import time


class Snowflake:
    def __init__(self, datacenter_id, worker_id):
        self.sequence = 0
        self.last_timestamp = -1
        self.datacenter_id = datacenter_id
        self.worker_id = worker_id
        self.DATACENTER_ID_BITS = 5
        self.WORKER_ID_BITS = 5
        self.SEQUENCE_BITS = 12
        self.MAX_DATACENTER_ID = -1 ^ (-1 << self.DATACENTER_ID_BITS)
        self.MAX_WORKER_ID = -1 ^ (-1 << self.WORKER_ID_BITS)
        self.MAX_SEQUENCE = -1 ^ (-1 << self.SEQUENCE_BITS)
        self.DATA_CENTER_SHIFT = self.WORKER_ID_BITS + self.SEQUENCE_BITS
        self.WORKER_SHIFT = self.SEQUENCE_BITS
        self.TIMESTAMP_LEFT_SHIFT = self.DATACENTER_ID_BITS + self.WORKER_ID_BITS + self.SEQUENCE_BITS

    def generate_id(self):
        timestamp = int(time.time() * 1000)
        if timestamp < self.last_timestamp:
            raise Exception("Clock moved backwards. Refusing to generate id")
        if timestamp == self.last_timestamp:
            self.sequence = (self.sequence + 1) & self.MAX_SEQUENCE
            if self.sequence == 0:
                timestamp = self.wait_next_millis(self.last_timestamp)
        else:
            self.sequence = 0
        self.last_timestamp = timestamp
        return (
                (timestamp << self.TIMESTAMP_LEFT_SHIFT) |
                (self.datacenter_id << self.DATA_CENTER_SHIFT) |
                (self.worker_id << self.WORKER_SHIFT) |
                self.sequence
        )

    def wait_next_millis(self, last_timestamp):
        timestamp = int(time.time() * 1000)
        while timestamp <= last_timestamp:
            timestamp = int(time.time() * 1000)
        return timestamp


if __name__ == "__main__":
    # 假设数据中心ID为1，工作机器ID为1
    snowflake = Snowflake(231, 111)
    for _ in range(10):
        print(snowflake.generate_id())