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

struct Node {
    long int id;
    char name[10];
    double score;
    struct Node *next;
};

struct LinkedList {
    struct Node *head;
    struct Node *tail;
};

struct Node* createNode() {
    struct Node* newNode = (struct Node*)malloc(sizeof(struct Node));
    if (newNode == NULL) {
        printf("記憶體分配失敗\n");
        exit(1);
    }
    newNode->next = NULL;
    return newNode;
}

void insertNode(struct LinkedList* list, long int id, const char* name, double score) {
    struct Node* newNode = createNode();
    newNode->id = id;
    strncpy(newNode->name, name, 9);
    newNode->name[9] = '\0';
    newNode->score = score;
    
    if (list->head == NULL) {
        list->head = newNode;
        list->tail = newNode;
    } else {
        list->tail->next = newNode;
        list->tail = newNode;
    }
}

void printList(struct LinkedList* list) {
    struct Node* current = list->head;
    while (current != NULL) {
        printf("學號: %ld, 姓名: %s, 分數: %.2f\n", current->id, current->name, current->score);
        current = current->next;
    }
}

void freeList(struct LinkedList* list) {
    struct Node* current = list->head;
    while (current != NULL) {
        struct Node* temp = current;
        current = current->next;
        free(temp);
    }
    list->head = NULL;
    list->tail = NULL;
}

void readFromFile(struct LinkedList* list, const char* filename) {
    FILE* file = fopen(filename, "r");
    if (file == NULL) {
        printf("無法打開檔案 %s\n", filename);
        return;
    }
    
    long int id;
    char name[10];
    double score;
    
    while (fscanf(file, "%ld %9s %lf", &id, name, &score) == 3) {
        insertNode(list, id, name, score);
    }
    
    fclose(file);
}

void saveToFile(struct LinkedList* list, const char* filename) {
    FILE* file = fopen(filename, "w");
    if (file == NULL) {
        printf("無法打開檔案 %s 進行寫入\n", filename);
        return;
    }
    
    struct Node* current = list->head;
    while (current != NULL) {
        fprintf(file, "%ld %s %.2f\n", current->id, current->name, current->score);
        current = current->next;
    }
    
    fclose(file);
    printf("資料已成功儲存到 %s\n", filename);
}

void inputFromKeyboard(struct LinkedList* list) {
    long int id;
    char name[10];
    double score;
    
    printf("請輸入學號: ");
    scanf("%ld", &id);
    printf("請輸入姓名 (最多9個字符): ");
    scanf("%9s", name);
    printf("請輸入分數: ");
    scanf("%lf", &score);
    
    insertNode(list, id, name, score);
    printf("資料已成功添加到串列中\n");
}

void deleteNode(struct LinkedList* list, long int id) {
    struct Node* current = list->head;
    struct Node* prev = NULL;

    // 如果要刪除的是頭節點
    if (current != NULL && current->id == id) {
        list->head = current->next;
        free(current);
        if (list->head == NULL) {
            list->tail = NULL;  // 如果刪除後列表為空，更新 tail
        }
        printf("學號為 %ld 的資料已刪除\n", id);
        return;
    }

    // 搜尋要刪除的節點
    while (current != NULL && current->id != id) {
        prev = current;
        current = current->next;
    }

    // 如果沒找到要刪除的節點
    if (current == NULL) {
        printf("找不到學號為 %ld 的資料\n", id);
        return;
    }

    // 刪除節點
    prev->next = current->next;
    if (current == list->tail) {
        list->tail = prev;  // 如果刪除的是尾節點，更新 tail
    }
    free(current);
    printf("學號為 %ld 的資料已刪除\n", id);
}

int main() {
    struct LinkedList list = {NULL, NULL};
    int choice;
    long int id_to_delete;
    const char* filename = "list.txt";

    readFromFile(&list, filename);
    
    do {
        printf("\n1. 顯示所有資料\n");
        printf("2. 從鍵盤輸入新資料\n");
        printf("3. 刪除特定資料\n");
        printf("4. 儲存並退出\n");
        printf("請選擇操作 (1-4): ");
        scanf("%d", &choice);
        
        switch(choice) {
            case 1:
                printf("\n所有資料:\n");
                printList(&list);
                break;
            case 2:
                inputFromKeyboard(&list);
                break;
            case 3:
                printf("請輸入要刪除的學號: ");
                scanf("%ld", &id_to_delete);
                deleteNode(&list, id_to_delete);
                break;
            case 4:
                saveToFile(&list, filename);
                break;
            default:
                printf("無效的選擇，請重新輸入\n");
        }
    } while (choice != 4);
    
    freeList(&list);
    return 0;
}