using System;
using System.Diagnostics.CodeAnalysis;
using StardewModdingAPI.Toolkit;

namespace StardewModdingAPI.Web.Framework.LogParsing.Models
{
    /// <summary>Metadata about a mod or content pack in the log.</summary>
    public class LogModInfo
    {
        /*********
        ** Private fields
        *********/
        /// <summary>The parsed mod version, if valid.</summary>
        private Lazy<ISemanticVersion?> ParsedVersionImpl;


        /*********
        ** Accessors
        *********/
        /// <summary>The mod name.</summary>
        public string Name { get; }

        /// <summary>The mod author.</summary>
        public string Author { get; }

        /// <summary>The mod version.</summary>
        public string Version { get; private set; }

        /// <summary>The mod description.</summary>
        public string Description { get; }

        /// <summary>The update version.</summary>
        public string? UpdateVersion { get; private set; }

        /// <summary>The update link.</summary>
        public string? UpdateLink { get; private set; }

        /// <summary>The name of the mod for which this is a content pack (if applicable).</summary>
        public string? ContentPackFor { get; }

        /// <summary>The number of errors logged by this mod.</summary>
        public int Errors { get; set; }

        /// <summary>Whether the mod was loaded into the game.</summary>
        public bool Loaded { get; }

        /// <summary>Whether the mod has an update available.</summary>
        [MemberNotNullWhen(true, nameof(LogModInfo.UpdateVersion), nameof(LogModInfo.UpdateLink))]
        public bool HasUpdate => this.UpdateVersion != null && this.Version != this.UpdateVersion;

        /// <summary>Whether this is an actual mod (rather than a special entry for SMAPI or the game itself).</summary>
        public bool IsMod { get; }

        /// <summary>Whether this is a C# code mod.</summary>
        public bool IsCodeMod { get; }

        /// <summary>Whether this is a content pack for another mod.</summary>
        [MemberNotNullWhen(true, nameof(LogModInfo.ContentPackFor))]
        public bool IsContentPack { get; }


        /*********
        ** Public methods
        *********/
        /// <summary>Construct an instance.</summary>
        /// <param name="name">The mod name.</param>
        /// <param name="author">The mod author.</param>
        /// <param name="version">The mod version.</param>
        /// <param name="description">The mod description.</param>
        /// <param name="updateVersion">The update version.</param>
        /// <param name="updateLink">The update link.</param>
        /// <param name="contentPackFor">The name of the mod for which this is a content pack (if applicable).</param>
        /// <param name="errors">The number of errors logged by this mod.</param>
        /// <param name="loaded">Whether the mod was loaded into the game.</param>
        /// <param name="isMod">Whether this is an actual mod (instead of a special entry for SMAPI or the game).</param>
        public LogModInfo(string name, string author, string version, string description, string? updateVersion = null, string? updateLink = null, string? contentPackFor = null, int errors = 0, bool loaded = true, bool isMod = true)
        {
            this.Name = name;
            this.Author = author;
            this.Description = description;
            this.UpdateVersion = updateVersion;
            this.UpdateLink = updateLink;
            this.ContentPackFor = contentPackFor;
            this.Errors = errors;
            this.Loaded = loaded;

            if (isMod)
            {
                this.IsMod = true;
                this.IsContentPack = !string.IsNullOrWhiteSpace(this.ContentPackFor);
                this.IsCodeMod = !this.IsContentPack;
            }

            this.OverrideVersion(version);
        }

        /// <summary>Add an update alert for this mod.</summary>
        /// <param name="updateVersion">The update version.</param>
        /// <param name="updateLink">The update link.</param>
        public void SetUpdate(string updateVersion, string updateLink)
        {
            this.UpdateVersion = updateVersion;
            this.UpdateLink = updateLink;
        }

        /// <summary>Override the version number, for cases like SMAPI itself where the version is only known later during parsing.</summary>
        /// <param name="version">The new mod version.</param>
        [MemberNotNull(nameof(LogModInfo.Version), nameof(LogModInfo.ParsedVersionImpl))]
        public void OverrideVersion(string version)
        {
            this.Version = version;
            this.ParsedVersionImpl = new Lazy<ISemanticVersion?>(this.ParseVersion);
        }

        /// <summary>Get the semantic version for this mod, if it's valid.</summary>
        public ISemanticVersion? GetParsedVersion()
        {
            return this.ParsedVersionImpl.Value;
        }


        /*********
        ** Private methods
        *********/
        /// <summary>Get the semantic version for this mod, if it's valid.</summary>
        public ISemanticVersion? ParseVersion()
        {
            return !string.IsNullOrWhiteSpace(this.Version) && SemanticVersion.TryParse(this.Version, out ISemanticVersion? version)
                ? version
                : null;
        }
    }
}