// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;
using System.Collections.Generic;
using System.Diagnostics;

namespace Microsoft.Extensions.Logging.Abstractions
{
    /// <summary>
    /// Represents a buffered log record to be written in batch to an <see cref="IBufferedLogger" />.
    /// </summary>
    /// <remarks>
    /// Instances of this type can be pooled and reused. Implementations of <see cref="IBufferedLogger" /> must
    /// not hold onto instance of <see cref="BufferedLogRecord" /> passed to its <see cref="IBufferedLogger.LogRecords" /> method
    /// beyond the invocation of that method.
    /// </remarks>
    public abstract class BufferedLogRecord
    {
        /// <summary>
        /// Gets the time when the log record was first created.
        /// </summary>
        public abstract DateTimeOffset Timestamp { get; }

        /// <summary>
        /// Gets the record's logging severity level.
        /// </summary>
        public abstract LogLevel LogLevel { get; }

        /// <summary>
        /// Gets the record's event ID.
        /// </summary>
        public abstract EventId EventId { get; }

        /// <summary>
        /// Gets an exception string for this record.
        /// </summary>
        public virtual string? Exception => null;

        /// <summary>
        /// Gets an activity span ID for this record, representing the state of the thread that created the record.
        /// </summary>
        public virtual ActivitySpanId? ActivitySpanId => null;

        /// <summary>
        /// Gets an activity trace ID for this record, representing the state of the thread that created the record.
        /// </summary>
        public virtual ActivityTraceId? ActivityTraceId => null;

        /// <summary>
        /// Gets the ID of the thread that created the log record.
        /// </summary>
        public virtual int? ManagedThreadId => null;

        /// <summary>
        /// Gets the formatted log message.
        /// </summary>
        public virtual string? FormattedMessage => null;

        /// <summary>
        /// Gets the original log message template.
        /// </summary>
        public virtual string? MessageTemplate => null;

        /// <summary>
        /// Gets the variable set of name/value pairs associated with the record.
        /// </summary>
        public virtual IReadOnlyList<KeyValuePair<string, object?>> Attributes => [];
    }
}