/**
 * Copyright 2016 Confluent 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.
 */

package kafka

import (
	"unsafe"
)

/*
#include <stdlib.h>
#include <librdkafka/rdkafka.h>

struct rd_kafka_metadata_broker *_getMetadata_broker_element(struct rd_kafka_metadata *m, int i) {
  return &m->brokers[i];
}

struct rd_kafka_metadata_topic *_getMetadata_topic_element(struct rd_kafka_metadata *m, int i) {
  return &m->topics[i];
}

struct rd_kafka_metadata_partition *_getMetadata_partition_element(struct rd_kafka_metadata *m, int topic_idx, int partition_idx) {
  return &m->topics[topic_idx].partitions[partition_idx];
}

int32_t _get_int32_element (int32_t *arr, int i) {
  return arr[i];
}

*/
import "C"

// BrokerMetadata contains per-broker metadata
type BrokerMetadata struct {
	ID   int32
	Host string
	Port int
}

// PartitionMetadata contains per-partition metadata
type PartitionMetadata struct {
	ID       int32
	Error    Error
	Leader   int32
	Replicas []int32
	Isrs     []int32
}

// TopicMetadata contains per-topic metadata
type TopicMetadata struct {
	Topic      string
	Partitions []PartitionMetadata
	Error      Error
}

// Metadata contains broker and topic metadata for all (matching) topics
type Metadata struct {
	Brokers []BrokerMetadata
	Topics  map[string]TopicMetadata

	OriginatingBroker BrokerMetadata
}

// getMetadata queries broker for cluster and topic metadata.
// If topic is non-nil only information about that topic is returned, else if
// allTopics is false only information about locally used topics is returned,
// else information about all topics is returned.
func getMetadata(H Handle, topic *string, allTopics bool, timeoutMs int) (*Metadata, error) {
	h := H.gethandle()

	var rkt *C.rd_kafka_topic_t
	if topic != nil {
		rkt = h.getRkt(*topic)
	}

	var cMd *C.struct_rd_kafka_metadata
	cErr := C.rd_kafka_metadata(h.rk, bool2cint(allTopics),
		rkt, &cMd, C.int(timeoutMs))
	if cErr != C.RD_KAFKA_RESP_ERR_NO_ERROR {
		return nil, newError(cErr)
	}

	m := Metadata{}
	defer C.rd_kafka_metadata_destroy(cMd)

	m.Brokers = make([]BrokerMetadata, cMd.broker_cnt)
	for i := 0; i < int(cMd.broker_cnt); i++ {
		b := C._getMetadata_broker_element(cMd, C.int(i))
		m.Brokers[i] = BrokerMetadata{int32(b.id), C.GoString(b.host),
			int(b.port)}
	}

	m.Topics = make(map[string]TopicMetadata, int(cMd.topic_cnt))
	for i := 0; i < int(cMd.topic_cnt); i++ {
		t := C._getMetadata_topic_element(cMd, C.int(i))

		thisTopic := C.GoString(t.topic)
		m.Topics[thisTopic] = TopicMetadata{Topic: thisTopic,
			Error:      newError(t.err),
			Partitions: make([]PartitionMetadata, int(t.partition_cnt))}

		for j := 0; j < int(t.partition_cnt); j++ {
			p := C._getMetadata_partition_element(cMd, C.int(i), C.int(j))
			m.Topics[thisTopic].Partitions[j] = PartitionMetadata{
				ID:     int32(p.id),
				Error:  newError(p.err),
				Leader: int32(p.leader)}
			m.Topics[thisTopic].Partitions[j].Replicas = make([]int32, int(p.replica_cnt))
			for ir := 0; ir < int(p.replica_cnt); ir++ {
				m.Topics[thisTopic].Partitions[j].Replicas[ir] = int32(C._get_int32_element(p.replicas, C.int(ir)))
			}

			m.Topics[thisTopic].Partitions[j].Isrs = make([]int32, int(p.isr_cnt))
			for ii := 0; ii < int(p.isr_cnt); ii++ {
				m.Topics[thisTopic].Partitions[j].Isrs[ii] = int32(C._get_int32_element(p.isrs, C.int(ii)))
			}
		}
	}

	m.OriginatingBroker = BrokerMetadata{int32(cMd.orig_broker_id),
		C.GoString(cMd.orig_broker_name), 0}

	return &m, nil
}

// queryWatermarkOffsets returns the broker's low and high offsets for the given topic
// and partition.
func queryWatermarkOffsets(H Handle, topic string, partition int32, timeoutMs int) (low, high int64, err error) {
	h := H.gethandle()

	ctopic := C.CString(topic)
	defer C.free(unsafe.Pointer(ctopic))

	var cLow, cHigh C.int64_t

	e := C.rd_kafka_query_watermark_offsets(h.rk, ctopic, C.int32_t(partition),
		&cLow, &cHigh, C.int(timeoutMs))
	if e != C.RD_KAFKA_RESP_ERR_NO_ERROR {
		return 0, 0, newError(e)
	}

	low = int64(cLow)
	high = int64(cHigh)
	return low, high, nil
}