<?php

/*
 * Licensed to Elasticsearch B.V. under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch B.V. 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
 *
 *     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.
 */

declare(strict_types=1);

namespace Elastic\Apm\Impl;

use Elastic\Apm\Impl\BackendComm\SerializationUtil;
use Elastic\Apm\Impl\Log\LoggableInterface;
use Elastic\Apm\Impl\Log\LoggableTrait;
use Elastic\Apm\Impl\Util\IdGenerator;

/**
 * An error or a logged error message captured by an agent occurring in a monitored service
 *
 * @link https://github.com/elastic/apm-server/blob/7.0/docs/spec/errors/error.json
 *
 * Code in this file is part of implementation internals and thus it is not covered by the backward compatibility.
 *
 * @internal
 */
class Error implements SerializableDataInterface, LoggableInterface
{
    use LoggableTrait;

    /**
     * @var float
     *
     * UTC based and in microseconds since Unix epoch
     *
     * @link https://github.com/elastic/apm-server/blob/7.0/docs/spec/errors/error.json#L6
     */
    private $timestamp;

    /**
     * @var string
     *
     * Hex encoded 128 random bits ID of the error.
     *
     * The length of a value is limited to 1024.
     *
     * @link https://github.com/elastic/apm-server/blob/7.0/docs/spec/errors/error.json#L9
     */
    public $id;

    /**
     * @var ?string
     *
     * Hex encoded 128 random bits ID of the correlated trace.
     * Must be present if transaction_id and parent_id are set.
     *
     * The length of a value is limited to 1024.
     *
     * @link https://github.com/elastic/apm-server/blob/7.0/docs/spec/errors/error.json#L14
     */
    private $traceId = null;

    /**
     * @var ?string
     *
     * Hex encoded 64 random bits ID of the correlated transaction.
     * Must be present if trace_id and parent_id are set.
     *
     * The length of a value is limited to 1024.
     *
     * @link https://github.com/elastic/apm-server/blob/7.0/docs/spec/errors/error.json#L19
     */
    private $transactionId = null;

    /**
     * @var ?string
     *
     * Hex encoded 64 random bits ID of the parent transaction or span.
     * Must be present if trace_id and transaction_id are set.
     *
     * The length of a value is limited to 1024.
     *
     * @link https://github.com/elastic/apm-server/blob/7.0/docs/spec/errors/error.json#L24
     */
    private $parentId = null;

    /**
     * @var ?ErrorTransactionData
     *
     * Data for correlating errors with transactions
     *
     * @link https://github.com/elastic/apm-server/blob/7.0/docs/spec/errors/error.json#L29
     */
    private $transaction = null;

    /**
     * @var ?TransactionContext
     *
     * @link https://github.com/elastic/apm-server/blob/7.0/docs/spec/errors/error.json#L44
     */
    private $context = null;

    /**
     * @var ?string
     *
     * Function call which was the primary perpetrator of this event
     *
     * The length of a string value is limited to 1024.
     *
     * @link https://github.com/elastic/apm-server/blob/v7.0.0/docs/spec/errors/error.json#L47
     */
    private $culprit = null;

    /**
     * @var ?ErrorExceptionData
     *
     * Data for correlating errors with transactions
     *
     * @link https://github.com/elastic/apm-server/blob/7.0/docs/spec/errors/error.json#L29
     */
    private $exception = null;

    public static function build(Tracer $tracer, ErrorExceptionData $errorExceptionData, ?Transaction $transaction, ?Span $span): Error
    {
        $result = new Error();

        $result->timestamp = $tracer->getClock()->getSystemClockCurrentTime();
        $result->id = IdGenerator::generateId(Constants::ERROR_ID_SIZE_IN_BYTES);

        if ($transaction !== null) {
            $result->transaction = ErrorTransactionData::build($transaction);
            $result->context = $transaction->cloneContextData();
            $result->traceId = $transaction->getTraceId();
            $result->transactionId = $transaction->getId();
            $result->parentId = ($span === null ? $transaction->getId() : $span->getId());
        }

        // Set culprit to the highest frame non-null 'function'
        if ($errorExceptionData->stacktrace !== null) {
            foreach ($errorExceptionData->stacktrace as $stackTraceFrame) {
                if ($stackTraceFrame->function !== null) {
                    $result->culprit = Tracer::limitKeywordString($stackTraceFrame->function);
                    break;
                }
            }
        }

        $result->exception = $errorExceptionData;

        $result->prepareForSerialization();
        return $result;
    }

    private function prepareForSerialization(): void
    {
        SerializationUtil::prepareForSerialization(/* ref */ $this->context);
        SerializationUtil::prepareForSerialization(/* ref */ $this->exception);
    }

    /** @inheritDoc */
    public function jsonSerialize()
    {
        $result = [];

        $timestamp = SerializationUtil::adaptTimestamp($this->timestamp);
        SerializationUtil::addNameValue('timestamp', $timestamp, /* ref */ $result);

        SerializationUtil::addNameValueIfNotNull('context', $this->context, /* ref */ $result);
        SerializationUtil::addNameValueIfNotNull('culprit', $this->culprit, /* ref */ $result);
        SerializationUtil::addNameValueIfNotNull('exception', $this->exception, /* ref */ $result);
        SerializationUtil::addNameValue('id', $this->id, /* ref */ $result);
        SerializationUtil::addNameValueIfNotNull('parent_id', $this->parentId, /* ref */ $result);
        SerializationUtil::addNameValueIfNotNull('trace_id', $this->traceId, /* ref */ $result);
        SerializationUtil::addNameValueIfNotNull('transaction', $this->transaction, /* ref */ $result);
        SerializationUtil::addNameValueIfNotNull('transaction_id', $this->transactionId, /* ref */ $result);

        return SerializationUtil::postProcessResult($result);
    }
}