#!/usr/bin/env python3
"""
时间片轮转调度算法 (RR)
Round Robin
"""

from collections import deque
from typing import List, Dict

from base import (
    Process,
    ProcessScheduler,
    generate_random_processes,
    print_processes
)


class RoundRobinScheduler(ProcessScheduler):
    """时间片轮转调度 (Round Robin)"""
    
    def __init__(self, processes: List[Process], time_slice: int = 4):
        super().__init__(processes)
        self.time_slice = time_slice
    
    def schedule(self) -> Dict:
        """RR 调度算法"""
        processes = sorted(self.processes, key=lambda p: p.arrival_time)
        ready_queue = deque()
        current_time = 0
        completed = 0
        index = 0
        
        while completed < len(processes):
            while index < len(processes) and processes[index].arrival_time <= current_time:
                ready_queue.append(processes[index])
                index += 1
            
            if ready_queue:
                p = ready_queue.popleft()
                
                if p.start_time == -1:
                    p.start_time = current_time
                
                exec_time = min(self.time_slice, p.remaining_time)
                p.remaining_time -= exec_time
                current_time += exec_time
                
                while index < len(processes) and processes[index].arrival_time <= current_time:
                    ready_queue.append(processes[index])
                    index += 1
                
                if p.remaining_time > 0:
                    ready_queue.append(p)
                else:
                    self.calculate_metrics(p, current_time)
                    self.results.append(p)
                    completed += 1
            else:
                current_time += 1
        
        return self.print_results(f"RR (时间片轮转, time_slice={self.time_slice})")


if __name__ == "__main__":
    processes = generate_random_processes(n=5, seed=42)
    print_processes(processes, "测试数据")
    
    for ts in [2, 4, 8]:
        print("\n" + "="*60)
        print(f"时间片轮转 (time_slice={ts})")
        print("="*60)
        scheduler = RoundRobinScheduler(processes, time_slice=ts)
        scheduler.schedule()