/*
 * util.c - shared utility layer for rawnix.org package tools
 * https://rawnix.org
 *
 * Copyright (c) 2025 zorz@gmx.com
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include "util.h"

#include <ctype.h>
#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <ftw.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/wait.h>

/* ── Allocation ──────────────────────────────────────────────────────── */

void *xmalloc(size_t size)
{
    void *p = malloc(size);
    if (!p)
        err(1, "malloc(%zu)", size);
    return p;
}

void *xrealloc(void *ptr, size_t size)
{
    void *p = realloc(ptr, size);
    if (!p)
        err(1, "realloc(%zu)", size);
    return p;
}

char *xstrdup(const char *s)
{
    char *p;
    if (!s)
        return NULL;
    p = strdup(s);
    if (!p)
        err(1, "strdup");
    return p;
}

/* ── String utilities ────────────────────────────────────────────────── */

char *str_trim(char *s)
{
    char *end;

    if (!s)
        return s;

    /* Left trim */
    while (isspace((unsigned char)*s))
        s++;

    if (*s == '\0')
        return s;

    /* Right trim */
    end = s + strlen(s) - 1;
    while (end > s && isspace((unsigned char)*end))
        end--;
    end[1] = '\0';

    return s;
}

int str_starts_with(const char *s, const char *pfx)
{
    if (!s || !pfx)
        return 0;
    return strncmp(s, pfx, strlen(pfx)) == 0;
}

int str_ends_with(const char *s, const char *sfx)
{
    size_t slen, sfxlen;

    if (!s || !sfx)
        return 0;
    slen   = strlen(s);
    sfxlen = strlen(sfx);
    if (sfxlen > slen)
        return 0;
    return strcmp(s + slen - sfxlen, sfx) == 0;
}

/* ── Path utilities ──────────────────────────────────────────────────── */

char *path_join(const char *dir, const char *file)
{
    char *path;
    size_t dlen, flen, len;

    if (!dir  || !dir[0])  return xstrdup(file ? file : "");
    if (!file || !file[0]) return xstrdup(dir);

    dlen = strlen(dir);
    flen = strlen(file);

    /* +2: one for '/', one for '\0' */
    len  = dlen + flen + 2;
    path = xmalloc(len);

    if (dir[dlen - 1] == '/' || file[0] == '/')
        snprintf(path, len, "%s%s", dir, file);
    else
        snprintf(path, len, "%s/%s", dir, file);

    return path;
}

int mkdirp(const char *path, mode_t mode)
{
    char *tmp, *p;
    size_t len;

    if (!path || !path[0]) {
        errno = EINVAL;
        return -1;
    }

    tmp = xstrdup(path);
    len = strlen(tmp);

    /* Strip trailing slash */
    if (len > 1 && tmp[len - 1] == '/')
        tmp[len - 1] = '\0';

    /* Create each component */
    for (p = tmp + 1; *p; p++) {
        if (*p == '/') {
            *p = '\0';
            if (mkdir(tmp, mode) < 0 && errno != EEXIST) {
                free(tmp);
                return -1;
            }
            *p = '/';
        }
    }

    if (mkdir(tmp, mode) < 0 && errno != EEXIST) {
        free(tmp);
        return -1;
    }

    free(tmp);
    return 0;
}

int file_exists(const char *path)
{
    struct stat st;
    return lstat(path, &st) == 0;
}

/* ── rmrf ────────────────────────────────────────────────────────────── */

/*
 * nftw callback: remove each entry depth-first.
 * FTW_DEPTH ensures directories are visited after their contents.
 */
static int rmrf_cb(const char *path, const struct stat *sb,
                   int typeflag, struct FTW *ftwbuf)
{
    (void)sb;
    (void)ftwbuf;

    if (typeflag == FTW_DP || typeflag == FTW_D)
        return rmdir(path) == 0 || errno == ENOENT ? 0 : -1;

    return remove(path) == 0 || errno == ENOENT ? 0 : -1;
}

int rmrf(const char *path)
{
    struct stat st;
    int ret;

    if (!path || !path[0])
        return 0;

    if (lstat(path, &st) != 0) {
        if (errno == ENOENT)
            return 0;
        return -1;
    }

    if (!S_ISDIR(st.st_mode))
        return remove(path);

    ret = nftw(path, rmrf_cb, 64, FTW_DEPTH | FTW_PHYS);
    if (ret != 0) {
        /* fallback: fork rm -rf for large/complex trees */
        pid_t pid = fork();
        if (pid == 0) {
            execl("/bin/rm", "rm", "-rf", path, (char *)NULL);
            _exit(1);
        } else if (pid > 0) {
            int status;
            waitpid(pid, &status, 0);
            ret = (WIFEXITED(status) && WEXITSTATUS(status) == 0) ? 0 : -1;
        }
    }
    return ret;
}

/* ── String array ────────────────────────────────────────────────────── */

strarray_t *strarray_new(void)
{
    strarray_t *a = xmalloc(sizeof(strarray_t));
    a->count    = 0;
    a->capacity = 32;
    a->sorted   = 1;   /* empty is trivially sorted */
    a->items    = xmalloc(a->capacity * sizeof(char *));
    return a;
}

void strarray_free(strarray_t *a)
{
    size_t i;

    if (!a)
        return;
    for (i = 0; i < a->count; i++)
        free(a->items[i]);
    free(a->items);
    free(a);
}

int strarray_add(strarray_t *a, const char *s)
{
    if (a->count >= a->capacity) {
        a->capacity *= 2;
        a->items = xrealloc(a->items, a->capacity * sizeof(char *));
    }
    a->items[a->count++] = xstrdup(s);
    a->sorted = 0;
    return 0;
}

/*
 * Binary search when sorted (>16 items), linear otherwise.
 * Caller must call strarray_sort() before relying on binary search.
 */
int strarray_contains(const strarray_t *a, const char *s)
{
    size_t lo, hi, mid;
    int cmp;

    if (!a || !s)
        return 0;

    if (a->sorted && a->count > 16) {
        lo = 0;
        hi = a->count;
        while (lo < hi) {
            mid = lo + (hi - lo) / 2;
            cmp = strcmp(a->items[mid], s);
            if (cmp == 0) return 1;
            if (cmp < 0)  lo = mid + 1;
            else          hi = mid;
        }
        return 0;
    }

    for (lo = 0; lo < a->count; lo++)
        if (strcmp(a->items[lo], s) == 0)
            return 1;
    return 0;
}

/*
 * Remove by swapping with last element.
 * Clears sorted flag — caller must re-sort if needed.
 */
int strarray_remove(strarray_t *a, const char *s)
{
    size_t i;

    for (i = 0; i < a->count; i++) {
        if (strcmp(a->items[i], s) == 0) {
            free(a->items[i]);
            a->items[i] = a->items[--a->count];
            a->sorted = 0;
            return 0;
        }
    }
    return -1;
}

static int strcmp_wrap(const void *a, const void *b)
{
    return strcmp(*(const char **)a, *(const char **)b);
}

void strarray_sort(strarray_t *a)
{
    if (!a || a->sorted)
        return;
    if (a->count > 1)
        qsort(a->items, a->count, sizeof(char *), strcmp_wrap);
    a->sorted = 1;
}

/* ── Output ──────────────────────────────────────────────────────────── */

void info(const char *fmt, ...)
{
    va_list ap;
    fputs("mkpkg: ", stdout);
    va_start(ap, fmt);
    vfprintf(stdout, fmt, ap);
    va_end(ap);
    fputc('\n', stdout);
    fflush(stdout);
}


void warning(const char *fmt, ...)
{
    va_list ap;
    fputs("mkpkg: warning: ", stderr);
    va_start(ap, fmt);
    vfprintf(stderr, fmt, ap);
    va_end(ap);
    fputc('\n', stderr);
}

void die(const char *fmt, ...)
{
    va_list ap;
    fputs("mkpkg: error: ", stderr);
    va_start(ap, fmt);
    vfprintf(stderr, fmt, ap);
    va_end(ap);
    fputc('\n', stderr);
    exit(1);
}

/* ── signify trust anchor ─────────────────────────────────────────────── */

/*
 * The base64 line of a signify public key: the first non-empty line
 * that is not the "untrusted comment:" line, trimmed.  0 or -1.
 */
static int signify_key_line(const char *text, char *out, size_t outsz)
{
    const char *p = text;

    while (*p) {
        const char *e   = strchr(p, '\n');
        size_t      len = e ? (size_t)(e - p) : strlen(p);
        const char *s   = p;

        while (len && isspace((unsigned char)*s)) { s++; len--; }
        while (len && isspace((unsigned char)s[len - 1])) len--;

        if (len && strncmp(s, "untrusted comment:", 18) != 0) {
            if (len >= outsz)
                return -1;
            memcpy(out, s, len);
            out[len] = '\0';
            return 0;
        }
        if (!e)
            break;
        p = e + 1;
    }
    return -1;
}

/*
 * Why this exists: the key that verified a port used to be the one in
 * the MAKEPKG being verified, and both arrive over `ports -u` — rsync's
 * daemon protocol, plaintext, no server authentication.  Whoever could
 * alter that stream could swap the key and sign with their own.  The
 * anchor is local: a key is only good if root put its .pub here.
 */
int signify_trusted_pubkey(const char *keytext, char *path, size_t pathsz)
{
    char           want[512], have[512], buf[2048];
    char           fpath[PATH_MAX_LEN];
    DIR           *dp;
    struct dirent *de;
    struct stat    st;
    int            found = -1;

    if (!keytext || signify_key_line(keytext, want, sizeof(want)) != 0)
        return -1;

    dp = opendir(TRUSTED_KEYS_DIR);
    if (!dp)
        return -1;

    while (found != 0 && (de = readdir(dp)) != NULL) {
        size_t n = strlen(de->d_name);
        FILE  *fp;
        size_t r;

        if (n < 5 || strcmp(de->d_name + n - 4, ".pub") != 0)
            continue;
        snprintf(fpath, sizeof(fpath), "%s/%s", TRUSTED_KEYS_DIR, de->d_name);
        if (stat(fpath, &st) != 0 || !S_ISREG(st.st_mode))
            continue;
        fp = fopen(fpath, "r");
        if (!fp)
            continue;
        r = fread(buf, 1, sizeof(buf) - 1, fp);
        fclose(fp);
        buf[r] = '\0';

        if (signify_key_line(buf, have, sizeof(have)) == 0 &&
            strcmp(want, have) == 0) {
            snprintf(path, pathsz, "%s", fpath);
            found = 0;
        }
    }
    closedir(dp);
    return found;
}