#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <getopt.h>
#include <assert.h>

#include <jansson.h>

#include "nghttp2_hd.h"

static void to_hex(char *dest, const uint8_t *src, size_t len)
{
  size_t i;
  for(i = 0; i < len; ++i) {
    sprintf(dest, "%02x", src[i]);
    dest += 2;
  }
}

static void output_to_json(const uint8_t *buf, size_t len, size_t inputlen,
                           int seq)
{
  json_t *obj;
  char hex[16*1024];

  if(len * 2 > sizeof(hex)) {
    fprintf(stderr, "Output too large at %d\n", seq);
    exit(EXIT_FAILURE);
  }
  obj = json_object();
  json_object_set_new(obj, "seq", json_integer(seq));
  json_object_set_new(obj, "inputLen", json_integer(inputlen));
  json_object_set_new(obj, "outputLength", json_integer(len));
  json_object_set_new(obj, "PercentageOfOriginalSize",
                      json_real((double)len / inputlen * 100));
  to_hex(hex, buf, len);
  json_object_set_new(obj, "output", json_pack("s#", hex, len * 2));
  json_dumpf(obj, stdout, JSON_PRESERVE_ORDER);
  printf("\n");
  json_decref(obj);
}

static int deflate_hd(json_t *obj, nghttp2_hd_context *deflater, int seq)
{
  json_t *js;
  uint8_t *buf = NULL;
  size_t buflen = 0;
  nghttp2_nv nva[128];
  size_t len;
  size_t i;
  ssize_t rv;
  size_t inputlen = 0;

  js = json_object_get(obj, "headers");
  if(js == NULL) {
    fprintf(stderr, "headers key is missing at %d\n", seq);
    return -1;
  }
  if(!json_is_array(js)) {
    fprintf(stderr, "headers value must be an array at %d\n", seq);
    return -1;
  }
  len = json_array_size(js);
  if(len > sizeof(nva)/sizeof(nva[0])) {
    fprintf(stderr, "Too many headers (> %zu) at %d\n",
            sizeof(nva)/sizeof(nva[0]), seq);
    return -1;
  }
  for(i = 0; i < len; ++i) {
    json_t *nv_pair = json_array_get(js, i);
    json_t *s;
    if(!json_is_array(nv_pair) || json_array_size(nv_pair) != 2) {
      fprintf(stderr, "bad formatted name/value pair array at %d\n", seq);
      return -1;
    }
    s = json_array_get(nv_pair, 0);
    if(!json_is_string(s)) {
      fprintf(stderr, "bad formatted name/value pair array at %d\n", seq);
      return -1;
    }
    nva[i].name = (uint8_t*)json_string_value(s);
    nva[i].namelen = strlen(json_string_value(s));

    s = json_array_get(nv_pair, 1);
    if(!json_is_string(s)) {
      fprintf(stderr, "bad formatted name/value pair array at %d\n", seq);
      return -1;
    }
    nva[i].value = (uint8_t*)json_string_value(s);
    nva[i].valuelen = strlen(json_string_value(s));
    inputlen += nva[i].namelen + nva[i].valuelen;
  }
  rv = nghttp2_hd_deflate_hd(deflater, &buf, &buflen, 0, nva, len);
  if(rv < 0) {
    fprintf(stderr, "deflate failed with error code %zd at %d\n", rv, seq);
    exit(EXIT_FAILURE);
  }
  output_to_json(buf, rv, inputlen, seq);
  nghttp2_hd_end_headers(deflater);
  free(buf);
  return 0;
}

static int perform(nghttp2_hd_side side)
{
  nghttp2_hd_context deflater;
  int i = 0;
  json_t *json;
  json_error_t error;
  size_t len;

  json = json_loadf(stdin, 0, &error);
  if(json == NULL) {
    fprintf(stderr, "JSON loading failed\n");
    return -1;
  }
  nghttp2_hd_deflate_init(&deflater, side);
  printf("[\n");
  len = json_array_size(json);
  for(i = 0; i < len; ++i) {
    json_t *obj = json_array_get(json, i);
    if(!json_is_object(obj)) {
      fprintf(stderr, "Unexpected JSON type at %d. It should be object.\n", i);
      continue;
    }
    if(deflate_hd(obj, &deflater, i) != 0) {
      continue;
    }
    if(i + 1 < len) {
      printf(",\n");
    }
  }
  printf("]\n");
  nghttp2_hd_deflate_free(&deflater);
  json_decref(json);
  return 0;
}

static void print_help()
{
  printf("Usage: deflatehd [-r] < INPUT\n\n"
         "Reads JSON array from stdin and outputs deflated header block\n"
         "in JSON array.\n"
         "The element of input array must be a JSON object. Each object must\n"
         "have following key:\n"
         "\n"
         "    headers: a JSON array of name/value pairs. The each element is\n"
         "             a JSON array of 2 strings. The index 0 must\n"
         "             contain header name and the index 1 must contain\n"
         "             header value.\n"
         "\n"
         "Example:\n"
         "[\n"
         "  {\n"
         "   \"headers\": [\n"
         "      [ \":method\", \"GET\" ],\n"
         "      [ \":path\", \"/\" ]\n"
         "    ]\n"
         "  },\n"
         "  {\n"
         "   \"headers\": [\n"
         "      [ \":method\", \"POST\" ],\n"
         "      [ \":path\", \"/\" ]\n"
         "    ]\n"
         "  }\n"
         "]\n"
         "\n"
         "The output of this program can be used as input for inflatehd.\n"
         "\n"
         "OPTIONS:\n"
         "    -r, --response    Use response compression context instead of\n"
         "                      request.\n");
}

static struct option long_options[] = {
  {"response", no_argument, NULL, 'r'},
  {NULL, 0, NULL, 0 }
};

int main(int argc, char **argv)
{
  nghttp2_hd_side side = NGHTTP2_HD_SIDE_REQUEST;
  while(1) {
    int option_index = 0;
    int c = getopt_long(argc, argv, "hr", long_options, &option_index);
    if(c == -1) {
      break;
    }
    switch(c) {
    case 'r':
      /* --response */
      side = NGHTTP2_HD_SIDE_RESPONSE;
      break;
    case 'h':
      print_help();
      exit(EXIT_SUCCESS);
    case '?':
      exit(EXIT_FAILURE);
    default:
      break;
    }
  }
  perform(side);
  return 0;
}