'use strict';

var _helpers = require('./helpers');

var _helpers2 = _interopRequireDefault(_helpers);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/**
 * Base Database Driver
 *
 * @module driver
 */
var d = {
	identifierStartChar: '"',
	identifierEndChar: '"',
	tablePrefix: null,
	hasTruncate: true,

	/**
  * Low level function for naive quoting of strings
 	 * @param {String} str
  * @return {String}
  * @private
  */
	_quote: function _quote(str) {
		return _helpers2.default.isString(str) && !(str.startsWith(d.identifierStartChar) || str.endsWith(d.identifierEndChar)) ? d.identifierStartChar + str + d.identifierEndChar : str;
	},

	/**
  * Set the limit clause
 	 * @param {String} sql
  * @param {Number} limit
  * @param {Number|null} offset
  * @return {String}
  */
	limit: function limit(sql, _limit, offset) {
		sql += " LIMIT " + _limit;

		if (_helpers2.default.isNumber(offset)) {
			sql += " OFFSET " + offset;
		}

		return sql;
	},

	/**
  * Quote database table name, and set prefix
  *
  * @param {String} table
  * @return {String}
  */
	quoteTable: function quoteTable(table) {
		// Quote after prefix
		return d.quoteIdentifiers(table);
	},

	/**
  * Use the driver's escape character to quote identifiers
  *
  * @param {String|Array}
  * @return {String|Array}
  */
	quoteIdentifiers: function quoteIdentifiers(str) {
		var hiers, raw;
		var pattern = new RegExp(d.identifierStartChar + '(' + '([a-zA-Z0-9_]+)' + '(\((.*?)\))' + ')' + d.identifierEndChar, 'ig');

		// Recurse for arrays of identifiiers
		if (Array.isArray(str)) {
			return str.map(d.quoteIdentifiers);
		}

		// Handle commas
		if (str.includes(',')) {
			var parts = str.split(',').map(_helpers2.default.stringTrim);
			str = parts.map(d.quoteIdentifiers).join(',');
		}

		// Split identifiers by period
		hiers = str.split('.').map(d._quote);
		raw = hiers.join('.');

		// Fix functions
		if (raw.includes('(') && raw.includes(')')) {
			var funcs = pattern.exec(raw);

			// Unquote the function
			raw = raw.replace(funcs[0], funcs[1]);

			// Quote the identifiers inside of the parens
			var inParens = funcs[3].substring(1, funcs[3].length - 1);
			raw = raw.replace(inParens, d.quoteIdentifiers(inParens));
		}

		return raw;
	},

	/**
  * SQL to truncate the passed table
  *
  * @param {String} table
  * @return {String} - sql
  */
	truncate: function truncate(table) {
		var sql = d.hasTruncate ? 'TRUNCATE ' : 'DELETE FROM ';

		sql += d.quoteTable(table);

		return sql;
	},

	/**
  * SQL to insert a group of rows
  *
  * @param {String} table - The table to insert to
  * @param {Array} [data] - The array of object containing data to insert
  * @return {String}
  */
	insertBatch: function insertBatch(table, data) {
		var vals = [],
		    fields = Object.keys(data[0]),
		    sql = "",
		    params = [],
		    paramString = "",
		    paramList = [];

		// Get the data values to insert, so they can
		// be parameterized
		data.forEach(function (obj) {
			Object.keys(obj).forEach(function (key) {
				vals.push(obj[key]);
			});
		});

		// Get the field names from the keys of the first
		// object inserted
		table = d.quoteTable(table);

		sql += "INSERT INTO " + table + " (" + d.quoteIdentifiers(fields).join(",") + ") VALUES ";

		// Create placeholder groups
		params = Array(fields.length).fill('?');
		paramString = "(" + params.join(',') + ")";
		paramList = Array(data.length).fill(paramString);

		sql += paramList.join(',');

		return {
			sql: sql,
			values: vals
		};
	}

};

module.exports = d;
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