using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using System.Linq;
using StardewModdingAPI.Framework.ModHelpers;
using StardewModdingAPI.Toolkit.Framework.Clients.WebApi;
using StardewModdingAPI.Toolkit.Framework.ModData;
using StardewModdingAPI.Toolkit.Framework.UpdateData;
using StardewModdingAPI.Toolkit.Utilities;

namespace StardewModdingAPI.Framework.ModLoading
{
    /// <summary>Metadata for a mod.</summary>
    internal class ModMetadata : IModMetadata
    {
        /*********
        ** Fields
        *********/
        /// <summary>The non-error issues with the mod, including warnings suppressed by the data record.</summary>
        private ModWarning ActualWarnings = ModWarning.None;

        /// <summary>The mod IDs which are listed as a requirement by this mod. The value for each pair indicates whether the dependency is required (i.e. not an optional dependency).</summary>
        private readonly Lazy<IDictionary<string, bool>> Dependencies;


        /*********
        ** Accessors
        *********/
        /// <inheritdoc />
        public string DisplayName { get; }

        /// <inheritdoc />
        public string RootPath { get; }

        /// <inheritdoc />
        public string DirectoryPath { get; }

        /// <inheritdoc />
        public string RelativeDirectoryPath { get; }

        /// <inheritdoc />
        public IManifest Manifest { get; }

        /// <inheritdoc />
        public ModDataRecordVersionedFields? DataRecord { get; }

        /// <inheritdoc />
        public ModMetadataStatus Status { get; private set; }

        /// <inheritdoc />
        public ModFailReason? FailReason { get; private set; }

        /// <inheritdoc />
        public ModWarning Warnings => this.ActualWarnings & ~(this.DataRecord?.DataRecord.SuppressWarnings ?? ModWarning.None);

        /// <inheritdoc />
        public string? Error { get; private set; }

        /// <inheritdoc />
        public string? ErrorDetails { get; private set; }

        /// <inheritdoc />
        public bool IsIgnored { get; }

        /// <inheritdoc />
        public IMod? Mod { get; private set; }

        /// <inheritdoc />
        public IContentPack? ContentPack { get; private set; }

        /// <inheritdoc />
        public TranslationHelper? Translations { get; private set; }

        /// <inheritdoc />
        public IMonitor? Monitor { get; private set; }

        /// <inheritdoc />
        public object? Api { get; private set; }

        /// <inheritdoc />
        public ModEntryModel? UpdateCheckData { get; private set; }

        /// <inheritdoc />
        [MemberNotNullWhen(true, nameof(ModMetadata.ContentPack))]
        [SuppressMessage("ReSharper", "ConditionalAccessQualifierIsNonNullableAccordingToAPIContract", Justification = "The manifest may be null for broken mods while loading.")]
        public bool IsContentPack => this.Manifest?.ContentPackFor != null;

        /// <summary>The fake content packs created by this mod, if any.</summary>
        public ISet<WeakReference<ContentPack>> FakeContentPacks { get; } = new HashSet<WeakReference<ContentPack>>();


        /*********
        ** Public methods
        *********/
        /// <summary>Construct an instance.</summary>
        /// <param name="displayName">The mod's display name.</param>
        /// <param name="directoryPath">The mod's full directory path within the <paramref name="rootPath"/>.</param>
        /// <param name="rootPath">The root path containing mods.</param>
        /// <param name="manifest">The mod manifest.</param>
        /// <param name="dataRecord">Metadata about the mod from SMAPI's internal data (if any).</param>
        /// <param name="isIgnored">Whether the mod folder should be ignored. This should be <c>true</c> if it was found within a folder whose name starts with a dot.</param>
        public ModMetadata(string displayName, string directoryPath, string rootPath, IManifest? manifest, ModDataRecordVersionedFields? dataRecord, bool isIgnored)
        {
            this.DisplayName = displayName;
            this.DirectoryPath = directoryPath;
            this.RootPath = rootPath;
            this.RelativeDirectoryPath = PathUtilities.GetRelativePath(this.RootPath, this.DirectoryPath);
            this.Manifest = manifest!; // manifest may be null in low-level SMAPI code, but won't be null once it's received by mods via IModInfo
            this.DataRecord = dataRecord;
            this.IsIgnored = isIgnored;

            this.Dependencies = new Lazy<IDictionary<string, bool>>(this.ExtractDependencies);
        }

        /// <inheritdoc />
        public IModMetadata SetStatusFound()
        {
            this.SetStatus(ModMetadataStatus.Found, ModFailReason.Incompatible, null);
            this.FailReason = null;
            return this;
        }

        /// <inheritdoc />
        public IModMetadata SetStatus(ModMetadataStatus status, ModFailReason reason, string? error, string? errorDetails = null)
        {
            this.Status = status;
            this.FailReason = reason;
            this.Error = error;
            this.ErrorDetails = errorDetails;
            return this;
        }

        /// <inheritdoc />
        public IModMetadata SetWarning(ModWarning warning)
        {
            this.ActualWarnings |= warning;
            return this;
        }

        /// <inheritdoc />
        public IModMetadata RemoveWarning(ModWarning warning)
        {
            this.ActualWarnings &= ~warning;
            return this;
        }

        /// <inheritdoc />
        public IModMetadata SetMod(IMod mod, TranslationHelper translations)
        {
            if (this.ContentPack != null)
                throw new InvalidOperationException("A mod can't be both an assembly mod and content pack.");

            this.Mod = mod;
            this.Monitor = mod.Monitor;
            this.Translations = translations;
            return this;
        }

        /// <inheritdoc />
        public IModMetadata SetMod(IContentPack contentPack, IMonitor monitor, TranslationHelper translations)
        {
            if (this.Mod != null)
                throw new InvalidOperationException("A mod can't be both an assembly mod and content pack.");

            this.ContentPack = contentPack;
            this.Monitor = monitor;
            this.Translations = translations;
            return this;
        }

        /// <inheritdoc />
        public IModMetadata SetApi(object? api)
        {
            this.Api = api;
            return this;
        }

        /// <inheritdoc />
        public IModMetadata SetUpdateData(ModEntryModel data)
        {
            this.UpdateCheckData = data;
            return this;
        }

        /// <inheritdoc />
        [MemberNotNullWhen(true, nameof(IModInfo.Manifest))]
        public bool HasManifest()
        {
            return this.Manifest != null;
        }

        /// <inheritdoc />
        public bool HasID()
        {
            return
                this.HasManifest()
                && !string.IsNullOrWhiteSpace(this.Manifest.UniqueID);
        }

        /// <inheritdoc />
        public bool HasID(string? id)
        {
            return
                this.HasID()
                && string.Equals(this.Manifest.UniqueID.Trim(), id?.Trim(), StringComparison.OrdinalIgnoreCase);
        }

        /// <inheritdoc />
        public IEnumerable<UpdateKey> GetUpdateKeys(bool validOnly = false)
        {
            if (!this.HasManifest())
                yield break;

            foreach (string rawKey in this.Manifest.UpdateKeys)
            {
                UpdateKey updateKey = UpdateKey.Parse(rawKey);
                if (updateKey.LooksValid || !validOnly)
                    yield return updateKey;
            }
        }

        /// <inheritdoc />
        public bool HasRequiredModId(string modId, bool includeOptional)
        {
            return
                this.Dependencies.Value.TryGetValue(modId, out bool isRequired)
                && (includeOptional || isRequired);
        }

        /// <inheritdoc />
        public IEnumerable<string> GetRequiredModIds(bool includeOptional = false)
        {
            foreach (var pair in this.Dependencies.Value)
            {
                if (includeOptional || pair.Value)
                    yield return pair.Key;
            }
        }

        /// <inheritdoc />
        public bool HasValidUpdateKeys()
        {
            return this.GetUpdateKeys(validOnly: true).Any();
        }

        /// <inheritdoc />
        public bool HasWarnings(params ModWarning[] warnings)
        {
            ModWarning curWarnings = this.Warnings;
            return warnings.Any(warning => curWarnings.HasFlag(warning));
        }

        /// <inheritdoc />
        public string GetRelativePathWithRoot()
        {
            string rootFolderName = Path.GetFileName(this.RootPath);
            return Path.Combine(rootFolderName, this.RelativeDirectoryPath);
        }

        /// <summary>Get the currently live fake content packs created by this mod.</summary>
        public IEnumerable<ContentPack> GetFakeContentPacks()
        {
            foreach (var reference in this.FakeContentPacks.ToArray())
            {
                if (!reference.TryGetTarget(out ContentPack? pack))
                {
                    this.FakeContentPacks.Remove(reference);
                    continue;
                }

                yield return pack;
            }
        }


        /*********
        ** Private methods
        *********/
        /// <summary>Extract mod IDs from the manifest that must be installed to load this mod.</summary>
        /// <returns>Returns a dictionary of mod ID => is required (i.e. not an optional dependency).</returns>
        public IDictionary<string, bool> ExtractDependencies()
        {
            var ids = new Dictionary<string, bool>(StringComparer.OrdinalIgnoreCase);

            if (this.HasManifest())
            {
                // yield dependencies
                foreach (IManifestDependency entry in this.Manifest.Dependencies)
                {
                    if (!string.IsNullOrWhiteSpace(entry.UniqueID))
                        ids[entry.UniqueID] = entry.IsRequired;
                }

                // yield content pack parent
                if (!string.IsNullOrWhiteSpace(this.Manifest.ContentPackFor?.UniqueID))
                    ids[this.Manifest.ContentPackFor.UniqueID] = true;
            }

            return ids;
        }
    }
}