// Live-reloading config layer. Mirrors Recap's config.js pattern: read
// /data/config/relay-config.json on every access (filesystem watcher
// pulls in StartOS-action changes without a daemon restart), parse,
// and expose typed accessors.
//
// All defaults match the schema in startos/file-models/config.json.ts.

import fs from "fs/promises";
import path from "path";

let dataDir = "/data";
let cached = { mtimeMs: 0, snapshot: defaultConfig() };

function defaultConfig() {
  return {
    relay_gemini_api_key: "",
    relay_parakeet_base_url: "",
    relay_gemma_base_url: "",
    relay_parakeet_model: "parakeet-tdt-0.6b-v3",
    relay_gemma_model: "gemma3:27b",
    relay_keysat_base_url: "https://keysat.xyz",
    relay_admin_username: "",
    relay_admin_password_hash: "",
    relay_admin_password_salt: "",
    relay_admin_session_secret: "",
    relay_tier_quotas_json: JSON.stringify({
      core: {
        lifetime: 10,
        geminiCapLifetime: 5,
        monthly: null,
        geminiCapMonthly: null,
      },
      pro: { lifetime: null, monthly: 50, geminiCapMonthly: 25 },
      max: { lifetime: null, monthly: null, geminiCapMonthly: 50 },
    }),
  };
}

function configPath() {
  return path.join(dataDir, "config", "relay-config.json");
}

export async function initConfig({ dataDir: dd }) {
  if (dd) dataDir = dd;
  await fs.mkdir(path.dirname(configPath()), { recursive: true }).catch(() => {});
  // Prime the cache so the first request doesn't pay for a file-read.
  await getConfigSnapshot();
}

// Reads the on-disk config and merges with defaults. Cheap — single
// stat + read per call, but the result is cached until the file mtime
// changes so repeat callers within one request don't re-read.
export async function getConfigSnapshot() {
  const p = configPath();
  let stat;
  try {
    stat = await fs.stat(p);
  } catch {
    return cached.snapshot;
  }
  if (stat.mtimeMs === cached.mtimeMs) return cached.snapshot;
  try {
    const raw = await fs.readFile(p, "utf8");
    const parsed = JSON.parse(raw);
    cached = {
      mtimeMs: stat.mtimeMs,
      snapshot: { ...defaultConfig(), ...parsed },
    };
  } catch (err) {
    console.warn(`[config] failed to parse ${p}: ${err?.message}`);
  }
  return cached.snapshot;
}

// Parsed view of relay_tier_quotas_json, with safe fallbacks if the
// blob is missing or malformed. geminiCapLifetime is the new field
// added in relay 0.2.3 — splits a Core install's lifetime budget into
// Gemini-served vs hardware-served credits.
export async function getTierQuotas() {
  const cfg = await getConfigSnapshot();
  try {
    const parsed = JSON.parse(cfg.relay_tier_quotas_json);
    return {
      core: {
        lifetime: parsed?.core?.lifetime ?? 10,
        geminiCapLifetime: parsed?.core?.geminiCapLifetime ?? 5,
        monthly: parsed?.core?.monthly ?? null,
        geminiCapMonthly: parsed?.core?.geminiCapMonthly ?? null,
      },
      pro: {
        lifetime: parsed?.pro?.lifetime ?? null,
        monthly: parsed?.pro?.monthly ?? 50,
        geminiCapMonthly: parsed?.pro?.geminiCapMonthly ?? 25,
      },
      max: {
        lifetime: parsed?.max?.lifetime ?? null,
        monthly: parsed?.max?.monthly ?? null,
        geminiCapMonthly: parsed?.max?.geminiCapMonthly ?? 50,
      },
    };
  } catch {
    return {
      core: {
        lifetime: 10,
        geminiCapLifetime: 5,
        monthly: null,
        geminiCapMonthly: null,
      },
      pro: { lifetime: null, monthly: 50, geminiCapMonthly: 25 },
      max: { lifetime: null, monthly: null, geminiCapMonthly: 50 },
    };
  }
}