#include "list.h"

static void eatline(void)
{
    while (getchar() != '\n')
        continue;
}

static char get_answer(void)
{
    printf("\e[39m\nPlease enter choice > ");
    return tolower(getchar());
}

static bool CheckList(bool flag)
{
    if (!flag)
    {
        printf("List does not exist! Please initialize it!\n");
        return false;
    }
    return true;
}

int main(void)
{
    List L;
    char ans;
    ElemType e;
    int pos;
    bool flag = false;

    printf("\e[1;1H\e[2J");

    OperateMenu();

    while ((ans = get_answer()) != 'q')
    {
        if (strchr("abcdefghijklq",ans) == NULL)
        {
            fprintf(stderr,"Please enter choice labeled above!\n");
            if (ans != '\n')
                eatline();
            continue;
        }

        eatline();

        if (ans == 'k')                     // Show menu
        {
            putchar('\n');
            OperateMenu();
            continue;
        }

        if (ans == 'b')                     // Initialize list
        {
            InitList(&L);
            flag = true;
            continue;
        }

        if (CheckList(flag) == false)      // Check initialization
            continue;

        else if (ans == 'l')               // Destroy list
            DestroyList(&L);
        
        else if (ans == 'a')               // Add element
        {
            printf("Please enter an number: ");
            scanf("%d", &e);
            eatline();
            if (AddElem(&L, e))
                printf("Element adding successful!\n");
            else
                printf("Element adding failed, please run debug mode!\n");
        }

        else if (ans == 'c')               // Show list length
            printf("List contains %d element!\n",ListLength(&L));

        else if (ans == 'd')               // Get element by position
        {
            printf("Enter position you want to get: ");
            scanf("%d",&pos);
            eatline();
            int i = ListLength(&L);

            if (pos > i || pos <= 0)
            {
                printf("Position error, List now has %i elements!\n", i);
                continue;
            }

            printf("Position %d:  %d",pos,GetElem(&L,pos));
        }

        else if (ans == 'e')             // Get position by element
        {
            printf("Enter element value: ");
            scanf("%d", &e);
            eatline();

            if ((pos = LocateElem(&L,e)) == 0)
            {
                printf("Element %d is not in this list!\n",e);
                continue;
            }

            printf("Element position: %d\n",pos);
        }

        else if (ans == 'f')            // Get prior element
        {
            printf("Enter element: ");
            scanf("%d", &e);
            eatline();

            if ((pos = LocateElem(&L,e)) == 0)
            {
                printf("Element %d is not in this list!\n",e);
                continue;
            }

            else if (pos == 1)
            {
                printf("First element, no prior element!\n");
                continue;
            }

            printf("Prior element of element %d is %d\n",
                    e,PriorElem(&L,e));
        }

        else if (ans == 'g')            // Get next element
        {
            printf("Enter element: ");
            scanf("%d", &e);
            eatline();

            if ((pos = LocateElem(&L,e)) == 0)
            {
                printf("Element %d is not in this list!\n",e);
                continue;
            }

            else if(pos == ListLength(&L))
            {
                printf("Last element, no next element!\n");
                continue;
            }

            printf("Next element of element %d is %d\n",
                    e,NextElem(&L,e));
        }

        else if (ans == 'h')            // Insert an element
        {
            printf("Enter position you want to put: ");
            scanf("%d", &pos);
            printf("Enter element you want to add: ");
            scanf("%d", &e);
            eatline();

            if (!InsertElem(&L,e,pos))
            {
                printf("Insert error!\n");
                continue;
            }
            printf("Insert successful!\n");
        }
        
        else if (ans == 'i')           // Delete an element
        {
            int i = ListLength(&L);
            printf("Enter position you want to delete: ");
            scanf("%d", &pos);
            eatline();

            if (pos <= 0)
            {
                printf("position should be greater than 0!\n");
                continue;
            }

            else if (pos > i || !DeleteElem(&L,pos))
            {
                printf("Position error, %d elements in list\n",
                        i);
                puts("Delete failed");
                continue;
            }
            puts("Delete successful!");
        }

        else if (ans == 'j')
            TraverseList(&L);
    }

    if (flag)
        free(L);

    puts("Thanks for using this utility!\n");

    return 0;
}