#include "errno.h"
#include "globals.h"

#include "test/proctest.h"
#include "test/usertest.h"

#include "util/debug.h"
#include "util/printf.h"
#include "util/string.h"

#include "proc/kthread.h"
#include "proc/proc.h"
#include "proc/sched.h"

/*
 * Set up a testing function for the process to execute. 
*/
void *test_func(long arg1, void *arg2)
{
    proc_t *proc_as_arg = (proc_t *)arg2;
    test_assert(arg1 == proc_as_arg->p_pid, "Arguments are not set up correctly");
    test_assert(proc_as_arg->p_state == PROC_RUNNING, "Process state is not running");
    test_assert(list_empty(&proc_as_arg->p_children), "There should be no child processes");
    dbg(DBG_TEST, "Process %s is running\n", proc_as_arg->p_name);
    return NULL;
}

void test_termination()
{
    int num_procs_created = 0;
    proc_t *new_proc1 = proc_create("proc test 1");
    kthread_t *new_kthread1 = kthread_create(new_proc1, test_func, 2, new_proc1);
    num_procs_created++;
    sched_make_runnable(new_kthread1);

    int count = 0;
    int status;
    while (do_waitpid(-1, &status, 0) != -ECHILD)
    {
        dbg(DBG_TEST, "Waiting for child process to terminate\n");
        test_assert(status == 0, "Returned status not set correctly");
        count++;
    }
    test_assert(count == num_procs_created,
                "Expected: %d, Actual: %d number of processes have been cleaned up\n", num_procs_created, count);
}

/*
    Tests the edge cases of do_waitpid.
    1. No child processes to wait for
    2. Waiting on a specific process id
    3. Waiting any child process (-1)
*/
void test_do_waitpid()
{
    int status;
    int ret = do_waitpid(-1, &status, 0);
    test_assert(ret == -ECHILD, "No child processes to wait for");

    proc_t *new_proc1 = proc_create("proc test 1");
    kthread_t *new_kthread1 = kthread_create(new_proc1, test_func, new_proc1->p_pid, new_proc1);
    sched_make_runnable(new_kthread1);

    proc_t *new_proc2 = proc_create("proc test 2");
    kthread_t *new_kthread2 = kthread_create(new_proc2, test_func, new_proc2->p_pid, new_proc2);
    sched_make_runnable(new_kthread2);

    proc_t *new_proc3 = proc_create("proc test 3");
    kthread_t *new_kthread3 = kthread_create(new_proc3, test_func, new_proc3->p_pid, new_proc3);
    sched_make_runnable(new_kthread3);

    // wait for a specific process id
    ret = do_waitpid(new_proc2->p_pid, &status, 0);
    test_assert(ret == new_proc2->p_pid, "Waiting for a specific process id");

    dbg(DBG_TEST, "Successfully removed proc 2 with pid: %d\n", new_proc2->p_pid);

    // wait for any child process
    ret = do_waitpid(-1, &status, 0);
    test_assert(ret == new_proc1->p_pid, "Waiting for any child process");
    dbg(DBG_TEST, "Successfully removed proc 1 with pid: %d\n", new_proc1->p_pid);
    ret = do_waitpid(-1, &status, 0);
    test_assert(ret == new_proc3->p_pid, "Waiting for any child process");
    dbg(DBG_TEST, "Successfully removed proc 3 with pid: %d\n", new_proc3->p_pid);

    ret = do_waitpid(-1, &status, 0);
    test_assert(ret == -ECHILD, "No child processes to wait for");
}
 
/*
    Tests proc_kill_all on a single process.
*/
void *test_func_kill(long arg1, void *arg2)
{
    // function to be called by the process
    proc_t *proc_as_arg = (proc_t *)arg2;
    test_assert(arg1 == proc_as_arg->p_pid, "Arguments are not set up correctly");
    test_assert(proc_as_arg->p_state == PROC_RUNNING, "Process state is not running");
    test_assert(list_empty(&proc_as_arg->p_children), "There should be no child processes");
    dbg(DBG_TEST, "Process with pid=%d is running and calling proc_kill_all\n", proc_as_arg->p_pid);
    proc_kill_all();
    return NULL;
}
void test_proc_kill_all()
{
    proc_t *new_proc_kill = proc_create("proc test kill");
    kthread_t *new_kthread_kill = kthread_create(new_proc_kill, test_func_kill, new_proc_kill->p_pid, new_proc_kill);
    sched_make_runnable(new_kthread_kill);

    proc_t *new_proc1 = proc_create("proc test 1");
    kthread_t *new_kthread1 = kthread_create(new_proc1, test_func, new_proc1->p_pid, new_proc1);
    sched_make_runnable(new_kthread1);

    proc_t *new_proc2 = proc_create("proc test 2");
    kthread_t *new_kthread2 = kthread_create(new_proc2, test_func, new_proc2->p_pid, new_proc2);
    sched_make_runnable(new_kthread2);

    // wait on the process that calls proc_kill_all
    int status;
    int ret = do_waitpid(new_proc_kill->p_pid, &status, 0);
    test_assert(ret == new_proc_kill->p_pid, "Waiting for a specific process id");
    dbg(DBG_TEST, "Successfully removed proc_kill with pid: %d\n", new_proc_kill->p_pid);

    // wait for all the threads to finish
    int count = 0;
    while (do_waitpid(-1, &status, 0) != -ECHILD)
    {
        dbg(DBG_TEST, "Waiting for child process to terminate\n");
        test_assert(status == 0, "Returned status not set correctly");
        count++;
    }
    test_assert(count == 2,
                "Expected: %d, Actual: %d number of processes have been cleaned up\n", 2, count);

}

/*
    Test to run several threads and processes concurrently. 
*/
void test_multiple()
{
    int num_procs_created = 0;
    proc_t *new_proc1 = proc_create("proc test 1");
    kthread_t *new_kthread1 = kthread_create(new_proc1, test_func, new_proc1->p_pid, new_proc1);
    num_procs_created++;
    sched_make_runnable(new_kthread1);

    proc_t *new_proc2 = proc_create("proc test 2");
    kthread_t *new_kthread2 = kthread_create(new_proc2, test_func, new_proc2->p_pid, new_proc2);
    num_procs_created++;
    sched_make_runnable(new_kthread2);

    proc_t *new_proc3 = proc_create("proc test 3");
    kthread_t *new_kthread3 = kthread_create(new_proc3, test_func, new_proc3->p_pid, new_proc3);
    num_procs_created++;
    sched_make_runnable(new_kthread3);

    // print all of the threads in the system
    list_iterate(&curproc->p_threads, thread, kthread_t, kt_plink)
    {
        dbg(DBG_THR, "Thread: %s\n", thread->kt_proc->p_name);
    }

    // wait for all the threads to finish
    int count = 0;
    int status;
    while (do_waitpid(-1, &status, 0) != -ECHILD)
    {
        dbg(DBG_TEST, "Waiting for child process to terminate\n");
        test_assert(status == 0, "Returned status not set correctly");
        count++;
    }
    test_assert(count == num_procs_created,
                "Expected: %d, Actual: %d number of processes have been cleaned up\n", num_procs_created, count);
}

/*
    Test that creates several child processes and forces them to terminate out of order.
    Then it checks to see if the processes are cleaned up correctly.
*/
void *func_forever_yielding(long arg1, void *arg2)
{
    // function that always just yields
    // goal is that it is cleaned up by a different process
    while (1)
    {
        // have a way to stop the thread
        int *to_stop = (int *)arg2;
        if (*to_stop)
        {
            dbg(DBG_TEST, "Thread with pid=%d is stopping yield loop\n", curproc->p_pid);
            do_exit(1); // return different status code
            break;
        }
        // wait a bit
        for (int i = 0; i < 1000000; i++)
        {
            ;
        }
        dbg(DBG_TEST, "Thread with pid=%d is yielding on it's parent\n", curproc->p_pid);
        sched_yield();
    }
    return NULL;
}
void test_out_of_order_termination()
{
    // create a yielding proc that will last for a long time
    proc_t *new_proc1 = proc_create("yieling proc 1");
    int stop_func_1 = 0;
    kthread_t *new_kthread1 = kthread_create(new_proc1, func_forever_yielding, new_proc1->p_pid, &stop_func_1);
    sched_make_runnable(new_kthread1);

    proc_t *new_proc2 = proc_create("yielding proc 2");
    int stop_func_2 = 0;
    kthread_t *new_kthread2 = kthread_create(new_proc2, func_forever_yielding, new_proc2->p_pid, &stop_func_2);
    sched_make_runnable(new_kthread2);

    proc_t *new_proc3 = proc_create("proc test 3");
    kthread_t *new_kthread3 = kthread_create(new_proc3, test_func, new_proc3->p_pid, new_proc3);
    sched_make_runnable(new_kthread3);

    proc_t *new_proc4 = proc_create("proc test 4");
    kthread_t *new_kthread4 = kthread_create(new_proc4, test_func, new_proc4->p_pid, new_proc4);
    sched_make_runnable(new_kthread4);

    // let to first and second procs go and yield
    sched_yield();

    // the first and second proc should yield to the third proc and fourth proc
    // which will return here to the init proc
    test_assert(curproc->p_pid == PID_INIT, "Should have returned to init proc");
    test_assert(new_proc3->p_state == PROC_DEAD, "Third proc should be dead");
    test_assert(new_proc4->p_state == PROC_DEAD, "Fourth proc should be dead");

    // destroy procs 3 and 4

    // terminate the second proc
    stop_func_2 = 1;
    sched_yield();

    // we should return back to the init proc
    test_assert(curproc->p_pid == PID_INIT, "Should have returned to init proc");
    test_assert(new_proc2->p_state == PROC_DEAD, "Second proc should be dead");

    // terminate the first proc
    stop_func_1 = 1;
    sched_yield();

    // we should return back to the init proc
    test_assert(curproc->p_pid == PID_INIT, "Should have returned to init proc");
    test_assert(new_proc1->p_state == PROC_DEAD, "First proc should be dead");

    // clean up proc 2 using do_waitpid, with specific status 1
    int status;
    int ret = do_waitpid(new_proc2->p_pid, &status, 0);
    test_assert(ret == new_proc2->p_pid, "wrong specific process id");
    test_assert(status == 1, "Returned status not set correctly");
    test_assert(new_proc2->p_status == 1, "Status not set correctly");

    // clean up the rest of the dead procs using do_waitpid
    int count = 0;
    while ((ret = do_waitpid(-1, &status, 0)) != -ECHILD)
    {
        dbg(DBG_TEST, "found child with pid=%d that needs to be cleaned up\n", ret);
        if (ret == new_proc1->p_pid) {
            test_assert(status == 1, "Returned status not set correctly for proc 1 with pid=%d", new_proc1->p_pid);
        } else {
            test_assert(status == 0, "Returned status not set correctly");
        }
        count++;
    }
    test_assert(count == 3,
                "Expected: %d, Actual: %d number of processes have been cleaned up\n", 3, count);
}


long proctest_main(long arg1, void *arg2)
{
    dbg(DBG_TEST, "\nStarting Procs tests\n");
    test_init();
    test_termination();

    // Add more tests here!
    // We highly recommend looking at section 3.8 on the handout for help!
    dbg(DBG_TEST, "\nStarting test_multiple\n");
    test_multiple();
    dbg(DBG_TEST, "\nStarting test_do_waitpid\n");
    test_do_waitpid();
    dbg(DBG_TEST, "\nStarting test_proc_kill_all\n");
    test_proc_kill_all();
    dbg(DBG_TEST, "\nStarting test_out_of_order_termination\n");
    test_out_of_order_termination();

    test_fini();
    return 0;
}