#define _CRT_SECURE_NO_WARNINGS

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

#define INPUT_FILE "input.txt"

/* The maximum name length and number of people and movies */
#define MAX_NAME_LENGTH 200
#define MAX_PEOPLE 700
#define MAX_MOVIES 200

/* The only global variables permitted in this project are below */
char movieData[MAX_MOVIES][MAX_NAME_LENGTH] = {0};
char personData[MAX_PEOPLE][MAX_NAME_LENGTH] = {0};
int  ratingsMatrix[MAX_PEOPLE][MAX_MOVIES] = {0};
int  numberOfMovies = 0;
int  numberOfPeople = 0;

void GetData (void);
int  GetPersonId (char *person) ;
int  GetMovieId (char *movie) ;
void AlgorithmOne (int personId) ;
void AlgorithmTwo (int personId);

int main(void)
{
    int  personId;
    char person[MAX_NAME_LENGTH];

    GetData();

    printf("\nENGGEN 131 2011, Project 2\nCalculate Recommendations for: " );
    scanf("%s", person);

    personId = GetPersonId(person);

    AlgorithmOne(personId);

    AlgorithmTwo(personId);

    return 0;
}

void GetData (void)
{
    char person[MAX_NAME_LENGTH];
    char movie[MAX_NAME_LENGTH];
    int  personId;
    int  movieId;
    int  rating;

    FILE *fp;
    fp = fopen(INPUT_FILE, "r");

    if (fp == NULL){
        printf("Sorry, the file could not be opened");
    } else {
        while (fscanf(fp, "%s", person) != EOF){

            personId = GetPersonId(person);
            fscanf(fp, "%s", movie);

            movieId = GetMovieId(movie);
            fscanf(fp, "%d", &rating);

            ratingsMatrix[personId][movieId] = rating;
        }
    }
}

int GetPersonId(char *person)
{
    int i;
    int duplicate = 0;
    int test = 0;

    for(i=0; i < numberOfPeople; i++){

        duplicate = strcmp(personData[i], person);

        if (duplicate == 0){
            test = 1;
            return (i);
            break;
        } else
            test = 0;
    }
    if (!test){
        strcpy(personData[numberOfPeople], person);
        numberOfPeople++;
    }

    return (numberOfPeople - 1);

}

int GetMovieId(char *movie)
{
    int i;
    int duplicate = 0;
    int test = 0;

    for(i=0; i < numberOfMovies; i++){

        duplicate = strcmp(movieData[i], movie);

        if (duplicate == 0){
            test = 1;
            return (i);
            break;
        } else
            test = 0;
    }
    if (!test){
        strcpy(movieData[numberOfMovies], movie);
        numberOfMovies = numberOfMovies + 1;
    }

    return (numberOfMovies - 1);
}

void AlgorithmOne (int personId)
{
    double avg[MAX_MOVIES] = {0};
    double seen[MAX_MOVIES] = {0};
    double sum[MAX_MOVIES]  = {0};
    double maximumAverage =  0;
    char *recommendation = {0};
    int i ;
    int j ;

    for (i=0; i <numberOfMovies; i++){
        seen[i] = 0;
        for (j=0;j<numberOfPeople; j++){

            if(j==personId && ratingsMatrix[j][i]!=0){
                sum[i]=0;
                seen[i]= MAX_PEOPLE;
                break;
            }

            else if (ratingsMatrix[j][i] !=0 && j != personId){
                sum[i] = sum[i] + (ratingsMatrix[j][i]);
                seen[i] = seen[i]+ 1;
            }
        }
        avg[i] = sum[i]/seen[i];
    }

    for (i=0; i <numberOfMovies; i++){
        if (avg[i] > maximumAverage){
            maximumAverage = avg[i];
            recommendation = movieData[i];
        }
    }

    printf("\nAlgorithm 1:\nRecommended movie: %s\n",  recommendation);
    printf("Average rating: %f \n\n" , maximumAverage);

}

void AlgorithmTwo (int personId)
{
    int similarity[MAX_PEOPLE] = {0};
    double maximumSimilarity = 0;
    int personPosition = 0;
    int most_similar[MAX_PEOPLE] = {0};
    int highestRankedMovie = 0;
    int moviePosition = 0;
    int i;
    int j;

    for(i=0; i < numberOfPeople; i++){
        for (j =0; j < numberOfMovies; j++){

            if (i == personId){
                similarity[i] = 0;
            }
            else{
                similarity[i] = (ratingsMatrix[personId][j]*ratingsMatrix[i][j]) + similarity[i];
            }
        }
    }

    for (i=0; i <numberOfPeople; i++){
        if (similarity[i] > maximumSimilarity){
            maximumSimilarity = similarity[i];
            personPosition = i;
        }
    }

    for(i=0; i <numberOfMovies; i++){

        if (ratingsMatrix[personId][i] != 0){
            most_similar[i] = 0;
        }
        else{
            most_similar[i] = ratingsMatrix[personPosition][i];
        }
    }

    for (i=0; i <numberOfMovies; i++){
        if (most_similar[i] > highestRankedMovie){
            highestRankedMovie = most_similar[i];
            moviePosition = i;
        }
    }

    printf("Algorithm 2:\nRecommended movie: %s\n",movieData[moviePosition]);
    printf("Similarity rating = ""%f with ""%s\n",maximumSimilarity, personData[personPosition]);

}