package com.hao.chapter06;

import com.hao.chapter05.ClickSource;
import com.hao.chapter05.Event;
import org.apache.flink.api.common.eventtime.SerializableTimestampAssigner;
import org.apache.flink.api.common.eventtime.WatermarkStrategy;
import org.apache.flink.api.common.functions.AggregateFunction;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.windowing.ProcessWindowFunction;
import org.apache.flink.streaming.api.windowing.assigners.TumblingEventTimeWindows;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.streaming.api.windowing.windows.TimeWindow;
import org.apache.flink.util.Collector;

import java.sql.Timestamp;
import java.time.Duration;
import java.util.HashSet;

public class UvCountExample {
    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        env.setParallelism(1);
        // 读取数据，并提取时间戳、生成水位线
        DataStream<Event> stream = env.addSource(new ClickSource())
                .assignTimestampsAndWatermarks(WatermarkStrategy.<Event>forBoundedOutOfOrderness(Duration.ZERO)
                        .withTimestampAssigner(new SerializableTimestampAssigner<Event>() {
                            @Override
                            public long extractTimestamp(Event element, long recordTimestamp) {
                                return element.timestamp;
                            }
                        }));

        //使用AggregateFunction 和 ProcessWindowFunction结合计算UV
        stream.keyBy(data -> true)
                .window(TumblingEventTimeWindows.of(Time.seconds(5)))
                .aggregate(new UvAgg(), new UvCountResult())
                .print();

        stream.print("data");

        env.execute();
    }

    //自定义实现 AggregateFunction 增量聚合计算UV值
    public static class UvAgg implements AggregateFunction<Event, HashSet<String>, Long> {

        @Override
        public HashSet<String> createAccumulator() {
            return new HashSet<>();
        }

        @Override
        public HashSet<String> add(Event value, HashSet<String> accumulator) {
            accumulator.add(value.user);
            return accumulator;
        }

        @Override
        public Long getResult(HashSet<String> accumulator) {
            return (long) accumulator.size();
        }

        @Override
        public HashSet<String> merge(HashSet<String> a, HashSet<String> b) {
            return null;
        }
    }


    //自定义实现 ProcessWindowFunction 包装窗口信息输出
    public static class UvCountResult extends ProcessWindowFunction<Long, String, Boolean, TimeWindow> {

        @Override
        public void process(Boolean aBoolean, ProcessWindowFunction<Long, String, Boolean, TimeWindow>.Context context, Iterable<Long> elements, Collector<String> out) throws Exception {
            //获取UV信息
            Long uv = elements.iterator().next();
            //获取开始时间和结束时间
            Long start = context.window().getStart();
            Long end = context.window().getEnd();
            //打印
            out.collect("窗口 " + new Timestamp(start) + " ~ " + new Timestamp(end) + " UV值为:" + uv);
        }
    }
}