/* finance.c - Implementasi operasi Finance */
#include "finance.h"

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

void finance_init(Finance *f) {
    if (f == NULL) {
        return;
    }
    f->count = 0;
    f->next_id = 1;
}

/* Helper: case-insensitive string equality. */
static int eq_ci(const char *a, const char *b) {
    if (a == NULL || b == NULL) {
        return 0;
    }
    while (*a != '\0' && *b != '\0') {
        if (tolower((unsigned char)*a) != tolower((unsigned char)*b)) {
            return 0;
        }
        a++;
        b++;
    }
    return *a == '\0' && *b == '\0';
}

int finance_add(Finance *f, TxnType type, double amount,
                const char *description, const char *category,
                const char *date) {
    if (f == NULL || description == NULL || category == NULL || date == NULL) {
        return -1;
    }
    if (f->count >= FINANCE_CAPACITY) {
        return -1;
    }
    Transaction *slot = &f->items[f->count];
    int id = f->next_id;
    if (transaction_create(slot, id, type, amount, description,
                           category, date) != 0) {
        return -1;
    }
    f->next_id++;
    f->count++;
    return id;
}

int finance_delete(Finance *f, int id) {
    if (f == NULL) {
        return -1;
    }
    for (int i = 0; i < f->count; i++) {
        if (f->items[i].id == id) {
            memmove(&f->items[i], &f->items[i + 1],
                    (size_t)(f->count - i - 1) * sizeof(Transaction));
            f->count--;
            return 0;
        }
    }
    return -1;
}

int finance_filter_by_category(const Finance *f, const char *category,
                                Transaction *out, int out_cap) {
    if (f == NULL || out == NULL || out_cap <= 0) {
        return 0;
    }
    int found = 0;
    for (int i = 0; i < f->count && found < out_cap; i++) {
        if (eq_ci(f->items[i].category, category)) {
            out[found++] = f->items[i];
        }
    }
    return found;
}

int finance_filter_by_date(const Finance *f, const char *from,
                           const char *to, Transaction *out, int out_cap) {
    if (f == NULL || out == NULL || out_cap <= 0) {
        return 0;
    }
    int found = 0;
    for (int i = 0; i < f->count && found < out_cap; i++) {
        const char *d = f->items[i].date;
        if (from != NULL && strcmp(d, from) < 0) {
            continue;
        }
        if (to != NULL && strcmp(d, to) > 0) {
            continue;
        }
        out[found++] = f->items[i];
    }
    return found;
}

void finance_summary(const Finance *f, double *total_income,
                     double *total_expense, double *balance) {
    double inc = 0.0;
    double exp = 0.0;
    if (f != NULL) {
        for (int i = 0; i < f->count; i++) {
            if (f->items[i].type == TXN_INCOME) {
                inc += f->items[i].amount;
            } else {
                exp += f->items[i].amount;
            }
        }
    }
    if (total_income != NULL) {
        *total_income = inc;
    }
    if (total_expense != NULL) {
        *total_expense = exp;
    }
    if (balance != NULL) {
        *balance = inc - exp;
    }
}

void finance_print_all(const Finance *f) {
    if (f == NULL) {
        return;
    }
    printf("Total transaksi: %d/%d\n", f->count, FINANCE_CAPACITY);
    for (int i = 0; i < f->count; i++) {
        transaction_print(&f->items[i]);
    }
}

/* main.c - Program utama Pengelola Keuangan Pribadi */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "finance.h"
#include "storage.h"
#include "report.h"

#define DB_PATH "finance.csv"

static int read_line(char *buf, size_t cap) {
    if (fgets(buf, (int)cap, stdin) == NULL) {
        return -1;
    }
    size_t len = strlen(buf);
    while (len > 0 && (buf[len - 1] == '\n' || buf[len - 1] == '\r')) {
        buf[--len] = '\0';
    }
    return 0;
}

static void print_menu(void) {
    puts("");
    puts("=== Pengelola Keuangan Pribadi ===");
    puts("1. Catat pemasukan");
    puts("2. Catat pengeluaran");
    puts("3. Daftar semua transaksi");
    puts("4. Ringkasan keuangan");
    puts("5. Filter per kategori");
    puts("6. Filter per tanggal");
    puts("7. Laporan per kategori");
    puts("8. Laporan bulanan");
    puts("9. Hapus transaksi");
    puts("S. Simpan ke file");
    puts("L. Muat dari file");
    puts("Q. Keluar");
    printf("Pilihan: ");
}

static int ask_txn_type(TxnType wanted) {
    char buf[256];
    double amount;
    printf("Jumlah (Rp): ");
    if (read_line(buf, sizeof(buf)) != 0) {
        return -1;
    }
    amount = strtod(buf, NULL);
    if (amount <= 0) {
        printf("Jumlah harus positif.\n");
        return -1;
    }
    char desc[TXN_DESC_MAX];
    printf("Deskripsi: ");
    if (read_line(desc, sizeof(desc)) != 0) {
        return -1;
    }
    char cat[TXN_CATEGORY_MAX];
    printf("Kategori: ");
    if (read_line(cat, sizeof(cat)) != 0) {
        return -1;
    }
    char date[16];
    printf("Tanggal (YYYY-MM-DD, kosongkan = hari ini): ");
    if (read_line(date, sizeof(date)) != 0) {
        return -1;
    }
    if (date[0] == '\0') {
        strcpy(date, "2024-01-01");
    }
    int id = finance_add(NULL, wanted, 0, NULL, NULL, NULL);
    (void)id;
    return 0;
}

static void do_add(Finance *f, TxnType type) {
    char buf[256];
    printf("Jumlah (Rp): ");
    if (read_line(buf, sizeof(buf)) != 0) {
        return;
    }
    double amount = strtod(buf, NULL);
    if (amount <= 0) {
        printf("Jumlah harus positif.\n");
        return;
    }
    char desc[TXN_DESC_MAX];
    printf("Deskripsi: ");
    if (read_line(desc, sizeof(desc)) != 0) {
        return;
    }
    char cat[TXN_CATEGORY_MAX];
    printf("Kategori: ");
    if (read_line(cat, sizeof(cat)) != 0) {
        return;
    }
    char date[16];
    printf("Tanggal (YYYY-MM-DD): ");
    if (read_line(date, sizeof(date)) != 0) {
        return;
    }
    int id = finance_add(f, type, amount, desc, cat, date);
    if (id < 0) {
        printf("Gagal menambah transaksi. Periksa kembali input.\n");
        return;
    }
    printf("Transaksi dicatat dengan id=%d\n", id);
}

static void do_summary(const Finance *f) {
    double inc, exp, bal;
    finance_summary(f, &inc, &exp, &bal);
    printf("\n=== Ringkasan Keuangan ===\n");
    printf("Total pemasukan : Rp%12.2f\n", inc);
    printf("Total pengeluaran: Rp%12.2f\n", exp);
    printf("Saldo bersih    : Rp%12.2f\n", bal);
}

static void do_filter_category(const Finance *f) {
    char cat[TXN_CATEGORY_MAX];
    printf("Kategori: ");
    if (read_line(cat, sizeof(cat)) != 0) {
        return;
    }
    Transaction out[64];
    int n = finance_filter_by_category(f, cat, out, 64);
    printf("Ditemukan %d transaksi:\n", n);
    for (int i = 0; i < n; i++) {
        transaction_print(&out[i]);
    }
}

static void do_filter_date(const Finance *f) {
    char from[16], to[16];
    printf("Dari (YYYY-MM-DD): ");
    if (read_line(from, sizeof(from)) != 0) {
        return;
    }
    printf("Sampai (YYYY-MM-DD): ");
    if (read_line(to, sizeof(to)) != 0) {
        return;
    }
    Transaction out[64];
    int n = finance_filter_by_date(f, from, to, out, 64);
    printf("Ditemukan %d transaksi:\n", n);
    for (int i = 0; i < n; i++) {
        transaction_print(&out[i]);
    }
}

static void do_report_category(const Finance *f) {
    CategoryReport reports[32];
    int n = report_by_category(f, reports, 32);
    report_print_category(reports, n);
}

static void do_delete(Finance *f) {
    char buf[16];
    printf("Masukkan id transaksi: ");
    if (read_line(buf, sizeof(buf)) != 0) {
        return;
    }
    int id = (int)strtol(buf, NULL, 10);
    if (finance_delete(f, id) != 0) {
        printf("Transaksi id %d tidak ditemukan.\n", id);
        return;
    }
    printf("Transaksi id %d dihapus.\n", id);
}

int main(void) {
    Finance f;
    finance_init(&f);
    if (storage_load(&f, DB_PATH) > 0) {
        printf("Memuat %d transaksi dari %s\n", f.count, DB_PATH);
    }

    char choice[8];
    int running = 1;
    while (running) {
        print_menu();
        if (read_line(choice, sizeof(choice)) != 0) {
            break;
        }
        char c = (char)tolower((unsigned char)choice[0]);
        switch (c) {
            case '1': do_add(&f, TXN_INCOME); break;
            case '2': do_add(&f, TXN_EXPENSE); break;
            case '3': finance_print_all(&f); break;
            case '4': do_summary(&f); break;
            case '5': do_filter_category(&f); break;
            case '6': do_filter_date(&f); break;
            case '7': do_report_category(&f); break;
            case '8': report_print_monthly(&f); break;
            case '9': do_delete(&f); break;
            case 's': {
                int n = storage_save(&f, DB_PATH);
                if (n >= 0) {
                    printf("Menyimpan %d transaksi ke %s\n", n, DB_PATH);
                } else {
                    printf("Gagal menyimpan ke %s\n", DB_PATH);
                }
                break;
            }
            case 'l': {
                int n = storage_load(&f, DB_PATH);
                if (n >= 0) {
                    printf("Memuat %d transaksi dari %s\n", n, DB_PATH);
                } else {
                    printf("Gagal memuat dari %s\n", DB_PATH);
                }
                break;
            }
            case 'q': running = 0; break;
            default:  printf("Pilihan tidak dikenal: %c\n", c); break;
        }
    }
    /* Hindari warning unused function. */
    (void)ask_txn_type;
    puts("Terima kasih telah menggunakan Pengelola Keuangan.");
    return 0;
}

/* report.c - Implementasi laporan keuangan */
#include "report.h"

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

static int eq_ci(const char *a, const char *b) {
    while (*a != '\0' && *b != '\0') {
        if (tolower((unsigned char)*a) != tolower((unsigned char)*b)) {
            return 0;
        }
        a++;
        b++;
    }
    return *a == '\0' && *b == '\0';
}

static void cat_report_init(CategoryReport *r, const char *category) {
    memset(r, 0, sizeof(*r));
    strncpy(r->category, category, TXN_CATEGORY_MAX - 1);
    r->category[TXN_CATEGORY_MAX - 1] = '\0';
}

int report_by_category(const Finance *f, CategoryReport *out, int out_cap) {
    if (f == NULL || out == NULL || out_cap <= 0) {
        return 0;
    }
    int unique = 0;
    for (int i = 0; i < f->count; i++) {
        const Transaction *t = &f->items[i];
        /* Cari kategori yang sudah ada di `out`. */
        int found = -1;
        for (int k = 0; k < unique; k++) {
            if (eq_ci(out[k].category, t->category)) {
                found = k;
                break;
            }
        }
        if (found < 0) {
            if (unique >= out_cap) {
                continue;
            }
            cat_report_init(&out[unique], t->category);
            found = unique;
            unique++;
        }
        if (t->type == TXN_INCOME) {
            out[found].income += t->amount;
        } else {
            out[found].expense += t->amount;
        }
        out[found].balance += transaction_signed_value(t);
        out[found].count++;
    }
    return unique;
}

void report_print_category(const CategoryReport *r, int count) {
    if (r == NULL || count <= 0) {
        printf("Tidak ada data untuk laporan.\n");
        return;
    }
    printf("\n=== Laporan per Kategori ===\n");
    printf("%-20s %12s %12s %12s  %6s\n",
           "Kategori", "Pemasukan", "Pengeluaran", "Saldo", "#Txn");
    double total_inc = 0, total_exp = 0;
    for (int i = 0; i < count; i++) {
        printf("%-20s %12.2f %12.2f %12.2f  %6d\n",
               r[i].category, r[i].income, r[i].expense,
               r[i].balance, r[i].count);
        total_inc += r[i].income;
        total_exp += r[i].expense;
    }
    printf("%-20s %12.2f %12.2f %12.2f\n",
           "TOTAL", total_inc, total_exp, total_inc - total_exp);
}

void report_print_monthly(const Finance *f) {
    if (f == NULL || f->count == 0) {
        printf("Tidak ada data untuk laporan bulanan.\n");
        return;
    }
    printf("\n=== Laporan Bulanan ===\n");
    printf("%-8s %12s %12s %12s\n",
           "Bulan", "Pemasukan", "Pengeluaran", "Saldo");

    char current[8] = "";
    double m_inc = 0, m_exp = 0;
    for (int i = 0; i < f->count; i++) {
        const Transaction *t = &f->items[i];
        char month[8];
        /* YYYY-MM diambil dari 7 karakter pertama date. */
        snprintf(month, sizeof(month), "%.7s", t->date);
        if (strcmp(month, current) != 0) {
            if (current[0] != '\0') {
                printf("%-8s %12.2f %12.2f %12.2f\n",
                       current, m_inc, m_exp, m_inc - m_exp);
            }
            strcpy(current, month);
            m_inc = 0;
            m_exp = 0;
        }
        if (t->type == TXN_INCOME) {
            m_inc += t->amount;
        } else {
            m_exp += t->amount;
        }
    }
    if (current[0] != '\0') {
        printf("%-8s %12.2f %12.2f %12.2f\n",
               current, m_inc, m_exp, m_inc - m_exp);
    }
}

/* storage.c - Implementasi persistensi CSV untuk Finance */
#include "storage.h"

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

static void strip_newline(char *s) {
    size_t len = strlen(s);
    while (len > 0 && (s[len - 1] == '\n' || s[len - 1] == '\r')) {
        s[--len] = '\0';
    }
}

/* Parse satu baris CSV dengan field yang mungkin mengandung koma
 * jika dibungkus tanda kutip. Implementasi sederhana: kita asumsikan
 * description dan category tidak mengandung koma. */
static int parse_line(const char *line, int *id, int *type,
                      double *amount, char *desc, size_t desc_cap,
                      char *cat, size_t cat_cap, char *date, size_t date_cap) {
    char tmp_desc[TXN_DESC_MAX];
    char tmp_cat[TXN_CATEGORY_MAX];
    char tmp_date[16];
    int consumed = 0;
    int items = sscanf(line, "%d,%d,%lf,%63[^,],%31[^,],%10s%n",
                       id, type, amount, tmp_desc, tmp_cat, tmp_date,
                       &consumed);
    if (items != 6) {
        return 0;
    }
    char trailing = line[consumed];
    if (trailing != '\0' && trailing != '\n' && trailing != '\r') {
        return 0;
    }
    if (desc_cap < sizeof(tmp_desc) || cat_cap < sizeof(tmp_cat) ||
        date_cap < sizeof(tmp_date)) {
        return 0;
    }
    strcpy(desc, tmp_desc);
    strcpy(cat, tmp_cat);
    strcpy(date, tmp_date);
    return 1;
}

int storage_save(const Finance *f, const char *path) {
    if (f == NULL || path == NULL) {
        return -1;
    }
    FILE *fp = fopen(path, "w");
    if (fp == NULL) {
        return -1;
    }
    fprintf(fp, "# id,type,amount,description,category,date\n");
    int written = 0;
    for (int i = 0; i < f->count; i++) {
        const Transaction *t = &f->items[i];
        int n = fprintf(fp, "%d,%d,%.2f,%s,%s,%s\n",
                        t->id, t->type, t->amount,
                        t->description, t->category, t->date);
        if (n < 0) {
            fclose(fp);
            return -1;
        }
        written++;
    }
    fclose(fp);
    return written;
}

int storage_load(Finance *f, const char *path) {
    if (f == NULL || path == NULL) {
        return -1;
    }
    FILE *fp = fopen(path, "r");
    if (fp == NULL) {
        return -1;
    }
    finance_init(f);
    char line[256];
    int read = 0;
    int max_id_seen = 0;
    while (fgets(line, sizeof(line), fp) != NULL) {
        if (line[0] == '#' || line[0] == '\n' || line[0] == '\r') {
            continue;
        }
        strip_newline(line);
        int id, type;
        double amount;
        char desc[TXN_DESC_MAX];
        char cat[TXN_CATEGORY_MAX];
        char date[16];
        if (!parse_line(line, &id, &type, &amount, desc, sizeof(desc),
                       cat, sizeof(cat), date, sizeof(date))) {
            continue;
        }
        if (f->count >= FINANCE_CAPACITY) {
            break;
        }
        if (type != TXN_INCOME && type != TXN_EXPENSE) {
            continue;
        }
        Transaction *slot = &f->items[f->count];
        if (transaction_create(slot, id, (TxnType)type, amount,
                               desc, cat, date) != 0) {
            continue;
        }
        if (id > max_id_seen) {
            max_id_seen = id;
        }
        f->count++;
        read++;
    }
    f->next_id = max_id_seen + 1;
    fclose(fp);
    return read;
}

/* tests.c - Unit test untuk modul keuangan */
#include <stdio.h>
#include <string.h>

#include "finance.h"
#include "storage.h"
#include "report.h"

static int tests_run = 0;
static int tests_pass = 0;

#define ASSERT(cond, msg) \
    do { \
        tests_run++; \
        if (cond) { \
            tests_pass++; \
        } else { \
            printf("FAIL: %s (line %d)\n", msg, __LINE__); \
        } \
    } while (0)

static void test_transaction_create(void) {
    Transaction t;
    int rc = transaction_create(&t, 1, TXN_INCOME, 1000000.0,
                                "Gaji bulanan", "Gaji", "2024-03-01");
    ASSERT(rc == 0, "transaction_create valid harus sukses");
    ASSERT(t.id == 1, "id harus 1");
    ASSERT(t.type == TXN_INCOME, "type harus INCOME");
    ASSERT(transaction_signed_value(&t) == 1000000.0, "signed = +1M");

    Transaction t2;
    rc = transaction_create(&t2, 2, TXN_EXPENSE, 25000.0,
                            "Makan siang", "Makan", "2024-03-02");
    ASSERT(rc == 0, "transaction_create expense sukses");
    ASSERT(transaction_signed_value(&t2) == -25000.0, "signed = -25K");
}

static void test_transaction_invalid(void) {
    Transaction t;
    ASSERT(transaction_create(&t, 0, TXN_INCOME, 100, "X", "C", "2024-01-01") != 0,
           "id=0 ditolak");
    ASSERT(transaction_create(&t, 1, TXN_INCOME, -1, "X", "C", "2024-01-01") != 0,
           "amount negatif ditolak");
    ASSERT(transaction_create(&t, 1, TXN_INCOME, 100, "X", "C", "2024/01/01") != 0,
           "format tanggal salah ditolak");
    ASSERT(transaction_create(&t, 1, TXN_INCOME, 100, "X", "C", "2024-13-01") != 0,
           "bulan 13 ditolak");
    ASSERT(transaction_create(&t, 1, TXN_INCOME, 100, "X", "C", "2024-01-32") != 0,
           "hari 32 ditolak");
}

static void test_finance_add_summary(void) {
    Finance f;
    finance_init(&f);
    int id1 = finance_add(&f, TXN_INCOME, 5000000.0, "Gaji", "Gaji", "2024-03-01");
    int id2 = finance_add(&f, TXN_EXPENSE, 50000.0, "Bensin", "Transport", "2024-03-02");
    int id3 = finance_add(&f, TXN_EXPENSE, 30000.0, "Makan", "Makan", "2024-03-02");
    ASSERT(id1 == 1 && id2 == 2 && id3 == 3, "id berurutan");
    ASSERT(f.count == 3, "count harus 3");

    double inc, exp, bal;
    finance_summary(&f, &inc, &exp, &bal);
    ASSERT(inc == 5000000.0, "total income 5M");
    ASSERT(exp == 80000.0, "total expense 80K");
    ASSERT(bal == 4920000.0, "balance 4.92M");
}

static void test_finance_filter_category(void) {
    Finance f;
    finance_init(&f);
    finance_add(&f, TXN_EXPENSE, 10000.0, "Kopi", "Makan", "2024-03-01");
    finance_add(&f, TXN_EXPENSE, 20000.0, "Bakso", "Makan", "2024-03-01");
    finance_add(&f, TXN_EXPENSE, 50000.0, "Bensin", "Transport", "2024-03-02");

    Transaction out[16];
    int n = finance_filter_by_category(&f, "makan", out, 16);
    ASSERT(n == 2, "filter 'makan' case-insensitive = 2");

    n = finance_filter_by_category(&f, "TidakAda", out, 16);
    ASSERT(n == 0, "kategori tidak ada = 0");
}

static void test_finance_filter_date(void) {
    Finance f;
    finance_init(&f);
    finance_add(&f, TXN_EXPENSE, 10000.0, "A", "X", "2024-03-01");
    finance_add(&f, TXN_EXPENSE, 20000.0, "B", "X", "2024-03-02");
    finance_add(&f, TXN_EXPENSE, 30000.0, "C", "X", "2024-03-05");
    finance_add(&f, TXN_EXPENSE, 40000.0, "D", "X", "2024-03-10");

    Transaction out[16];
    int n = finance_filter_by_date(&f, "2024-03-02", "2024-03-05", out, 16);
    ASSERT(n == 2, "rentang tanggal 02-05 = 2 transaksi");

    n = finance_filter_by_date(&f, NULL, "2024-03-02", out, 16);
    ASSERT(n == 2, "hanya sampai 02 = 2");

    n = finance_filter_by_date(&f, "2024-03-06", NULL, out, 16);
    ASSERT(n == 1, "hanya dari 06 = 1");
}

static void test_storage_roundtrip(void) {
    Finance f;
    finance_init(&f);
    finance_add(&f, TXN_INCOME, 1000000.0, "Gaji", "Gaji", "2024-03-01");
    finance_add(&f, TXN_EXPENSE, 50000.0, "Bensin", "Transport", "2024-03-02");

    const char *path = "/tmp/test_finance.csv";
    int written = storage_save(&f, path);
    ASSERT(written == 2, "harus menulis 2 baris");

    Finance loaded;
    int read = storage_load(&loaded, path);
    ASSERT(read == 2, "harus membaca 2 baris");
    ASSERT(loaded.count == 2, "count=2 setelah load");
    ASSERT(loaded.next_id == 3, "next_id=3 setelah load");
    ASSERT(strcmp(loaded.items[0].description, "Gaji") == 0,
           "deskripsi[0] = Gaji");
}

static void test_report_category(void) {
    Finance f;
    finance_init(&f);
    finance_add(&f, TXN_INCOME, 1000000.0, "Gaji", "Gaji", "2024-03-01");
    finance_add(&f, TXN_EXPENSE, 50000.0, "Bensin", "Transport", "2024-03-02");
    finance_add(&f, TXN_EXPENSE, 30000.0, "Makan", "Makan", "2024-03-02");
    finance_add(&f, TXN_EXPENSE, 20000.0, "Cafe", "Makan", "2024-03-03");

    CategoryReport r[16];
    int n = report_by_category(&f, r, 16);
    ASSERT(n == 3, "harus ada 3 kategori unik");

    int found_gaji = 0, found_makan = 0, found_transport = 0;
    for (int i = 0; i < n; i++) {
        if (strcmp(r[i].category, "Gaji") == 0) {
            found_gaji = 1;
            ASSERT(r[i].income == 1000000.0, "Gaji income 1M");
            ASSERT(r[i].count == 1, "Gaji count 1");
        }
        if (strcmp(r[i].category, "Makan") == 0) {
            found_makan = 1;
            ASSERT(r[i].expense == 50000.0, "Makan expense 50K");
            ASSERT(r[i].count == 2, "Makan count 2");
        }
        if (strcmp(r[i].category, "Transport") == 0) {
            found_transport = 1;
        }
    }
    ASSERT(found_gaji && found_makan && found_transport,
           "ketiga kategori harus ada");
}

int main(void) {
    test_transaction_create();
    test_transaction_invalid();
    test_finance_add_summary();
    test_finance_filter_category();
    test_finance_filter_date();
    test_storage_roundtrip();
    test_report_category();

    printf("\n=== Hasil Test ===\n");
    printf("Total : %d\n", tests_run);
    printf("Lulus : %d\n", tests_pass);
    printf("Gagal : %d\n", tests_run - tests_pass);
    return (tests_run == tests_pass) ? 0 : 1;
}

/* transaction.c - Implementasi model Transaction */
#include "transaction.h"

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

int transaction_date_is_valid(const char *date) {
    if (date == NULL) {
        return 0;
    }
    /* Format: YYYY-MM-DD = 10 karakter. */
    if (strlen(date) != 10) {
        return 0;
    }
    for (int i = 0; i < 10; i++) {
        char c = date[i];
        if (i == 4 || i == 7) {
            if (c != '-') {
                return 0;
            }
        } else {
            if (!isdigit((unsigned char)c)) {
                return 0;
            }
        }
    }
    /* Validasi rentang bulan dan hari secara kasar. */
    int y, m, d;
    if (sscanf(date, "%d-%d-%d", &y, &m, &d) != 3) {
        return 0;
    }
    if (y < 1900 || y > 2999) {
        return 0;
    }
    if (m < 1 || m > 12) {
        return 0;
    }
    if (d < 1 || d > 31) {
        return 0;
    }
    return 1;
}

int transaction_create(Transaction *t, int id, TxnType type,
                       double amount, const char *description,
                       const char *category, const char *date) {
    if (t == NULL || description == NULL || category == NULL || date == NULL) {
        return -1;
    }
    if (id <= 0) {
        return -2;
    }
    if (type != TXN_INCOME && type != TXN_EXPENSE) {
        return -3;
    }
    if (amount <= 0.0 || isnan(amount) || isinf(amount)) {
        return -4;
    }
    if (!transaction_date_is_valid(date)) {
        return -5;
    }

    t->id = id;
    t->type = type;
    t->amount = amount;
    strncpy(t->description, description, TXN_DESC_MAX - 1);
    t->description[TXN_DESC_MAX - 1] = '\0';
    strncpy(t->category, category, TXN_CATEGORY_MAX - 1);
    t->category[TXN_CATEGORY_MAX - 1] = '\0';
    strncpy(t->date, date, sizeof(t->date) - 1);
    t->date[sizeof(t->date) - 1] = '\0';
    return 0;
}

double transaction_signed_value(const Transaction *t) {
    if (t == NULL) {
        return 0.0;
    }
    return t->type * t->amount;
}

void transaction_print(const Transaction *t) {
    if (t == NULL) {
        printf("(null transaction)\n");
        return;
    }
    const char *sign = (t->type == TXN_INCOME) ? "+" : "-";
    const char *label = (t->type == TXN_INCOME) ? "MASUK " : "KELUAR";
    printf("[%04d] %s %s %s  Rp%12.2f  %s\n",
           t->id, t->date, label, t->category,
           t->type * t->amount, t->description);
    (void)sign;
}