#include <stdio.h>
#include <string.h>

#define MAX_PROC 10   //最多模拟10个进程，可按需改大

//进程状态枚举
typedef enum {
    READY,
    RUNNING,
    FINISHED
} ProcStatus;

//进程控制块PCB结构体
typedef struct {
    int pid;
    char name[20];
    int run_time;
    ProcStatus status;
} Process;

Process procList[MAX_PROC];
int procCount = 0;       //当前存在的进程数目
int globalCounter = 0;   //临界共享计数器
int nextPid = 1;

//状态转中文字符串
const char* getStatusStr(ProcStatus s)
{
    switch(s)
    {
        case READY: return "就绪";
        case RUNNING: return "运行";
        case FINISHED: return "结束";
        default: return "未知";
    }
}

//1. 添加进程
void addProcess()
{
    if(procCount >= MAX_PROC)
    {
        printf("❌ 进程数量已达上限，无法新增\n");
        return;
    }
    Process p;
    p.pid = nextPid++;
    printf("请输入进程名称：");
    scanf("%s", p.name);
    printf("请输入模拟运行时长(整数)：");
    scanf("%d", &p.run_time);
    p.status = READY;

    procList[procCount++] = p;
    printf("✅ 进程添加成功，PID=%d\n", p.pid);
}

//2. 打印全部进程列表
void printAllProcess()
{
    int i;
    printf("\n==================== 进程列表 ====================\n");
    printf("%-8s%-12s%-12s%-10s\n", "PID", "进程名", "运行时长", "状态");
    printf("---------------------------------------------------\n");
    for(i = 0; i < procCount; i++)
    {
        printf("%-8d%-12s%-12d%-10s\n",
               procList[i].pid,
               procList[i].name,
               procList[i].run_time,
               getStatusStr(procList[i].status));
    }
    printf("===================================================\n\n");
}

//3. 删除指定PID进程
void delProcess()
{
    int pid, i, j;
    printf("输入要删除的进程PID：");
    scanf("%d", &pid);
    for(i = 0; i < procCount; i++)
    {
        if(procList[i].pid == pid)
        {
            //后面元素前移覆盖，完成删除
            for(j = i; j < procCount - 1; j++)
            {
                procList[j] = procList[j+1];
            }
            procCount--;
            printf("✅ PID=%d 已删除\n", pid);
            return;
        }
    }
    printf("❌ 找不到该PID进程\n");
}

//4. FCFS先来先服务调度 + 临界资源模拟
void fcfsSchedule()
{
    int i;
    printf("\n---------- 开始 FCFS 先来先服务调度 ----------\n");
    for(i = 0; i < procCount; i++)
    {
        if(procList[i].status != READY)
            continue;

        procList[i].status = RUNNING;
        printf("[调度日志] PID:%d(%s) 进入运行状态\n", procList[i].pid, procList[i].name);
        printf("[调度日志] PID:%d 模拟运行，运行时长=%d\n", procList[i].pid, procList[i].run_time);

        //临界区
        printf("[临界区] PID:%d 进入临界区，准备修改共享计数器\n", procList[i].pid);
        globalCounter += procList[i].run_time;
        printf("[临界区] PID:%d 修改共享计数器，计数器当前值 = %d\n", procList[i].pid, globalCounter);
        printf("[临界区] PID:%d 离开临界区\n", procList[i].pid);

        procList[i].status = FINISHED;
        printf("[调度日志] PID:%d 运行完成，状态变为【结束】\n\n", procList[i].pid);
    }
    printf("---------- FCFS调度全部就绪进程执行完毕 ----------\n");
    printf("调度结束后共享计数器最终值：%d\n\n", globalCounter);
}

//5. 拓展加分：打印就绪队列
void printReadyQueue()
{
    int i;
    printf("\n-------- 就绪队列(加分功能) --------\n");
    int hasReady = 0;
    for(i = 0; i < procCount; i++)
    {
        if(procList[i].status == READY)
        {
            printf("PID:%d  %s\n", procList[i].pid, procList[i].name);
            hasReady = 1;
        }
    }
    if(!hasReady)
        printf("就绪队列为空\n");
    printf("------------------------------------\n");
}

//菜单
void showMenu()
{
    printf("======== 简易进程管理模拟器(C语言) ========\n");
    printf("1. 添加模拟进程\n");
    printf("2. 打印全部进程列表\n");
    printf("3. 删除指定PID进程\n");
    printf("4. FCFS先来先服务调度模拟(演示临界资源)\n");
    printf("5. 打印就绪队列【拓展加分】\n");
    printf("0. 退出程序\n");
    printf("==========================================\n");
    printf("请输入操作序号：");
}

int main()
{
    int op;
    while(1)
    {
        showMenu();
        scanf("%d", &op);
        switch(op)
        {
            case 1: addProcess(); break;
            case 2: printAllProcess(); break;
            case 3: delProcess(); break;
            case 4: fcfsSchedule(); break;
            case 5: printReadyQueue(); break;
            case 0:
                printf("程序退出。\n");
                return 0;
            default:
                printf("输入无效，请重新选择！\n");
        }
    }
    return 0;
}