/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you 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
 * 
 * https://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. 
 */

#include "avro_private.h"
#include "avro/errors.h"
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include "encoding.h"
#include "schema.h"

static int skip_array(avro_reader_t reader, const avro_encoding_t * enc,
		      struct avro_array_schema_t *writers_schema)
{
	int rval;
	int64_t i;
	int64_t block_count;
	int64_t block_size;

	check_prefix(rval, enc->read_long(reader, &block_count),
		     "Cannot read array block count: ");

	while (block_count != 0) {
		if (block_count < 0) {
			block_count = block_count * -1;
			check_prefix(rval, enc->read_long(reader, &block_size),
				     "Cannot read array block size: ");
		}

		for (i = 0; i < block_count; i++) {
			check_prefix(rval, avro_skip_data(reader, writers_schema->items),
				     "Cannot skip array element: ");
		}

		check_prefix(rval, enc->read_long(reader, &block_count),
			     "Cannot read array block count: ");
	}
	return 0;
}

static int skip_map(avro_reader_t reader, const avro_encoding_t * enc,
		    struct avro_map_schema_t *writers_schema)
{
	int rval;
	int64_t i, block_count;

	check_prefix(rval, enc->read_long(reader, &block_count),
		     "Cannot read map block count: ");
	while (block_count != 0) {
		int64_t block_size;
		if (block_count < 0) {
			block_count = block_count * -1;
			check_prefix(rval, enc->read_long(reader, &block_size),
				     "Cannot read map block size: ");
		}
		for (i = 0; i < block_count; i++) {
			check_prefix(rval, enc->skip_string(reader),
				     "Cannot skip map key: ");
			check_prefix(rval,
				     avro_skip_data(reader,
						    avro_schema_to_map(writers_schema)->
						    values),
				     "Cannot skip map value: ");
		}
		check_prefix(rval, enc->read_long(reader, &block_count),
			     "Cannot read map block count: ");
	}
	return 0;
}

static int skip_union(avro_reader_t reader, const avro_encoding_t * enc,
		      struct avro_union_schema_t *writers_schema)
{
	int rval;
	int64_t index;
	avro_schema_t branch_schema;

	check_prefix(rval, enc->read_long(reader, &index),
		     "Cannot read union discriminant: ");
	branch_schema = avro_schema_union_branch(&writers_schema->obj, index);
	if (!branch_schema) {
		return EILSEQ;
	}
	return avro_skip_data(reader, branch_schema);
}

static int skip_record(avro_reader_t reader, const avro_encoding_t * enc,
		       struct avro_record_schema_t *writers_schema)
{
	int rval;
	long i;

	AVRO_UNUSED(enc);

	for (i = 0; i < writers_schema->fields->num_entries; i++) {
		avro_schema_t  field_schema;

		field_schema = avro_schema_record_field_get_by_index
		    (&writers_schema->obj, i);
		check_prefix(rval, avro_skip_data(reader, field_schema),
			     "Cannot skip record field: ");
	}
	return 0;
}

int avro_skip_data(avro_reader_t reader, avro_schema_t writers_schema)
{
	check_param(EINVAL, reader, "reader");
	check_param(EINVAL, is_avro_schema(writers_schema), "writer schema");

	int rval = EINVAL;
	const avro_encoding_t *enc = &avro_binary_encoding;

	switch (avro_typeof(writers_schema)) {
	case AVRO_NULL:
		rval = enc->skip_null(reader);
		break;

	case AVRO_BOOLEAN:
		rval = enc->skip_boolean(reader);
		break;

	case AVRO_STRING:
		rval = enc->skip_string(reader);
		break;

	case AVRO_INT32:
		rval = enc->skip_int(reader);
		break;

	case AVRO_INT64:
		rval = enc->skip_long(reader);
		break;

	case AVRO_FLOAT:
		rval = enc->skip_float(reader);
		break;

	case AVRO_DOUBLE:
		rval = enc->skip_double(reader);
		break;

	case AVRO_BYTES:
		rval = enc->skip_bytes(reader);
		break;

	case AVRO_FIXED:
		rval =
		    avro_skip(reader,
			      avro_schema_to_fixed(writers_schema)->size);
		break;

	case AVRO_ENUM:
		rval = enc->skip_long(reader);
		break;

	case AVRO_ARRAY:
		rval =
		    skip_array(reader, enc,
			       avro_schema_to_array(writers_schema));
		break;

	case AVRO_MAP:
		rval =
		    skip_map(reader, enc, avro_schema_to_map(writers_schema));
		break;

	case AVRO_UNION:
		rval =
		    skip_union(reader, enc,
			       avro_schema_to_union(writers_schema));
		break;

	case AVRO_RECORD:
		rval =
		    skip_record(reader, enc,
				avro_schema_to_record(writers_schema));
		break;

	case AVRO_LINK:
		rval =
		    avro_skip_data(reader,
				   (avro_schema_to_link(writers_schema))->to);
		break;
	}

	return rval;
}