hitting a cap shows what unlocks more, never a dead end.
'use strict';
const fs = require('fs');
const path = require('path');

let DATA_DIR = null;
function init(opts) { DATA_DIR = opts.dataDir; }
function file() { return path.join(DATA_DIR, 'suite-usage.json'); }
function readAll() { try { return JSON.parse(fs.readFileSync(file(), 'utf8')); } catch (e) { return {}; } }
function writeAll(v) { try { fs.writeFileSync(file(), JSON.stringify(v)); } catch (e) {} }
function monthKey() { const d = new Date(); return d.getUTCFullYear() + '-' + String(d.getUTCMonth() + 1).padStart(2, '0'); }

// tool -> minimum level, and per-level monthly allowance (index = level-1).
const TOOLS = {
  copy:  { minLevel: 2, quota: [0, 150, 250, 400, 600, 800, 1000, 1500], label: 'Copy Engine' },
  page:  { minLevel: 2, quota: [0, 3, 5, 15, 25, 50, 50, 50], label: 'Page Builder' },
  email: { minLevel: 3, quota: [0, 0, 100, 200, 300, 500, 500, 500], label: 'Email Engine' },
  video: { minLevel: 3, quota: [0, 0, 4, 8, 12, 20, 20, 20], label: 'Video Maker' }
};

function quotaFor(tool, level) {
  const t = TOOLS[tool];
  if (!t) return 0;
  const lv = Math.max(1, Math.min(8, Number(level) || 1));
  if (lv < t.minLevel) return 0;
  return t.quota[lv - 1] || 0;
}

function used(memberId, tool) {
  const all = readAll();
  const m = all[monthKey()] || {};
  const rec = m[String(memberId)] || {};
  return Number(rec[tool] || 0);
}

// Can this position use this tool right now? Returns the full meter state so
// the UI can render it without a second call.
function check(memberId, level, tool) {
  const t = TOOLS[tool];
  if (!t) return { allowed: false, reason: 'unknown-tool', used: 0, limit: 0, remaining: 0 };
  const limit = quotaFor(tool, level);
  const u = used(memberId, tool);
  if (limit <= 0) {
    return { allowed: false, reason: 'locked', minLevel: t.minLevel, used: u, limit: 0, remaining: 0, label: t.label };
  }
  const remaining = Math.max(0, limit - u);
  return {
    allowed: remaining > 0,
    reason: remaining > 0 ? 'ok' : 'quota',
    used: u, limit, remaining, label: t.label, resets: monthKey()
  };
}

function record(memberId, tool, n) {
  const all = readAll();
  const mk = monthKey();
  if (!all[mk]) all[mk] = {};
  const id = String(memberId);
  if (!all[mk][id]) all[mk][id] = {};
  all[mk][id][tool] = Number(all[mk][id][tool] || 0) + (Number(n) || 1);
  // keep only the last 3 months of counters — the file stays tiny forever
  const keep = Object.keys(all).sort().slice(-3);
  const trimmed = {};
  keep.forEach(function (k) { trimmed[k] = all[k]; });
  writeAll(trimmed);
  return all[mk][id][tool];
}

// Every meter for one position — powers the Suite's usage strip.
function meters(memberId, level) {
  const out = {};
  Object.keys(TOOLS).forEach(function (tool) { out[tool] = check(memberId, level, tool); });
  return out;
}

module.exports = { init, check, record, meters, quotaFor, TOOLS };