/**
 * AKSRT Page Edit — 前台编辑增强
 *
 * 提供前台编辑页面的增强功能：
 * - 自动保存草稿
 * - 字数统计
 * - 标签建议
 * - 快捷键支持
 *
 * @package AKSRT
 */

(function () {
  'use strict';

  var DRAFT_KEY_PREFIX = 'aksrt_draft_';

  /**
   * 初始化页面编辑增强
   *
   * @param {Object} options 配置项
   */
  function PageEdit(options) {
    this.options = Object.assign({
      formSelector: 'form[data-aksrt-edit]',
      titleSelector: 'input[name="title"], input[name="topic_title"]',
      contentSelector: 'textarea[name="content"], textarea[name="topic_content"]',
      tagsSelector: 'input[name="tags"], input[name="topic_tags"]',
      autoSaveInterval: 30000, // 30秒
      maxTitleLength: 200,
      maxContentLength: 100000,
      draftKey: '',
    }, options || {});

    this.form = document.querySelector(this.options.formSelector);
    if (!this.form) return;

    this.autoSaveTimer = null;
    this.lastSavedContent = '';
    this.init();
  }

  PageEdit.prototype.init = function () {
    var self = this;

    this.titleInput = this.form.querySelector(this.options.titleSelector);
    this.contentTextarea = this.form.querySelector(this.options.contentSelector);
    this.tagsInput = this.form.querySelector(this.options.tagsSelector);

    // 字数统计
    this.initWordCount();

    // 自动保存草稿
    this.initAutoSave();

    // 快捷键
    this.initShortcuts();

    // 标签输入增强
    this.initTagInput();

    // 表单提交时清除草稿
    this.form.addEventListener('submit', function () {
      self.clearDraft();
    });

    // 页面离开提醒
    window.addEventListener('beforeunload', function (e) {
      if (self.hasUnsavedChanges()) {
        e.preventDefault();
        e.returnValue = '您有未保存的修改，确定要离开吗？';
      }
    });
  };

  PageEdit.prototype.initWordCount = function () {
    var self = this;

    // 创建字数统计显示
    this.wordCountEl = document.createElement('div');
    this.wordCountEl.className = 'aksrt-page-edit__word-count';

    if (this.titleInput) {
      var titleCount = document.createElement('span');
      titleCount.className = 'aksrt-page-edit__title-count';
      this.titleInput.parentNode.appendChild(titleCount);

      this.titleInput.addEventListener('input', function () {
        var len = self.titleInput.value.length;
        titleCount.textContent = len + '/' + self.options.maxTitleLength;
        titleCount.classList.toggle('aksrt-page-edit__count--warn', len > self.options.maxTitleLength * 0.9);
        titleCount.classList.toggle('aksrt-page-edit__count--error', len > self.options.maxTitleLength);
      });
    }

    if (this.contentTextarea) {
      this.contentTextarea.parentNode.appendChild(this.wordCountEl);
      this.updateWordCount();

      this.contentTextarea.addEventListener('input', function () {
        self.updateWordCount();
      });
    }
  };

  PageEdit.prototype.updateWordCount = function () {
    if (!this.contentTextarea || !this.wordCountEl) return;

    var text = this.contentTextarea.value;
    var chars = text.length;
    var words = text.trim() ? text.trim().split(/\s+/).length : 0;
    var chinese = (text.match(/[一-鿿]/g) || []).length;

    this.wordCountEl.textContent = '字数: ' + chars + ' | 词数: ' + words + ' | 中文: ' + chinese;
    this.wordCountEl.classList.toggle('aksrt-page-edit__count--warn', chars > this.options.maxContentLength * 0.9);
    this.wordCountEl.classList.toggle('aksrt-page-edit__count--error', chars > this.options.maxContentLength);
  };

  PageEdit.prototype.initAutoSave = function () {
    var self = this;

    if (!this.options.draftKey) {
      // 从页面 URL 生成 draft key
      this.options.draftKey = DRAFT_KEY_PREFIX + (window.location.pathname.replace(/\//g, '_') || 'page');
    }

    // 恢复草稿
    this.restoreDraft();

    // 定时自动保存
    if (this.options.autoSaveInterval > 0) {
      this.autoSaveTimer = setInterval(function () {
        self.saveDraft();
      }, this.options.autoSaveInterval);
    }
  };

  PageEdit.prototype.saveDraft = function () {
    if (!this.form) return;

    var data = {};
    if (this.titleInput) data.title = this.titleInput.value;
    if (this.contentTextarea) data.content = this.contentTextarea.value;
    if (this.tagsInput) data.tags = this.tagsInput.value;

    var content = JSON.stringify(data);
    if (content === this.lastSavedContent) return;

    try {
      localStorage.setItem(this.options.draftKey, content);
      this.lastSavedContent = content;

      // 显示保存提示
      var toast = document.getElementById('aksrt-draft-toast');
      if (!toast) {
        toast = document.createElement('div');
        toast.id = 'aksrt-draft-toast';
        toast.className = 'aksrt-page-edit__toast';
        document.body.appendChild(toast);
      }
      toast.textContent = '草稿已自动保存';
      toast.classList.add('aksrt-page-edit__toast--visible');
      setTimeout(function () {
        toast.classList.remove('aksrt-page-edit__toast--visible');
      }, 2000);
    } catch (e) {
      console.error('[AKSRT PageEdit] 保存草稿失败:', e);
    }
  };

  PageEdit.prototype.restoreDraft = function () {
    try {
      var saved = localStorage.getItem(this.options.draftKey);
      if (!saved) return;

      var data = JSON.parse(saved);
      var hasContent = false;

      if (this.titleInput && data.title && !this.titleInput.value) {
        this.titleInput.value = data.title;
        hasContent = true;
      }
      if (this.contentTextarea && data.content && !this.contentTextarea.value) {
        this.contentTextarea.value = data.content;
        hasContent = true;
      }
      if (this.tagsInput && data.tags && !this.tagsInput.value) {
        this.tagsInput.value = data.tags;
        hasContent = true;
      }

      if (hasContent) {
        this.lastSavedContent = saved;
      }
    } catch (e) {
      console.error('[AKSRT PageEdit] 恢复草稿失败:', e);
    }
  };

  PageEdit.prototype.clearDraft = function () {
    try {
      localStorage.removeItem(this.options.draftKey);
    } catch (e) {}
  };

  PageEdit.prototype.hasUnsavedChanges = function () {
    if (!this.form) return false;

    var data = {};
    if (this.titleInput) data.title = this.titleInput.value;
    if (this.contentTextarea) data.content = this.contentTextarea.value;
    if (this.tagsInput) data.tags = this.tagsInput.value;

    return JSON.stringify(data) !== this.lastSavedContent;
  };

  PageEdit.prototype.initShortcuts = function () {
    var self = this;

    this.form.addEventListener('keydown', function (e) {
      // Ctrl+S / Cmd+S 保存草稿
      if ((e.ctrlKey || e.metaKey) && e.key === 's') {
        e.preventDefault();
        self.saveDraft();
      }
    });
  };

  PageEdit.prototype.initTagInput = function () {
    if (!this.tagsInput) return;

    // 回车键添加标签
    this.tagsInput.addEventListener('keydown', function (e) {
      if (e.key === 'Enter') {
        e.preventDefault();
      }
    });
  };

  // 自动初始化
  function autoInit() {
    var form = document.querySelector('form[data-aksrt-edit]');
    if (form) {
      new PageEdit();
    }
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', autoInit);
  } else {
    autoInit();
  }

  window.AksrtPageEdit = PageEdit;
})();