/* ============================================
   GrubFlip — Core App Module
   API client, auth, utilities, toast system
   ============================================ */

const GrubFlip = (() => {
  'use strict';

  // --- Config ---
  const API_BASE = '/api';
  let authToken = localStorage.getItem('gf_token') || null;

  // --- Auth ---
  function setToken(token) {
    authToken = token;
    if (token) {
      localStorage.setItem('gf_token', token);
    } else {
      localStorage.removeItem('gf_token');
    }
  }

  function getToken() {
    return authToken;
  }

  function isLoggedIn() {
    return !!authToken;
  }

  // --- API Client ---
  async function api(endpoint, options = {}) {
    const url = `${API_BASE}${endpoint}`;
    const headers = {
      'Accept': 'application/json',
      ...options.headers,
    };

    if (authToken) {
      headers['Authorization'] = `Bearer ${authToken}`;
    }

    // Don't set Content-Type for FormData (browser sets boundary)
    if (options.body && !(options.body instanceof FormData)) {
      headers['Content-Type'] = 'application/json';
      if (typeof options.body === 'object') {
        options.body = JSON.stringify(options.body);
      }
    }

    try {
      const response = await fetch(url, {
        ...options,
        headers,
      });

      if (response.status === 401) {
        setToken(null);
        window.location.href = '/grubflip/login.html';
        return null;
      }

      const data = await response.json();

      if (!response.ok) {
        throw new ApiError(
          data.error || data.message || `Request failed (${response.status})`,
          response.status,
          data
        );
      }

      return data;
    } catch (err) {
      if (err instanceof ApiError) throw err;
      throw new ApiError('Network error — check your connection', 0);
    }
  }

  class ApiError extends Error {
    constructor(message, status, data = null) {
      super(message);
      this.name = 'ApiError';
      this.status = status;
      this.data = data;
    }
  }

  // Convenience methods
  api.get = (endpoint, params = {}) => {
    const query = new URLSearchParams(params).toString();
    const url = query ? `${endpoint}?${query}` : endpoint;
    return api(url, { method: 'GET' });
  };

  api.post = (endpoint, body) => {
    return api(endpoint, { method: 'POST', body });
  };

  api.put = (endpoint, body) => {
    return api(endpoint, { method: 'PUT', body });
  };

  api.delete = (endpoint) => {
    return api(endpoint, { method: 'DELETE' });
  };

  api.upload = (endpoint, file, fieldName = 'file') => {
    const formData = new FormData();
    formData.append(fieldName, file);
    return api(endpoint, { method: 'POST', body: formData });
  };

  // --- Toast System ---
  let toastContainer = null;

  function ensureToastContainer() {
    if (!toastContainer) {
      toastContainer = document.createElement('div');
      toastContainer.className = 'toast-container';
      toastContainer.setAttribute('role', 'status');
      toastContainer.setAttribute('aria-live', 'polite');
      document.body.appendChild(toastContainer);
    }
    return toastContainer;
  }

  function toast(message, type = 'default', duration = 3000) {
    const container = ensureToastContainer();
    const el = document.createElement('div');
    el.className = `toast${type !== 'default' ? ` toast--${type}` : ''}`;
    el.textContent = message;
    container.appendChild(el);

    setTimeout(() => {
      el.style.opacity = '0';
      el.style.transform = 'translateY(-0.5rem)';
      el.style.transition = 'all 0.2s';
      setTimeout(() => el.remove(), 200);
    }, duration);
  }

  // --- Time Helpers ---
  function timeAgo(dateStr) {
    const now = Date.now();
    const then = new Date(dateStr).getTime();
    const diff = Math.max(0, now - then);
    const minutes = Math.floor(diff / 60000);
    const hours = Math.floor(diff / 3600000);
    const days = Math.floor(diff / 86400000);

    if (minutes < 1) return 'just now';
    if (minutes < 60) return `${minutes}m ago`;
    if (hours < 24) return `${hours}h ago`;
    if (days < 7) return `${days}d ago`;
    return new Date(dateStr).toLocaleDateString();
  }

  function timeUntil(dateStr) {
    const now = Date.now();
    const then = new Date(dateStr).getTime();
    const diff = Math.max(0, then - now);
    const hours = Math.floor(diff / 3600000);
    const minutes = Math.floor((diff % 3600000) / 60000);

    if (diff <= 0) return 'expired';
    if (hours > 0) return `${hours}h ${minutes}m left`;
    return `${minutes}m left`;
  }

  // --- DOM Helpers ---
  function $(selector, parent = document) {
    return parent.querySelector(selector);
  }

  function $$(selector, parent = document) {
    return [...parent.querySelectorAll(selector)];
  }

  function el(tag, attrs = {}, children = []) {
    const element = document.createElement(tag);
    for (const [key, val] of Object.entries(attrs)) {
      if (key === 'className') element.className = val;
      else if (key === 'textContent') element.textContent = val;
      else if (key === 'innerHTML') element.innerHTML = val;
      else if (key.startsWith('on')) element.addEventListener(key.slice(2).toLowerCase(), val);
      else if (key === 'dataset') Object.assign(element.dataset, val);
      else element.setAttribute(key, val);
    }
    for (const child of children) {
      if (typeof child === 'string') {
        element.appendChild(document.createTextNode(child));
      } else if (child) {
        element.appendChild(child);
      }
    }
    return element;
  }

  // --- Star rating HTML ---
  function starsHTML(rating, count = null) {
    const full = Math.floor(rating);
    const half = rating % 1 >= 0.5 ? 1 : 0;
    const empty = 5 - full - half;
    let html = '<span class="stars" aria-label="' + rating + ' out of 5 stars">';
    for (let i = 0; i < full; i++) html += '★';
    if (half) html += '★'; // simplified — half star shown as full
    for (let i = 0; i < empty; i++) html += '☆';
    if (count !== null) html += ` <span style="color:var(--gf-neutral-400)">(${count})</span>`;
    html += '</span>';
    return html;
  }

  // --- Debounce ---
  function debounce(fn, delay = 300) {
    let timer;
    return (...args) => {
      clearTimeout(timer);
      timer = setTimeout(() => fn(...args), delay);
    };
  }

  // --- Public API ---
  return {
    api,
    ApiError,
    setToken,
    getToken,
    isLoggedIn,
    toast,
    timeAgo,
    timeUntil,
    $, $$, el,
    starsHTML,
    debounce,
  };
})();