const fs = require('fs');
const path = require('path');
const crypto = require('crypto');
const webpush = require('web-push');

const ENV_PATH = path.join(__dirname, '..', '.env');

function loadEnv() {
  const env = {};
  if (fs.existsSync(ENV_PATH)) {
    for (const line of fs.readFileSync(ENV_PATH, 'utf8').split('\n')) {
      const m = line.match(/^\s*([A-Z0-9_]+)\s*=\s*(.*)\s*$/);
      if (m && !line.trim().startsWith('#')) env[m[1]] = m[2].replace(/^["']|["']$/g, '');
    }
  }
  return env;
}

function saveEnv(env) {
  const lines = [];
  for (const [k, v] of Object.entries(env)) lines.push(`${k}=${v}`);
  fs.writeFileSync(ENV_PATH, lines.join('\n') + '\n', 'utf8');
}

function ensure(key, generator) {
  if (process.env[key] || env[key]) return process.env[key] || env[key];
  const value = generator();
  env[key] = value;
  saveEnv(env);
  return value;
}

const env = loadEnv();

function ensureVapidPair() {
  if ((process.env.VAPID_PUBLIC_KEY || env.VAPID_PUBLIC_KEY) && (process.env.VAPID_PRIVATE_KEY || env.VAPID_PRIVATE_KEY)) {
    return {
      publicKey: process.env.VAPID_PUBLIC_KEY || env.VAPID_PUBLIC_KEY,
      privateKey: process.env.VAPID_PRIVATE_KEY || env.VAPID_PRIVATE_KEY,
    };
  }
  const pair = webpush.generateVAPIDKeys();
  env.VAPID_PUBLIC_KEY = pair.publicKey;
  env.VAPID_PRIVATE_KEY = pair.privateKey;
  saveEnv(env);
  return pair;
}

const vapid = ensureVapidPair();

const config = {
  port: Number(process.env.PORT || env.PORT || 3000),
  apiKey: process.env.DEEPSEEK_API_KEY || env.DEEPSEEK_API_KEY || '',
  openrouterApiKey: process.env.OPENROUTER_API_KEY || env.OPENROUTER_API_KEY || '',
  appPassword: process.env.APP_PASSWORD || env.APP_PASSWORD || '',
  model: process.env.MODEL || env.MODEL || 'deepseek-v4-flash',
  thinking: process.env.THINKING || env.THINKING || 'enabled',
  maxTokens: Number(process.env.MAX_TOKENS || env.MAX_TOKENS || 64000),
  baseUrl: process.env.DEEPSEEK_BASE_URL || env.DEEPSEEK_BASE_URL || 'https://api.deepseek.com',
  loginMaxAttempts: Number(process.env.LOGIN_MAX_ATTEMPTS || env.LOGIN_MAX_ATTEMPTS || 5),
  loginLockMinutes: Number(process.env.LOGIN_LOCK_MINUTES || env.LOGIN_LOCK_MINUTES || 5),
  nominatimEmail: process.env.NOMINATIM_EMAIL || env.NOMINATIM_EMAIL || '',
  osrmUrl: process.env.OSRM_URL || env.OSRM_URL || 'https://router.project-osrm.org',
  sessionSecret: ensure('SESSION_SECRET', () => crypto.randomBytes(32).toString('hex')),
  vapidPublicKey: vapid.publicKey,
  vapidPrivateKey: vapid.privateKey,
};

const envOr = (key, def) => process.env[key] || env[key] || def;

// ---------------------------------------------------------------------------
// Modell-Registry: DeepSeek direkt + OpenRouter-Modelle (z.B. GLM 5.3 Flash)
// ---------------------------------------------------------------------------

const MODELS = [
  {
    id: 'deepseek-v4-flash',
    label: 'DeepSeek V4 Flash',
    provider: 'deepseek',
    vision: false,
    // Max. Output laut Doku: 384K – großzügiges Limit gegen abgeschnittene Dashboards
    maxTokens: 131072,
    reasoningEffort: () => envOr('DEEPSEEK_REASONING_EFFORT', 'max'),
    prices: { inputCacheHit: 0.014, inputCacheMiss: 0.44, output: 1.32 },
  },
  {
    id: 'z-ai/glm-5.3-flash',
    label: 'GLM 5.3 Flash (OpenRouter)',
    provider: 'openrouter',
    vision: true,
    // Max. Completion laut OpenRouter: 131072
    maxTokens: 131072,
    reasoningEffort: () => envOr('GLM_REASONING_EFFORT', 'max'),
    prices: { inputCacheHit: 0.015, inputCacheMiss: 0.075, output: 0.25 },
    costNote: 'Schätzung (OpenRouter, Rabatt bis Sep 2026)',
  },
];

/** Registry inkl. benutzerdefiniertem Modell aus der Env (MODEL), falls nicht bekannt. */
function getModels() {
  if (MODELS.some((m) => m.id === config.model)) return MODELS;
  return [
    ...MODELS,
    {
      id: config.model,
      label: config.model,
      provider: 'deepseek',
      vision: false,
      maxTokens: config.maxTokens,
      reasoningEffort: () => envOr('DEEPSEEK_REASONING_EFFORT', 'max'),
      prices: { inputCacheHit: 0.014, inputCacheMiss: 0.44, output: 1.32 },
    },
  ];
}

/** Modell per ID auflösen (Fallback: Default-Modell aus Env). */
function getModel(id) {
  const models = getModels();
  return models.find((m) => m.id === id) || models.find((m) => m.id === config.model) || models[0];
}

module.exports = { config, MODELS, getModels, getModel };