#include "main.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// Read a line from stdin, strip the eventual newline and return a pointer
// to the string. Remember to free the pointer.
char *read_input() {
    char *buf = NULL;
    size_t buf_size = 0;
    size_t read = getline(&buf, &buf_size, stdin);
    if (read == -1) {
        free(buf);
        buf = NULL;
    } else if (read >= 1 && buf[read - 1] == '\n') {
        buf[read - 1] = '\0';
    }
    return buf;
}

int read_int() {
    char *buf = read_input();
    int res = -1;
    if (!buf) {
        printf("Failed to read int from stdin\n");
    } else {
        res = atoi(buf);
    }
    free(buf);
    return res;
}

// Fetch a student name from the terminal input and add it to the list.
void insert(struct list *student_list) {
    struct student *student = malloc(sizeof(struct student));
    char *name = read_input();
    if (!name) {
        printf("Failed to read student name\n");
        free(student);
    } else {
        student->name = name;
        printf("Inserted student with name '%s'\n", student->name);
        list_push_front(student_list, &student->elem);
    }
}

// Get a student name from the terminal input, remove it from the list and
// deallocate the appropriate memory (if needed).
void delete(struct list *student_list) {
    list(student_list);
    printf("Name of student to delete:\n");

    char *name = read_input();
    if (!name) {
        printf("Failed to read student name\n");
    } else {
        struct list_elem *e;
        int removed_student = 0;
        for (e = list_begin(student_list); e != list_end(student_list);
                e = list_next(e))
        {
            struct student *student = list_entry(e, struct student, elem);
            if (strcmp(student->name, name) == 0) {
                printf("Removing student '%s'\n", student->name);
                list_remove(&student->elem);
                free(student->name);
                free(student);
                removed_student = 1;
                break;
            }
        }
        if (!removed_student) {
            printf("No student named '%s' found\n", name);
        }
    }
    free(name);
}

// Print the entire list.
void list(struct list *student_list) {
    struct list_elem *e;
    for (e = list_begin(student_list); e != list_end(student_list);
            e = list_next(e))
    {
        struct student *student = list_entry(e, struct student, elem);
        printf("Student: %s\n", student->name);
    }
}

// Clear the list and deallocate the memory.
void quit(struct list *student_list) {
    struct list_elem *e;
    struct student *student;
    while (!list_empty(student_list)) {
        e = list_pop_front(student_list);
        student = list_entry(e, struct student, elem);
        printf("Removing '%s'\n", student->name);
        free(student->name);
        free(student);
    }
    exit(0);
}

int main() {
    struct list student_list;
    list_init(&student_list);
    int opt;

    do {
        printf("Menu:\n");
        printf("1 - Insert student\n");
        printf("2 - Delete student\n");
        printf("3 - List students\n");
        printf("4 - Exit\n");
        switch (read_int()) {
            case 1:
                {
                    insert(&student_list);
                    break;
                }
            case 2:
                {
                    delete(&student_list);
                    break;
                }
            case 3:
                {
                    list(&student_list);
                    break;
                }

            case 4:
                {
                    quit(&student_list);
                    break;
                }
            default:
                {
                    printf("Quit? (1/0):\n");
                    if (read_int())
                        quit(&student_list);
                    break;
                }
        }
    } while(1);

    return 0;
}