/*
 * Copyright 2013 MongoDB Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


#undef MONGOC_LOG_DOMAIN
#define MONGOC_LOG_DOMAIN "gridfs"

#include "mongoc-bulk-operation.h"
#include "mongoc-client-private.h"
#include "mongoc-collection.h"
#include "mongoc-collection-private.h"
#include "mongoc-error.h"
#include "mongoc-index.h"
#include "mongoc-gridfs.h"
#include "mongoc-gridfs-private.h"
#include "mongoc-gridfs-file.h"
#include "mongoc-gridfs-file-private.h"
#include "mongoc-gridfs-file-list.h"
#include "mongoc-gridfs-file-list-private.h"
#include "mongoc-client.h"
#include "mongoc-trace.h"

#define MONGOC_GRIDFS_STREAM_CHUNK 4096


/**
 * _mongoc_gridfs_ensure_index:
 *
 * ensure gridfs indexes
 *
 * Ensure fast searches for chunks via [ files_id, n ]
 * Ensure fast searches for files via [ filename ]
 */
static bool
_mongoc_gridfs_ensure_index (mongoc_gridfs_t *gridfs,
                             bson_error_t    *error)
{
   bson_t keys;
   mongoc_index_opt_t opt;
   bool r;

   ENTRY;

   bson_init (&keys);

   bson_append_int32 (&keys, "files_id", -1, 1);
   bson_append_int32 (&keys, "n", -1, 1);

   mongoc_index_opt_init (&opt);
   opt.unique = 1;

   r = mongoc_collection_create_index (gridfs->chunks, &keys, &opt, error);

   bson_destroy (&keys);

   if (!r) { RETURN (r); }

   bson_init (&keys);

   bson_append_int32 (&keys, "filename", -1, 1);
   opt.unique = 0;

   r = mongoc_collection_create_index (gridfs->chunks, &keys, &opt, error);

   bson_destroy (&keys);

   if (!r) { RETURN (r); }

   RETURN (1);
}


mongoc_gridfs_t *
_mongoc_gridfs_new (mongoc_client_t *client,
                    const char      *db,
                    const char      *prefix,
                    bson_error_t    *error)
{
   mongoc_gridfs_t *gridfs;
   char buf[128];
   bool r;

   ENTRY;

   BSON_ASSERT (client);
   BSON_ASSERT (db);

   if (!prefix) {
      prefix = "fs";
   }

   /* make sure prefix is short enough to bucket the chunks and files
    * collections
    */
#ifndef BSON_DISABLE_ASSERT
   {
      uint32_t prefix_len;
      prefix_len = (uint32_t)strlen (prefix);
      BSON_ASSERT (prefix_len + sizeof (".chunks") < sizeof (buf));
   }
#endif

   gridfs = bson_malloc0 (sizeof *gridfs);

   gridfs->client = client;

   bson_snprintf (buf, sizeof(buf), "%s.chunks", prefix);
   gridfs->chunks = _mongoc_collection_new (client, db, buf, NULL, NULL);

   bson_snprintf (buf, sizeof(buf), "%s.files", prefix);
   gridfs->files = _mongoc_collection_new (client, db, buf, NULL, NULL);

   r = _mongoc_gridfs_ensure_index (gridfs, error);

   if (!r) { return NULL; }

   RETURN (gridfs);
}


bool
mongoc_gridfs_drop (mongoc_gridfs_t *gridfs,
                    bson_error_t    *error)
{
   bool r;

   ENTRY;

   r = mongoc_collection_drop (gridfs->files, error);
   if (!r) {
      RETURN (0);
   }

   r = mongoc_collection_drop (gridfs->chunks, error);
   if (!r) {
      RETURN (0);
   }

   RETURN (1);
}


void
mongoc_gridfs_destroy (mongoc_gridfs_t *gridfs)
{
   ENTRY;

   BSON_ASSERT (gridfs);

   mongoc_collection_destroy (gridfs->files);
   mongoc_collection_destroy (gridfs->chunks);

   bson_free (gridfs);

   EXIT;
}


/** find all matching gridfs files */
mongoc_gridfs_file_list_t *
mongoc_gridfs_find (mongoc_gridfs_t *gridfs,
                    const bson_t    *query)
{
   return _mongoc_gridfs_file_list_new (gridfs, query, 0);
}


/** find a single gridfs file */
mongoc_gridfs_file_t *
mongoc_gridfs_find_one (mongoc_gridfs_t *gridfs,
                        const bson_t    *query,
                        bson_error_t    *error)
{
   mongoc_gridfs_file_list_t *list;
   mongoc_gridfs_file_t *file;

   ENTRY;

   list = _mongoc_gridfs_file_list_new (gridfs, query, 1);

   file = mongoc_gridfs_file_list_next (list);
   mongoc_gridfs_file_list_error(list, error);

   mongoc_gridfs_file_list_destroy (list);

   RETURN (file);
}


/** find a single gridfs file by filename */
mongoc_gridfs_file_t *
mongoc_gridfs_find_one_by_filename (mongoc_gridfs_t *gridfs,
                                    const char      *filename,
                                    bson_error_t    *error)
{
   mongoc_gridfs_file_t *file;

   bson_t query;

   bson_init (&query);

   bson_append_utf8 (&query, "filename", -1, filename, -1);

   file = mongoc_gridfs_find_one (gridfs, &query, error);

   bson_destroy (&query);

   return file;
}


/** create a gridfs file from a stream
 *
 * The stream is fully consumed in creating the file
 */
mongoc_gridfs_file_t *
mongoc_gridfs_create_file_from_stream (mongoc_gridfs_t          *gridfs,
                                       mongoc_stream_t          *stream,
                                       mongoc_gridfs_file_opt_t *opt)
{
   mongoc_gridfs_file_t *file;
   ssize_t r;
   uint8_t buf[MONGOC_GRIDFS_STREAM_CHUNK];
   mongoc_iovec_t iov;
   int timeout;

   ENTRY;

   BSON_ASSERT (gridfs);
   BSON_ASSERT (stream);

   iov.iov_base = (void *)buf;
   iov.iov_len = 0;

   file = _mongoc_gridfs_file_new (gridfs, opt);
   timeout = gridfs->client->cluster.sockettimeoutms;

   for (;; ) {
      r = mongoc_stream_read (stream, iov.iov_base, MONGOC_GRIDFS_STREAM_CHUNK,
                              0, timeout);

      if (r > 0) {
         iov.iov_len = r;
         mongoc_gridfs_file_writev (file, &iov, 1, timeout);
      } else if (r == 0) {
         break;
      } else {
         mongoc_gridfs_file_destroy (file);
         RETURN (NULL);
      }
   }

   mongoc_stream_destroy (stream);

   mongoc_gridfs_file_seek (file, 0, SEEK_SET);

   RETURN (file);
}


/** create an empty gridfs file */
mongoc_gridfs_file_t *
mongoc_gridfs_create_file (mongoc_gridfs_t          *gridfs,
                           mongoc_gridfs_file_opt_t *opt)
{
   mongoc_gridfs_file_t *file;

   ENTRY;

   bson_return_val_if_fail (gridfs, NULL);

   file = _mongoc_gridfs_file_new (gridfs, opt);

   RETURN (file);
}

/** accessor functions for collections */
mongoc_collection_t *
mongoc_gridfs_get_files (mongoc_gridfs_t *gridfs)
{
   bson_return_val_if_fail (gridfs, NULL);

   return gridfs->files;
}

mongoc_collection_t *
mongoc_gridfs_get_chunks (mongoc_gridfs_t *gridfs)
{
   bson_return_val_if_fail (gridfs, NULL);

   return gridfs->chunks;
}


bool
mongoc_gridfs_remove_by_filename (mongoc_gridfs_t *gridfs,
                                  const char      *filename,
                                  bson_error_t    *error)
{
   mongoc_bulk_operation_t *bulk_files = NULL;
   mongoc_bulk_operation_t *bulk_chunks = NULL;
   mongoc_cursor_t *cursor = NULL;
   bson_error_t files_error;
   bson_error_t chunks_error;
   const bson_t *doc;
   const char *key;
   char keybuf[16];
   int count = 0;
   bool chunks_ret;
   bool files_ret;
   bool ret = false;
   bson_iter_t iter;
   bson_t *files_q = NULL;
   bson_t *chunks_q = NULL;
   bson_t q = BSON_INITIALIZER;
   bson_t fields = BSON_INITIALIZER;
   bson_t ar = BSON_INITIALIZER;

   bson_return_val_if_fail (gridfs, false);

   if (!filename) {
      bson_set_error (error,
                      MONGOC_ERROR_GRIDFS,
                      MONGOC_ERROR_GRIDFS_INVALID_FILENAME,
                      "A non-NULL filename must be specified.");
      return false;
   }

   /*
    * Find all files matching this filename. Hopefully just one, but not
    * strictly required!
    */

   BSON_APPEND_UTF8 (&q, "filename", filename);
   BSON_APPEND_INT32 (&fields, "_id", 1);

   cursor = mongoc_collection_find (gridfs->files, MONGOC_QUERY_NONE, 0, 0, 0,
                                    &q, &fields, NULL);
   BSON_ASSERT (cursor);

   while (mongoc_cursor_next (cursor, &doc)) {
      if (bson_iter_init_find (&iter, doc, "_id")) {
         const bson_value_t *value = bson_iter_value (&iter);

         bson_uint32_to_string (count, &key, keybuf, sizeof keybuf);
         BSON_APPEND_VALUE (&ar, key, value);
      }
   }

   if (mongoc_cursor_error (cursor, error)) {
      goto failure;
   }

   bulk_files = mongoc_collection_create_bulk_operation (gridfs->files, false, NULL);
   bulk_chunks = mongoc_collection_create_bulk_operation (gridfs->chunks, false, NULL);

   files_q = BCON_NEW ("_id", "{", "$in", BCON_ARRAY (&ar), "}");
   chunks_q = BCON_NEW ("files_id", "{", "$in", BCON_ARRAY (&ar), "}");

   mongoc_bulk_operation_remove (bulk_files, files_q);
   mongoc_bulk_operation_remove (bulk_chunks, chunks_q);

   files_ret = mongoc_bulk_operation_execute (bulk_files, NULL, &files_error);
   chunks_ret = mongoc_bulk_operation_execute (bulk_chunks, NULL, &chunks_error);

   if (error) {
      if (!files_ret) {
         memcpy (error, &files_error, sizeof *error);
      } else if (!chunks_ret) {
         memcpy (error, &chunks_error, sizeof *error);
      }
   }

   ret = (files_ret && chunks_ret);

failure:
   if (cursor) {
      mongoc_cursor_destroy (cursor);
   }
   if (bulk_files) {
      mongoc_bulk_operation_destroy (bulk_files);
   }
   if (bulk_chunks) {
      mongoc_bulk_operation_destroy (bulk_chunks);
   }
   bson_destroy (&q);
   bson_destroy (&fields);
   bson_destroy (&ar);
   if (files_q) {
      bson_destroy (files_q);
   }
   if (chunks_q) {
      bson_destroy (chunks_q);
   }

   return ret;
}
