#include "process.h"
#include "alloc.h"
#include "irq.h"
#include "klibc.h"
#include "list.h"
#include "mmuContext.h"
#include "types.h"
#include "thread.h"
#include "uaddrspace.h"

struct process {
    char name[PROCESS_NAME_MAX_LENGTH];
    int ref;
    pid_t pid;
    pid_t nextTid;
    struct uAddrSpace *addrSpace;
    struct thread *thList;

    struct process *prev, *next;
};

static struct process *processList;
static int nextPid;

int processSetup()
{
    list_init(processList);
    allocBookSlab(sizeof(struct process), PAGE_SIZE * 3, 0, 0);
    nextPid = 0;

    return 0;
}

struct process *processCreate(char *name)
{
    uint32_t flags;

    struct process *new = (struct process *)malloc(sizeof(struct process));
    if (new == NULL)
        return NULL;

    new->addrSpace = uAddrSpaceCreate(new);
    if(new->addrSpace == NULL){
        free(new);
        return NULL;
    }

    strzcpy(new->name, name, PROCESS_NAME_MAX_LENGTH);
    new->ref = 1;

    disable_IRQs(flags);
    new->pid     = nextPid++;
    new->nextTid = new->pid;
    list_add_tail(processList, new);
    restore_IRQs(flags);

    return new;
}

void processListPrint()
{
    struct process *proc;
    int nbProcs;
    struct thread *cur = getCurrentThread();

    printf("PID NAME    NBTHREAD    REF\n");
    list_foreach(processList, proc, nbProcs)
    {
        struct thread *th;
        int nbTh;

        printf("%lu %s %d %d\n", proc->pid, proc->name, processCountThread(proc), proc->ref);
        list_foreach_named(proc->thList, th, nbTh, prevInProcess, nextInProcess)
        {
            if (th == cur) {
                printf("    th: 0x%lx Current\n", (vaddr_t)th);
            } else {
                printf("    th: 0x%lx in 0x%lx\n", (vaddr_t)th, cpu_context_get_PC(th->cpuState));
            }
        }
    }
}

int processCountThread(struct process *proc)
{
    int count;
    struct thread *th;

    list_foreach_named(proc->thList, th, count, prevInProcess, nextInProcess) {}

    return count;
}

int processRef(struct process *proc)
{
    uint32_t flags;
    // ref == 0 -> delete
    assert(proc->ref > 0);

    disable_IRQs(flags);
    proc->ref++;
    restore_IRQs(flags);

    return 0;
}

int processUnref(struct process *proc)
{
    uint32_t flags;
    int ret;

    assert(proc->ref > 0);

    disable_IRQs(flags);

    proc->ref--;
    if (proc->ref > 0) {
        restore_IRQs(flags);
        return -EBUSY;
    }
    list_delete(processList, proc);
    restore_IRQs(flags);

    ret = uAddrSpaceDelete(proc->addrSpace);
    free(proc);

    return ret;
}

int processAddThread(struct process *proc, struct thread *th)
{
    uint32_t flags;

    assert(proc->ref > 0);

    th->process = proc;

    disable_IRQs(flags);
    processRef(proc);
    list_add_tail_named(proc->thList, th, prevInProcess, nextInProcess);

    restore_IRQs(flags);

    return 0;
}

int processRemoveThread(struct thread *th)
{
    uint32_t flags;
    struct process *proc;

    disable_IRQs(flags);
    proc = th->process;

    list_delete_named(proc->thList, th, prevInProcess, nextInProcess);
    restore_IRQs(flags);
    processUnref(proc);

    return 0;
}

int processSetName(struct process *proc, char *name)
{
    assert(name != NULL);
    strzcpy(proc->name, name, PROCESS_NAME_MAX_LENGTH);

    return 0;
}

char *processGetName(struct process *proc){
    return proc->name;
}

struct mmu_context *processGetMMUContext(struct process *proc)
{
    return uAddrSpaceGetMMUContext(proc->addrSpace);
}

struct uAddrSpace *processGetAddrSpace(struct process *proc){
    return proc->addrSpace;
}

int processInitHeap(struct process *proc, uaddr_t lastUserAddr){
    return uAddrSpaceSetHeap(proc->addrSpace, lastUserAddr, 0);
}

pid_t processGetId(struct process *proc){
    return proc->pid;
}

pid_t processGetNextTid(struct process *proc){
    return proc->nextTid++;
}

//Should be called with IRQ disabled
struct thread *processGetThread(struct process *proc, pid_t tid)
{
    int count;
    struct thread *th;
    struct thread *thFound = NULL;

    list_foreach_named(proc->thList, th, count, prevInProcess, nextInProcess)
    {
        if (th->tid == tid) {
            thFound = th;
            break;
        }
    }
    return thFound;
}

int processJoinThread(struct process *proc, pid_t tid)
{
    uint32_t flags;
    struct thread *th;
    int ret = -1;

    disable_IRQs(flags);

    th = processGetThread(proc, tid);
    if (th && th->wqExit) {
        wait(th->wqExit);
        ret = 0;
    }

    restore_IRQs(flags);

    return ret;
}