#include <dirent.h>
#include <errno.h>
#include <locale.h>
#include <math.h>
#include <ncursesw/ncurses.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#include "client.h"
#include "tui.h"
#include "formula.h"
#include "util.h"
#include "version.h"
#include "yyjson.h"
#include "ui.h"

/* ^C quits the application; Esc is navigation only */
int g_quit = 0;
/* ^R re-execs the binary, keeping session, org, year and screen */
int g_reload = 0;
char g_scene[32] = "dashboard";
char g_reload_scene[32];

int ui_getch(void)
{
    int ch = getch();
    if (ch == 3) { /* ^C */
        g_quit = 1;
        return 27; /* behave like "back" so screens unwind */
    }
    if (ch == 18) { /* ^R */
        g_reload = 1;
        snprintf(g_reload_scene, sizeof g_reload_scene, "%s", g_scene);
        return 27;
    }
    return ch;
}

void request_quit(void)
{
    g_quit = 1;
}
/* ------------------------------------------------------------------ */
/* json helpers                                                         */
/* ------------------------------------------------------------------ */

yyjson_val *jget(yyjson_val *root, const char *path)
{
    char tmp[128];
    snprintf(tmp, sizeof tmp, "%s", path);
    yyjson_val *v = root;
    char *save = NULL;
    for (char *tok = strtok_r(tmp, ".", &save); tok;
         tok = strtok_r(NULL, ".", &save)) {
        if (!v)
            return NULL;
        if (yyjson_is_obj(v))
            v = yyjson_obj_get(v, tok);
        else if (yyjson_is_arr(v)) {
            char *end = NULL;
            long idx = strtol(tok, &end, 10);
            if (!end || *end)
                return NULL;
            v = yyjson_arr_get(v, (size_t)idx);
        } else {
            return NULL;
        }
    }
    return v;
}

yyjson_doc *parse(const char *resp)
{
    return resp ? yyjson_read(resp, strlen(resp), 0) : NULL;
}

char *jstr_dup(const char *resp, const char *path)
{
    yyjson_doc *d = parse(resp);
    yyjson_val *v = d ? jget(yyjson_doc_get_root(d), path) : NULL;
    char *out = v && yyjson_is_str(v) ? xstrdup(yyjson_get_str(v)) : NULL;
    yyjson_doc_free(d);
    return out;
}

int64_t jint_val(const char *resp, const char *path, int64_t def)
{
    yyjson_doc *d = parse(resp);
    yyjson_val *v = d ? jget(yyjson_doc_get_root(d), path) : NULL;
    int64_t out = v && yyjson_is_int(v) ? yyjson_get_int(v) : def;
    yyjson_doc_free(d);
    return out;
}

size_t jarr_size(const char *resp, const char *path)
{
    yyjson_doc *d = parse(resp);
    yyjson_val *v = d ? jget(yyjson_doc_get_root(d), path) : NULL;
    size_t n = v && yyjson_is_arr(v) ? yyjson_arr_size(v) : 0;
    yyjson_doc_free(d);
    return n;
}

int jbool_val(const char *resp, const char *path, int def)
{
    yyjson_doc *d = parse(resp);
    yyjson_val *v = d ? jget(yyjson_doc_get_root(d), path) : NULL;
    int out = v && yyjson_is_bool(v) ? yyjson_get_bool(v) : def;
    yyjson_doc_free(d);
    return out;
}

/* ------------------------------------------------------------------ */
/* ui primitives                                                        */
/* ------------------------------------------------------------------ */

char g_server_version[32];

/* Whole kronor with space thousands, öre truncated like the blankett. */
void kr_whole(int64_t ore, char *buf, size_t n)
{
    char tmp[48];
    tui_kr_format((ore / 100) * 100, tmp, sizeof tmp);
    char *comma = strchr(tmp, ',');
    if (comma)
        *comma = '\0';
    snprintf(buf, n, "%s", tmp);
}

int parse_x_double(const char *s, double *out)
{
    if (!s)
        return 0;
    char buf[64];
    size_t j = 0;
    for (const char *p = s; *p && j < sizeof buf - 1; p++) {
        if (*p == ' ' || *p == '\t')
            continue;
        buf[j++] = (*p == ',') ? '.' : *p;
    }
    buf[j] = '\0';
    if (!j)
        return 0;
    char *end = NULL;
    double v = strtod(buf, &end);
    if (!end || *end)
        return 0;
    *out = v;
    return 1;
}

void replace_x_into(const char *src, double x, char *dst, size_t cap)
{
    size_t o = 0;
    for (const char *p = src; *p && o + 1 < cap;) {
        if (p[0] == '{' && p[1] == 'x' && p[2] == '}') {
            char tmp[64];
            snprintf(tmp, sizeof tmp, "%.2f", x);
            for (size_t k = 0; tmp[k] && o + 1 < cap; k++)
                dst[o++] = tmp[k];
            p += 3;
        } else {
            dst[o++] = *p++;
        }
    }
    dst[o] = '\0';
}

/* Display width in terminal columns, counting UTF-8 lead bytes. Good enough
   for Swedish text; combining marks are ignored. */


/* ------------------------------------------------------------------ */
/* app helpers                                                          */
/* ------------------------------------------------------------------ */

void app_refresh_context(struct app *a)
{
    char args[64];
    snprintf(args, sizeof args, "{\"org\":%lld}", (long long)a->org);
    char *resp = client_rpc(&a->conn, "session.use_org", a->session, 0, args);
    free(resp);

    resp = client_rpc(&a->conn, "org.get", a->session, a->org, "{}");
    if (resp && client_ok(resp)) {
        char *name = jstr_dup(resp, "result.name");
        if (name) {
            snprintf(a->org_name, sizeof a->org_name, "%s", name);
            free(name);
        }
    }
    free(resp);

    resp = client_rpc(&a->conn, "org.list", a->session, 0, "{}");
    if (resp) {
        size_t n = jarr_size(resp, "result.items");
        for (size_t i = 0; i < n; i++) {
            char path[64];
            snprintf(path, sizeof path, "result.items.%zu.id", i);
            if (jint_val(resp, path, -1) == a->org) {
                snprintf(path, sizeof path, "result.items.%zu.role", i);
                char *role = jstr_dup(resp, path);
                if (role) {
                    snprintf(a->role, sizeof a->role, "%s", role);
                    free(role);
                }
            }
        }
    }
    free(resp);

    snprintf(a->default_series, sizeof a->default_series, "%s", "A");
    a->attachment_dir[0] = '\0';
    resp = client_rpc(&a->conn, "settings.get", a->session, a->org, "{}");
    if (resp && client_ok(resp)) {
        char *ser = jstr_dup(resp, "result.default_series");
        if (ser && *ser)
            snprintf(a->default_series, sizeof a->default_series, "%s", ser);
        free(ser);
        char *dir = jstr_dup(resp, "result.attachment_dir");
        if (dir && *dir)
            snprintf(a->attachment_dir, sizeof a->attachment_dir, "%s", dir);
        free(dir);
    }
    free(resp);

    a->max_attachment_bytes = 10 * 1024 * 1024;
    resp = client_rpc(&a->conn, "meta", NULL, 0, NULL);
    if (resp && client_ok(resp)) {
        char *ver = jstr_dup(resp, "result.version");
        if (ver && *ver)
            snprintf(g_server_version, sizeof g_server_version, "%s", ver);
        free(ver);
        int64_t v =
            jint_val(resp, "result.limits.max_attachment_bytes", 0);
        if (v > 0)
            a->max_attachment_bytes = (long)v;
    }
    free(resp);

    resp = client_rpc(&a->conn, "fiscal_year.get", a->session, a->org, "{}");
    if (resp && client_ok(resp)) {
        a->fy = jint_val(resp, "result.id", 0);
        char *label = jstr_dup(resp, "result.label");
        char *start = jstr_dup(resp, "result.start_date");
        char *end = jstr_dup(resp, "result.end_date");
        if (label)
            snprintf(a->fy_label, sizeof a->fy_label, "%s", label);
        if (start)
            snprintf(a->fy_start, sizeof a->fy_start, "%s", start);
        if (end)
            snprintf(a->fy_end, sizeof a->fy_end, "%s", end);
        free(label);
        free(start);
        free(end);
    }
    free(resp);
}
void show_error(const char *title, const char *resp)
{
    char *code = jstr_dup(resp, "error.code");
    char *msg = jstr_dup(resp, "error.message");
    if ((!code || !*code) && (!msg || !*msg)) {
        tui_message(title, "%s", resp && *resp
                                ? resp
                                : "Inget svar från servern (kör daemonen?)");
    } else {
        tui_message(title, "%s: %s", code && *code ? code : "fel",
                msg && *msg ? msg : "okänt fel");
    }
    free(code);
    free(msg);
}

char *read_file_b64(const char *path)
{
    FILE *f = fopen(path, "rb");
    if (!f)
        return NULL;
    struct buf b;
    buf_init(&b);
    unsigned char chunk[65536];
    size_t rn;
    while ((rn = fread(chunk, 1, sizeof chunk, f)) > 0)
        buf_append(&b, chunk, rn);
    int bad = ferror(f);
    fclose(f);
    if (bad) {
        buf_free(&b);
        return NULL;
    }
    char *b64 = util_b64(b.p ? b.p : (const unsigned char *)"", b.len);
    buf_free(&b);
    return b64;
}
struct fentry {
    char name[300];
    int isdir;
};

static int fentry_cmp(const void *a, const void *b)
{
    const struct fentry *x = a;
    const struct fentry *y = b;
    if (x->isdir != y->isdir)
        return y->isdir - x->isdir;
    return strcasecmp(x->name, y->name);
}

/* Expands a leading ~ to $HOME (no ~user support). */
static void expand_path(const char *in, char *out, size_t n)
{
    if (in && in[0] == '~' && (in[1] == '\0' || in[1] == '/')) {
        const char *home = getenv("HOME");
        if (home)
            snprintf(out, n, "%s%s", home, in + 1);
        else
            snprintf(out, n, "%s", in[1] ? in + 2 : ".");
    } else {
        snprintf(out, n, "%s", in ? in : ".");
    }
}

/* File browser for choosing underlag. Starts in start_dir or $HOME.
   Returns a malloc'd path, or NULL on cancel. */
char *file_browser(struct app *a, const char *start_dir)
{
    (void)a;
    if (g_quit)
        return NULL;
    char dir[1024];
    const char *start = (start_dir && *start_dir) ? start_dir : getenv("HOME");
    expand_path(start, dir, sizeof dir);
    if (!dir[0])
        snprintf(dir, sizeof dir, ".");
    for (;;) {
        DIR *d = opendir(dir);
        if (!d) {
            tui_message("Filväljare", "Kan inte öppna %s", dir);
            return NULL;
        }
        struct fentry *ents = NULL;
        size_t n = 0, cap = 0;
        struct dirent *de;
        while ((de = readdir(d)) != NULL) {
            if (strcmp(de->d_name, ".") == 0 ||
                strcmp(de->d_name, "..") == 0)
                continue; /* ".." is the first item in the list */
            if (de->d_name[0] == '.')
                continue; /* hidden files */
            char full[1600];
            snprintf(full, sizeof full, "%.1200s/%.299s", dir, de->d_name);
            struct stat st;
            if (stat(full, &st) != 0)
                continue;
            if (n == cap) {
                cap = cap ? cap * 2 : 64;
                ents = xrealloc(ents, cap * sizeof *ents);
            }
            snprintf(ents[n].name, sizeof ents[n].name, "%s", de->d_name);
            ents[n].isdir = S_ISDIR(st.st_mode);
            n++;
            if (n >= 2000)
                break;
        }
        closedir(d);
        qsort(ents, n, sizeof *ents, fentry_cmp);
        char **items = xcalloc(n + 1, sizeof(char *));
        items[0] = xstrdup(".. (uppåt)");
        for (size_t i = 0; i < n; i++) {
            char line[340];
            snprintf(line, sizeof line, "%s%s", ents[i].name,
                     ents[i].isdir ? "/" : "");
            items[i + 1] = xstrdup(line);
        }
        char title[1200];
        snprintf(title, sizeof title, "Välj fil — %.200s", dir);
        int sel = tui_select_list(title, items, (int)n + 1, 0, 1, NULL, 0, NULL, 0);
        for (size_t i = 0; i <= n; i++)
            free(items[i]);
        free(items);
        if (sel < 0) {
            free(ents);
            return NULL;
        }
        if (sel == 0) {
            char *slash = strrchr(dir, '/');
            if (slash && slash != dir)
                *slash = '\0';
            else if (slash == dir)
                dir[1] = '\0';
            free(ents);
            continue;
        }
        size_t idx = (size_t)sel - 1;
        char full[1600];
        snprintf(full, sizeof full, "%.1200s/%.299s", dir, ents[idx].name);
        if (ents[idx].isdir) {
            snprintf(dir, sizeof dir, "%.1023s", full);
            free(ents);
            continue;
        }
        free(ents);
        return xstrdup(full);
    }
}

/* Valid UTF-8 without NUL bytes: good enough to call a receipt text. */
static int bytes_look_text(const unsigned char *p, size_t n)
{
    for (size_t i = 0; i < n;) {
        unsigned char c = p[i];
        if (c == 0)
            return 0;
        if (c < 0x80) {
            i++;
            continue;
        }
        int len;
        if ((c & 0xE0) == 0xC0)
            len = 2;
        else if ((c & 0xF0) == 0xE0)
            len = 3;
        else if ((c & 0xF8) == 0xF0)
            len = 4;
        else
            return 0;
        if (i + (size_t)len > n)
            return 0;
        for (int k = 1; k < len; k++)
            if ((p[i + k] & 0xC0) != 0x80)
                return 0;
        i += (size_t)len;
    }
    return 1;
}

/* Directory for generated PDFs. */
static void pdf_cache_dir(char *buf, size_t n)
{
    const char *cache = getenv("XDG_CACHE_HOME");
    if (cache && *cache) {
        snprintf(buf, n, "%s/bokf", cache);
        return;
    }
    snprintf(buf, n, "/tmp");
}

/* Keep a user-supplied name from escaping the directory. */
static void safe_fname(const char *in, char *out, size_t n)
{
    size_t o = 0;
    for (const char *p = in ? in : ""; *p && o + 1 < n; p++) {
        unsigned char c = (unsigned char)*p;
        if (c < 32 || c == '/')
            c = '-';
        out[o++] = (char)c;
    }
    out[o] = '\0';
}

static int write_pdf_b64(const char *b64, const char *path)
{
    unsigned char *data = NULL;
    size_t len = 0;
    if (!b64 || util_b64_decode(b64, strlen(b64), &data, &len) != 0)
        return -1;
    FILE *fp = fopen(path, "wb");
    if (!fp) {
        free(data);
        return -1;
    }
    size_t wrote = fwrite(data, 1, len, fp);
    fclose(fp);
    free(data);
    return wrote == len ? 0 : -1;
}

/* Open a saved PDF with xdg-open when a desktop session is present;
   otherwise (or on fork failure) show where it was saved. */
static void open_pdf(const char *path, const char *title)
{
    const char *display = getenv("DISPLAY");
    const char *wayland = getenv("WAYLAND_DISPLAY");
    if ((!display || !*display) && (!wayland || !*wayland)) {
        tui_message(title, "Sparad: %s", path);
        return;
    }
    pid_t pid = fork();
    if (pid == 0) {
        pid_t gc = fork();
        if (gc == 0) {
            setsid();
            execlp("xdg-open", "xdg-open", path, (char *)NULL);
            _exit(127);
        }
        _exit(gc < 0 ? 1 : 0);
    }
    if (pid > 0)
        waitpid(pid, NULL, 0);
    else
        tui_message(title, "Sparad: %s", path);
}

void pdf_save_and_open(const char *b64, const char *filename,
                       const char *title)
{
    char dir[512], path[700], safe[600];
    pdf_cache_dir(dir, sizeof dir);
    safe_fname(filename, safe, sizeof safe);
    if (snprintf(path, sizeof path, "%s/%s", dir, safe) >= (int)sizeof path) {
        tui_message(title, "Sökvägen blir för lång.");
        return;
    }
    config_mkdirs(path);
    if (write_pdf_b64(b64, path) != 0) {
        tui_message(title, "Kunde inte spara %s", path);
        return;
    }
    open_pdf(path, title);
}

/* Fetch one attachment, save it to a prompted path and verify its hash.
   Text attachments are shown inline after saving. */
void attachment_download(struct app *a, int64_t att_id)
{
    char args[64];
    snprintf(args, sizeof args, "{\"id\":%lld}", (long long)att_id);
    char *resp =
        client_rpc(&a->conn, "attachment.get", a->session, a->org, args);
    if (!resp || !client_ok(resp)) {
        show_error("Kunde inte hämta underlaget", resp);
        free(resp);
        return;
    }
    char *fn = jstr_dup(resp, "result.filename");
    char *mime = jstr_dup(resp, "result.mime");
    char *sha = jstr_dup(resp, "result.sha256");
    char *b64 = jstr_dup(resp, "result.content_base64");
    unsigned char *data = NULL;
    size_t n = 0;
    if (!b64 || util_b64_decode(b64, strlen(b64), &data, &n) != 0) {
        tui_message("Underlag", "Kunde inte avkoda innehållet.");
        goto done;
    }
    const char *home = getenv("HOME");
    char def[600], dl[512];
    snprintf(dl, sizeof dl, "%s/Downloads", home && *home ? home : ".");
    struct stat sb;
    if (stat(dl, &sb) != 0 || !S_ISDIR(sb.st_mode))
        snprintf(dl, sizeof dl, "%s", home && *home ? home : ".");
    snprintf(def, sizeof def, "%s/%s", dl, fn && *fn ? fn : "underlag");
    char pathbuf[512]; char *path = tui_prompt_into(pathbuf, sizeof pathbuf, "Spara underlag: ", def, 0) ? pathbuf : NULL;
    if (!path || !*path)
        goto done;
    char full[600];
    if (path[0] == '~' && (path[1] == '/' || path[1] == '\0'))
        snprintf(full, sizeof full, "%s%s", home ? home : "", path + 1);
    else
        snprintf(full, sizeof full, "%s", path);
    if (stat(full, &sb) == 0) {
        char ansbuf[512]; char *ans = tui_prompt_into(ansbuf, sizeof ansbuf, "Filen finns, skriv över? (j/n): ", "n", 0) ? ansbuf : NULL;
        if (!ans || (ans[0] != 'j' && ans[0] != 'J'))
            goto done;
    }
    FILE *f = fopen(full, "wb");
    if (!f || fwrite(data, 1, n, f) != n) {
        tui_message("Underlag", "Kunde inte skriva %s: %s", full, strerror(errno));
        if (f)
            fclose(f);
        goto done;
    }
    fclose(f);
    unsigned char raw[32];
    char hex[65];
    util_sha256(data, n, raw);
    util_hex(raw, sizeof raw, hex);
    if (sha && *sha && strcmp(hex, sha) != 0)
        tui_message("Underlag", "VARNING: kontrollsumman stämmer inte.\nSparat: %s",
                full);
    else
        tui_message("Underlag", "Sparat: %s\n(%zu byte)", full, n);
    int is_text = (mime && strncmp(mime, "text/", 5) == 0) ||
                  (n > 0 && bytes_look_text(data, n));
    if (is_text && n <= 256 * 1024) {
        char *copy = xmalloc(n + 1);
        memcpy(copy, data, n);
        copy[n] = '\0';
        tui_pager("Underlag", copy, NULL);
        free(copy);
    }
done:
    free(data);
    free(b64);
    free(sha);
    free(mime);
    free(fn);
    free(resp);
}
const char *vstr(yyjson_val *o, const char *k)
{
    yyjson_val *v = o ? yyjson_obj_get(o, k) : NULL;
    return v && yyjson_is_str(v) ? yyjson_get_str(v) : "";
}

int64_t vint(yyjson_val *o, const char *k)
{
    yyjson_val *v = o ? yyjson_obj_get(o, k) : NULL;
    return v && yyjson_is_int(v) ? (int64_t)yyjson_get_int(v) : 0;
}

void buf_line(struct buf *b, const char *fmt, ...)
{
    char line[1024];
    va_list ap;
    va_start(ap, fmt);
    int n = vsnprintf(line, sizeof line, fmt, ap);
    va_end(ap);
    if (n < 0)
        return;
    buf_append(b, line, (size_t)n < sizeof line ? (size_t)n : sizeof line - 1);
}

void buf_rule(struct buf *b, int width)
{
    char line[128];
    if (width > (int)sizeof line - 3)
        width = (int)sizeof line - 3;
    if (width < 1)
        return;
    line[0] = MK_RULE[0];
    memset(line + 1, '-', (size_t)width);
    line[width + 1] = '\n';
    buf_append(b, line, (size_t)width + 2);
}
int acct_in(const char *number, int lo, int hi)
{
    int n = atoi(number);
    return n >= lo && n <= hi;
}
const char *const BS_KEYS[3] = { "assets", "equity", "liabilities" };

const struct is_group IS_GROUPS[] = {
    { "Rörelseintäkter, lagerförändringar m.m.", "Nettoomsättning", 3000, 3799,
      1 },
    { "Rörelseintäkter, lagerförändringar m.m.", "Övriga rörelseintäkter",
      3800, 3999, 1 },
    { "Rörelsekostnader", "Råvaror och förnödenheter", 4000, 4999, 0 },
    { "Rörelsekostnader", "Övriga externa kostnader", 5000, 6999, 0 },
    { "Rörelsekostnader", "Personalkostnader", 7000, 7699, 0 },
    { "Rörelsekostnader", "Avskrivningar och nedskrivningar", 7700, 7899, 0 },
    { "Rörelsekostnader", "Övriga rörelsekostnader", 7900, 7999, 0 },
};

/* Pick a voucher in the active fiscal year; returns its id or 0. */
int64_t pick_voucher(struct app *a)
{
    char args[96];
    snprintf(args, sizeof args, "{\"fiscal_year\":%lld,\"limit\":200}",
             (long long)a->fy);
    char *resp =
        client_rpc(&a->conn, "voucher.list", a->session, a->org, args);
    if (!resp || !client_ok(resp)) {
        show_error("Verifikat", resp);
        free(resp);
        return 0;
    }
    size_t n = jarr_size(resp, "result.items");
    if (n == 0) {
        tui_message("Verifikat", "Inga verifikat i räkenskapsåret.");
        free(resp);
        return 0;
    }
    char **items = xcalloc(n, sizeof(char *));
    int64_t *ids = xcalloc(n, sizeof(int64_t));
    for (size_t i = 0; i < n; i++) {
        char path[64], ver[32], line[512];
        snprintf(path, sizeof path, "result.items.%zu.id", i);
        ids[i] = jint_val(resp, path, 0);
        snprintf(path, sizeof path, "result.items.%zu.series", i);
        char *series = jstr_dup(resp, path);
        snprintf(path, sizeof path, "result.items.%zu.number", i);
        int64_t number = jint_val(resp, path, 0);
        snprintf(path, sizeof path, "result.items.%zu.date", i);
        char *date = jstr_dup(resp, path);
        snprintf(path, sizeof path, "result.items.%zu.description", i);
        char *desc = jstr_dup(resp, path);
        snprintf(ver, sizeof ver, "%s%lld", series ? series : "",
                 (long long)number);
        snprintf(line, sizeof line, "%-8s %-10s %s", ver, date ? date : "",
                 desc ? desc : "");
        items[i] = xstrdup(line);
        free(series);
        free(date);
        free(desc);
    }
    int sel = tui_select_list("Välj verifikat", items, (int)n, 0, 1, NULL, 0,
                          NULL, 0);
    int64_t out = sel >= 0 ? ids[sel] : 0;
    for (size_t i = 0; i < n; i++)
        free(items[i]);
    free(items);
    free(ids);
    free(resp);
    return out;
}
/* client_rpc() cannot carry the protocol's top-level dry_run, so build
   the request by hand. */
char *rpc_dry(struct app *a, const char *cmd, const char *args)
{
    size_t n = strlen(args) + strlen(cmd) + strlen(a->session) + 160;
    char *raw = xmalloc(n);
    snprintf(raw, n,
             "{\"v\":1,\"id\":\"tui\",\"cmd\":\"%s\",\"session\":\"%s\","
             "\"org\":%lld,\"dry_run\":true,\"args\":%s}",
             cmd, a->session, (long long)a->org, args);
    char *r = NULL;
    if (client_send_line(&a->conn, raw) == 0)
        r = client_read_line(&a->conn);
    free(raw);
    return r;
}
/* Small append-only log for connection/reload problems. */
void tui_log(const char *fmt, ...)
{
    char path[600], dir[512];
    const char *cache = getenv("XDG_CACHE_HOME");
    if (cache && *cache)
        snprintf(dir, sizeof dir, "%s/bokf", cache);
    else {
        const char *home = getenv("HOME");
        snprintf(dir, sizeof dir, "%s/.cache/bokf", home && *home ? home : ".");
    }
    if (snprintf(path, sizeof path, "%s/tui.log", dir) >= (int)sizeof path)
        return;
    config_mkdirs(path);
    FILE *f = fopen(path, "a");
    if (!f)
        return;
    time_t now = time(NULL);
    struct tm tm;
    gmtime_r(&now, &tm);
    fprintf(f, "%04d-%02d-%02dT%02d:%02d:%02dZ ",
            tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
            tm.tm_min, tm.tm_sec);
    va_list ap;
    va_start(ap, fmt);
    vfprintf(f, fmt, ap);
    va_end(ap);
    fputc('\n', f);
    fclose(f);
}