const { format } = require('date-fns');
const config = require('../../config/app');
const models = require('../../models');

/**
 * 清理填色页标签数组。
 * 执行以下过滤操作：
 * 1. 去除重复的标签。
 * 2. 移除包含中文字符的标签。
 * 3. 移除以 "album" 开头的标签（不区分大小写）。
 * 4. 移除以数字开头的标签。
 *
 * @param {string[]} tags - 原始标签数组。
 * @returns {string[]} 过滤和去重后的标签数组。
 */
function cleanAndFilterTags(tags) {
    if (!Array.isArray(tags)) {
        console.warn("Input is not an array. Returning empty array.");
        return [];
    }

    // 1. 使用 Set 去除重复项，并转换为小写以进行后续统一比较
    const uniqueTags = new Set(tags.map(tag => typeof tag === 'string' ? tag.trim().toLowerCase() : ''));

    const filteredTags = [];

    // 正则表达式用于匹配中文字符
    const chineseRegex = /[\u4e00-\u9fa5]/; 
    // 正则表达式用于匹配数字开头
    const startsWithNumberRegex = /^[0-9]/;

    for (const tag of uniqueTags) {
        // 确保标签非空
        if (!tag) {
            continue;
        }

        // 2. 移除中文标签
        if (chineseRegex.test(tag)) {
            continue;
        }

        // 3. 移除以 "album" 开头的标签
        if (tag.startsWith('album')) { // 已经在转换为小写后，所以直接用'album'
            continue;
        }

        // 4. 移除以"ps_"开头的标签
        if (tag.startsWith('ps_') || tag.startsWith('dgt') || tag.startsWith('PS_')) {
          continue;
        }

        // 5. 移除以数字开头的标签
        if (startsWithNumberRegex.test(tag)) {
            continue;
        }

        filteredTags.push(tag);
    }

    return filteredTags;
}

function dateFormat(date) {
  return format(new Date(date), 'MMMM do, yyyy');
}

const organizeData = (data) => {
  data.forEach(doc => {
    let host = config.cdnHost ?? config.resHost;
    let publishVersion = doc.publishVersion || 0;
    let version = publishVersion + 1500;

    doc.thumb = `${host}/thumbs/coloring-page/page/480/${doc._id}.webp`;
    doc.work = `${host}/thumbs/coloring-page/work/480/${doc._id}.webp`;
    doc.zip = `${host}/zips/v2/number_mini/${version}/${doc._id}.zip`;

    if (doc.title) {
      try {
        let titleJson = JSON.parse(doc.title);
        doc.title = titleJson && titleJson['en'] ? titleJson['en'] : doc.name;
      } catch (e) {
        console.error(e.message);
      }
    } else {
      doc.title = doc.name;
    }

    doc.publishTime = format(new Date(doc.publishTime), 'MMMM do, yyyy');
    
    doc.tags = cleanAndFilterTags(doc.tags);

    doc.uri = `/coloring-page/${doc._id}`;

    delete doc.hasSpecial;
    delete doc.useSpecialThumb;
    delete doc.publishVersion;
    delete doc.desc;
  })
}


const organizeDetail = (doc) => {
  let host = config.cdnHost ?? config.resHost;
  let publishVersion = doc.publishVersion || 0;
  let version = publishVersion + 1500;

  doc.poster = `${host}/thumbs/coloring-page/page/640/${doc._id}.webp`;
  doc.thumb = `${host}/thumbs/coloring-page/page/480/${doc._id}.webp`;
  doc.work = `${host}/thumbs/coloring-page/work/480/${doc._id}.webp`;
  doc.zip = `${host}/zips/v2/number_mini/${version}/${doc._id}.zip`
  doc.user.avatar = `/thumbs/v1/avatar/128/${doc.user._id}.webp`;

  if (doc.title) {
    try {
      let titleJson = JSON.parse(doc.title);
      doc.title = titleJson && titleJson['en'] ? titleJson['en'] : doc.name;
    } catch (e) {
      console.error(e.message);
    }
  } else {
    doc.title = doc.name;
  }
  if (doc.desc) {
    try {
      let descJson = JSON.parse(doc.desc);
      doc.desc = descJson && descJson['en'] ? descJson['en'] : '';
    } catch (e) {
      console.error(e.message);
    }
  }
  if (doc.seoTitle) {
    try {
      let seoTitleJson = JSON.parse(doc.seoTitle);
      doc.seoTitle = seoTitleJson && seoTitleJson['en'] ? seoTitleJson['en'] : '';
    } catch (e) {
      console.error(e.message);
    }
  }
  if (doc.seoDescription) {
    try {
      let seoDescriptionJson = JSON.parse(doc.seoDescription);
      doc.seoDescription = seoDescriptionJson && seoDescriptionJson['en'] ? seoDescriptionJson['en'] : '';
    } catch (e) {
      console.error(e.message);
    }
  }

  doc.publishTime = format(new Date(doc.publishTime), 'MMMM do, yyyy');

  doc.tags = cleanAndFilterTags(doc.tags);

  doc.downlink = `${host}/thumbs/coloring-page/page/1200/${doc._id}.webp`;

  delete doc.hasSpecial;
  delete doc.useSpecialThumb;
  delete doc.publishVersion;
}

// 替换URI中的page参数
function replaceUriParams(uri, page) {
  if (!uri.includes('page=')) {
    if (uri.includes('?')) uri += `&page=${page}`;
    else uri += `?page=${page}`
  } else {
    // 使用正则表达式替换page参数
    uri = uri.replace(/(page=)\d+/, `page=${page}`);
  }

  if (page == 1) {
    uri = uri.replace(/(?:\?|&)((page)=\d+)/g, '');
  }

  // 返回替换后的URI
  return uri;
}

const userMap = {};
async function getUserIdByUsername(username) {
  let userId = userMap[username];
  if (!userId) {
    let doc = await models.User.findOne({ username });
    if (doc) {
      userId = doc._id;
      userMap[username] = userId;
    }
  }
  return userId;
}


module.exports = {
  organizeData,
  organizeDetail,
  replaceUriParams,
  getUserIdByUsername,
  dateFormat,
}