#include "miniDB.h"

Movie* head = NULL;
int size = 0;

int main(int argc, char** argv) {
    if (argc < 4) {
        printf("Usage: miniDB <database> <commands> <output>\n");
    } else {
        if (load(argv[1]) != 0) {
            printf("Error while loading database from '%s'.\n", argv[1]);
            return 2;
        }
        if (read(argv[2], argv[3]) != 0) {
            printf("Error while reading commands from '%s'.\n", argv[2]);
            return 3;
        }
        if (save(argv[1]) != 0) {
            printf("Error while saving database to '%s'.\n", argv[1]);
            return 4;
        }
    }

    return 0;
}

int read(char* filename, char* fileOut) {
    if (filename == NULL) {
        return 1;
    }

    FILE* file = fopen(filename, "r");
    if (file == NULL)
        return 2;
    
    FILE* output = fopen(fileOut, "w"); // If appending, switch to "a".
    if (output == NULL)
        return 3;

    int length = 512*3;
    char buffer[length];

    while (fgets(buffer, length, file) != NULL && strcmp(buffer, "") != 0) {
        printf("Command read: %s\n", buffer);
        
        char* token = strtok(buffer, ", ");
        if (token == NULL) {
            token = strtok(buffer, ",");
            if (token == NULL)
                return 4;
        }

        if (strcmp(token, "ADD") == 0) {
            token = strtok(buffer, NULL);
            if (token == NULL)
                return 5;
            char* title = strdup(token);
        
            token = strtok(buffer, NULL);
            if (token == NULL)
                return 5;
            char* date = strdup(token);

            token = strtok(buffer, NULL);
            if (token == NULL)
                return 5;
            char* director = strdup(token);

            token = strtok(buffer, NULL);
            if (token == NULL)
                return 5;
            int id = atoi(token);
        
            if (add(title, date, director, id) != 0)
                return 6;

            free(title);
            free(date);
            free(director);
            title = NULL;
            date = NULL;
            director = NULL;    
        } else if (strcmp(token, "LOOKUP") == 0) {
            token = strtok(buffer, NULL);
            if (token == NULL)
                return 5;
            char* feature = strdup(token);

            token = strtok(buffer, NULL);
            if (token == NULL)
                return 5;
            char* data = strdup(token);

            if (lookup(feature, data, output) != 0)
                return 6;
            
            free(feature);
            free(data);
            feature = NULL;
            data = NULL;
        } else if (strcmp(token, "DISPLAY") == 0) {
            token = strtok(buffer, NULL);
            if (token == NULL)
                return 5;
            char* feature = strdup(token);

            token = strtok(buffer, NULL);
            if (token == NULL)
                return 5;
            int order = atoi(token);

            token = strtok(buffer, NULL);
            if (token == NULL)
                return 5;
            int max = atoi(token);

            if (display(feature, order, max, output) != 0)
                return 6;
            free(feature);
            feature = NULL;
        } else if (strcmp(token, "EDIT") == 0) {
            token = strtok(buffer, NULL);
            if (token == NULL)
                return 5;
            int id = atoi(token);

            token = strtok(buffer, NULL);
            if (token == NULL)
                return 5;
            char* feature = strdup(token);

            token = strtok(buffer, NULL);
            if (token == NULL)
                return 5;
            char* data = strdup(token);

            if (edit(id, feature, data) != 0)
                return 6;
            
            free(feature);
            free(data);
            feature = NULL;
            data = NULL;
        } else if (strcmp(token, "REMOVE") == 0) {
            token = strtok(buffer, NULL);
            if (token == NULL)
                return 5;
            int id = atoi(token);
        
            if (removeId(id) != 0)
                return 6;
        }
    }

    printf("End of commands.\n");

    if (fclose(file) != 0)
        return 7;
    if (fclose(output) != 0)
        return 8;

    return 0;
}

int load(char* filename) {
    if (filename == NULL) {
        return 1;
    }

    FILE* file = fopen(filename, "r");
    if (file == NULL)
        return 2;

    int length = 512*3; // HOLD ALL THE CHARS!
    char buffer[length];

    while (fgets(buffer, length, file) != NULL && strcmp(buffer, "") != 0) {
        printf("Line read: %s\n", buffer);
        
        char* token = strtok(buffer, ", ");
        if (token == NULL) {
            token = strtok(buffer, ",");
            if (token == NULL)
                return 3;
        } // Now that it's kicked off with the correct delimeter...
        
        char* title = strdup(token);
        
        token = strtok(buffer, NULL);
        if (token == NULL)
            return 5;
        char* date = strdup(token);

        token = strtok(buffer, NULL);
        if (token == NULL)
            return 5;
        char* director = strdup(token);

        token = strtok(buffer, NULL);
        if (token == NULL)
            return 5;
        int id = atoi(token);
        
        if (add(title, date, director, id) != 0)
            return 6;

        free(title);
        free(date);
        free(director);
        title = NULL;
        date = NULL;
        director = NULL;
    }
    printf("End of file.\n");

    if (fclose(file) != 0) {
        return 4;
    }

    return 0;
}

Movie* get(int id) {
    if (head == NULL) {
        return NULL;
    }

    Movie* target = head;
    while (target->id != id) {
        if (target->next != NULL) {
            target = target->next;
        } else
            return NULL;
    }

    return target;
}

int add(char* title, char* date, char* director, int id) {
    if (title == NULL || date == NULL || director == NULL)
        return 1;
    
    Movie* mov = (Movie *) malloc(sizeof(Movie));
    if (mov == NULL)
        return 2;

    if (head == NULL) {
        head = mov;
    } else {
        Movie* target = head;
        while (target->next != NULL) {
            target = target->next;
        }
        target->next = mov;
        mov->next = NULL;
    }

    size++;

    mov->title = strdup(title);
    mov->date = strdup(date);
    mov->director = strdup(director);
    mov->id = id;

    return 0;
}

int edit(int id, char* feature, char* data) {
    if (feature == NULL || data == NULL)
        return 1;

    Movie* mov = get(id);
    if (mov == NULL)
        return 2;

    if (strcmp(feature, "ID") == 0) {
        mov->id = atoi(data);
    } else if (strcmp(feature, "TITLE") == 0) {
        free(mov->title);
        mov->title = strdup(data);
    } else if (strcmp(feature, "DATE") == 0) {
        free(mov->date);
        mov->date = strdup(data);
    } else if (strcmp(feature, "DIRECTOR") == 0) {
        free(mov->director);
        mov->director = strdup(data);
    } else {
        return 3;
    }

    return 0;
}

int removeId(int id) {
    if (head == NULL) {
        return 1;
    }
    
    Movie* prev = NULL;
    Movie* target = head;
    while (target->id != id) {
        if (target->next != NULL) {
            prev = target;
            target = target->next;
        } else
            return 2;
    }

    if (prev == NULL && target != NULL) {
        head = target->next; // If next is NULL, that's okay.
    } else {
        prev->next = target->next; // Again, a NULL next is okay.
    }
    
    size--;

    free(target->title);
    free(target->date);
    free(target->director);
    target->title = NULL;
    target->date = NULL;
    target->director = NULL;
    free(target);
    target = NULL;

    return 0;
}

int lookup(char* feature, char* data, FILE* out) {
    if (feature == NULL || data == NULL || head == NULL) {
        return 1;
    }

    printf("LOOKUP, %s, %s\n", feature, data);
    fprintf(out, "LOOKUP, %s, %s\n", feature, data);

    Movie* target = head;

    while (target != NULL) {
        char success = 0;
        
        if (strcmp(feature, "ID") == 0) {
            if (get(atoi(data)) == NULL)
                success++;
        } else if (strcmp(feature, "TITLE") == 0) {
            success += fnmatch(data, target->title, "FNM_NOCASE");
        } else if (strcmp(feature, "DATE") == 0) {
            success += fnmatch(data, target->date, "FNM_NOCASE");
        } else if (strcmp(feature, "DIRECTOR") == 0) {
            success += fnmatch(data, target->director, "FNM_NOCASE");
        } 

        if (success == 0) {
            printf("%s, %s, %s, %d\n", target->title, target->date, target->director, target->id);
            fprintf(out, "%s, %s, %s, %d\n", target->title, target->date, target->director, target->id);
        }

        target = target->next;
    }  

    return 0;
}

int display(char* feature, int order, int max, FILE* out) {
    if (feature == NULL)
        return 1;

    printf("DISPLAY, %s, %d, %d\n", feature, order, max);
    fprintf(out, "DISPLAY, %s, %d, %d\n", feature, order, max);

    if (max <= 0) {
        return 0;
    } else if (max > size) {
        max = size;
    }

    Movie* target = head;
    int count = 0; // Number of Movies displayed.
    int* countedIds = calloc(max, sizeof(int)); // Set 'em all to 0.
    Movie* best = target;
    
    while (count < max) {
        while (target != NULL) {
            if (idIncluded(target->id, countedIds, max) == 0) { // ID not counted yet. (Ignore counted ones)
                if (order == 0) { // Ascending: smallest first.
                    if (       (strcmp(feature, "TITLE") == 0    && strcmp(target->title, best->title) < 0)
                            || (strcmp(feature, "DATE") == 0     && strcmp(target->date, best->date) < 0)
                            || (strcmp(feature, "DIRECTOR") == 0 && strcmp(target->director, best->director) < 0)
                            || (strcmp(feature, "ID") == 0       && target->id < best->id) ) {
                        best = target;
                    }    
                } else { // Descending: largest first.
                    if (       (strcmp(feature, "TITLE") == 0    && strcmp(target->title, best->title) > 0)
                            || (strcmp(feature, "DATE") == 0     && strcmp(target->date, best->date) > 0)
                            || (strcmp(feature, "DIRECTOR") == 0 && strcmp(target->director, best->director) > 0)
                            || (strcmp(feature, "ID") == 0       && target->id > best->id) ) {
                        best = target;
                    }    
                }
            }
            target = target->next; // Okay if target is NULL.
        }

        countedIds[count] = best->id;
        printf("%s, %s, %s, %d\n", best->title, best->date, best->director, best->id);
        fprintf(out, "%s, %s, %s, %d\n", best->title, best->date, best->director, best->id);
        count++;
        
        // Set best to an uncounted ID.
        Movie* nextBest = head;
        while (nextBest != NULL) {
            if (idIncluded(nextBest->id, countedIds, max) == 0) {
                best = nextBest;
                break;
            } else
                nextBest = nextBest->next;
        }

    }

    return 0;
}

int idIncluded(int id, int* idList, size_t len) {
    for (int i = 0; i < len; i++) {
        if (id == idList[i])
            return 1;
    }

    return 0;
}