class RailsAdminContent::Client < Mysql2::Client

	Syntax = /limit\s+\d+,\d+|limit\s+\d+/
	Syntax_table = /from\s+(\w+)/

	cattr_accessor :query_str, :total_nums, :table_name

	def self.select_field(type)
		case type.gsub(/\(.*?\)/,'')
		when "tinyint" then [['等于', '='], ['不等于', '≠']]
		when "datetime" then [['等于', '='], ['不等于', '≠'], ['大于', '>'], ['小于','<']]
		when "int" then [['等于', '='], ['不等于', '≠'], ['大于', '>'], ['小于','<'], ['含有', 'IN']]
		else
			[['等于', '='], ['不等于', '≠'], ['包含', 'LIKE']]
		end
	end

	def self.conn
		@client ||= new ActiveRecord::Base.connection_config
	end

	alias :origin_query :query

	def self.query(query_sql, page=nil, stint=nil)
		self.table_name = query_sql.downcase.match(Syntax_table)[1] if query_sql.downcase.match(Syntax_table)
		self.total_nums = conn.origin_query(query_sql).size
		query_sql = limit(query_sql, page, stint) if stint && page
		query_sql = query_sql.gsub(/;/, '')
		conn.origin_query(query_sql)
	end

	def self.limit(query_sql, page=1, stint)
		page = page == 1 ? page = 0 : page.to_i*stint.to_i-stint.to_i
		query_sql.downcase.match(Syntax).present? ? query_sql.downcase.gsub(Syntax, "LIMIT #{page},#{stint}") : "#{query_sql} LIMIT #{page},#{stint}"
	end

	def self.get_tables
		@tables ? @tables : @tables = conn.origin_query('SHOW TABLES')
	end

	def self.compose(params)
		"SELECT * FROM #{params[:id]} WHERE #{params["field"].inject([]){|a, (key,value)| a << compose_key(params["calc"][key],key, value); a }.join('and')}"
	end

	def self.compose_key(calc,key,value)
		case calc
		when '=', '>', '<'
			" `#{key}` #{calc} '#{value}' "
		when 'IN'
			" `#{key}` IN (#{value}) "
		when '≠'
			" `#{key}`  != '#{value}' "
		when 'LIKE'
			" `#{key}` LIKE '%#{value}%' "
		when '≥'
			" `#{key}`  >= '#{value}' "
		when '≤'
			" `#{key}`  <= '#{value}' "
		end
	end


	def self.delete(table_name, ids)
		conn.origin_query("DELETE FROM #{table_name} WHERE id IN (#{ids.join(',')})") if ids.is_a?(Array)
	end

	def self.insert(table_name, field)
		conn.origin_query("INSERT INTO #{table_name} (#{field.keys.join(',')}) VALUES ('#{field.values.join("','")}')")
	end

	def self.update(table_name, id, fields)
		update_str = "UPDATE #{table_name} SET #{compose_update_sql(table_name, fields.to_a)}  WHERE id = #{id}"
		conn.origin_query update_str
	end

	def self.compose_update_sql(table_name,fields)
		columns = desc_table(table_name)
		fields.inject([]) do |array, field|
			columns.each do |column|
				if field[0] == column["Field"]
					array << (%w(int decimal tinyint).include?(column["Type"].gsub(/\(.*?\)/,'')) ? "#{field[0]} = #{field[1]}" : "#{field[0]} = REPLACE(REPLACE(REPLACE('#{field[1]}', '&','&amp;'), '>', '&gt;'), '<', '&lt;')")
				end
			end
			array
		end.join(',')
	end

	def self.desc_table(table_name)
		conn.origin_query("DESC #{table_name}").each
	end

	def self.show_create_sql(table_name)
		conn.origin_query("SHOW CREATE TABLE #{table_name}").each
	end


end