/*
Serval DNA HTTP RESTful interface
Copyright (C) 2013-2015 Serval Project Inc.
 
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

#include "serval.h"
#include "conf.h"
#include "httpd.h"
#include "server.h"
#include "keyring.h"
#include "strbuf_helpers.h"

#define keyring_TOKEN_STRLEN (BASE64_ENCODED_LEN(sizeof(rhizome_bid_t) + sizeof(uint64_t)))
#define alloca_keyring_token(bid, offset) keyring_    token_to_str(alloca(keyring_TOKEN_STRLEN + 1), (bid), (offset))

DECLARE_HANDLER("/restful/keyring/", restful_keyring_);

static HTTP_HANDLER restful_keyring_identitylist_json;
static HTTP_HANDLER restful_keyring_add;
static HTTP_HANDLER restful_keyring_set;

static int restful_keyring_(httpd_request *r, const char *remainder)
{
  r->http.response.header.content_type = CONTENT_TYPE_JSON;
  int ret = authorize_restful(&r->http);
  if (ret)
    return ret;
  const char *verb = HTTP_VERB_GET;
  http_size_t content_length = CONTENT_LENGTH_UNKNOWN;
  HTTP_HANDLER *handler = NULL;
  const char *end;
  if (strcmp(remainder, "identities.json") == 0) {
    handler = restful_keyring_identitylist_json;
    verb = HTTP_VERB_GET;
    remainder = "";
  }
  else if (strcmp(remainder, "add") == 0) {
    handler = restful_keyring_add;
    verb = HTTP_VERB_GET;
    remainder = "";
  }
  else if (parse_sid_t(&r->sid1, remainder, -1, &end) != -1) {
    remainder = end;
    if (strcmp(remainder, "/set") == 0) {
      handler = restful_keyring_set;
      remainder = "";
    }
  }
  if (handler == NULL)
    return 404;
  if (	 content_length != CONTENT_LENGTH_UNKNOWN
      && r->http.request_header.content_length != CONTENT_LENGTH_UNKNOWN
      && r->http.request_header.content_length != content_length) {
    http_request_simple_response(&r->http, 400, "Bad content length");
    return 400;
  }
  if (r->http.verb != verb)
    return 405;
  return handler(r, remainder);
}

static int http_request_keyring_response(struct httpd_request *r, uint16_t result, const char *message)
{
  http_request_simple_response(&r->http, result, message);
  return result;
}

static int http_request_keyring_response_identity(struct httpd_request *r, uint16_t result, const char *message, const keyring_identity *id)
{
  const sid_t *sidp = NULL;
  const char *did = NULL;
  const char *name = NULL;
  keyring_identity_extract(id, &sidp, &did, &name);
  if (!sidp)
    return http_request_keyring_response(r, 500, "Identity has no SID");
  struct json_atom json_id;
  struct json_key_value json_id_kv[3];
  struct json_atom json_sid;
  struct json_atom json_did;
  struct json_atom json_name;
  json_id.type = JSON_OBJECT;
  json_id.u.object.itemc = 1;
  json_id.u.object.itemv = json_id_kv;
  json_id_kv[0].key = "sid";
  json_id_kv[0].value = &json_sid;
  json_sid.type = JSON_STRING_NULTERM;
  json_sid.u.string.content = alloca_tohex_sid_t(*sidp);
  if (did) {
    json_id_kv[json_id.u.object.itemc].key = "did";
    json_id_kv[json_id.u.object.itemc].value = &json_did;
    ++json_id.u.object.itemc;
    json_did.type = JSON_STRING_NULTERM;
    json_did.u.string.content = did;
  }
  if (name) {
    json_id_kv[json_id.u.object.itemc].key = "name";
    json_id_kv[json_id.u.object.itemc].value = &json_name;
    ++json_id.u.object.itemc;
    json_name.type = JSON_STRING_NULTERM;
    json_name.u.string.content = name;
  }
  r->http.response.result_extra[0].label = "identity";
  r->http.response.result_extra[0].value = json_id;
  return http_request_keyring_response(r, result, message);
}

static HTTP_CONTENT_GENERATOR restful_keyring_identitylist_json_content;

static int restful_keyring_identitylist_json(httpd_request *r, const char *remainder)
{
  if (*remainder)
    return 404;
  const char *pin = http_request_get_query_param(&r->http, "pin");
  if (pin)
    keyring_enter_pin(keyring, pin);
  r->u.sidlist.phase = LIST_HEADER;
  keyring_iterator_start(keyring, &r->u.sidlist.it);
  http_request_response_generated(&r->http, 200, CONTENT_TYPE_JSON, restful_keyring_identitylist_json_content);
  return 1;
}

static HTTP_CONTENT_GENERATOR_STRBUF_CHUNKER restful_keyring_identitylist_json_content_chunk;

static int restful_keyring_identitylist_json_content(struct http_request *hr, unsigned char *buf, size_t bufsz, struct http_content_generator_result *result)
{
  return generate_http_content_from_strbuf_chunks(hr, (char *)buf, bufsz, result, restful_keyring_identitylist_json_content_chunk);
}

static int restful_keyring_identitylist_json_content_chunk(struct http_request *hr, strbuf b)
{
  httpd_request *r = (httpd_request *) hr;
  // The "my_sid" and "their_sid" per-conversation fields allow the same JSON structure to be used
  // in a future, non-SID-specific request, eg, to list all conversations for all currently open
  // identities.
  const char *headers[] = {
    "sid",
    "did",
    "name"
  };
  switch (r->u.sidlist.phase) {
    case LIST_HEADER:
      strbuf_puts(b, "{\n\"header\":[");
      unsigned i;
      for (i = 0; i != NELS(headers); ++i) {
	if (i)
	  strbuf_putc(b, ',');
	strbuf_json_string(b, headers[i]);
      }
      strbuf_puts(b, "],\n\"rows\":[");
      if (!strbuf_overrun(b)){
	r->u.sidlist.phase = LIST_FIRST;
	if (!keyring_next_identity(&r->u.sidlist.it))
	  r->u.sidlist.phase = LIST_END;
      }
      return 1;
      
    case LIST_ROWS:
      strbuf_putc(b, ',');
    case LIST_FIRST:
      r->u.sidlist.phase = LIST_ROWS;
      const sid_t *sidp = NULL;
      const char *did = NULL;
      const char *name = NULL;
      keyring_identity_extract(r->u.sidlist.it.identity, &sidp, &did, &name);
      if (sidp || did) {
	strbuf_puts(b, "\n[");
	strbuf_json_string(b, alloca_tohex_sid_t(*sidp));
	strbuf_puts(b, ",");
	strbuf_json_string(b, did);
	strbuf_puts(b, ",");
	strbuf_json_string(b, name);
	strbuf_puts(b, "]");
      }

      if (!strbuf_overrun(b)) {
	if (!keyring_next_identity(&r->u.sidlist.it))
	  r->u.sidlist.phase = LIST_END;
      }
      return 1;
      
    case LIST_END:
      strbuf_puts(b, "\n]\n}\n");
      if (strbuf_overrun(b))
	return 1;
      
      r->u.sidlist.phase = LIST_DONE;
      // fall through...
    case LIST_DONE:
      return 0;
  }
  abort();
  return 0;
}

static int restful_keyring_add(httpd_request *r, const char *remainder)
{
  if (*remainder)
    return 404;
  const char *pin = http_request_get_query_param(&r->http, "pin");
  const char *did = http_request_get_query_param(&r->http, "did");
  const char *name = http_request_get_query_param(&r->http, "name");
  keyring_identity *id = keyring_create_identity(keyring, pin ? pin : "");
  if (id == NULL)
    return http_request_keyring_response(r, 500, "Could not create identity");
  if (did || name){
    if (keyring_set_did(id, did ? did : "", name ? name : "") == -1)
      return http_request_keyring_response(r, 500, "Could not set identity DID/Name");
  }
  if (keyring_commit(keyring) == -1)
    return http_request_keyring_response(r, 500, "Could not store new identity");
  return http_request_keyring_response_identity(r, 200, CONTENT_TYPE_JSON, id);
}

static int restful_keyring_set(httpd_request *r, const char *remainder)
{
  if (*remainder)
    return 404;
  const char *pin = http_request_get_query_param(&r->http, "pin");
  const char *did = http_request_get_query_param(&r->http, "did");
  const char *name = http_request_get_query_param(&r->http, "name");
  if (pin)
    keyring_enter_pin(keyring, pin);
  keyring_iterator it;
  keyring_iterator_start(keyring, &it);
  if (!keyring_find_sid(&it, &r->sid1))
    return http_request_keyring_response(r, 404, "Identity not found");
  if (keyring_set_did(it.identity, did ? did : "", name ? name : "") == -1)
    return http_request_keyring_response(r, 500, "Could not set identity DID/Name");
  if (keyring_commit(keyring) == -1)
    return http_request_keyring_response(r, 500, "Could not store new identity");
  return http_request_keyring_response_identity(r, 200, CONTENT_TYPE_JSON, it.identity);
}