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

#define MAX_LINE_LENGTH 256
#define DATE_LENGTH 10
#define TIME_LENGTH 5
#define CATEGORY_LENGTH 10
#define FREETEXT_MAX_LENGTH 80
#define CNOTES_DIR ".local/share/cnotes"
#define CNOTES_FILE "cnotes.csv"

typedef struct {
    char date[DATE_LENGTH + 1];
    char time[TIME_LENGTH + 1];
    char category[CATEGORY_LENGTH + 1];
    char freetext[FREETEXT_MAX_LENGTH + 1];
} Entry;

/* ReSharper disable CppParameterMayBeConst */
void print_horizontal_line(char left, char middle, char right, char fill) {
    /* ReSharper restore CppParameterMayBeConst */
    int i;
    printf("%c", left);
    
    /* Date column */
    for (i = 0; i < DATE_LENGTH + 2; i++) printf("%c", fill);
    printf("%c", middle);
    
    /* Time column */
    for (i = 0; i < TIME_LENGTH + 2; i++) printf("%c", fill);
    printf("%c", middle);
    
    /* Category column */
    for (i = 0; i < CATEGORY_LENGTH + 2; i++) printf("%c", fill);
    printf("%c", middle);
    
    /* Free text column */
    for (i = 0; i < FREETEXT_MAX_LENGTH + 2; i++) printf("%c", fill);
    printf("%c\n", right);
}

void print_header(void) {
    /* Top border (double line) */
    print_horizontal_line('+', '+', '+', '=');
    
    /* Header row */
    printf("| %-*s | %-*s | %-*s | %-*s |\n",
           DATE_LENGTH, "Date",
           TIME_LENGTH, "Time",
           CATEGORY_LENGTH, "Category",
           FREETEXT_MAX_LENGTH, "Free Text");
    
    /* Bottom border (double line) */
    print_horizontal_line('+', '+', '+', '=');
}

void print_entry(const Entry *entry) {
    printf("| %-*s | %-*s | %-*s | %-*s |\n",
           DATE_LENGTH, entry->date,
           TIME_LENGTH, entry->time,
           CATEGORY_LENGTH, entry->category,
           FREETEXT_MAX_LENGTH, entry->freetext);
}

void print_footer(void) {
    print_horizontal_line('+', '+', '+', '-');
}

int parse_line(const char *line, Entry *entry) {
    const char *ptr;
    int i;
    
    ptr = line;
    
    /* Parse date (10 chars) */
    if (strlen(ptr) < DATE_LENGTH) return 0;
    strncpy(entry->date, ptr, DATE_LENGTH);
    entry->date[DATE_LENGTH] = '\0';
    ptr += DATE_LENGTH;
    
    /* Skip comma */
    if (*ptr != ',') return 0;
    ptr++;
    
    /* Parse time (5 chars) */
    if (strlen(ptr) < TIME_LENGTH) return 0;
    strncpy(entry->time, ptr, TIME_LENGTH);
    entry->time[TIME_LENGTH] = '\0';
    ptr += TIME_LENGTH;
    
    /* Skip comma */
    if (*ptr != ',') return 0;
    ptr++;
    
    /* Parse category (10 chars) */
    if (strlen(ptr) < CATEGORY_LENGTH) return 0;
    strncpy(entry->category, ptr, CATEGORY_LENGTH);
    entry->category[CATEGORY_LENGTH] = '\0';
    ptr += CATEGORY_LENGTH;
    
    /* Skip comma */
    if (*ptr != ',') return 0;
    ptr++;
    
    /* Parse free text (quoted) */
    if (*ptr != '"') return 0;
    ptr++;
    
    i = 0;
    while (*ptr != '\0' && *ptr != '"' && i < FREETEXT_MAX_LENGTH) {
        entry->freetext[i++] = *ptr++;
    }
    entry->freetext[i] = '\0';
    
    /* Should end with quote */
    if (*ptr != '"') return 0;
    
    return 1;
}

int get_cnotes_path(char *buffer, size_t bufsize) {
    const char *home;
    size_t len;
    
    home = getenv("HOME");
    if (home == NULL) {
        fprintf(stderr, "Error: HOME environment variable not set\n");
        return 0;
    }
    
    /* Build path: $HOME/.local/share/cnotes/cnotes.csv */
    len = strlen(home);
    if (len + strlen(CNOTES_DIR) + strlen(CNOTES_FILE) + 3 > bufsize) {
        fprintf(stderr, "Error: Path too long\n");
        return 0;
    }
    
    sprintf(buffer, "%s/%s/%s", home, CNOTES_DIR, CNOTES_FILE);
    return 1;
}

int main(void) {
    FILE *file;
    char file_path[600];
    char line[MAX_LINE_LENGTH];
    Entry entry;
    int line_count;
    int first_entry;
    
    /* Get cnotes file path */
    if (!get_cnotes_path(file_path, sizeof(file_path))) {
        return 1;
    }
    
    file = fopen(file_path, "r");
    if (file == NULL) {
        fprintf(stderr, "Error: Cannot open file '%s'\n", file_path);
        fprintf(stderr, "Hint: Use 'addnote' to create your first entry\n");
        return 1;
    }
    
    line_count = 0;
    first_entry = 1;
    
    while (fgets(line, sizeof(line), file) != NULL) {
        line_count++;
        
        /* Remove trailing newline */
        line[strcspn(line, "\n")] = '\0';
        
        /* Skip empty lines */
        if (strlen(line) == 0) continue;
        
        if (parse_line(line, &entry)) {
            if (first_entry) {
                print_header();
                first_entry = 0;
            }
            print_entry(&entry);
        } else {
            fprintf(stderr, "Warning: Skipping malformed line %d\n", line_count);
        }
    }
    
    if (!first_entry) {
        print_footer();
    } else {
        printf("No valid entries found.\n");
    }
    
    fclose(file);
    return 0;
}