using System;
#if NET40_OR_GREATER || NETCOREAPP
using System.Collections.Concurrent;
#endif
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text.RegularExpressions;
#if NET40_OR_GREATER || NETCOREAPP
using System.Threading.Tasks;
#endif
using SabreTools.Core;
using SabreTools.Core.Tools;
using SabreTools.DatFiles;
using SabreTools.DatItems;
using SabreTools.Logging;

[assembly: InternalsVisibleTo("SabreTools.Test")]
namespace SabreTools.Filtering
{
    /// <summary>
    /// Represents the cleaning operations that need to be performed on a set of items, usually a DAT
    /// </summary>
    public class Cleaner
    {
        #region Fields

        /// <summary>
        /// Clean all names to WoD standards
        /// </summary>
        public bool Clean { get; set; }

        /// <summary>
        /// Deduplicate items using the given method
        /// </summary>
        public DedupeType DedupeRoms { get; set; }

        /// <summary>
        /// Set Machine Description from Machine Name
        /// </summary>
        public bool DescriptionAsName { get; set; }

        /// <summary>
        /// Keep machines that don't contain any items
        /// </summary>
        public bool KeepEmptyGames { get; set; }

        /// <summary>
        /// Enable "One Rom, One Region (1G1R)" mode
        /// </summary>
        public bool OneGamePerRegion { get; set; }

        /// <summary>
        /// Ordered list of regions for "One Rom, One Region (1G1R)" mode
        /// </summary>
        public List<string>? RegionList { get; set; }

        /// <summary>
        /// Ensure each rom is in their own game
        /// </summary>
        public bool OneRomPerGame { get; set; }

        /// <summary>
        /// Remove all unicode characters
        /// </summary>
        public bool RemoveUnicode { get; set; }

        /// <summary>
        /// Include root directory when determing trim sizes
        /// </summary>
        public string? Root { get; set; }

        /// <summary>
        /// Remove scene dates from the beginning of machine names
        /// </summary>
        public bool SceneDateStrip { get; set; }

        /// <summary>
        /// Change all machine names to "!"
        /// </summary>
        public bool Single { get; set; }

        /// <summary>
        /// Trim total machine and item name to not exceed NTFS limits
        /// </summary>
        public bool Trim { get; set; }

        #endregion

        #region Logging

        /// <summary>
        /// Logging object
        /// </summary>
        private readonly Logger logger = new();

        #endregion

        #region Running

        /// <summary>
        /// Apply cleaning methods to the DatFile
        /// </summary>
        /// <param name="datFile">Current DatFile object to run operations on</param>
        /// <param name="throwOnError">True if the error that is thrown should be thrown back to the caller, false otherwise</param>
        /// <returns>True if cleaning was successful, false on error</returns>
        public bool ApplyCleaning(DatFile datFile, bool throwOnError = false)
        {
            InternalStopwatch watch = new("Applying cleaning steps to DAT");

            try
            {
                // Perform item-level cleaning
                CleanDatItems(datFile);

                // Bucket and dedupe according to the flag
                if (DedupeRoms == DedupeType.Full)
                    datFile.Items.BucketBy(ItemKey.CRC, DedupeRoms);
                else if (DedupeRoms == DedupeType.Game)
                    datFile.Items.BucketBy(ItemKey.Machine, DedupeRoms);

                // Process description to machine name
                if (DescriptionAsName == true)
                {
                    datFile.Items.MachineDescriptionToName(throwOnError);
                    datFile.ItemsDB.MachineDescriptionToName(throwOnError);
                }

                // If we are removing scene dates, do that now
                if (SceneDateStrip == true)
                    StripSceneDatesFromItems(datFile);

                // Run the one rom per game logic, if required
                if (OneGamePerRegion == true && RegionList != null)
                {
                    SetOneGamePerRegion(datFile);
                    datFile.ItemsDB.SetOneGamePerRegion(RegionList);
                }

                // Run the one rom per game logic, if required
                if (OneRomPerGame == true)
                    SetOneRomPerGame(datFile);

                // Remove all marked items
                datFile.Items.ClearMarked();
                datFile.ItemsDB.ClearMarked();

                // We remove any blanks, if we aren't supposed to have any
                if (KeepEmptyGames == false)
                {
                    datFile.Items.ClearEmpty();
                    datFile.ItemsDB.ClearEmpty();
                }
            }
            catch (Exception ex) when (!throwOnError)
            {
                logger.Error(ex);
                return false;
            }
            finally
            {
                watch.Stop();
            }

            return true;
        }

        /// <summary>
        /// Clean individual items based on the current filter
        /// </summary>
        /// <param name="datFile">Current DatFile object to run operations on</param>
        internal void CleanDatItems(DatFile datFile)
        {
            List<string> keys = datFile.Items.Keys.ToList();
            foreach (string key in keys)
            {
                // For every item in the current key
                var items = datFile.Items[key];
                if (items == null)
                    continue;

                foreach (DatItem item in items)
                {
                    // If we have a null item, we can't clean it it
                    if (item == null)
                        continue;

                    // Run cleaning per item
                    CleanDatItem(item);
                }

                // Assign back for caution
                datFile.Items[key] = items;
            }
        }

        /// <summary>
        /// Clean a DatItem according to the cleaner
        /// </summary>
        /// <param name="datItem">DatItem to clean</param>
        internal void CleanDatItem(DatItem datItem)
        {
            // If we're stripping unicode characters, strip machine name and description
            if (RemoveUnicode)
            {
                datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.SetFieldValue<string?>(Models.Metadata.Machine.NameKey, TextHelper.RemoveUnicodeCharacters(datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.NameKey)));
                datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.SetFieldValue<string?>(Models.Metadata.Machine.DescriptionKey, TextHelper.RemoveUnicodeCharacters(datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.DescriptionKey)));
                datItem.SetName(TextHelper.RemoveUnicodeCharacters(datItem.GetName()));
            }

            // If we're in cleaning mode, sanitize machine name and description
            if (Clean)
            {
                datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.SetFieldValue<string?>(Models.Metadata.Machine.NameKey, TextHelper.NormalizeCharacters(datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.NameKey)));
                datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.SetFieldValue<string?>(Models.Metadata.Machine.DescriptionKey, TextHelper.NormalizeCharacters(datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.DescriptionKey)));
            }

            // If we are in single game mode, rename the machine
            if (Single)
                datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.SetFieldValue<string?>(Models.Metadata.Machine.NameKey, "!");

            // If we are in NTFS trim mode, trim the item name
            if (Trim && datItem.GetName() != null)
            {
                // Windows max name length is 260
                int usableLength = 260 - datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.NameKey)!.Length - (Root?.Length ?? 0);
                if (datItem.GetName()!.Length > usableLength)
                {
                    string ext = Path.GetExtension(datItem.GetName()!);
                    datItem.SetName(datItem.GetName()!.Substring(0, usableLength - ext.Length) + ext);
                }
            }
        }

        /// <summary>
        /// Filter a DAT using 1G1R logic given an ordered set of regions
        /// </summary>
        /// <param name="datFile">Current DatFile object to run operations on</param>
        /// <remarks>
        /// In the most technical sense, the way that the region list is being used does not
        /// confine its values to be just regions. Since it's essentially acting like a
        /// specialized version of the machine name filter, anything that is usually encapsulated
        /// in parenthesis would be matched on, including disc numbers, languages, editions,
        /// and anything else commonly used. Please note that, unlike other existing 1G1R 
        /// solutions, this does not have the ability to contain custom mappings of parent
        /// to clone sets based on name, nor does it have the ability to match on the 
        /// Release DatItem type.
        /// </remarks>
        internal void SetOneGamePerRegion(DatFile datFile)
        {
            // If we have null region list, make it empty
            RegionList ??= [];

            // For sake of ease, the first thing we want to do is bucket by game
            datFile.Items.BucketBy(ItemKey.Machine, DedupeType.None, norename: true);

            // Then we want to get a mapping of all machines to parents
            Dictionary<string, List<string>> parents = [];
            foreach (string key in datFile.Items.Keys)
            {
                DatItem item = datFile.Items[key]![0];

                // Match on CloneOf first
                if (!string.IsNullOrEmpty(item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.CloneOfKey)))
                {
                    if (!parents.ContainsKey(item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.CloneOfKey)!.ToLowerInvariant()))
                        parents.Add(item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.CloneOfKey)!.ToLowerInvariant(), []);

                    parents[item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.CloneOfKey)!.ToLowerInvariant()].Add(item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.NameKey)!.ToLowerInvariant());
                }

                // Then by RomOf
                else if (!string.IsNullOrEmpty(item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.RomOfKey)))
                {
                    if (!parents.ContainsKey(item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.RomOfKey)!.ToLowerInvariant()))
                        parents.Add(item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.RomOfKey)!.ToLowerInvariant(), []);

                    parents[item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.RomOfKey)!.ToLowerInvariant()].Add(item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.NameKey)!.ToLowerInvariant());
                }

                // Otherwise, treat it as a parent
                else
                {
                    if (!parents.ContainsKey(item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.NameKey)!.ToLowerInvariant()))
                        parents.Add(item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.NameKey)!.ToLowerInvariant(), []);

                    parents[item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.NameKey)!.ToLowerInvariant()].Add(item.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.NameKey)!.ToLowerInvariant());
                }
            }

            // Once we have the full list of mappings, filter out games to keep
            foreach (string key in parents.Keys)
            {
                // Find the first machine that matches the regions in order, if possible
                string? machine = default;
                foreach (string region in RegionList)
                {
                    machine = parents[key].FirstOrDefault(m => Regex.IsMatch(m, @"\(.*" + region + @".*\)", RegexOptions.IgnoreCase));
                    if (machine != default)
                        break;
                }

                // If we didn't get a match, use the parent
                if (machine == default)
                    machine = key;

                // Remove the key from the list
                parents[key].Remove(machine);

                // Remove the rest of the items from this key
                parents[key].ForEach(k => datFile.Items.Remove(k));
            }

            // Finally, strip out the parent tags
            Splitter.RemoveTagsFromChild(datFile);
            datFile.ItemsDB.RemoveTagsFromChild();
        }

        /// <summary>
        /// Ensure that all roms are in their own game (or at least try to ensure)
        /// </summary>
        /// <param name="datFile">Current DatFile object to run operations on</param>
        internal static void SetOneRomPerGame(DatFile datFile)
        {
            // Because this introduces subfolders, we need to set the SuperDAT type
            datFile.Header.SetFieldValue<string?>(Models.Metadata.Header.TypeKey, "SuperDAT");

            datFile.Items.SetOneRomPerGame();
            datFile.ItemsDB.SetOneRomPerGame();
        }

        /// <summary>
        /// Set internal names to match One Rom Per Game (ORPG) logic
        /// </summary>
        /// <param name="datItem">DatItem to run logic on</param>
        internal static void SetOneRomPerGame(DatItem datItem)
        {
            if (datItem.GetName() == null)
                return;

            string[] splitname = datItem.GetName()!.Split('.');
#if NET20 || NET35
            datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.SetFieldValue<string?>(Models.Metadata.Machine.NameKey, datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.NameKey) + $"/{string.Join(".", splitname.Take(splitname.Length > 1 ? splitname.Length - 1 : 1).ToArray())}");
#else
            datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.SetFieldValue<string?>(Models.Metadata.Machine.NameKey, datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.NameKey) + $"/{string.Join(".", splitname.Take(splitname.Length > 1 ? splitname.Length - 1 : 1))}");
#endif
            datItem.SetName(Path.GetFileName(datItem.GetName()));
        }

        /// <summary>
        /// Strip the dates from the beginning of scene-style set names
        /// </summary>
        /// <param name="datFile">Current DatFile object to run operations on</param>
        internal void StripSceneDatesFromItems(DatFile datFile)
        {
            // Output the logging statement
            logger.User("Stripping scene-style dates");

            datFile.Items.StripSceneDatesFromItems();
            datFile.ItemsDB.StripSceneDatesFromItems();
        }

        #endregion
    }
}