/*
 * cnfind - Search note entries
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "platform.h"
#include "config.h"

#define MAX_LENGTH 500
#define DATE_LENGTH 10
#define TIME_LENGTH 5
#define TXTMSG_LENGTH 125

typedef struct {
    char date[DATE_LENGTH + 1];
    char time[TIME_LENGTH + 1];
    char category[CATEGORY_LENGTH + 1];
    char text[TXTMSG_LENGTH + 1];
    int line_num;
} Entry;

/* Case-insensitive substring search */
static char *stristr(const char *haystack, const char *needle) {
    const char *h;
    const char *n;
    const char *start;

    if (*needle == '\0') return (char *)haystack;

    for (start = haystack; *start != '\0'; start++) {
        h = start;
        n = needle;
        while (*h != '\0' && *n != '\0' && tolower((unsigned char)*h) == tolower((unsigned char)*n)) {
            h++;
            n++;
        }
        if (*n == '\0') return (char *)start;
    }
    return NULL;
}

/* Parse a line into an Entry struct */
static int parse_line(const char *line, Entry *entry) {
    const char *ptr = line;
    int i;

    /* Parse date */
    if (strlen(line) < DATE_LENGTH) return 0;
    strncpy(entry->date, ptr, DATE_LENGTH);
    entry->date[DATE_LENGTH] = '\0';
    ptr += DATE_LENGTH;
    if (*ptr != ',') return 0;
    ptr++;

    /* Parse time */
    if (strlen(ptr) < TIME_LENGTH) return 0;
    strncpy(entry->time, ptr, TIME_LENGTH);
    entry->time[TIME_LENGTH] = '\0';
    ptr += TIME_LENGTH;
    if (*ptr != ',') return 0;
    ptr++;

    /* Parse category (up to comma) */
    i = 0;
    while (*ptr != ',' && *ptr != '\0' && i < CATEGORY_LENGTH) {
        entry->category[i++] = *ptr++;
    }
    entry->category[i] = '\0';
    /* Trim trailing spaces */
    while (i > 0 && entry->category[i - 1] == ' ') {
        entry->category[--i] = '\0';
    }
    if (*ptr != ',') return 0;
    ptr++;

    /* Parse text (quoted) */
    if (*ptr != '"') return 0;
    ptr++;
    i = 0;
    while (*ptr != '"' && *ptr != '\0' && i < TXTMSG_LENGTH) {
        entry->text[i++] = *ptr++;
    }
    entry->text[i] = '\0';

    return 1;
}

int get_cnotes_path(char *buffer, size_t bufsize, const char *filename) {
    const char *custom_path;
    const char *home;
    size_t len;

    custom_path = getenv(CNOTES_PATH_ENV);
    if (custom_path != NULL && strlen(custom_path) > 0) {
        if (strlen(custom_path) + strlen(filename) + 2 > bufsize) {
            fprintf(stderr, "Error: Path too long\n");
            return 0;
        }
        sprintf(buffer, "%s" PATH_SEP_STR "%s", custom_path, filename);
        return 1;
    }

    home = getenv(HOME_ENV);
    if (home == NULL) {
        fprintf(stderr, "Error: %s environment variable not set\n", HOME_ENV);
        fprintf(stderr, "Hint: Set %s to specify notes directory\n", CNOTES_PATH_ENV);
        return 0;
    }

    len = strlen(home);
    if (strlen(CNOTES_DIR) == 0) {
        if (len + strlen(filename) + 2 > bufsize) {
            fprintf(stderr, "Error: Path too long\n");
            return 0;
        }
        sprintf(buffer, "%s" PATH_SEP_STR "%s", home, filename);
    } else {
        if (len + strlen(CNOTES_DIR) + strlen(filename) + 3 > bufsize) {
            fprintf(stderr, "Error: Path too long\n");
            return 0;
        }
        sprintf(buffer, "%s" PATH_SEP_STR "%s" PATH_SEP_STR "%s", home, CNOTES_DIR, filename);
    }
    return 1;
}

void print_horizontal_line(char left, char middle, char right, char fill) {
    int i;
    printf("%c", left);

    /* Line number column */
    for (i = 0; i < 5; i++) printf("%c", fill);
    printf("%c", middle);

    /* 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 < TXTMSG_LENGTH + 2; i++) printf("%c", fill);
    printf("%c\n", right);
}

void print_header(int is_archive) {
    print_horizontal_line('+', '+', '+', '=');
    printf("| %-3s | %-*s | %-*s | %-*s | %-*s |\n",
           "Ln",
           DATE_LENGTH, "Date",
           TIME_LENGTH, "Time",
           CATEGORY_LENGTH, "Category",
           TXTMSG_LENGTH, is_archive ? "Free Text (ARCHIVED)" : "Free Text");
    print_horizontal_line('+', '+', '+', '=');
}

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

void print_entry(const Entry *entry) {
    printf("| %3d | %-*s | %-*s | %-*s | %-*s |\n",
           entry->line_num,
           DATE_LENGTH, entry->date,
           TIME_LENGTH, entry->time,
           CATEGORY_LENGTH, entry->category,
           TXTMSG_LENGTH, entry->text);
}

void print_usage(const char *prog_name) {
    fprintf(stderr, "Usage: %s [OPTIONS] [PATTERN]\n", prog_name);
    fprintf(stderr, "\n");
    fprintf(stderr, "Search notes by text, category, or date.\n");
    fprintf(stderr, "\n");
    fprintf(stderr, "Options:\n");
    fprintf(stderr, "  -c CATEGORY   Filter by category (case-insensitive)\n");
    fprintf(stderr, "  -d DATE       Filter by date (YYYY-MM-DD)\n");
    fprintf(stderr, "  -i            Case-sensitive search (default is case-insensitive)\n");
    fprintf(stderr, "  -n            Show only count of matches\n");
    fprintf(stderr, "  -a, --archive Search archived entries instead of active\n");
    fprintf(stderr, "  -h, --help    Show this help message\n");
    fprintf(stderr, "\n");
    fprintf(stderr, "Examples:\n");
    fprintf(stderr, "  %s meeting              Search for 'meeting' in text\n", prog_name);
    fprintf(stderr, "  %s -c Work              Show all entries in Work category\n", prog_name);
    fprintf(stderr, "  %s -d 2025-01-30        Show all entries from a date\n", prog_name);
    fprintf(stderr, "  %s -c Work meeting      Search 'meeting' in Work category\n", prog_name);
    fprintf(stderr, "  %s -a meeting           Search archived entries\n", prog_name);
}

int main(int argc, char *argv[]) {
    int i;
    FILE *notesfile;
    char file_path[600];
    char line[MAX_LENGTH + 1];
    Entry entry;
    int line_num = 0;
    int match_count = 0;
    int header_printed = 0;

    /* Search options */
    char *pattern = NULL;
    char *filter_category = NULL;
    char *filter_date = NULL;
    int case_sensitive = 0;
    int count_only = 0;
    int search_archive = 0;
    const char *target_file;

    /* Parse command line arguments */
    for (i = 1; i < argc; i++) {
        if (strcmp(argv[i], "-c") == 0) {
            if (i + 1 >= argc) {
                fprintf(stderr, "cnfind: -c requires a category\n");
                print_usage(argv[0]);
                return 1;
            }
            filter_category = argv[++i];
        }
        else if (strcmp(argv[i], "-d") == 0) {
            if (i + 1 >= argc) {
                fprintf(stderr, "cnfind: -d requires a date (YYYY-MM-DD)\n");
                print_usage(argv[0]);
                return 1;
            }
            filter_date = argv[++i];
            if (strlen(filter_date) != DATE_LENGTH) {
                fprintf(stderr, "cnfind: invalid date format '%s' (use YYYY-MM-DD)\n", filter_date);
                return 1;
            }
        }
        else if (strcmp(argv[i], "-i") == 0) {
            case_sensitive = 1;
        }
        else if (strcmp(argv[i], "-n") == 0) {
            count_only = 1;
        }
        else if (strcmp(argv[i], "-a") == 0 || strcmp(argv[i], "--archive") == 0) {
            search_archive = 1;
        }
        else if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "--help") == 0) {
            print_usage(argv[0]);
            return 0;
        }
        else if (argv[i][0] == '-') {
            fprintf(stderr, "cnfind: unknown option '%s'\n", argv[i]);
            print_usage(argv[0]);
            return 1;
        }
        else {
            /* Positional argument is the search pattern */
            pattern = argv[i];
        }
    }

    /* Must have at least one filter criteria */
    if (pattern == NULL && filter_category == NULL && filter_date == NULL) {
        fprintf(stderr, "cnfind: must specify a search pattern, -c CATEGORY, or -d DATE\n");
        print_usage(argv[0]);
        return 1;
    }

    /* Select target file */
    target_file = search_archive ? CNOTES_ARCHIVE_FILE : CNOTES_FILE;

    /* Get file path */
    if (!get_cnotes_path(file_path, sizeof(file_path), target_file)) {
        return 1;
    }

    notesfile = fopen(file_path, "r");
    if (notesfile == NULL) {
        if (search_archive) {
            fprintf(stderr, "No archived entries found.\n");
        } else {
            fprintf(stderr, "Error: Cannot open file '%s'\n", file_path);
            fprintf(stderr, "Hint: Use 'cnadd' to create your first entry\n");
        }
        return 1;
    }

    /* Search entries */
    while (fgets(line, MAX_LENGTH, notesfile) != NULL) {
        int matches = 1;

        if (strlen(line) < DATE_LENGTH) continue;
        line_num++;

        if (!parse_line(line, &entry)) {
            continue;
        }
        entry.line_num = line_num;

        /* Check date filter */
        if (filter_date != NULL) {
            if (strncmp(entry.date, filter_date, DATE_LENGTH) != 0) {
                matches = 0;
            }
        }

        /* Check category filter */
        if (matches && filter_category != NULL) {
            if (stristr(entry.category, filter_category) == NULL) {
                matches = 0;
            }
        }

        /* Check text pattern */
        if (matches && pattern != NULL) {
            if (case_sensitive) {
                if (strstr(entry.text, pattern) == NULL) {
                    matches = 0;
                }
            } else {
                if (stristr(entry.text, pattern) == NULL) {
                    matches = 0;
                }
            }
        }

        if (matches) {
            match_count++;
            if (!count_only) {
                if (!header_printed) {
                    print_header(search_archive);
                    header_printed = 1;
                }
                print_entry(&entry);
            }
        }
    }

    fclose(notesfile);

    if (!count_only && header_printed) {
        print_footer();
    }

    /* Print summary */
    if (count_only) {
        printf("%d\n", match_count);
    } else {
        printf("\n%d match(es) found%s.\n", match_count, search_archive ? " in archive" : "");
    }

    return (match_count > 0) ? 0 : 1;
}