#!/usr/bin/env python3
"""
多级反馈队列调度算法 (MLFQ)
Multilevel Feedback Queue
"""

from collections import deque
from typing import List, Dict

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


class MLFQScheduler(ProcessScheduler):
    """多级反馈队列调度 (Multilevel Feedback Queue)"""
    
    def __init__(self, processes: List[Process], queues: List[int] = None):
        super().__init__(processes)
        # 每层队列的时间片大小
        self.queues = queues or [4, 8, 16]
        self.aging_time = 50
    
    def schedule(self) -> Dict:
        """MLFQ 调度算法"""
        processes = sorted(self.processes, key=lambda p: p.arrival_time)
        
        queues = [deque() for _ in self.queues]
        current_time = 0
        completed = 0
        index = 0
        
        while completed < len(processes):
            while index < len(processes) and processes[index].arrival_time <= current_time:
                queues[0].append(processes[index])
                index += 1
            
            # 老化
            for i in range(1, len(queues)):
                for p in list(queues[i]):
                    wait_time = current_time - p.arrival_time - (p.burst_time - p.remaining_time)
                    if wait_time > self.aging_time:
                        queues[i].remove(p)
                        queues[max(0, i-1)].append(p)
            
            queue_idx = -1
            for i in range(len(queues)):
                if queues[i]:
                    queue_idx = i
                    break
            
            if queue_idx >= 0:
                p = queues[queue_idx].popleft()
                
                if p.start_time == -1:
                    p.start_time = current_time
                
                exec_time = min(self.queues[queue_idx], p.remaining_time)
                p.remaining_time -= exec_time
                current_time += exec_time
                
                while index < len(processes) and processes[index].arrival_time <= current_time:
                    queues[0].append(processes[index])
                    index += 1
                
                if p.remaining_time > 0:
                    if queue_idx < len(queues) - 1:
                        queues[queue_idx + 1].append(p)
                    else:
                        queues[queue_idx].append(p)
                else:
                    self.calculate_metrics(p, current_time)
                    self.results.append(p)
                    completed += 1
            else:
                current_time += 1
        
        return self.print_results(f"MLFQ (多级反馈队列, 队列时间片={self.queues})")


if __name__ == "__main__":
    processes = generate_random_processes(n=5, seed=42)
    print_processes(processes, "测试数据")
    
    print("\n" + "="*60)
    print("多级反馈队列调度 (默认配置)")
    print("="*60)
    scheduler1 = MLFQScheduler(processes)
    scheduler1.schedule()
    
    print("\n" + "="*60)
    print("多级反馈队列调度 (自定义配置 [2, 5, 10])")
    print("="*60)
    scheduler2 = MLFQScheduler(processes, queues=[2, 5, 10])
    scheduler2.schedule()