// Copyright (C) 2024, The Duplicati Team
// https://duplicati.com, hello@duplicati.com
// 
// Permission is hereby granted, free of charge, to any person obtaining a 
// copy of this software and associated documentation files (the "Software"), 
// to deal in the Software without restriction, including without limitation 
// the rights to use, copy, modify, merge, publish, distribute, sublicense, 
// and/or sell copies of the Software, and to permit persons to whom the 
// Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in 
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.

using System;
using System.Collections.Generic;
using System.Linq;

namespace Duplicati.Library.Logging
{
    /// <summary>
    /// Instance of a log entry
    /// </summary>
    public class LogEntry
    {
        /// <summary>
        /// The time when the entry was logged
        /// </summary>
        public DateTime When;

        /// <summary>
        /// The message that was logged
        /// </summary>
        public readonly string Message;

        /// <summary>
        /// The string format arguments, if any
        /// </summary>
        public readonly object[] Arguments;

        /// <summary>
        /// The message level
        /// </summary>
        public readonly LogMessageType Level;

        /// <summary>
        /// The filter tag for the message
        /// </summary>
        public readonly string FilterTag;

        /// <summary>
        /// The filter tag for the message
        /// </summary>
        public readonly string Tag;

        /// <summary>
        /// The message help-id
        /// </summary>
        public readonly string Id;

        /// <summary>
        /// An optional exception
        /// </summary>
        public readonly Exception Exception;

        /// <summary>
        /// The log context data, if any
        /// </summary>
        private Dictionary<string, string> m_logContext;

        /// <summary>
        /// Gets or sets the <see cref="T:Duplicati.Library.Logging.LogEntry"/> with the specified value.
        /// </summary>
        /// <param name="value">The key to use.</param>
        public string this[string key]
        {
            get
            {
                if (m_logContext == null)
                    return null;
                m_logContext.TryGetValue(key, out var s);
                return s;
            }

            set
            {
                if (m_logContext == null)
                    m_logContext = new Dictionary<string, string>();

                m_logContext[key] = value;

            }
        }

        /// <summary>
        /// Gets the keys in this log context
        /// </summary>
        /// <value>The context keys.</value>
        public IEnumerable<string> ContextKeys
        {
            get
            {
                if (m_logContext == null)
                    return new string[0];

                return m_logContext.Keys;
            }
        }

        /// <summary>
        /// Gets the message, formatted with arguments
        /// </summary>
        /// <value>The formatted message.</value>
        public string FormattedMessage
        {
            get
            {
                if (Arguments == null || Arguments.Length == 0)
                    return Message;

                try
                {
                    return string.Format(Message, Arguments);
                }
                catch
                {
                    // Try no to crash ...
                    return string.Format("Error while formating: \"{0}\" with arguments: [{1}]", Message, string.Join(", ", Arguments.Select(x => x == null ? "(null)" : x.ToString())));

                }
            }
        }


        /// <summary>
        /// Initializes a new instance of the <see cref="T:Duplicati.Library.Logging.LogEntry"/> class.
        /// </summary>
        /// <param name="message">The message to use.</param>
        /// <param name="arguments">An optional set of arguments.</param>
        /// <param name="level">The log level.</param>
        /// <param name="tag">The tag to use.</param>
        /// <param name="id">The message ID.</param>
        /// <param name="exception">An optional exception.</param>
        public LogEntry(string message, object[] arguments, LogMessageType level, string tag, string id, Exception exception)
        {
            When = DateTime.Now;
            Message = message;
            Arguments = arguments;
            Level = level;
            Tag = tag;
            Id = id;
            Exception = exception;
            FilterTag = level + "-" + tag + "-" + id;
        }

        /// <summary>
        /// Returns a <see cref="T:System.String"/> that represents the current <see cref="T:Duplicati.Library.Logging.LogEntry"/>.
        /// </summary>
        /// <returns>A <see cref="T:System.String"/> that represents the current <see cref="T:Duplicati.Library.Logging.LogEntry"/>.</returns>
        public override string ToString()
        {
            return string.Format("{0:yyyy-MM-dd HH:mm:ss zz} - [{1}]: {2}", When.ToLocalTime(), FilterTag, FormattedMessage);
        }

        /// <summary>
        /// Returns the item as a string optionally with exception details
        /// </summary>
        /// <returns>A <see cref="T:System.String"/> that represents the current <see cref="T:Duplicati.Library.Logging.LogEntry"/>.</returns>
        /// <param name="withExceptionDetails">If set to <c>true</c> the result has expanded exception details.</param>
        public string AsString(bool withExceptionDetails)
        {
            if (Exception == null)
            {
                return ToString();
            }
            else
            {
                return this + Environment.NewLine
                    + (withExceptionDetails ? Exception.ToString() : (Exception.GetType().Name + ": " + Exception.Message));
            }
        }
    }
}