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

#define NUM_USERS 611
#define NUM_MOVIES 9743
#define NUM_GENRES 20

typedef struct Movies
{
    int movieID;
    struct Movies *next;
} Movies;

typedef struct Genres
{
    int genreID;
    struct Genres *next;
} Genres;

const char *genreMap[] = {"Action", "Adventure", "Animation", "Children",
                          "Comedy", "Crime", "Documentary", "Drama",
                          "Fantasy", "Film-Noir", "Horror", "IMAX", "Musical",
                          "Mystery", "Romance", "Sci-Fi", "Thriller",
                          "War", "Western"};

//输入电影风格返回其映射的id
int getGenreID(char *style)
{

    // int index = 0;
    // const char *genreMap[] = {"Action", "Adventure", "Animation", "Children's",
    //                         "Comedy", "Crime", "Documentary", "Drama",
    //                         "Fantasy", "Film-Noir", "Horror", "IMAX", "Musical",
    //                         "Mystery", "Romance", "Sci-Fi", "Thriller",
    //                         "War", "Western"};

    // while (strcmp(genreMap[index], style) != 0)
    // {
    //     index++;
    // }

    int found = 0;
    int i;
    for (i = 0; i < NUM_GENRES - 1; i++) {
        if (strcmp(genreMap[i], style) == 0) {
            found = 1;
            break;
        }
    }
    if (found == 1) {
        return i;
    }
    else {
        return -1;
    }
}

// 函数原型
Movies *appendMovies(Movies *last, int id);
Genres *appendGenres(Genres *head, int id);
void incremendGenres(int count[], int movieID, Genres **movies); // 传入movieID,输出风格下标
void clearArrInt(int *arr, int size);                            // 将所有元素设为0
void parseGenreString(char *inputStr, int movieID, Genres **movies_arr);
// inputStr: "Adventure|IMAX..." movieID: the id to make genre linked list. movies_arr[]: to store the linked list.

int main(void)
{
    // Firstly open the ratings.csv
    FILE *fp;
    fp = fopen("./ratings.csv", "r");

    char *buf = malloc(256 * sizeof(char));

    // Declare the users table and init with null.
    Movies *users[NUM_USERS];
    for (int i = 0; i < NUM_USERS; i++)
    {
        users[i] = NULL;
    }

    fgets(buf, 256 * sizeof(char), fp);

    // 看每个用户喜欢什么电影
    int userID, movieID, rating;
    char input[64];
    int loc, loc1;
    while (fgets(buf, 256 * sizeof(char), fp) != NULL)
    {
        loc = 0;
        input[0] = '\0'; // clear the array
        // get userID
        while (buf[loc] != ',')
        {
            input[loc] = buf[loc];
            loc++;
        }
        input[loc++] = '\0';
        userID = atoi(input);
        // printf("UserID: %d\n", userID);

        // get movieID
        loc1 = 0;
        input[0] = '\0';
        while (buf[loc] != ',')
        {
            input[loc1++] = buf[loc];
            loc++;
        }
        input[loc1] = '\0';
        loc++;

        // ATOI(3)                   Linux Programmer's Manual                  ATOI(3)
        // NAMint count[], E
        //  atoi, atol, atoll - convert a string to an integer

        movieID = atoi(input);
        // printf("movieID: %d\n", movieID);

        // get ratings
        input[0] = '\0';
        loc1 = 0;
        while (buf[loc] != ',')
        {
            input[loc1++] = buf[loc];
            loc++;
        }
        input[loc1] = '\0';
        rating = atoi(input);

        if (rating >= 3)
        {
            printf("Rate: %d, userID: %d, movieID: %d\n", rating, userID, movieID);
            users[userID] = appendMovies(users[userID], movieID);
        }
    }

    fclose(fp);

    fp = fopen("./movies.csv", "r");

    // 下标表示电影id
    Genres *movies[NUM_MOVIES];

    // TODO: 仿照我的代码填充*movies数组
    // 李王子写 ok 你写吧

    for (int i = 0; i < NUM_MOVIES; i++)
    {
        movies[i] = NULL;
    }

    char *str = (char *)malloc(256 * sizeof(char));

    //读第一行
    fgets(str, 256 * sizeof(char), fp);

    //        fgets() returns s on success, and NULL on error or when end  of  file
    //   occurs while no characters have been read.
    //      你那个该写!=NULL 你看注释
    //  ok

    int movie_id = 0;

    while (fgets(str, 256 * sizeof(char), fp) != NULL)
    {
        // get the movie's id
        loc = 0;
        input[0] = '\0';

        while (str[loc] != ',')
        {
            input[loc] = str[loc];
            loc++;
        }
        input[loc++] = '\0'; // 现在loc指向电影名字的第0个字符
        movie_id = atoi(input);
        printf("Debug: movie_id: %d\n", movie_id);

        if (str[loc] == '"')
        { // in case the title has comma inside.
            loc++;
            while (str[loc] != '"')
            {
                loc++;
            }
            loc += 2; // 现在指向genres第0个字符
        }
        else
        {
            // go to genres
            while (str[loc] != ',')
                loc++;
            loc++; // 现在loc指向风格
        }

        loc1 = 0;
        input[0] = '\0';

        while (str[loc] != '\n' && str[loc] != '\0' && str[loc] != '\r')
        {
            input[loc1++] = str[loc++];
        }
        input[loc1] = '\0';
        parseGenreString(input, movie_id, movies);
    }

    fclose(fp);

    // 开始输出答案到文件answer.txt

    fp = fopen("./answer.txt", "w+"); // w+: 如果文件已存在先清空

    int count[NUM_GENRES] = {};

    // 开始从第一个用户循环 (1)
    Movies *ptr;
    for (int i = 1; i < NUM_USERS; i++)
    {
        clearArrInt(count, NUM_GENRES);
        // 便历他喜欢的电影
        ptr = users[i];
        while (ptr != NULL)
        {
            incremendGenres(count, ptr->movieID, movies);
            printf("Debug: userID: %d, movieID: %d\n", i, ptr->movieID);
            ptr = ptr->next;
        }

        // 输出答案
        fprintf(fp, "User id: %d\n", i);
        for (int j = 0; j < NUM_GENRES - 1; j++)
        {
            fprintf(fp, "%s: %d\t", genreMap[j], count[j]);
        }
        fprintf(fp, "\n");
    }

    fclose(fp);

    return 0;
}

Movies *appendMovies(Movies *last, int id)
{
    Movies *new = malloc(sizeof(Movies));

    new->movieID = id;
    new->next = NULL;

    // 1.如果是null
    if (last == NULL)
    {
        return new;
    }
    // 2.不是null，在最后加上新节点
    Movies *ptr = last;

    while (ptr->next != NULL)
    {
        ptr = ptr->next;
    }

    ptr->next = new;

    return last;
}

void incremendGenres(int count[], int movieID, Genres **movies)
{
    Genres *ptr = movies[movieID];
    while (ptr != NULL)
    {
        count[ptr->genreID]++;
        printf("Debug: movidID: %d, genreID: %d, genre: %s\n", movieID, ptr->genreID, genreMap[ptr->genreID]);
        ptr = ptr->next;
    }
}

void clearArrInt(int *arr, int size)
{
    for (int i = 0; i < size; i++)
    {
        arr[i] = 0;
    }
}

void parseGenreString(char *inputStr, int movieID, Genres **movies_arr)
{
    // 处理输入的string
    int strLen = strlen(inputStr);
    char buf[64];
    int locPtr = 0;
    printf("Debug: inputStr: %s\n", inputStr);
    int genreID;

    for (int i = 0; i < strLen; i++)
    {
        if (inputStr[i] == '|')
        { // time to divide the string and make magic happen
            buf[locPtr] = '\0';
            printf("Debug: buf: %s, genreID: %d\n", buf, getGenreID(buf));
            genreID = getGenreID(buf);
            if (genreID != -1)
                movies_arr[movieID] = appendGenres(movies_arr[movieID], genreID);
            locPtr = 0;
        }
        else
        {
            buf[locPtr++] = inputStr[i];
        }
    }
    
    // do this again
    buf[locPtr] = '\0';
    printf("Debug: buf: %s, genreID: %d\n", buf, getGenreID(buf));
    genreID = getGenreID(buf);
    if (genreID != -1)
        movies_arr[movieID] = appendGenres(movies_arr[movieID], genreID);
    locPtr = 0;
}

Genres *appendGenres(Genres *head, int id)
{
    Genres *new = malloc(sizeof(Genres));

    new->genreID = id;
    new->next = NULL;

    if (head == NULL)
    {
        return new;
    }

    Genres *ptr = head;

    while (ptr->next != NULL)
    {
        ptr = ptr->next;
    }
    ptr->next = new;

    return head;
}