#include "barev_avatar.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "barev_sha1.h"

static const char b64tab[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

static void scpy(char *d, size_t n, const char *s) {
  size_t i;
  if (!d || n == 0) return;
  if (!s) { d[0] = '\0'; return; }
  for (i = 0; i + 1 < n && s[i]; ++i) d[i] = s[i];
  d[i] = '\0';
}

static int detect_mime(const char *p, char *out, size_t n) {
  const char *ext = strrchr(p, '.');
  if (!ext) { scpy(out, n, "application/octet-stream"); return 1; }
  if (strcmp(ext, ".png") == 0) scpy(out, n, "image/png");
  else if (strcmp(ext, ".jpg") == 0 || strcmp(ext, ".jpeg") == 0) scpy(out, n, "image/jpeg");
  else if (strcmp(ext, ".gif") == 0) scpy(out, n, "image/gif");
  else scpy(out, n, "application/octet-stream");
  return 1;
}

static char *b64_encode(const unsigned char *in, size_t n) {
  size_t out_n = ((n + 2) / 3) * 4;
  size_t i, o = 0;
  char *out = (char *)malloc(out_n + 1);
  if (!out) return 0;
  for (i = 0; i < n; i += 3) {
    unsigned a = in[i];
    unsigned b = (i + 1 < n) ? in[i + 1] : 0;
    unsigned c = (i + 2 < n) ? in[i + 2] : 0;
    unsigned t = (a << 16) | (b << 8) | c;
    out[o++] = b64tab[(t >> 18) & 63];
    out[o++] = b64tab[(t >> 12) & 63];
    out[o++] = (i + 1 < n) ? b64tab[(t >> 6) & 63] : '=';
    out[o++] = (i + 2 < n) ? b64tab[t & 63] : '=';
  }
  out[o] = '\0';
  return out;
}

void barev_avatar_init(barev_avatar_mgr_t *m) { if (m) memset(m, 0, sizeof(*m)); }

void barev_avatar_free(barev_avatar_mgr_t *m) {
  if (!m) return;
  free(m->my_avatar_b64);
  m->my_avatar_b64 = 0;
}

void barev_avatar_clear_my(barev_avatar_mgr_t *m) {
  if (!m) return;
  free(m->my_avatar_b64);
  m->my_avatar_b64 = 0;
  m->my_avatar_path[0] = '\0';
  m->my_avatar_hash[0] = '\0';
  m->my_avatar_mime[0] = '\0';
}

int barev_avatar_load_my(barev_avatar_mgr_t *m, const char *path) {
  FILE *f;
  unsigned char *buf;
  long n;
  if (!m || !path) return 0;
  f = fopen(path, "rb");
  if (!f) return 0;
  if (fseek(f, 0, SEEK_END) != 0) { fclose(f); return 0; }
  n = ftell(f);
  if (n < 0) { fclose(f); return 0; }
  if (fseek(f, 0, SEEK_SET) != 0) { fclose(f); return 0; }
  buf = (unsigned char *)malloc((size_t)n);
  if (!buf) { fclose(f); return 0; }
  if ((long)fread(buf, 1, (size_t)n, f) != n) { free(buf); fclose(f); return 0; }
  fclose(f);

  barev_avatar_clear_my(m);
  m->my_avatar_b64 = b64_encode(buf, (size_t)n);
  if (!m->my_avatar_b64) { free(buf); return 0; }
  detect_mime(path, m->my_avatar_mime, sizeof(m->my_avatar_mime));
  scpy(m->my_avatar_path, sizeof(m->my_avatar_path), path);
  barev_sha1_hex((const unsigned char *)m->my_avatar_b64, strlen(m->my_avatar_b64), m->my_avatar_hash);
  free(buf);
  return 1;
}

int barev_avatar_generate_vcard(const barev_avatar_mgr_t *m, char *out, size_t out_n) {
  int w;
  if (!m || !out || out_n == 0) return 0;
  if (!m->my_avatar_b64 || !m->my_avatar_b64[0]) {
    w = snprintf(out, out_n, "<vCard xmlns=\"vcard-temp\"></vCard>");
  } else {
    w = snprintf(out, out_n,
      "<vCard xmlns=\"vcard-temp\"><PHOTO><TYPE>%s</TYPE><BINVAL>%s</BINVAL></PHOTO></vCard>",
      m->my_avatar_mime, m->my_avatar_b64);
  }
  return (w > 0 && (size_t)w < out_n) ? 1 : 0;
}