/**
 * AKSRT Mini Upload — 小型文件上传器
 *
 * 提供拖拽上传、进度显示、预览功能。
 * 用于前台投稿、商品编辑等需要文件上传的页面。
 *
 * @package AKSRT
 */

(function () {
  'use strict';

  /**
   * 初始化小型上传器
   *
   * @param {HTMLElement} container 上传器容器
   * @param {Object} options 配置项
   */
  function MiniUpload(container, options) {
    if (!container) return;

    this.options = Object.assign({
      maxFileSize: 5 * 1024 * 1024, // 5MB
      allowedTypes: ['image/jpeg', 'image/png', 'image/gif', 'image/webp'],
      multiple: false,
      uploadUrl: '',
      fieldName: 'file',
      nonce: '',
      onSelect: null,
      onSuccess: null,
      onError: null,
    }, options || {});

    this.container = container;
    this.files = [];
    this.init();
  }

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

    // 创建文件输入
    this.input = document.createElement('input');
    this.input.type = 'file';
    this.input.accept = this.options.allowedTypes.join(',');
    this.input.multiple = this.options.multiple;
    this.input.style.display = 'none';
    this.container.appendChild(this.input);

    // 创建拖拽区域
    this.dropzone = document.createElement('div');
    this.dropzone.className = 'aksrt-mini-upload__dropzone';
    this.dropzone.innerHTML =
      '<div class="aksrt-mini-upload__icon"><i class="fa fas fa-cloud-upload-alt"></i></div>' +
      '<div class="aksrt-mini-upload__text">点击或拖拽文件到此处上传</div>' +
      '<div class="aksrt-mini-upload__hint">支持 ' + this.options.allowedTypes.map(function (t) {
        return t.split('/')[1].toUpperCase();
      }).join(', ') + '，最大 ' + Math.round(this.options.maxFileSize / 1024 / 1024) + 'MB</div>';
    this.container.appendChild(this.dropzone);

    // 创建预览区域
    this.preview = document.createElement('div');
    this.preview.className = 'aksrt-mini-upload__preview';
    this.container.appendChild(this.preview);

    // 事件绑定
    this.dropzone.addEventListener('click', function () {
      self.input.click();
    });

    this.dropzone.addEventListener('dragover', function (e) {
      e.preventDefault();
      self.dropzone.classList.add('aksrt-mini-upload__dropzone--dragover');
    });

    this.dropzone.addEventListener('dragleave', function () {
      self.dropzone.classList.remove('aksrt-mini-upload__dropzone--dragover');
    });

    this.dropzone.addEventListener('drop', function (e) {
      e.preventDefault();
      self.dropzone.classList.remove('aksrt-mini-upload__dropzone--dragover');
      if (e.dataTransfer.files.length > 0) {
        self.handleFiles(e.dataTransfer.files);
      }
    });

    this.input.addEventListener('change', function () {
      if (self.input.files.length > 0) {
        self.handleFiles(self.input.files);
      }
    });
  };

  MiniUpload.prototype.handleFiles = function (fileList) {
    var self = this;
    var files = Array.prototype.slice.call(fileList);

    files.forEach(function (file) {
      // 验证文件类型
      if (self.options.allowedTypes.length > 0 && self.options.allowedTypes.indexOf(file.type) === -1) {
        self.showError('不支持的文件类型: ' + file.type);
        return;
      }

      // 验证文件大小
      if (file.size > self.options.maxFileSize) {
        self.showError('文件大小超过限制: ' + Math.round(file.size / 1024 / 1024) + 'MB');
        return;
      }

      self.files.push(file);
      self.addPreview(file);

      if (typeof self.options.onSelect === 'function') {
        self.options.onSelect(file);
      }

      // 如果有上传 URL，自动上传
      if (self.options.uploadUrl) {
        self.uploadFile(file);
      }
    });
  };

  MiniUpload.prototype.addPreview = function (file) {
    var self = this;
    var item = document.createElement('div');
    item.className = 'aksrt-mini-upload__item';

    if (file.type.startsWith('image/')) {
      var reader = new FileReader();
      reader.onload = function (e) {
        item.innerHTML =
          '<img src="' + e.target.result + '" class="aksrt-mini-upload__thumb">' +
          '<div class="aksrt-mini-upload__info">' +
          '<span class="aksrt-mini-upload__name">' + file.name + '</span>' +
          '<span class="aksrt-mini-upload__size">' + self.formatSize(file.size) + '</span>' +
          '</div>' +
          '<button type="button" class="aksrt-mini-upload__remove"><i class="fa fas fa-times"></i></button>' +
          '<div class="aksrt-mini-upload__progress"><div class="aksrt-mini-upload__progress-bar"></div></div>';
        self.bindRemove(item, file);
      };
      reader.readAsDataURL(file);
    } else {
      item.innerHTML =
        '<div class="aksrt-mini-upload__file-icon"><i class="fa fas fa-file"></i></div>' +
        '<div class="aksrt-mini-upload__info">' +
        '<span class="aksrt-mini-upload__name">' + file.name + '</span>' +
        '<span class="aksrt-mini-upload__size">' + self.formatSize(file.size) + '</span>' +
        '</div>' +
        '<button type="button" class="aksrt-mini-upload__remove"><i class="fa fas fa-times"></i></button>' +
        '<div class="aksrt-mini-upload__progress"><div class="aksrt-mini-upload__progress-bar"></div></div>';
      this.bindRemove(item, file);
    }

    this.preview.appendChild(item);
  };

  MiniUpload.prototype.bindRemove = function (item, file) {
    var self = this;
    var removeBtn = item.querySelector('.aksrt-mini-upload__remove');
    if (removeBtn) {
      removeBtn.addEventListener('click', function () {
        var index = self.files.indexOf(file);
        if (index > -1) self.files.splice(index, 1);
        item.remove();
      });
    }
  };

  MiniUpload.prototype.uploadFile = function (file) {
    var self = this;
    var formData = new FormData();
    formData.append(this.options.fieldName, file);

    if (this.options.nonce) {
      formData.append('_wpnonce', this.options.nonce);
    }

    var xhr = new XMLHttpRequest();
    xhr.open('POST', this.options.uploadUrl, true);

    // 进度更新
    var item = this.preview.lastElementChild;
    var progressBar = item ? item.querySelector('.aksrt-mini-upload__progress-bar') : null;

    xhr.upload.onprogress = function (e) {
      if (e.lengthComputable && progressBar) {
        var percent = Math.round((e.loaded / e.total) * 100);
        progressBar.style.width = percent + '%';
      }
    };

    xhr.onload = function () {
      if (xhr.status >= 200 && xhr.status < 300) {
        try {
          var response = JSON.parse(xhr.responseText);
          if (typeof self.options.onSuccess === 'function') {
            self.options.onSuccess(response, file);
          }
          if (item) item.classList.add('aksrt-mini-upload__item--success');
        } catch (e) {
          self.showError('上传响应解析失败');
        }
      } else {
        self.showError('上传失败: HTTP ' + xhr.status);
      }
    };

    xhr.onerror = function () {
      self.showError('网络错误，上传失败');
      if (item) item.classList.add('aksrt-mini-upload__item--error');
    };

    xhr.send(formData);
  };

  MiniUpload.prototype.showError = function (msg) {
    if (typeof this.options.onError === 'function') {
      this.options.onError(msg);
    }
    console.error('[AKSRT MiniUpload]', msg);
  };

  MiniUpload.prototype.formatSize = function (bytes) {
    if (bytes < 1024) return bytes + ' B';
    if (bytes < 1024 * 1024) return (bytes / 1024).toFixed(1) + ' KB';
    return (bytes / (1024 * 1024)).toFixed(1) + ' MB';
  };

  MiniUpload.prototype.getFiles = function () {
    return this.files;
  };

  MiniUpload.prototype.clear = function () {
    this.files = [];
    this.preview.innerHTML = '';
    this.input.value = '';
  };

  /**
   * 分片上传大文件
   * @param {File} file - 要上传的文件
   * @param {Object} opts - { chunkSize, uploadUrl, fieldName, nonce, onProgress, onComplete, onError }
   */
  MiniUpload.prototype.uploadChunked = function (file, opts) {
    var chunkSize = (opts.chunkSize || 2) * 1024 * 1024; // default 2MB
    var totalChunks = Math.ceil(file.size / chunkSize);
    var currentChunk = 0;
    var fileId = file.name + '-' + file.size + '-' + file.lastModified;

    function uploadNext() {
      if (currentChunk >= totalChunks) {
        if (opts.onComplete) opts.onComplete({ fileId: fileId, totalChunks: totalChunks });
        return;
      }

      var start = currentChunk * chunkSize;
      var end = Math.min(start + chunkSize, file.size);
      var blob = file.slice(start, end);

      var formData = new FormData();
      formData.append(opts.fieldName || 'file', blob, file.name);
      formData.append('chunk', currentChunk);
      formData.append('total_chunks', totalChunks);
      formData.append('file_id', fileId);
      formData.append('file_name', file.name);
      formData.append('file_size', file.size);
      if (opts.nonce) formData.append('_ajax_nonce', opts.nonce);

      var xhr = new XMLHttpRequest();
      xhr.open('POST', opts.uploadUrl, true);

      xhr.upload.onprogress = function (e) {
        if (e.lengthComputable && opts.onProgress) {
          var chunkProgress = e.loaded / e.total;
          var totalProgress = (currentChunk + chunkProgress) / totalChunks;
          opts.onProgress(totalProgress, currentChunk, totalChunks);
        }
      };

      xhr.onload = function () {
        if (xhr.status >= 200 && xhr.status < 300) {
          currentChunk++;
          uploadNext();
        } else {
          if (opts.onError) opts.onError('上传失败: HTTP ' + xhr.status);
        }
      };

      xhr.onerror = function () {
        if (opts.onError) opts.onError('网络错误');
      };

      xhr.send(formData);
    }

    uploadNext();
  };

  /**
   * 快速文件标识（替代 spark-md5，用文件名+大小+最后修改时间生成简易 hash）
   */
  MiniUpload.prototype.getFileId = function (file) {
    return file.name + '-' + file.size + '-' + file.lastModified;
  };

  // 自动初始化
  function autoInit(root) {
    var containers = [];
    if (root && root.nodeType === 1 && root.matches('[data-aksrt-mini-upload]')) containers.push(root);
    Array.prototype.push.apply(containers, (root || document).querySelectorAll('[data-aksrt-mini-upload]'));
    containers.forEach(function (el) {
      if (el.dataset.miniUploadInit) return;
      el.dataset.miniUploadInit = '1';

      var options = {};
      try {
        options = JSON.parse(el.dataset.aksrtMiniUpload || '{}');
      } catch (e) {}

      new MiniUpload(el, options);
    });
  }

  window.AksrtFrontend.register('aksrt-mini-upload', autoInit);

  // 暴露到全局
  window.AksrtMiniUpload = MiniUpload;
})();