import { Low } from 'lowdb';
import { JSONFile } from 'lowdb/node';
import { mkdirSync } from 'fs';
import { dirname } from 'path';

const DB_PATH = process.env.DB_PATH || './data/budget.json';

const DEFAULT = {
  categories: [
    { id: 1, name: 'Kivra',     sort_order: 1, color: '#7C3AED' },
    { id: 2, name: 'eFaktura',  sort_order: 2, color: '#2563EB' },
    { id: 3, name: 'Manuella',  sort_order: 3, color: '#D97706' },
    { id: 4, name: 'Autogiro',  sort_order: 4, color: '#059669' },
  ],
  months:   [],
  income:   [],
  bills:    [],
  subscriptions: [],
  loans:    [],
  payments: [],
  banking: {
    enable_banking: {
      enabled: false,
      status: 'not_connected',
      institution: '',
      last_sync_at: null,
      notes: '',
      application_id: '',
      private_key_pem: '',
      redirect_url: '',
      country: 'SE',
      psu_type: 'personal',
      auto_sync_enabled: false,
      sync_interval_minutes: 360,
      import_from_date: null,
      incremental_sync_days: 7,
      pending_state: null,
      last_callback_at: null,
      last_callback_url: '',
      last_callback_code_present: false,
      last_callback_state: '',
      last_callback_exchange_at: null,
      last_callback_exchange_error: '',
      session_id: null,
      session_expires_at: null,
      session_created_at: null,
      account_aliases: {},
      transaction_categories: {},
      accounts: [],
      transactions: [],
      last_sync_summary: null,
      last_error: null,
    },
  },
  auth: {
    settings: {
      enabled: false,
      issuer: '',
      discovery_url: '',
      client_id: '',
      client_secret: '',
      redirect_uri: '',
      scope: 'openid profile email groups',
      session_secret: '',
      allowed_groups: '',
      allowed_emails: '',
      allowed_domains: '',
      session_ttl_hours: 12,
    },
    sessions: [],
    pending: [],
  },
  ai: {
    ollama: {
      enabled: false,
      base_url: 'http://host.docker.internal:11434',
      model: '',
      vision_model: '',
      system_prompt: '',
      include_budget_context: true,
      include_banking_context: true,
    },
    conversations: [],
  },
  app_settings: {
    finance_profile: {
      salary_day_of_month: 25,
      buffer_days_target: 7,
      salary_account_uid: '',
      recurring_income_note: '',
    },
    account_view: {
      primary_account_uid: '',
      include_savings_in_ai: false,
      hide_zero_balance_accounts: false,
    },
    notifications: {
      ntfy_enabled: false,
      ntfy_base_url: 'https://ntfy.sh',
      ntfy_topic: '',
      ntfy_access_token: '',
      ntfy_title: 'Enkelbudget',
      ntfy_tags: 'money_with_wings,bank',
      ntfy_click_url: '',
      ntfy_priority: 3,
      notify_new_transactions: true,
      include_pending_transactions: false,
      minimum_transaction_amount: 0,
      last_error: '',
      last_sent_at: null,
    },
  },
  _seq: { categories: 4, months: 0, income: 0, bills: 0, subscriptions: 0, loans: 0, payments: 0 },
};

let _db = null;

export async function getDb() {
  if (!_db) {
    mkdirSync(dirname(DB_PATH), { recursive: true });
    const adapter = new JSONFile(DB_PATH);
    _db = new Low(adapter, DEFAULT);
    await _db.read();
    _db.data ||= structuredClone(DEFAULT);
    _db.data.categories ||= structuredClone(DEFAULT.categories);
    _db.data.months ||= [];
    _db.data.income ||= [];
    _db.data.bills ||= [];
    _db.data.subscriptions ||= [];
    _db.data.loans ||= [];
    _db.data.payments ||= [];
    _db.data.banking ||= structuredClone(DEFAULT.banking);
    _db.data.banking.enable_banking ||= structuredClone(DEFAULT.banking.enable_banking);
    _db.data.auth ||= structuredClone(DEFAULT.auth);
    _db.data.auth.settings ||= structuredClone(DEFAULT.auth.settings);
    _db.data.auth.sessions ||= [];
    _db.data.auth.pending ||= [];
    _db.data.ai ||= structuredClone(DEFAULT.ai);
    _db.data.ai.ollama ||= structuredClone(DEFAULT.ai.ollama);
    _db.data.ai.conversations ||= [];
    _db.data.app_settings ||= structuredClone(DEFAULT.app_settings);
    _db.data.app_settings.finance_profile ||= structuredClone(DEFAULT.app_settings.finance_profile);
    _db.data.app_settings.account_view ||= structuredClone(DEFAULT.app_settings.account_view);
    _db.data.app_settings.notifications ||= structuredClone(DEFAULT.app_settings.notifications);
    _db.data._seq ||= {};
    for (const [key, value] of Object.entries(DEFAULT._seq)) {
      _db.data._seq[key] ??= value;
    }
  }
  return _db;
}

export function nextId(db, table) {
  db.data._seq[table] = (db.data._seq[table] ?? 0) + 1;
  return db.data._seq[table];
}