const crypto = require('crypto');
const {
  getPool,
  query,
  resolveUser,
} = require('./aiBuyerShowService');
const { uploadBufferToDefaultS3 } = require('./objectStorage');

const SEED_PACK_TABLE = 'pdd_seed_resource_packs';
const MAX_SEED_PACK_FILE_BYTES = 200 * 1024 * 1024;

let tableReady = false;

function normalizeString(value) {
  return String(value || '').trim();
}

function normalizeNullableString(value) {
  const text = normalizeString(value);
  return text || null;
}

// multer/busboy may decode multipart filenames as latin1, garbling non-ASCII
// names; re-encode to recover the original UTF-8 text.
function normalizeUploadFileName(value) {
  const text = normalizeString(value);
  if (!text) return '';
  try {
    const decoded = Buffer.from(text, 'latin1').toString('utf8');
    return /[\uFFFD]/.test(decoded) ? text : decoded;
  } catch (_) {
    return text;
  }
}

async function ensureSeedPackTable() {
  if (tableReady) return;
  await query(
    `CREATE TABLE IF NOT EXISTS ${SEED_PACK_TABLE} (
      id BIGINT PRIMARY KEY AUTO_INCREMENT COMMENT '资源包ID',
      pack_uid VARCHAR(64) NOT NULL COMMENT '资源包唯一标识',
      shop_name VARCHAR(128) NOT NULL COMMENT '店铺名称',
      product_id VARCHAR(64) NOT NULL COMMENT '商品ID',
      sku_name VARCHAR(255) NULL COMMENT 'SKU名称',
      file_name VARCHAR(255) NOT NULL COMMENT 'ZIP文件名',
      file_size BIGINT NOT NULL DEFAULT 0 COMMENT '文件大小(字节)',
      object_key VARCHAR(512) NOT NULL COMMENT '对象存储Key',
      file_url VARCHAR(1024) NULL COMMENT '公开下载地址',
      review_count INT NOT NULL DEFAULT 0 COMMENT '包含评价条数',
      operator_id VARCHAR(64) NULL COMMENT '上传人ID',
      operator_name VARCHAR(128) NOT NULL DEFAULT '' COMMENT '上传人',
      download_count INT NOT NULL DEFAULT 0 COMMENT '下载次数',
      created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '上传时间',
      updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间',
      UNIQUE KEY uk_pack_uid (pack_uid),
      KEY idx_seed_pack_shop (shop_name),
      KEY idx_seed_pack_product (product_id),
      KEY idx_seed_pack_created (created_at)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='种菜资源包'`
  );
  tableReady = true;
}

function normalizePackRow(row = {}) {
  return {
    id: Number(row.id),
    packUid: row.pack_uid ?? row.packUid ?? '',
    shopName: row.shop_name ?? row.shopName ?? '',
    productId: row.product_id ?? row.productId ?? '',
    skuName: row.sku_name ?? row.skuName ?? '',
    fileName: row.file_name ?? row.fileName ?? '',
    fileSize: Number(row.file_size ?? row.fileSize ?? 0),
    fileUrl: row.file_url ?? row.fileUrl ?? '',
    reviewCount: Number(row.review_count ?? row.reviewCount ?? 0),
    operatorName: row.operator_name ?? row.operatorName ?? '',
    downloadCount: Number(row.download_count ?? row.downloadCount ?? 0),
    createdAt: row.created_at || null,
  };
}

function validateSeedPackInput({ shopName, productId, file }) {
  if (!normalizeString(shopName)) {
    const error = new Error('店铺名称不能为空');
    error.statusCode = 400;
    return error;
  }
  if (!normalizeString(productId)) {
    const error = new Error('商品ID不能为空');
    error.statusCode = 400;
    return error;
  }
  if (!file?.buffer || !file.buffer.length) {
    const error = new Error('ZIP 文件不能为空');
    error.statusCode = 400;
    return error;
  }
  if (file.buffer.length > MAX_SEED_PACK_FILE_BYTES) {
    const error = new Error('ZIP 文件不能超过 200MB');
    error.statusCode = 413;
    return error;
  }
  return null;
}

async function createSeedPack({ shopName, productId, skuName, fileName, reviewCount, file }, user = {}) {
  await ensureSeedPackTable();
  const operator = resolveUser(user);
  const validationError = validateSeedPackInput({ shopName, productId, file });
  if (validationError) throw validationError;

  const uploaded = await uploadBufferToDefaultS3(
    file.buffer,
    'application/zip',
    'seed-packs',
    'zip'
  );

  const resolvedFileName = normalizeString(fileName)
    || normalizeUploadFileName(file?.originalname)
    || `种菜资源包_${Date.now()}.zip`;

  const packUid = crypto.randomUUID();
  const insertRows = await query(
    `INSERT INTO ${SEED_PACK_TABLE} (
       pack_uid, shop_name, product_id, sku_name, file_name, file_size,
       object_key, file_url, review_count, operator_id, operator_name
     ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
    [
      packUid,
      normalizeString(shopName).slice(0, 128),
      normalizeString(productId).slice(0, 64),
      normalizeNullableString(String(skuName || '').slice(0, 255)),
      resolvedFileName.slice(0, 255),
      file.buffer.length,
      uploaded.key,
      uploaded.url || '',
      Math.max(Number(reviewCount) || 0, 0),
      operator.id || null,
      operator.name,
    ]
  );

  const rows = await query(
    `SELECT * FROM ${SEED_PACK_TABLE} WHERE id = ? LIMIT 1`,
    [insertRows.insertId]
  );
  return normalizePackRow(rows[0]);
}

async function listSeedPacks({ page = 1, pageSize = 15, keyword = '' } = {}) {
  await ensureSeedPackTable();
  const normalizedPage = Math.max(Number(page) || 1, 1);
  const normalizedPageSize = Math.min(Math.max(Number(pageSize) || 15, 1), 100);
  const offset = (normalizedPage - 1) * normalizedPageSize;
  const normalizedKeyword = normalizeString(keyword);
  const likeKeyword = `%${normalizedKeyword}%`;
  const whereSql = normalizedKeyword
    ? 'WHERE shop_name LIKE ? OR product_id LIKE ? OR sku_name LIKE ? OR operator_name LIKE ? OR file_name LIKE ?'
    : '';
  const params = normalizedKeyword ? Array(5).fill(likeKeyword) : [];

  const countRows = await query(
    `SELECT COUNT(*) AS total FROM ${SEED_PACK_TABLE} ${whereSql}`,
    params
  );
  const rows = await query(
    `SELECT * FROM ${SEED_PACK_TABLE}
     ${whereSql}
     ORDER BY id DESC
     LIMIT ? OFFSET ?`,
    [...params, normalizedPageSize, offset]
  );

  return {
    rows: rows.map(normalizePackRow),
    total: Number(countRows[0]?.total || 0),
    page: normalizedPage,
    pageSize: normalizedPageSize,
  };
}

async function getSeedPackDownload(id) {
  await ensureSeedPackTable();
  const packId = Number(id);
  if (!Number.isFinite(packId) || packId <= 0) {
    const error = new Error('资源包不存在');
    error.statusCode = 404;
    throw error;
  }
  const rows = await query(
    `SELECT * FROM ${SEED_PACK_TABLE} WHERE id = ? LIMIT 1`,
    [packId]
  );
  const pack = rows[0];
  if (!pack) {
    const error = new Error('资源包不存在');
    error.statusCode = 404;
    throw error;
  }
  await query(
    `UPDATE ${SEED_PACK_TABLE} SET download_count = download_count + 1 WHERE id = ?`,
    [packId]
  );
  return {
    ...normalizePackRow(pack),
    downloadCount: Number(pack.downloadCount || 0) + 1,
  };
}

async function deleteSeedPack(id) {
  await ensureSeedPackTable();
  const packId = Number(id);
  if (!Number.isFinite(packId) || packId <= 0) {
    const error = new Error('资源包不存在');
    error.statusCode = 404;
    throw error;
  }
  const rows = await query(
    `SELECT id FROM ${SEED_PACK_TABLE} WHERE id = ? LIMIT 1`,
    [packId]
  );
  if (!rows.length) {
    const error = new Error('资源包不存在');
    error.statusCode = 404;
    throw error;
  }
  await query(`DELETE FROM ${SEED_PACK_TABLE} WHERE id = ?`, [packId]);
  return { id: packId };
}

module.exports = {
  createSeedPack,
  deleteSeedPack,
  getSeedPackDownload,
  listSeedPacks,
  MAX_SEED_PACK_FILE_BYTES,
};